After last week when some body asserted that adding 2 1/2 gallons of C-16 would dramatically effect the a/f ratio on a Evo I made a mental note to test the situation on the dyno

Here is what we did this car had pump gas tune - 21 psi of boost

Mods - HKS RS Intake - walbro pump - HKS 264 cams - 3" exhuast - MBC - Dyno Flash

Run 8 made with 1/4 tank pump gas

Poured in 5 gallons C-16 ran the car 5 minutes on the dyno to get the gas mix in

Run 9 made with 5 gallons C-16

My conclusion is that the C-16 has little or no difference on the power or the a/f - the slight variation is more than accounted for by normal run to run variance on the dyno

 

Science is the verification and testing of theories to find out the accurate conclusion

 

Good info!

 

The a/f graph shows it getting rich from about 5k rpm and on (prob from boost taper), so it looks like there's more power to be discovered if leaned out some up top.

Also, was the car retuned after adding the race fuel? It's not noted so I'm asking.

 

Yes - the car was re-tuned after we finished this test. For purposes of this test we did not touch anything - its a A - B test just to determine what if any changes would occur

 

I think it would have been seen a bit more to add 5 gallons to an empty tank rather than a tank with 3-4 gallons of pump gas and when you say pump gas what kind of pump gas? 91? 92? 93? 94?

bryan

 

Nice number, what kind of octane fuel is used ?

 

If the mix of pump and C16 wasn't a high enough octane, we would have seen knock activity on the high boost pulls that followed this test. No knock on high boost = very high octane. It was 94 octane pump gas.