Originally Posted by SfValley335i
I dont think anyone with RB turbos has run 100% e85. And even then I dont think so, meth is being used to cool the charge and as a fuel when boosting 20psi. Remember e85 is cheap race gas. People breaking 500whp on RB turbos are using Race gas (MS109) and meth. Not race as in 100octane from pump.
E85 is great but mpg drops so much when you get into high mixtures of it. If you literally dont have a e85 station within 10 miles, then running 50% or more e85 is just crazy. Because more than likely you'll be filling up twice a week.
On pump gas I get about 21mpg, on a 20% e85 mix I get 19.5mpg, on about a 80% e85 mix I was getting 15mpg.
If I had to throw out a number I'd say a car running RB turbo with e85 mixture would not be able to break 500whp. It would break 500wtq easily.
I've run an E45 mixture with stock fuel system (7-8 gallons or so of summer blend E85) I leaned out badly on RBs at around 19 psi north of 6000 RPM. Surprised it didn't lean out much sooner. Once I threw meth into the mix (CM10 nozzle, 800cc/min) my trims went negative. Meth = ultimate fueling band-aid!
I would guess it would lean out much sooner if I upped the methanol mix. Don't think it really matters though, I was running near 15 degrees of timing in the mid-range on that E45 mix and nary a peep out of my knock sensors, so there is a bit of diminishing returns at play here.