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Old 05-08-2008, 10:38 AM   #7 (permalink)
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Originally Posted by dremd View Post
My thoughts are in BOLD take them as you may

Good Idea maybe a standard supercharger would work better, but would require a smaller engine
I agree, but I don't have a smaller engine or a supercharger, which both cost $$$$. This is more of a "what can I do with my current setup" type of thought, fairly low cost, reduced displacement, and semi usefull use for the shut off cylinders.

2: Use a liquid to air charge cooler, keep the plumbing as short as posable, investigate the idea of warmer air for efficiency
I agree again that a liquid to air intercooler is more efficient than air to air, but adds more complexity to the project also. I did think about using one with engine coolant to warm the air, but warm air and boost are not exactly the best of friends to begin with, usually their buddy detonation takes over at that point.

3: 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
It does have the squirters, which I figured may help reduce some frictional losses. Which 2 is tricky, I guess I could just let it run on 2 and see which pair seems to work better.

4: 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
True, megasquirt would be nice indeed and probably make my life that much easier in the long run.
Good Point, that way it is measuring all the air that enters the engine, but it will then think that amount of air is being used by 4 injectors instead of just 2.
It just may not be possible with the stock ECU and maps.

5: 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)
Well, I am still debating this one.
If I put the TB on the compressors intake, then what no TB on the real cylinders, how quickly would it idle down when you snap the throttle shut?
I was thinking about running the compressor jugs on cone filters wide open all the time and let the RPMS be the controlling factor, but at high RPMs you snap the TB shut it would have excess boost it would have to blow off somewhere, no?
My other thought was to have both of them on TBs, the stock TB for the real cylinders. The compressor cylinders could have ITBs with cone filters. Would just need a multi TB cable of some kind to keep them in sync, or just drive the 2 ITBs from the stock TB via a second cable.
Could even play some with the opening timing compared to each other this way.

6: I take it crossflow indicates that intake and exaust are on opposite sides of the head?
Exactly, intake in the front and exhaust out the back.

7: Umm, I believe you
Now lets hope it works.

8: could add an old mr2 clutch type supercharger to gain back your needed hp, if you need them
It would kind of defeat the purpose of my idea as my goal is displacement reduction and HP/TQ reduction but only to a useable level, hopefully the 2 pumps would provide enough boost to the 1L that it would be driveable in every day driving.

9: 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
Acceptable is a relative term. I do have a need for speed at times, but I have dirt bikes, atvs, snowmobiles, etc for that kind of fun, 115HP/500lb snowmobile works for the fun factor. This is for my daily commuter which goes 105 miles per day, mostly steady highway speeds.

11: I don't know about where you live, but here the price "premium" for premium isn't that large % wise
Agreed, as long as my increase in MPG is large enough to more than offset the cost of running higher octane, then it's still win win.

12: 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?
Cost, complexity, etc. The better question here would be why not start with a 1L metro?
Water/meth injection does raise the octane of the mixture a little and has some cooling benefits too, but it doesn't raise the octane much at all from what I have read.

13: all depends on your expectations
True, all I want to do is not get run off the road and save some coin at the pumps.

14: I drove my TDI boost free for a few days, I know the feeling
And you still had more HP/TQ than my old rabbit did, but exactly, you just learn to drive the vehicle accordingly.

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
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