Conversion idea, 2L inline 4 -> piston boosted 1.0L 2 banger? Warning....Long thread
 

I had an idea pop into my head a while back and I need someone to help me disprove it, or maybe make it happen, too early to tell yet. Got a few minutes?

Theory:
What if I took my inline 4 banger (VW 2.0L ABA), modified the cam (double lobes 180 degreees out from one another for 2 of the 4 cylinders, intake and exhaust) so that 2 of the 4 cylinders acted like 2 stroke air pumps (basically just intake and exhaust strokes over and over again), I then pipe the "exhaust" (air only in this case) from these 2 cylinders into the 2 normal cylinders as it's intake air, then just run the 2 normal cylinders with fuel and spark, the other 2 would have no spark and no fuel.

The theory in my head would be that you could "convert" 2 of your "air pumps" into a source of forced induction for the other 2, not crazy boost, but something mild as 2 strokes would be completed for every one intake stroke of the normal cylinders. My idea is to turn my 2.0L 4 banger into a mildly boosted 1.0L 2 cylinder that, you guessed it, would get much better miles per gallon, granted slower than stock, but my goal here is mpg not high hp. Any thoughts on my latest brainstorm? Shoot away.

Some details that I have thought over so far: (in no particular order, sorry)
1: I would take the output of the 2 "air pump" cylinders and pump it through the MAF and into the 2 banger intake, that way the computer would know how much air is being fed into the real cylinders.

2: Depending on how you pipe the output to the input, you could even utilyze a front mount air to air intercooler. Granted you lose some of your boost, but at least it would be cooler air.

3: Another thought would be to run gapless rings in the air pump cylinders (the other ones wouldn't hurt either), so that they are more efficient at pumping air (less loss by the rings) and seeing these 2 cylinders would run much cooler as they are not actually "running" it may help as the parts would not expand much. Could also choose which cylinders to do based on heat too, say the middle 2 that way the outer 2 provide heat to the middle 2, but that would depend on which ones are "stroke pairs" for lack of a better term.

4: C2 motorsports has chips for forced inducted 2.0L engines, they run bigger injectors, and use MAF for air used by the motor. Obviously it would take a "special" program to be able to make decisions based on 2 cylinders only, or maybe it wouldn't I am not sure really.

5: I was reading about the old Geo Metro 1.0L 3 cylinder and it was rated at almost 60mpg. Made me think, do I really need 2 liters or just 1 powerful liter, which led to what do I do with the other liter, make it pump air twice as fast as I need it. Other than any pumping losses, it should increase flow with RPMs much like a supercharger does, so it wouldn't need any BOV or wastegate, well in theory at least.

6: The 2.0L crossflow would be a good platform for it due to the intake manifold being 2 parts and a crossflow head would just make the piping that much easier in my mind and less likely to suffer from heat soak.

7: Keep in mind, the air pump pistons will have the exhaust valves open from BDC all the way to TDC (give or take) to avoid having to compress the air much in the cylinder, so it's not like your opening the exhaust valve up while it's under a lot of pressure, just fill it up with air, then push it out. My theory here is if your running these air pumps at twice the speed (2 stroke sort of) of the regular cylinders, then you would produce less than double your air requirement for the other 2 due to inefficiencies, but more than what those 2 would have pulled in on their own (NA).

8: I highly doubt that it would produce more power, not really the goal of this idea. If everything was 100% efficient, in theory your stuffing twice as much air into half the cylinders, so it would be about the same power output, of course nothing is 100% efficient.

9: My thought is, would 2 mildly boosted cylinders produce enough hp & tq to drive the car (everyday use, not a go fast goal)? What kind of economy would it result in? Boosting will increase the efficiency of the boosted cylinders, but will it be a bigger gain than the drag from the 2 air pump pistons?

10: Everyone ranks on the poor 2.slow, don't get me wrong it is in no means a "fast" car, but it goes ok to me. In every day use, I never use more than 50% throttle, am almost always barely on the gas pedal at all, and I have no issues at all getting up to left lane highway speeds in a timely fashion. My thought here is I can live with less HP & TQ in a commuter car as long as I can see the return at the pumps.

11: Say my "system" was 50% efficient, that would mean I have 75% of my HP & TQ (which I could deal with as I've driven much slower cars before), but would that also equate to 45mpg +/-? I'd take that, TDI fuel milage at the cost of regular (hopefully boost stays low enough to avoid running higher octane, but hey, that's what knock sensors are for right?)

12: Think MPG, not 1/4 mile ETs or top speed.
Think, will it be more powerful than the geo metro 1.0L 3 cylinder with all of 53hp and 58 ft/lbs (but rated at almost 60mpg!). The car stock has 115hp and 120ft/lbs, so cut it in half and you've got 57.5hp & 60ft/lbs, there's the geo metro numbers already, now use the 2 dummy jugs to mildly boost the other 2, figure a few simple gains in theory.
10% gain = 63.25hp & 66ft/lbs
25% gain = 71.87hp & 75ft/lbs
50% gain = 86.25hp & 90ft/lbs

13: Realistic turbo setups take these motors (on stock internals as they are forged lower ends) from 100whp +/- in stock form to the 200whp +/- range. So, half the output of a mildly boosted setup, would be right around stock output, based on the fact that your now (under mild boost) making almost 50HP per cylinder, do you really need all 4? Even pulling off 35 to 40 HP per cylinder would give the car plently of power to everyday drive on just 2 cylinders, no?

14: I drove my old rabbit diesel (1.5L NON turbo) for years, it taught you how to maintain momentum as there was no acceleration and it had 49hp and 74 ft/lbs new, and mine had over 250K miles on it. I got 45-50mpg, granted the car was a touch lighter than mine, but you get the idea.

Thank you very much for your time, and your opinions and/or thoughts on my "out of the box" idea are greatly appreciated. Don't feel bad if you can poke holes in my theory, that is why I am asking. If it sounds promising, I have all the spare parts already and may actually try to start tinkering with them.

Just to let you know, I am no "kid" with goofy ideas and no money, I am in my 30s, have a degree in auto tech, work in the software industry, and obviously have way too many thoughts bouncing around in my head. Let me know what you think of my "totally new idea", well as far as I know at least. Maybe I should call it the JoJo cycle engine?

I am no VW expert, more of an all around mechanical guy, 2 strokes, 4 strokes, whatever. Working on a 2 stage air compressor made me think about this (one piston is twice the size of the other running at the same rpms), plus knowing motors and 2 strokes gave me this brainstorm.

I was thinking of a hacked lower intake manifold, a modified tri-y header, and other "swap" type parts to keep the cost down, obviously the cam will cost some dough to design and/or get made, but all other components could be fairly affordable. I am open to any and all ideas. Thanks again for your time. JoJoTheTireMan

Added Thoughts before posting:
I realize the air pump cylinders' valve train would be running at 2x's the engine's RPM, so ti valve springs would be a must. I never rev over 5K anyways, and barely ever over 4K, so getting valve springs that could handle 8-10K RPMS is not out of the question.

Ok, I think this post is long enough at this point, sorry but I had to get this idea out of my head in all it's disorganized glory or else I would have exploded and/or imploded, still not sure on that theory yet either :-( Thanks for your time. JoJo

While it might be crazy
 

There is already a company working on this.

I cannot remember if I read about it here or on The Car Lounge
but there was included a link to their website showing cutaways
of the motor in action and of course asking for support (money)
to help comercialize.

If I recall correctly, it utilized siamesed cylinders to do just what you are suggesting. However, would this not be another form of supercharging?

I think there would be less efficiency losses through friction from using either a supercharger or turbocharger.

If anyone has any info on the company working on something similar or a link it would be greatly appreciated.

Indeed, it would be another form of supercharging, that is the idea.

I also agree that a turbo or true supercharger would be more efficient, but I don't want more HP/TQ, I want more mpg out of my existing powerplant, so my idea was to shut off half the motor and turn it into a supercharger of sorts to help the remaining 2 cylinders make enough power to operate the car. Going on the theory that a boosted 1.0L 2 banger would use less fuel than a NA 4 banger yet still make enough power to keep up with the traffic. Never mind the fact that I wouldn't need to spend thousands on a supercharger/turbo kit. It just seems like a good way to effectively reduce the displacement of the motor, and hopefully it's fuel consumption.

I like your thinking
 

One of the other guys here is working on that idea also(Diesel John?)
A brazillion years ago, when I was overseas for the Army, I read in one of the Maint. Manuals about a kit the USArmy had for converting a four cyl Jeep (M151) to a two cyl air compressor.
Basically doing what you have described.
Two outer cyl's, #1&4, used for gas engine to drive the unit.
Two inner cyl's, #2&3, used for air pump.
However the Army setup used one way check valves (iirc) for the compressor cyl's.
So the intake and exhaust were split to allow the engine to run off of the two end cyl's.
Then the valve train was modified to keep the valves open during operation (No worry about pistons smacking the valves, these were very loose engines), and check valves put in place to allow air into the two center cyl's through the intake, so it would be filtered, and out the exhaust. then piped to a pressure vessel and used to run all manner of pneumatic tools.
Hope you can make it work.
BTW my 1 litre has very little torque.(it is more than adequate for a tiny car)
your 1 litre should have quite a bit more
bigger pistons X
longer stroke =
more torque:D
Schultz.

If anyone is working on a similar idea please post or contact me. Thanks
Indeed, I could see that working with a stepped up idle speed and the jeep parked, why not use the engine to make compressed air to run tools, afterall it is basically an air compressor anyways. I just have a different use for the compressed air :-)
I was thinking about using a type of reed valve on the output of the compressor cylinders to eliminate any reverse flow and to smoothen out the pulse effect of the compressor cylinders. Could even replace the valves with one way reed style valves to reduce some of the valve train friction as I will no longer have a a power stroke per se.
Keep the comments coming, any and all feedback is greatly appreciated. Thanks again....JoJotheTireMan

My thoughts are in BOLD take them as you may


[QUOTE=JoJotheTireMan;24002]

Some details that I have thought over so far: (in no particular order, sorry)
1: I would take the output of the 2 "air pump" cylinders and pump it through the MAF and into the 2 banger intake, that way the computer would know how much air is being fed into the real cylinders.Good Idea maybe a standard supercharger would work better, but would require a smaller engine

2: Depending on how you pipe the output to the input, you could even utilyze a front mount air to air intercooler. Granted you lose some of your boost, but at least it would be cooler air.Use a liquid to air charge cooler, keep the plumbing as short as posable, investigate the idea of warmer air for efficiency

3: Another thought would be to run gapless rings in the air pump cylinders (the other ones wouldn't hurt either), so that they are more efficient at pumping air (less loss by the rings) and seeing these 2 cylinders would run much cooler as they are not actually "running" it may help as the parts would not expand much. Could also choose which cylinders to do based on heat too, say the middle 2 that way the outer 2 provide heat to the middle 2, but that would depend on which ones are "stroke pairs" for lack of a better term.Gapless Lower tension rings, no need for oil squirters (if equipped) either which 2 to pick would be determined by which 2 running would still run best

4: C2 motorsports has chips for forced inducted 2.0L engines, they run bigger injectors, and use MAF for air used by the motor. Obviously it would take a "special" program to be able to make decisions based on 2 cylinders only, or maybe it wouldn't I am not sure really.probably a need for complete fuel/ spark control on a project like this, i'd look in to standalone ECU's Mega squirt is cheap, works well. Otherwise I'd throw the factroy maf on the intake of the 2 compressor cylinders, emove 2 injectors, and give it a go

5: I was reading about the old Geo Metro 1.0L 3 cylinder and it was rated at almost 60mpg. Made me think, do I really need 2 liters or just 1 powerful liter, which led to what do I do with the other liter, make it pump air twice as fast as I need it. Other than any pumping losses, it should increase flow with RPMs much like a supercharger does, so it wouldn't need any BOV or wastegate, well in theory at least. if the throttle body is before the air compressor there is no need for a BOV, a system like this should work correctly with out a wast gate (essentially a positive displacement supercharger)

6: The 2.0L crossflow would be a good platform for it due to the intake manifold being 2 parts and a crossflow head would just make the piping that much easier in my mind and less likely to suffer from heat soak.I take it crossflow indicates that intake and exaust are on opposite sides of the head?

7: Keep in mind, the air pump pistons will have the exhaust valves open from BDC all the way to TDC (give or take) to avoid having to compress the air much in the cylinder, so it's not like your opening the exhaust valve up while it's under a lot of pressure, just fill it up with air, then push it out. My theory here is if your running these air pumps at twice the speed (2 stroke sort of) of the regular cylinders, then you would produce less than double your air requirement for the other 2 due to inefficiencies, but more than what those 2 would have pulled in on their own (NA).Umm, I believe you

8: I highly doubt that it would produce more power, not really the goal of this idea. If everything was 100% efficient, in theory your stuffing twice as much air into half the cylinders, so it would be about the same power output, of course nothing is 100% efficient. could add an old mr2 clutch type supercharger to gain back your needed hp, if you need them

9: My thought is, would 2 mildly boosted cylinders produce enough hp & tq to drive the car (everyday use, not a go fast goal)? What kind of economy would it result in? Boosting will increase the efficiency of the boosted cylinders, but will it be a bigger gain than the drag from the 2 air pump pistons?It would be driveable, I don't know if it would be acceptable to you, or not. take a look at the power/ performance of the forkenswift, it is driveable



11: Say my "system" was 50% efficient, that would mean I have 75% of my HP & TQ (which I could deal with as I've driven much slower cars before), but would that also equate to 45mpg +/-? I'd take that, TDI fuel milage at the cost of regular (hopefully boost stays low enough to avoid running higher octane, but hey, that's what knock sensors are for right?)I don't know about where you live, but here the price "premium" for premium isn't that large % wise

12: Think MPG, not 1/4 mile ETs or top speed.
Think, will it be more powerful than the geo metro 1.0L 3 cylinder with all of 53hp and 58 ft/lbs (but rated at almost 60mpg!). The car stock has 115hp and 120ft/lbs, so cut it in half and you've got 57.5hp & 60ft/lbs, there's the geo metro numbers already, now use the 2 dummy jugs to mildly boost the other 2, figure a few simple gains in theory.
10% gain = 63.25hp & 66ft/lbs
25% gain = 71.87hp & 75ft/lbs
50% gain = 86.25hp & 90ft/lbs
Why not swap in a 1.0 metro motor? put an MR2 Clutch super charger on it, spray some water/ methanol in it when boosting so you can run 87 octane?

13: Realistic turbo setups take these motors (on stock internals as they are forged lower ends) from 100whp +/- in stock form to the 200whp +/- range. So, half the output of a mildly boosted setup, would be right around stock output, based on the fact that your now (under mild boost) making almost 50HP per cylinder, do you really need all 4? Even pulling off 35 to 40 HP per cylinder would give the car plently of power to everyday drive on just 2 cylinders, no? all depends on your expectations

14: I drove my old rabbit diesel (1.5L NON turbo) for years, it taught you how to maintain momentum as there was no acceleration and it had 49hp and 74 ft/lbs new, and mine had over 250K miles on it. I got 45-50mpg, granted the car was a touch lighter than mine, but you get the idea.
I drove my TDI boost free for a few days, I know the feeling


Thank you for throwing this idea out there, I'd like to see it tried, but I would do it low budget as a test.

Indeed, which is why I am trying to reuse as many parts as I can, or even use parts from different models of VWs as they have lots of semi-interchangeable parts among models and/or years. Other than MegaSquirt (which I may be able to avoid if I could get the stock ECU programmed for my application) the only costly part of this idea would be a custom cam, which could be a modified stock cam, or even maybe just a double valve actuater, a lever design that would open the valve as the cam lobe goes around the top of it's travel, then open it again the normal way on it's way around the bottom of it's travel circle. Could even get into using different pistons for the air pump jugs, something in a higher compression ratio to effectively move more air.

Like I said, I am open to any and all suggestions.

Lots of things can be designed a better way from the get go, but that way is super costly. I am hoping to have a "kit" so to speak that can be retrofitted to existing vehicles. More usefull from a cost perspective, to me at least as I am not exactly going to go into business designing new powerplants from scratch anytime in the near future.

Thanks for the feedback. JoJotheTireMan

Welcome
Where do I start?
Good technical writing job by the way.
Dido everything said so far.
Posts are a great place to get rid of those annoying inventions.
Usually if someone tells me it wouldn't work, I try it.

Probably the one of most efficient piston engines would be a slow turning, one cylinder diesel under full load 100% of the time. (diesel/electric)

Yes, IMHO, your idea will function.
In the big picture, IMHO, friction, pumping losses, etc. will eat up any possible gains. I am by no means an expert on engine cycles.

You can advance search on a user name and see all the posts a user has started.

I got your email, and what i am going to do is take out #2 & #3 pistons from a vw diesel. Take out the valve actuating buckets. Cover the oil holes in the crank with a hose clamp. Pipe the fuel from 2 & 3 to a flow measuring device and return that fuel to the tank. Use my gear shift lever a lot more. Also i am trying to figure out how run an alternator with my exhaust gas. So i can eliminate the the accessory drive belts. I don't want to hyjack your post.

Questions.
What type of fuel injection do you have?
Will the cam clear the valve stem if you take out the buckets? (or is that boo-kay:))
Would an umbrella type valve seal keep oil from getting sucked down the deactivated valve stems?

I don't know if the umbrella seal would prevent all oil from getting down the valve stem, but if the valves are never being opened in your case then there is no suction at those valve stems. In my case, yes I will have oil being sucked into my air pumps, small amounts, but yes it would be sucked down I would imagine, but a little oil never really hurt anything as just about every motor out there burns some oil to some degree.

I do like your idea, and I could go that route with a gas motor too, but I have a funny feeling that it just wouldn't produce enough HP/TQ to run smoothly and/or be very usefull in every day driving. But you may be able to get away with it on a diesel due to the increased TQ at lower RPMS. Best of luck with your experiment, JoJo

Well, first thought on this is a vortex supercharger. This is basically half of a turbo (output side) bolted to a pulley which is run by the accessory belt. If you did the opposite and ran the driven half of a turbo and use a pulley to drive the alternator.

Other ideas for turning the alternator:
Both of these thoughts would require forward motion to work, but I think the battery could handle things when your stopped.
One idea would be to weld/bolt a pulley to one of your driveshafts closest to the trans to avoid belt deflection due to suspension travel and make a bracket to hold the alternator and maybe a belt tensioner. All in all it will still be driven by the motor in this case, but would possibly make idling more efficient, which on a diesel is almost a mute point.
The other idea would be to duct air in from the grill/hood to spin a compressor/fan of some kind which in turn would spin your alternator, it may add a little to the aerodynamic drag but would allow the removal of the accessory drive belt system, well assuming that your water pump is timing belt driven.
Both of these would benefit from EOC as your still spinning the drive shafts and your still plowing through the air even when your coasting with the engine off.
Again, best of luck. JoJotheTireMan

I thought of the turbo-alternator as well.
Problem
Turbos spin at speeds reaching 100,000 rpm(i've seen the readouts, just today actually)
gear reduction will bring up the torque while reducing the rpm
By-pass the exhaust will lower rpm also
which is easier?
Idunno.
not my baby, just throwing in the old monkey wrench.
S.

I could tell you are a writer.

Actually I am trying to encourage you to try my idea.

The only thing stopping me right now is both my spare diesel heads need remanufactured. The valve seats are so worn that the valves cannot be adjusted any more. And if I take out the buckets, the stems hit the cam. Do you know if the seats can be replaced?

I wanna say that it's possible with some good welding/machining, since that's how cracks in between the seats are repaired, but don't quote me on that.

Sure, valve seats can be replaced, you will need a machine shop that does this type of work, and I doubt it will be overly cheap, but not a task for the home mechanic due to the specialized equipment needed for a job like this. Good Luck.

I would give your idea a shot, if I had a turbo diesel. I drove a 1981 NA rabbit diesel for a few years back in the early 90s. Speed limits were lower then, and I live in New England (read lots of hills here), and the car was a PITA to drive due to the lack of power. I can't imagine trying to drive one on half it's power at today's speeds. I used to down shift to 3rd (4 speed) just to climb some of the hills on the highway, foot to the floor, and you barely crawl over the hill at around 45mph. Try that on the highway today and your bound to get run off the road :-( It seems like everyone is flying these days.

To me a SVO/WVO kit would be the way to go with a diesel, I mean your not addressing mpg but you are cutting your cost per mile, while keeping the same HP/TQ. I am currently on the look out for a newer 96+ VW TDI for a decent price, but people seem to think they are worth double the book value just because they get 45-50 mpg :-( I have a long 50+ miles each way commute, so this option would work well for me, but if you do a lot of short trips then it probably won't benefit you as much.

Again, best of luck. JoJo

I think i'm going to go with a reman. head because the valve seats are so worn. There are a lot of these cars out there but they all need heads.
I don't see any thing wrong with shifting gears to go up hills. I drive over into West Virginia and Virginia and never had to go to low gear yet going up a hill. I am mystified that many think a vehicle is suppose to go up hills in high gear.:confused:
Also with good aero modds I don't need as much power.
When i have the aero modds right it feels strange to have the car accelerate at highway speeds, like a stock vw does at low speeds.

Reman head is probably a good choice as everything will have been checked out and it will probably last for a long time.
I was referring to hills on our highways, speed limit back then was 55mph and barely pulling off 45mph over some hills was nerve racking back then, never mind now that the speed limit is 65mph and it seems, around here at least, that the majority are going 75+mph. I didn't think it was overly economical to hold the peddle to the floor in 3rd gear all the way up the larger hills, and that was with all 4 cylinders.
Cut that down to 2 and I would think you would find some hills that you just can't climb, you may but I wouldn't want any part in trying to lug up a hill on the highway going 20-30mph as the whirr of 75+mph traffic goes screaming by. Just doesn't seem to pay off, risk vs reward.

I am all for economy, but done safely.
I mean, if your not worried about going too slow on the highway, then why not ride a moped at 35-40mph and get 100+mpg, no?
Sure, but I am not too sure that you would live long enough to see the potential fuel savings, well in my neck of the woods at least, out in the country it may be less crowded, but around here the roads are crazy, chuck full of speeding massholes who all seem to be in such a hurry to race up to the next red light or stop sign.

Best of luck with your car. JoJoTheTireMan

I am sorry, but I do not see how this would create any amount of gain, either FE or VE?

With reed valves the "compression" cylinders would create something less than twice their normal four-stroke displacement, and the actual mass of that displacement would net effectively less than indicated. The once-handled intake charge suffers thermal and flow losses from the "compression" cylinders so it is thinner and contains less air mass. You make less power than if the engine was kept stock, since less than 2 time 1/2 the engine does not equal 1.

Forced induction creates a higher thermal load, requiring a richer mixture at WOT to deal with combustion temperatures. See also: required ignition retard under boost. The system dynamics are awkward, wasteful, and not given to efficiency. FI is a power adder that increases VE at the expense of consuming more fuel; it is not an efficiency device.

Why do that but not futz around with gearing? Iono how forced induction would action, but at most there would be a minimal drop in BSFC, and you could achieve similar for the most part with the right size wheel/tire combo and maybe a fifth swap depending on what 020 you have. There's no need to drop power output for economy for most engines below 3-4L IMO.

The idea of the reed valves would just remove the valve train frictional losses for my 2 air pump cylinders, keep in mind they will only go through 2 strokes, intake, exhaust, intake, exhaust, etc.

I agree with all your input on forced induction characteristics, but my real quetion is this:
which would be more efficient for a commuter car
a NA 4 banger 2.0L
or a supercharged 1.0L?

You said:
"You make less power than if the engine was kept stock, since less than 2 time 1/2 the engine does not equal 1."

I agree, and that is the point here. I am only out to make slightly more power than 1/2 the engine would make.
I am not after a net gain here, I am after a net loss!
Less HP/TQ will require less fuel to achieve, no?

I just don't think shutting down 2 jugs would work as the car would not have enough power as a 1L even if I could eliminate the rotating mass of the unused 2, I just figured turn them into 2 stroke air pumps and see if you can get a little more power out of the remaining 2 compared to what they would make by themselves, not compared to the original 2.0L.

Does that explain how it would be a move for FE? A slightly boosted 1L would use less fuel, and yes make less HP and TQ, than my stock 2.0L, no?

Thanks for the feedback, it's all good, keeps me thinking.
JoJo

Gearing, yes I do have an 020, and I already have a .715:1 TDI 5th gear machined with the groove so it works in my trans. .75:1 was also an option over my stock .80:1.

You know of any 5th gear sets taller than those?

I can't change the R&P as there is no way to recalibrate vehicle speed sensor if I do that and still retain the stock ECU. That would be my prefferred way to gear taller, that way all gears get taller, but oh well I spend most of my miles in 5th anyways, so for $100 for the TDI 5th machined and delivered to me with tools for the install I couldn't beat it for the "bang for the buck" factor as far as gearing is concerned.

I ride motorcycles too, and swapping sprockets rocks, all gears get longer/shorter. Hell I have had my old 87 XR250 geared so tall that you had to be going 55+mph to even think of shifting into 6th gear, all the while I could cruise at low RPMS on secondary highways at 60+mph and get 75+ mpg!

Keep the comments coming, they keep my brain working.
JoJo

Mopeds are not legal on freeways here but perfectly legal on secondary roads.
Here if your going below 45 MPH your required to put on your emergency flashers. and usually there is a truck going slow up the hills. If i am streamlined i can gain more going down than the trucks can. I just pick the truck that has about the same power to weight as i do, to run with. Any time you are running full rack on a diesel and converting all that power into potenial energy you are being efficient no matter what gear and then coast down the next hill for free.The slower your speed up the hill the greater percentage is being stored in the mass of your vehicle and the less lost to push the air.
I have noticed people driving a lot slower the last few days. i think it's starting to hurt the imbeciles with 7 ladders on top of their truck arranged in the most aero inefficient manner possible, driving at 70 mph in a 60 zone. When you can make more money per hour by slowing down than rushing to the job site, then you will see traffic really slowing down. People don't know how little their time is really worth. Keep in mind if you slow down to the speed limit, everyone behind you is saving money also. I am finding people just don't want to be the first one, but once someone is going slow then they follow contently for miles. There will always be some who need a 2 X 4 up side the head to get their attention but their wallets are starting to smoke.
I have found reman. heads for the 1.6L soon to be 0.8L VW diesel for $400. Is that too much?

Indeed, the moped thing was more of a joke, but you get the idea.
I hope you can drive a .8L NA diesel and not get killed and/or run off the road. Best of luck, really.
I too have noticed that there are a lot more people driving the speed limit on the highways these days, and your right it is just recently, maybe it was the $3.50/gallon mark or something, who knows, but it's about time.
If everyone else slows down, then it will lower our demand for fuels, and in turn lower the price.....yeah I know wishfull thinking more than anything.
Really wierd part of the time argument is this, I go 110 miles round trip every day. I used to hammer along at 85+ the whole way (and I got 30 mpg doing it) and my best times ever were just under an hour.
Now, I have slowed down to 70mph max, usually 65ish, and I am EOCing any hill that is big enough to not lose much speed on, restarts at 60mph, pulse at top of hill before shutdown is max of 75mph. I just got 37.5mpg on my last tank this way. Not too bad as my car is EPA rated at 21/29.
All that said, and my typical time to commute to work and back, still just about an hour on the button, I don't even notice any extra time, so you are 1000% right, just not worth it to be in such a hurry these days.
Absolutely no clue how much you should pay for a reman diesel VW head, just haven't bought anything for a VW diesel since the early 90s.
I got stranded twice in cold weather with a tank full of jello, and hence have not owned a diesel since.
Also to note, gas was $.99/gallon and diesel was $.79/gallon back then, now those were the days to own a 50mpg diesel rabbit :-)

Loaded question. You can manifest most anything if you have the cubic dollars to spend. I've tuned 750 whp two liter engines that net 0.39 bsfc, which is better than any mill currently put out by the OEMs that I am aware of.

That being said it's going to be much easier to make your 2 liter fuel efficient than any FI car that will require boost to pull the vehicle up even mild hills. There is a lot to be said for the KISS principle. I take on a lot of odd projects, but I wouldn't even attempt yours for practical reasons. Better to spend your money de-stroking your engine or the like, would result in a more reliable and less expensive solution.



Probably not. FI cars like to run rich for combustion chamber cooling reasons, between the loss of pumping efficiency and richer mixtures under boost - which you WILL have to hit due to the lower power level of the setup -you will net a power and FE loss.

JoJoTheTireMan, veggie oil is ten times worst in cold weather than petro-diesel.


Joseph Davis,
How does this number compare to your .39 BFSC number?
18.65 Hp.-hr./Gallon of diesel.
http://www.deere.com/en_US/newsroom/...430trfuel.html

Gee and all this time I thought FI was for FE(Precise Control)
 

Most FI cars out there are trying to run in the 14.7/1 range all the time.
The only time they go rich is during WOT.
If you live at WOT then you may not be looking for FE any way.
I believe the idea has merit and would like to see some one here make a valid attempt. Thank You DieselJohn & JoJo.
FYI, I ran a 318 V8 Dodge for 10 months on 6 cyl because I (stupidly) blew the head (Not gasket) between 2 adjacent cyls.
It was FI and I disconnected the fuel injectors and grounded the plug leads to those cyl's until I had the money to repair the beast.
This was before I became interested in FE so I have no clue what the MPG was.
It did run (not smooth) and I used it for work and hauling engines & transmissions up the road forever.
I fixed it and then sold it(needed money)
For this example alone I believe their idea will work.
Go Boys, and don't let the mean kids ruin your day.
Schultz.

I could keep a couple gallons of propane in the bottle, just in case 0.8 L isn't enough in an emergency. Don't want to put the new head in orbit though. Combustion pressures tend to get kinda high when i start lighting fires with the piston half way up.

You're probably going to need a taller wheel/tire combo, what're ratios/tire size now?

I realize this, I had diesel from the pumps freeze up on me. The veggie oil kits all have to preheat the oil before you can switch over to it, which is fine on long commutes. It would work great for me, but not cost effective seeing how much diesel is these days and seeing how much the VW TDIs sell for these days. If I find a good deal on a TDI then I will probably go this route, utill then I will just try to get the best I can from what I already own as that is the cheapest solution in the short term.

I am running 195/60R14s and the other size recomended for my car is 185/60R14. Not sure what the R&P ratio is off the top of my head, but I do know that there are not too many R&Ps out there any taller than what I have as a starting point.

I have a suggestion. Don't use the extra two cylinders as a supercharger. I think that would reduce your fuel economy, shorten the engine life and give you lots of shaking at low RPM. I've tried running my Accord on two cylinders and it shook a lot when it ran at less than 2000 RPM. My front exhaust pipe cracked and my flex pipe developed a leak. At highway speeds it ran smoothly and had enough power to maintain speed up most hills.

For smoother operation and better fuel economy you could try using the two deactivated cylinders to expand the exhaust gas more before releasing it into the exhaust pipe. At full throttle, the pressure of the burned gases should be about 30 PSI above atmospheric pressure at the end of a power stroke. Sending that gas to two cylinders for expansion to double the volume before release will recover extra energy without using more fuel. If you pump a little water in the passage to the expansion cylinders, you may get some extra pressure by making steam.

When the load on the engine is small, it might be better to release the exhaust gas from the operational cylinders directly into the exhaust pipe. It won't do any good to expand the gasses until there is a vacuum. That would waste power. One way to solve that problem is to use one way valves between the exhaust valves of the expansion cylinders and the exhaust pipe. The gas from the expansion cylinder would not flow until the pressure in it exceeded the pressure in the exhaust pipe.

Ideally, it would be best to let the two expansion cylinders switch to normal operation when extra power or low RPM was needed. That would require some switching of valve timing and gas flow into and out of the cylinders.

It depends on what your trans code is but if you have a 3.67 R&P you're about as low as you can go stock. IMO your best bet for gearing experiments is to get a couple significantly taller tires on steelies from the j-yard with a scanguage or open equivalent (*plugs the instrumentation forum*) and do a few runs at 55mph over the same route switching tires between each to see if taller gearing will help you out much.

JoJo, I found it!
 

The link to the company that is already working on this same engine concept.

http://www.scuderigroup.com/

:thumbup: This looks to be more work than I would tackle. However, this company seems to think the idea has merit so perhaps you're onto something :cool:

Yes, 3.67 R&P sounds right, just do not have the book with me, but I do know it's what they put in almost all of the A3 cars, in other words I do not have the shorter geared GTI gearbox or anything. Indeed, I could try a little taller tire, but wheel well clearance will limit me from going much taller than stock. Due to my typical commute being mostly highway, I think I have exhausted my gearing options with the .715:1 TDI 5th gear, should do the trick, now if I can find the time this weekend to get the gearset swapped I'll be in better shape soon. JoJo

Thanks for the link, I will look it over. ^5 JoJo

OK, so their idea is similar yet different. I still may explore my idea further, and their site gave me some good input to this type of process. Very cool design on their part too.

See, I was after modest boost, they went all the way to 50 bar!
I am looking for less net HP, they (in theory) will achieve a net increase of HP, and a more efficient internal combustion engine than ever before. Very cool stuff indeed!

Anyone want to say it couldn't work now?

Granted my design is much simpler, but very similar and I had never heard of this until today, so much for my "original" idea, but hey at least it means that great minds think alike.

Being a huge VW nut I have to agree, destroking it would likely be a much cheaper option.

My great idea is to get a 1.8 crank in my 2.0 (thus lowering compression ratio and decreasing to a 1.9L), give it the mildest turbocharger (A turbocharger accomplishes what you were thinking of in the original post, except all of the cylinders are going to be pumping for you), and then put it into a VW Scirocco 2 (lowest drag, ~1800Lbs, dirt cheap when thrashed) with 175mm wide tires (or narrower, if available). Possibly adding a Diesel transmission to the setup.

That rig was really a hot-rod Idea from me, the lower compression is just to add turbo boost, and the de-stroking would just result in a better revving engine.

Better to get a 1.7L motor and just use that with Diesel trans, they have 3.4 final drive (IIRC, not 3.89/3.94 like all the rest), if you want to be insane, the TDI 6-speed trans from a euro model is said to make for insanely low revs (~1500 @ 65), for a 4-cyl. But the cost: xxx-x,xxx :(

Check out a "truck cam" grind http://www.techtonicstuning.com/show...artnum=109.07K (only for solid lifter motors?), this is said to deliver all the power from idle to 4,000. Pair that with a 1.7-1.8 motor and the Diesel trans and you would see a big deal.

Maybe a 1.6 crank is available for an ABA from a european car? You might need the pistons and rods though.

(I put a 2.0L 3A engine from an Audi 80 into my Rabbit Gti, it would roast the tires into 3rd gear, and still get 25mpg, while blowing the doors off of v8's :) )

I would investigate a torque tuned exhaust, a little smaller to get more torque.

Gearing Summary
 

Go here for the gearing specs of just about every VW tranny out there:
http://www.techtonicstuning.com/trannyratios.asp

Summary:
I have a 3.67 R&P now.
There are a few with 3.65 R&P, not worth the effort or cost involved for such a small drop, not to mention the vehicle speed sensor issue if you switch R&P ratios.
The VW motorsport 3.32 R&P would be nice, but good luck finding one of those, never mind the $$$$, and VSS issue.

As far as 5th gears go, the .71:1 is the lowest I can find for my 020, and I had to have it machined to even fit the retaining mechanism that my trans uses.
Even the 1.9L TDI uses the same R&P (3.67) with a .75:1 5th gear. I will be geared slightly taller than that in 5th.

I would love to combine that with the TDI 4th gear also as mine has a .97:1 4th where the TDI has a .91:1 4th.

Now, a 5th gear swap can be done in the car without removing the trans, but a 4th gear swap would be a whole lot more work, and not worth it as I spend most of my miles in 5th at highway speeds anyways.

I did the math, and if I average a 500RPM reduction in 5th gear at the same vehicle speeds, then I will spin my motor a quarter of a million times less per week! That just has to save some gas, no?

I fear if I go any taller in gearing without adding more HP/TQ, then I will be forced to downshift to 4th more often which will negate any 5th gear swap gains.

The bang for the buck factor really is why I am doing it this way. $100 and a few hours, hopefully this weekend, and I'm done with gearing. Any other option to go taller or mess with anything but 5th gear will require trans removal, tear down, and rebuild. There goes any potential fuel savings dollars as I would have to recoup the original cost of the rebuild, never mind the extra labor and down time.

I know anything is possible, some things just are not practical. Like the cost to import a euro 6 speed, although I would love a 6 speed, but that is not going to happen unless someone wants to mail me one for free, which I doubt will happen either.

Can anyone see any gearing options that I may be missing? I am not sure of compatibility between different types of trannies either, I am just comparing 020s.

I mean I could just go buy a prius, right? How long will it take me to save 20Gs on fuel? I doubt the prius would last that long, seeing I have 2 good A3 Jettas, and 1 for parts, and I paid 1G for all of them combined. Yes, I would spend less for gas per week with a prius, but I have no car payments and never will, worth more to me than the potential to save a whole gallon or two max per week.

Fuel costs are still only 20-30% of the total cost to own/operate a newish vehicle these days.

I try to look more at dollars per mile than miles per gallon.
I bought my current beater for $400, have about a grand into it total with repairs and what not. I have averaged 30+ mpg for just over 20K miles in 1 year. So, 20K miles for a grand, and I'm getting 30+mpg, how can I beat that?
Total cost of ownership/use is what our cars really cost us, not just what we pay at the pumps.

Now, that being said, not everyone wants an oldish beater with all the problems they typically come with, but I am lucky as I do all my own repairs/maintenance, so that keeps the costs down significantly. When most people think a car is worth next to nothing anymore due to age/mileage, that is when I will snag them on the super cheap and run them utill they are really done.

My wifes subaru has given us 70K+ miles for a total cost of maybe $1200 plus fuel. 200K+ on the clock now and she still runs great. We got it for next to nothing as it had a blown HG, their loss is my gain I guess.

I just don't see the point in buying a 20K+ car when I can get a $500 beater to get me to the same point a and b as the new car will. Don't need extra insurance as the car costs as much as the deductible anyways, crash it, recycle it, repeat. Cheaper excise taxes, cheaper parts, etc, etc, etc. If I didn't fix them myself, then maybe I would see things differently.

Much cheaper way to lower the CR on one of these VW motors is just to get a thicker HG, can make a drop of 10:1 down to 9:1 which would be more ideal for a boosted motor.

I can't see adding a turbo to even a smaller 1.8L saving any fuel compared to the 2.0L NA. That is why I was looking at supercharging (more low end HP/TQ gain than a turbo) a 1L as my alternative to save some fuel by displacement reduction. Never mind adding any kind of forced induction to an already decent powered 4 banger is just going to increase fuel usage, well for me at least because the temptation of using that extra power will get the best of me from time to time.

I do still have an 81 rabbit hiding out in my barn with 77K original miles on her, I have a 1.7L, and a 1.8L CIS motors, I have a 3 speed auto and the GTI 5 speed also. So I do have the ingrediants for a very light economy hatch, just need to find more time for that project.

The A3s have much better creature comforts though, like say something simple like a cupholder. The old rabbits are pretty much just a tin can with wheels, and that is what it sounds like when you hit a bump in one too.

Exhaust, I agree and when I find an OBX tri-y header on the cheap then I will snag one, as the tri-y design is much better at building low end and mid range. I believe they were initailly designed for motorhomes and whatnot.

I think I am on the right road for improvements to my current 2.0L NA, the EPA rating is 21/29 and my last tank I got 38 mpg, and I still need to swap the 5th gear in :-)

My other idea was more of a long term thing, would not cost all that much as I have the spare parts to begin with. It was just something I had to get out of my head and see what others think about it. I also think about how to run the cam at the same pace as the crank so my pumps run as 2 strokes and so would the charged 2, but need to sit down and figure out if the cam could handle this job if designed right. I'm still into it for a custom cam, and some ECU tuning at most as the rest is just stuff in comparison.

Thanks for the input, any and all ideas are appreciated.

Anyone else have any other ideas for my ride, well other than driving habits and aero mods as I do my best with driving technique and aero mods will be phase 2 of my plans.

Thanks again....JoJo

Like I said, VW nut:

83 Rabbit (junked and gone :( ) Free
84 Gti (no funds to get registered, smogged :( ) $300 initially (idiot I bought from put $1200 into a head job, the bottom end was completely trashed)
85 Jetta 3sp Auto $400
95 Jetta (daily driver)$500
96 Jetta (mom uses)$200

For sure go to VW vortex forums to see if anyone is doing this sort of thing :), here are some off-the-top of my head ideas that cost under $100

Transmission:
Go to a pull-it-yourself junkyard, they should have a manual 5sp Diesel :

AGS (86-90 1.6 Diesel) 3.94 3.45 1.94 1.29 0.91 0.75

While you are there, snag some output shafts (those cups that the axles connect to) from a 100mm axle car (or the inner CV joints from a 90mm car), and the .71 5th speed from another trans (no need to remove the trans, just pull it in the car!), and a decent looking clutch disk from a 1.8L 8v (smaller splined shaft on cars that aren't 2.0 ABA or 16v, 1.8L have the same size clutch disk otherwise)

According to some quick calcs that will net you ~300rpm drop or more just for that, and they should charge you around $100 for the whole mess. (we have a Pick n Pull brand store around, and all of the ones in CA do 25% off Wednesdays, and 50% off on holidays, like the upcoming memorial weekend).

I wouldn't do any custom machining for something as trivial as a 5th gear swap. You can get $400-700 for the used transmission from your Jetta (1994-1999 right?), maybe more if you know how to wheel and deal, or know a VW nut who needs it for a 1.8t swap into an A1/A2 chassis.

the Gti 5speed is not good for economy, it is a close ratio box, 5th is like 4th in the Jetta box, imagine that on the highway. I did a 5th swap into a close ratio box, it sucked to have such a huge jump in RPMs between 4th-5th.

I have swapped a close ratio with the smaller splines into my moms 96 with a stock 1.8L clutch disk (but it was the 100mm output shafts), and I have run my 84 GTi on a 100mm output flange tranny using Scirocco 16v or Late A1(89-92) Cabriolet axles. Neither of these is exactly what you are looking for though.

Header:
Don't bother with a header, the VW A3 (1994-1999.5) header is a 4-2-1 header already and is a damn good performer, you can't do better for less than $500, and since you want better torque and mileage, you would want one tuned for economy, which they don't make (afaik), it would be a bigger and tuned for higher RPMs, reduced low-end torque, increased high-end HP.

Crank/pistons/short block:
I would seriously keep an eye out for a complete set of 1.6 block stuff for an ABA (Euro/Mexico/Brazil/Canada??), that would really increase the fuel mileage. Double check to see if you are running 185 or 195 tires, if possible investigate 175 tires, that will help with the frictional losses.

The key to all of this is finding a pull-it-yourself yard, they have the best prices. I don't know about swapping parts down to a 1.6/1.7L for an ABA, but the whole short block is typically under $100.


Phenolic Spacer:
A phenolic gasket/spacer for your intake manifold, this prevents the heat from the engine warming up the intake and heating the incoming air, they claim better MPG for this. (I don't know if it is worth it though).


Camshaft/Adjust the timing:
I don't know about a better performing camshaft, but you could pull a late-model cam gear (skinny spokes) from a junk yard and have a machinist cut a couple new keyways in it to retard/advance the cam, giving you a more efficient engine with more torque down low. This shouldn't cost more than $30-50 total.


Bypass AC / Underdrive / Alternator bypass:
Edit, almost forgot, you can get a Vr6 water pump pulley and "A/C bypass kit" belts for $30 from a few places ($27??), when you don't need your AC you can swap it out in about 15mins and reduce the drag on your engine. Smaller alternater, I don't know if there is one, but the VW has a truck-sized battery, I can run mine for 3 days or more with no alternator, even coming back in the dark (no AC running). So if you top charge it at home and use an alternator disconnect switch while doing errands in town you can save some MPG and enjoy increased low-end torque (on the 3sp Jetta I could really feel the power it freed up!). You can always switch it back on if it needs to be on, a Voltmeter is $2-4 at Harbor Freight tool stores, mine works great (I have checked it against the Fluke meters where I used to work), so you could add it to the dash and keep an eye on the volts. A big solar panel on your rear-window deck lid can help keep it topped up (they aren't really worth much, but every little bit helps)

An Aluminum reduction pulley may not be worth it, but it could seriously reduce the drag on the engine from all the accessories. (keeping an eye on the temps and the battery is a good idea if you aren't racing with a reduction pulley). But if you top off the battery at home then it shouldn't be an issue. Why spend gas to charge a battery when the electrical grid is much more efficient and cheaper?

If you want to exercise your arms a little you could ditch the P/S (I wouldn't on the Jetta unless I used 175 tires pulled the AC out and moved the battery to the trunk.)

Daytime Lamps:
You could turn off one of your daytime running lights (they are always on), just like a late-model chevy, or add a daytime Running light and switch off the daytime lights altogether (I think vwvortex may have info on that), or if you live in a bright area (not the mountains), the lights may not even be visible. I think I heard a guy say it is removing one pin will disable them.

Engine Rocking/Wasted motion:
On the subject of wasted energy/motion, I am looking into putting a hockey puck in my front engine mount to reduce the engine rocking. It looks like removing the bottom of the front engine mount from underneath and swapping the rubber puck there with a stiffer/larger spacer will compress the top mount insert a little(soft rubber with lots of holes), reducing the rocking without removing the entire front engine mount. I typically slow down a quarter to a whole block ahead of time and shift into 2nd to slow my car to a near stop, then apply my brake, the reduction in engine rocking should make a huge difference. Too bad I forgot to look for a regulation puck last time I was in town.

Edit 3 (too much already?):

Aero Mods: Mirrors/Antenna:
Remove the passenger side mirror and swap the drivers to a more aerodynamic unit, make up for it by fitting a "rally" style mirror that goes across the entire car in the cab, you will be able to see nearly as easily (perhaps better in the usual VW blind spots :) ), and the law only requires 2 mirrors, one must be the inside mirror OR the Drivers side mirror. That is CA, I would check your laws.

I think you can cut a piece of plastic to cover that corner where you remove the mirror and use some 3M trim tape to attach it. I have found a very nice black plastic folder at Staples that I used to make a blanking plate for my mom's car because she doesn't have a radio.

I don't know about removing the antenna, but it couldn't hurt, you could swap to an inside one on the dash or rear parcel tray. (Being cheap and strange I might even hook up to the defrost grid during summer :P )

2 Cylinder mod:
I keep coming back to your 2 cylinder mod idea, I like the idea of a 1L in fact. I just wish that a 1L would actually do a good job of moving a Jetta (I know even my 1.7L Rabbit felt all too peppy, a 1L would do it good I think). I would like to remove 2 rods and pistons and grind off the cam on those two cylinders to keep the valves shut, but I don't know how you could balance the Crank at that point. You would need to fake out the engine management, unplug the injectors and ground out those two spark plugs, but it could be done I think.

If you were headed that route already, it is possible a short crank and a 1.8L block could get you in the 1.2-1.4L range. I would love to see that actually, but in reality I wish I could source the stuff from Euro OEM, I am sure they have smaller engines in their line-up over there. In fact I wish the Polo would come out already over here.