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

[JoJotheTireMan]

Originally Posted by nubie

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 )

Another VW bargain shopper, right on man.

I've tried the vortex forum, more about show cars and performance enhancements then fuel economy, but these days as prices keep rising that may change.

Transmission
I am better off with my setup, a 3.67 R&P with a .71:1 5th gear. The AGS you mentioned has a .75:1 5th gear and a 3.94 R&P. My setup will net a 500RPM reduction in 5th over stock.
No need to mess with halfshafts or anything else either.
The "custom" machining was hardly that, there is a guy who rebuilds trannies off of the vortex, I paid $100 total for a .71:1 5th gear set machined to fit my trans and it even came with a spacer tool to align it properly when you put it in. I think he charges $15 for just the machining if you want to mail him a 5th gear, not too bad for the bang for the buck, not to mention a lot less work involved.

Header
Your right, and this is one of the reasons I am still running the stock manifold and downpipe, if they are not broke then I'm not replacing them.

Crank/pistons/short block
Well, the down time would kill me on my daily, but I agree you have to love how so many different parts are interchangeable between models and years. You can almost create just about anything you want, within reason.

Phenolic Spacer
Well, I am not too sure how much of a difference one of these would make, but it would kind of be counter intuitive seeing I have rigged my airbox for WAI already.

Camshaft/Adjust the timing
I already own an adjustable cam sprocket, and I had been running an autotech 270 cam. I went back to the stock cam and gear for now as I could not stand the rough idle the 270 gave me. I plan to play with the cam timing a little to bring my torque curve down in the RPM range some.

Bypass AC / Underdrive / Alternator bypass
Underdrive pulley is already on, 10K+ miles so far and no cooling issues, plenty of juice from the alternator, AC works fine, and so does the power steering. I like my AC on my hour long commute in the summer, plus I think I am better off at highway speeds with the AC on rather than the windows down. Alternator bypass/switch, I have thought about this, and I will probably go down that road at some point in the near future, but I have a long commute so a switch would be my only option here as I do not want to stop to put a belt on half way home because it started raining and I need my lights and wipers. My A3 has a volt meter in the dash stock. EOC steering effort is increased, but tend to EOC mostly on straights and mild corners, tight corners take quite a bit of effort, so I don't think I'll ditch that anytime soon.

Daytime Lamps
Already off, one of the first mods I made as it cost nothing.

Engine Rocking/Wasted motion
I plan to replace the whole set of mounts with a slightly stiffer set, not that much coin if you stick with the ones that are only a little stiffer than stock, still rubber as I don't want to feel all the vibrations.

Aero Mods: Mirrors/Antenna
Mirrors, not 100% sure of the laws here in MA, but I don't think they make a huge difference anyways, very minor from an aero point of view, no?
The antenna, mine is still fender mount, I have seen people just yank them and lay them sideways under the cowl cover and they still work fine, out of sight, out of the wind, and still funtional, just zip-tie it so it doesn't interfere with the wiper motor/arms.
Both removals have a cover option on the cheap, I have seen mirror delete panels cheap on vortex, also have seen antenna hole plugs for the fender for cheap on the tex.

Aero mods will help me in my EOC efforts in addition to highway travel. EOC, I only do this down hills right now, and here in MA there are no shortage of hills. P&G doesn't seem to work very well here because the roads are always twisting, turning, and hilly. I also do not want to abuse my starter or clutch too much.

I was thinking grille blocks with fan actuated openings, underbelly work, smooth/fill body gaps, etc. Nothing too outrageous.

Thanks for all the input, it is all useful. JoJo

[JoJotheTireMan]

Originally Posted by nubie

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.

A NA 1L I am not sure would have the power to move the Jetta, as these years are a bit heavier than the older ones.
Indeed, crank balancing would become an issue, that is why I was trying to come up with a way not only to deactivate the cylinders, but to put them to work some other way to help the remaining 2 a little.
Couple of resistors to fake the computer into thinking it is firing 4 injectors instead of just 2, instead of leaving the connectors off as I'm pretty sure this would cause a CEL.
I would just yank 2 wires from the distributor cap, and remove 2 of the 4 pickup lugs from inside the distributor, no need to fire those extra 2 anyways, right?
Another thought is to just remove the hydraulic cam followers and see if the cam will clear the top of the valve stem, but the alternative would be to bust out the grinder and show the cam some love.

Indeed, a VW polo would be sweet. They run a 3 banger 1.3L I think, maybe 1.4L with factory head studs, meaning it is much smaller but could probably handle higher boost levels and/or compression ratios too.
The euro stuff I would love to see are the super small, super efficient, clean running TDIs.

What would the effective mpg be on a 1.4L TDI with a WVO kit in the trunk? Audi's A2 is rated at 74mpg I believe running solely on diesel in the main tank. Use your imagination here as I'm sure you would be well over 100mpg with a long enough commute to warm the oil and switch over to the WVO for the majority of the commute.

Even the US 1.9L TDI would work well for me this way as my whole highway portion could be replaced with free fuel both ways as my ride to the highway is long enough to warm the WVO up.

Your a bargain VW shopper, let me know if you run across any A3 Jetta TDIs in a 5 speed for under a grand. Now that gas prices have gone up people are selling them for double the book value around here, and that is with 300K on them already and they want 5Gs and up! It is crazy.
Now, find me one for a few hundred bucks and I'm all over it, till then I try to keep squeezing my 2.0Ls as much as I can within reason. JoJo

[nubie]

I know what you mean about the TDi's , they are so worth it though.

I found a place on the net that would rebuild an injection pump for $300 (I might have that wrong), and people will literally give you a diesel Rabbit. (try craigslist or keep an eye out for a parked bunny)

I would almost try a re-built injection pump and add a simple turbo to an older VW Diesel. Just any old turbo with good seals and a vw log manifold ground off and a plate welded to it.

I am a regular mechanic, not VW trained (I didn't look into it when I started school, I didn't know it was an option, the school only offered Toyota, Honda, and GM programs, I wish VW would get a good training program in place) no Diesel training either, and now I am looking for work in the PC repair field.

Mirrors:
I thought that the mirrors did make a big difference? I could be wrong. Couldn't hurt to try it though, could it? Now that I think of it shaved door handles might help too. I wonder if it might be possible to make your own "salt flats racer" wheel covers? Probably would need to add a brake duct if you did that.


http://en.wikipedia.org/wiki/Automob...g_coefficients
This site points out that a 1990 Honda CRX is one of the most aerodynamic cars, it might be worth looking for one cheap (if you can source engines for under $200). This chart shows the Cd already computed against the frontal area:

2.50 1986 Twike [3]
3.95 1996 GM EV1
5.10 1999 Honda Insight
5.71 1990 Honda CR-X Si
5.76 1968 Toyota 2000GT

Although the Jetta doesn't look abysmal
http://www.mayfco.com/tbls.htm:
6.94 Jetta III
6.96 Jetta III GLX


It looks like you are already on the way with a lot of good info and knowledge, I want a Voltsrabbit, but the batteries are way to expensive to even consider it, even as an auxiliary back axle type thing for the drive-thru or stop and go traffic.

[diesel_john]

if anyone knows where there is a rebuildable VW 1.6 diesel head hang on to it, core charges are going up. Most reman. shops cannot find cores, they want to rebuild your own head. New heads are over $600 if you can find one.

[metromizer]

Check out this air cooled flat-4 VW.

It's essentially an aircooled flat 4 converted to 2 stroke operation.

<notes taken from another site>
"The blower pressurizes the crankcase, which is overfilled with oil, and doesn't burn oil with the fuel, which is methanol. He had 60% of the fuel running thru the Eaton roots blower to cool it, and it got super hot, even idling. The welded together cylinders gave a problem with the lower oil control ring which resulted in the smoking. Rings had to be pinned to prevent rotating and aligning with the ports. Rods are almost 7" length carillos. (look at the pic showing the rods hanging out of the case)
The blower was running at 200%, so ran as high as 26,000 rpm with the engine at 13,000 rpm.
Powerband was insane going from 60 hp to 1000 hp in 50 rpm at first, shearing off the five bolts holding on the T4 flywheel like a laser cut!
The hall effect distributor was hand made, as well as the fuel injection system, as this was before he became an Electromotive dealer.
There are four expansion chambers on the engine, of which two are visible in the vid, and the other two are inside the car out of sight.
They were made with the help of an exhaust system engineer."

http://ecomodder.com/forum/showthread.php/www.mpsys.ca
click on media
then on the last pic

OR

Takes a while to load http://mpsys.ca/Video/MPS2StrokeBeetle.wmv

[bschloop]

just a thought, but wouldn't your two working cylinders be firing too far apart, timewise. you might have to run the engine at double the rpms in order to have them firing at the same rate as an actual two cylinder engine at idle.

[Andyman]

The timing of power strokes in a four cylinder engine converted to run on two cylinders would be the same as a normal two cylinder engine, assuming both are four stroke engines. It wouldn't make sense to turn off two cylinders that fire consecutively. That would be very shaky.

A two cylinder engine does require a higher speed than a four cylinder engine to be as smooth. In my experiment, the idle was pretty good at about 1100 RPM in neutral. When driving, I had to keep it over 2000 RPM for reasonable smoothness. When the torque converter locked up I needed to keep it over 2400 RPM to run smoothly. It was more practical on the highway than in local driving.

A flexible rubber coupling (called a guibo or flex disk) on the driveshaft or axle shafts would be helpful to reduce the shaking. Mercedes and BMW often use this at the front of the driveshaft.

[Chromedome]

Hi all. This is my first post but have been lurking here for years.

On the thoughts of converting a 4cyl to 2cyl operation, wouldn't be easier to use an OHC V6 and spin one banks cam at engine speed? That bank intakes air and the exhaust of that bank is tied to intake of second bank, which actually has the injectors and spark. Gives you an easy 3cyl engine.

[Heihetech]

Originally Posted by Chromedome

Hi all. This is my first post but have been lurking here for years.

On the thoughts of converting a 4cyl to 2cyl operation, wouldn't be easier to use an OHC V6 and spin one banks cam at engine speed? That bank intakes air and the exhaust of that bank is tied to intake of second bank, which actually has the injectors and spark. Gives you an easy 3cyl engine.

Hi all. This is my first post here, but I already posted my invention called
Dynamic Cylinder Deactivation, or DCD for short, in a thread with the same
name. DCD makes engine displacement variable by electronics. So just by
clicking the button, the number of active cylinders in DCD controlled engine
can be changed in no time, saving fuel with reduced power. But when you
need larger or full power, just clicking the botton to go back to it was no DCD
control.

DCD concept has been made into DCD Controller product these days. So
anyone who plans to do 4cyl to 2cyl mode, or 6cyl to 3cyl mode, is welcome
to try this electronics gudget before you start mechanical moding. DCD
will let your dream become true, with reasonable time and expense, saving
fuel while keeping good drivability.

[Floordford]

My first thought when I read the original post was that it might be beneficial to run two pairs of pistons. The two for power and two for pumping air. Also bore the two air pump cylinders out, port and polish the air pump intake and exhaust parts of the head, use bigger valves on the pump parts, and go with a bigger cam profile for the pump. This way air wont move neutral from the air pump to the power making cylinders.

But im guessing there might be extra load on those power cylinders because this is happening, assuming they are in opposing cycles and
Cylinder 1 is an air pump and Cylinder 2 is power making.

C1-pushes air/C2-draws pump air
C1-pulls in fresh air/C2-compresses fuel air mix
C1-compresses air into the intake/ C2-power stroke
C1-pulls in fresh air/ C2-exhausts burnt mix
C1-pushes air/C2-draws pump air

Cylinder 2 is having to now compress 2 cylinders of air instead of one.

And a problem may occur when cylinder 2 opens to get pressurized air. That pressure is going to go back towards cylinder 1 as the exhaust opens again. And because cylinder 1 will be at top dead bottom that air will go there first. Granted im talking hundredths of a second here but that might mess with the way fuel is delivered to cylinder 2. A large surge tank style intake might help remedy that.