[ZLRob]

Originally Posted by Megahurtz

Even if your low and high side fuel pressures are good, you only have so much time to inject fuel. Log your SOI, OEI and Injector Pulse width in milliseconds. This will show you the answer if your injectors can handle more airflow.

Originally Posted by Joshinator99

Running full pump E is not needed. E50-E60 will give you the octane you need. So blend down some and you can stretch your fuel system much further. Made my dyno number at E50, BTW.

Originally Posted by KingLT1

Full E85 requires 30% more volume vs gasoline. So yeah stock LT4 pump and +30 injectors will support roughly 900-950whp @ sea level on 100 octane race fuel @ LT4 compression vs 780whp on E85. Now go price what race gas cost per gallon(14-15.00 per gallon) and weigh your options.

Or you can dial back to E50-E60 and now the demands are roughly 18-20% more volume vs pump fuel and you still have 101-104 octane for 3.00 a gallon. and you just gained 100whp worth of fuel headroom. Yes full E85 will make a little more power than E50-60 but it's not a big difference depending on compression, setup, and how much more timing you allow on E85 vs E60. On stock compression LT4 stuff you can pretty much get all available timing on E50, but I often see the multiplier scaled so E50 is still down 2-3 degrees of timing vs full E. So that will skew actual gains.

Big thing to look at is your EOI and SOI. The cam valve events play a factor and how early you can start injection. Stock cam stuff I like to see < 370 SOI and EOI above > 160. Not all setups are the same either. You just have to spend time logging the data, change the injection timing, and see how it responds.

And for the record I am far from an expert. Just a guy that got tired of paying big name shops for average work and tuning. I spent a lot of time learning what E85 will do since it's everywhere in my area and relatively cheap.

First thing to learn about E85 is that it likes HEAT. Yes that is what I just said. If you run E, then you can quit worrying about air temps and spending big money on coolers and heat exchangers. Just raise the spark vs IAT threshold to allow commanded timing even if the blower is putting out 170 degree air.

If you pay attention to a lot of grudge race stuff. You will see turbo cars running C85 or M1 with no intercoolers and 25+ psi of boost. 200+ degree IAT's and the engine is fine because alcohol fuels need the heat to combust efficiently because they burn really cold in the cylinder.

All the intercooler talk and keeping IAT cool is old mythology based on trying to make power on pump gas. A lot of tuners out there don't understand this and they are limiting alot of potential gains from pump E. The only reason you will make more power in cool air vs hot summer air is because you will make more boost, otherwise if you kept boost the same power would be similar in both conditions on E. Where pump gas you will still make more power in cool air because it can not sustain the same timing advance without knock.

Excellent responses you guys, thanks a bunch for taking time out of your day to respond as honestly and thoroughly as you did. Especially you King!

Josh, the only reason I run pump E is because I don't like having to take the time to math out a blend on my phone and complicate things plus I have found some extra power squeeze out of E85 over E50 blend.

Megahurtz, I forgot that the most important thing to see is SOI and EOI. Currently I sit in very solid standings all around with low, high fuel, SOI, and EOI under full gun with my mods. The only thing showing high on my logging is injector PW's at 6.7 ms peak which eventually comes down to 6.5- 6.6 once it settles down.