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modified turbo car vs modified n/a car - fuel economy?
Topic Started: Feb 7 2010, 11:55 PM (1,899 Views)
rmcelwee
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starscream5000
Feb 10 2010, 01:14 PM
What I mean by conservative is in regards to your Air/Fuel Ratio's. The Methanol has a very high octane rating (over 100 if memory serves me correctly), this is used to keep from detonating while boosting.

How would you plan on boosting a 4psi? Most wastegates are preset to 6-7 at the lowest...
Yes, MEOH has an octane rating of 130+

I work in a chemical plant and have access to 1000s of gallons of Methanol but I've always used straight water for injection. Octane is a measurement of resistance to auto-ignition. Since I've never seen water auto-ignite it has to be better <G>.

FWIW, I've seen some pretty good uses of external springs and stuff to drop/raise boost pressures. This could be a way to get 4PSI out of a 6PSI WG can.
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starscream5000
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Got 70 MPG?

You know, now that I think about it, TiAl has a 2psi spring for one of their external wastegates, pretty expensive for the gate and spring though.

If you're just wanting to boost a tad bit for passing power when you need it, why don't you consider using a slightly larger than recommended turbo? It will flow more air at less psi, so you'll make more power, and it will not spool up until later on in the RPMs.

The reason I say this is for fuel mileage. When climbing hills and such, you place load on the motor.

Turbos love engine load. They spool up faster when the motor is loaded up. You probably don't want this in your DD. The more you stay in vacuum the better your mileage will be.
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Dallas


just fyi, in terms of water, meth, or washer fluid, there is quite a bit of differences. meth cools the intake charge more, but as it is a fuel (alcohol) it does combust and increase combustion temps. water doesnt combust, and turns to steam to help cool. you dont gain octane with water though, so some people run a 50/50 mix because imo it cools the best, and still adds octane. anything with a rating of about -40 for washer fluid (with no other additives, like bug wash etc etc) is the closest to 50/50 you could buy
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