92 vs 94 octane. lost 26awhp

[gtrjon]

So thought i would throw this out there in case anyone was curious as to 94 vs 92 octane. I was tuned before at 13psi on 94 chevron octane with 100% meth and i made 421awhp on rgs dyno. Just today i went back for a bit more boost and I am now running 92 chevron octane since it is more readily avaliable to me. long story short all other factors remaining the same at the same 13psi i made 395awhp on the same dyno.

[Zacho]

Large ambient temp/humidity change? How many pulls did you make each time (repeatability)?

Does one fuel have ethanol content and the other doesn't?

[MKIV]

Hey, that's still some real good numbers

But with that said, perhaps ethanol contained in the 92 octane could also play a factor? I'm not familiar with BC's petrol stations.

[newalliance123]

The guy who I buy my C16 from always keeps telling me Husky 91 is the best due to its 10% ethanol content. I typically get chevron 94...

[DarkCaporaL]

Ethanol lets you get a more agressive tune since it prevents premature detonation. I'm not surprised you were able to get more power with ethanol mixed fuel.

[cobrAA]

In this case.. get 94 + water-methanol aftermarket kit?

[Daryl @ RightDrive]

Was the engine retuned to 92? If not then that would probably explain the power loss.
My car made more power on 92 octane than Japanese 100-104 octane, simply because the ECU tuning was better dialed in when it was setup for the 92.

[GTR-Dad]

When you're tuned to the knock threshold, which usually comes at lower ignition advance than mean best torque, higher octane will enable more advance and more torque, which leads to more power.
Thanks for posting actual numbers! Good to know what a couple of octane points can do - assuming all else was as equal as possible.
I run Husky 94 with good success.
Dan

[Sharkus29]

I always use shell premium. Is it worth it do you think?

[gtrjon]

everyone is asking relatively the same questions. on both occasions the car was tuned to its full potential at the boost level. over 15 hours have been spent on the dyno with this car. i am running water meth in both occasions. literally nothing changed other than the fuel. same set up, same tuner, same dyno.

[ZinnZ32]

The ethanol content of the 92 Octane means a less volatile explosion. Many cars running E85 on high compression FI engines are experiencing unseen numbers without incurring engine damage, and considered completely 100% safe tunes. I have seen a stock block NA-Spec VG on E85 do 600WHP whereas it is a known fact, on ordinary premium, the wrist pins will snap above 400 whp!

- Ethanol combusts at a more linear, smooth rate, reducing stress during the combustion event. Gasoline is a very harsh combustion, which makes a lot of sense when tuning with different fuels. Pretty cool stuff that is being found out recently. So, in your case John it makes a lot of sense as well, but both fuels have their benefits. If you want more boost, 92 with ethanol means less resistance to detonation at a higher threshold. More timing, I would stay with pure 94, just for low-end power's sake. It's not going to really make a huge difference though I don't think, it's only 10% after all!

[gtrjon]

yea i didnt have the luxury of running 94 at this time since i can rarley get it. nick is right on the money. on a bright note i made 512awhp @18psi

[cooke24]

I thought all chevrons in the lowermain land have 94?? Personally I fill up in the states shell vpower 92 octane

[M13]

Jon has access to 94 in BC but he lives in WA most of the time hence why he tuned it for 92.

Keep in mind this is Racing Greed dyno number, which reads extremely low compared to other dynos.

C63AMG with chip made 3xxRWHP on this dyno and that thing pulls, so I can only imagine 512AWHP... ~700+BHP...

[Dakota_gsx]

I run Husky 94 with good success.
Dan

I run husky 94 aswell, love it!
By the way, GTR-Dad, love your build! i took a peak at it when i dropped my engine off with Cam last month. Jealous of your oil setup! other than that and your meth kit, it looks like we are running fairly similar set ups. Goodluck with yours.