During my last motor build, I switched to E-85 for track use, and as well running dual maps for 91 octane for road trips since E-85 is not available everywhere.
Here's the changes I made:
1000 cc injectors
Upgraded all Fuel Lines
MagnaFuel single fuel pump mounted external from the fuel tank. (Considering switching over to external dual Bosch 044’s)
100 micron Pre Pump Fuel Filter
25 micron Pre Injector Fuel Filter
AN 10 lines out of the gas tank with a modified gas tank cover plate and pick up, AN 8 lines to the fuel rails. Still running AN6 fuel rails but that about to be changed to AN 8 fuel rails being custom made.
All AN fittings everywhere.
Fuel Surge Tank mounted in the same location as the charcoal canister so the gas tank can breath, with a roll over valve and filter on top of the swirl tank. Removed all OEM gas tank breathing restrictions. The demand for more fuel will cause the pump(s) to cavitate and not supply the fuel needed if not getting enough air to replace the fuel being used. Learned this the hard way since I got stranded twice on road trips and burned up a $500.00 pump because of the cavitation. The vent tube and all of its check valves on the OEM gas tank are NOT big enough to supply the air needed to replace the fuel usage on E-85 with their restrictions.
Here’s what I’ve learned.
I get 15 miles to the gallon on long freeway drives on E-85, cruising with some playing here and there. Latest trip to California, 240 miles, 16 gallons.
On the track, I get 6 to 8.
14 lbs of boost, 550 rwhp is where I settled in and more than happy with the power it puts down safely. I could care less about my car being Dyno queen.
When we first tuned it just to see the potential, we got 600+ rwhp on 14lbs of boost with timing advanced, but we backed off the timing to give me some longevity with the motor. Motors are not cheap to build, as we all know.
Mitch Peterson does my tuning, continually monitors my data logs for me and makes any minor adjustments that have had to be done. So far, no major changes have had to be made in the original tune in the last 5000 miles and 12 track days.
We checked the intake temps on some hard driving at Firebird Raceway during an event and we were at 86 degrees on E-85.
Car runs noticeable cooler, oil temps and cooling temps.
Motor is much more alive and responsive on E-85
I have a Chevron 2 blocks from my house that sells E-85 so I run it 90% of the time.
On 91 octane I get 18 MPH on road trips. Coming back from California, 300 miles on 16 gallons. Cruising and some playing.
14 lbs of boost, timing reduced. 450 rwhp.
I run a GT-35R turbo and 14 lbs of boost off the wastegate spring only.
I run a crankcase breather can off both valve covers.
With E-85 I do get some water residual in the breather can, not very much but a little since the E-85 tents to hold moisture. I also found that E-85 tends to breakdown the oil a little faster than 91 octane.
Another thing I tested was the longevity of E-85 sitting in the tank for periods of time. E-85 stays at 85% for about 10 days and then starts to drop. This is something you have to be careful of since if you tune at 85% and don’t drive the car much and it sits for too long, you could be now running at 80% and tuned at 85% and this could lead to engine detonation.
E-85 also tends to collect moisture when not continually used.
There is about a 30% difference in usage, E-85 burning more. But with the cost of E-85 vs. 91 octane, it balances out the cost and the benefits of running 104 octane all the time goes without saying. Not to mention 105 octane gas for the track is $9.00+ a gallon.
Best change I ever made, glad I did it.
