Gains from E85 (ethanol) on an N/A bolt on 370Z

VitViper

I got the inspiration to test E85 on the Z and see what kind of quantifiable gains can be had. Not hearsay -- but actual scientific data collection. Thank goodness for these things we call dynos!

The car has bolt ons -- Stillen intakes, G35 test pipes (modified to fit), Agency Power 2.5" dual exhaust. Our pump gas is 92 octane, and on this fuel the motor is not ignition limited -- I can roll past MBT and see no detonation, there's just zero power gains to be had at that point.

VVEL and VTC were left alone as it was already dialed in.

The car took 16.5 gallons of E85 and on the dyno it went. First and foremost I tuned fuel, and only fuel to make sure the motor was getting a proper AFR -- running 100% the identical timing map. This is to demonstrate the gains to be had from the fuel -- and because of the properties of E85 (ethanol -- cooling effect and naturally oxygenated) simply switching to the fuel and making sure the motor has a proper AFR will make power! Regardless if you're comparing it to 91 octane, 92 octane, 93 octane, 94 octane, or whatever.


As you can see, there were gains across the whole curve.

Next, we adjusted the timing map -- and the gains were super minor and the timing added to get these gains were negligible over the pump gas timing map. 4hp on the top end. Essentially the small amount of timing just told me the fuel needed to be ignited a tad sooner to get a complete burn due to the larger quantity we're not injecting.


What's it look like overall? About 12whp and 12wtq in areas.


Not bad at all for just changing fuel and minor retuning. In fact, I saw more gains with the fuel than I did with all the work and money spent on the Stillen intakes on the car. This was also done with stock injectors and a stock pump -- worked perfectly fine, holds a clean AFR all the way to fuel cut (7800 rpm). Fuel economy while cruising on the freeway at 75mph was actually the same if not 1-2mpg better than pump gas. Go figure.

So if you want to run E85 -- the gains are there -- you should see 8-12whp regardless of the octane rating of your pump gas as the properties of the ethanol alone net gains over pump gas.