The cost benefit vs. “premium” pump gas (which is only 91 octane for me out in CA, but I think you fuck-sticks still have 93) might not seem so great. But once you consider that most of us are finding it out-performs ~110 unleaded (even though E85 is only ~104 octane) which is damn near $10/gallon it start to make a lot more sense.
I’m only at 12:1 compression because I wanted to be able to run 91 (with a different tune of course) when I needed to and I’m still seeing pretty good results.
I think one person posted the 30% figure on the internet and everybody just ran with it. It comes from the theory that by weight E85 has ~30% less stored energy. What nobody is taking into consideration is that BSFC is much better on E85 since you can run so much more timing and get a more complete/efficient burn. I think the fuel consumption per HP at part-throttle is a lot closer than most would expect. I don’t have a lot of street miles on the new setup but I’m seeing within 10% fuel economy of my old combo, BUT YOU HAVE TO CONSIDER THE NEW COMBO IS A 427 WITH A MID-240S/MID-250S CAM VS. THE OLD 348 WITH A 224/230 CAM. It’s hard to say I’ve lost any fuel economy with E85… oh and that’s also on 80# injectors up from 42s.
Yuuuuuuuuup, though it works great w/ NA motors too given enough compression (any stock LSX is enough, though more is better). The cooling advantage is huge for guys that do a lot of road-course stuff like me. I’m seeing at LEAST 20 degrees cooler oil and water on E85. In fact, on the freeway the car is running around 145* which is cooler than I’d like, but the thermostat is still closed at that temp so I can’t really make it run hotter. On the dyno with back to back to back pulls it was still only seeing 180.
I guarantee with no change other than E85, the necessary supporting mods (bigger injectors and perhaps pump/lines/rail etc if required to support the injectors), and of course a tune you’d see at least 550. I’m not saying 500 is bad by any means. But that’s just like saying “my car runs bottom 10s on pump gas and I think that’s pretty damn good.” Sure as hell is, but wouldn’t 9s be better?
Here’s my dyno graph NA on E85:
We haven’t done the 91 octane power-tune yet but I’ll be sure to post it once we do. We have more work to do though first. You can see it really lays-over on the top end, but this cam should pull stronger to 7k. The car is running the stock Ti catback and the stock 85mm MAF (in front of a 102/102 TB/intake) so we think those are really restricting things up top. We don’t want to mess w/ the 91 tune 'til we fab a better intake w/o MAF (it’s going to go Speed Density) and play around with exhausts.
-TJ