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

[metroschultz]

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.

[diesel_john]

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?

[roflwaffle]

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.

[JoJotheTireMan]

Originally Posted by diesel_john

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?

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

[diesel_john]

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.
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.

[JoJotheTireMan]

Originally Posted by diesel_john

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.
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

[Joseph Davis]

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.

[roflwaffle]

Originally Posted by JoJotheTireMan

Any thoughts on my latest brainstorm? Shoot away.

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.

[JoJotheTireMan]

Originally Posted by Joseph Davis

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.

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

[JoJotheTireMan]

Originally Posted by roflwaffle

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.

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