jjsC6

Their are cars that were actually rated with both fuels. The difference would be about 2-3% (I say that because people will say 10hp or whatever, but that only matters based upon how much you have to begin with.

As I said in my first post, throttle response is much more effected by minor timing changes. You might feel like it's a bit sluggish in throttle tip in as you said in your first post, but flat out through the gears is where I would really not believe anyone saying they feel a hp difference that small.

IknowHuhA6

Good question but I think wrong place to ask for a solid answer. But at least you will get pointed in right direction. I just had a debate about subject not too long ago. FWIW here's some more info related to octane difference if it helps you piece the puzzle together a bit better.

Fuel Rating - Octane Comparison - Dyno Tests Graphs - Hot Rod Magazine


If your intent is to start a spirited discussion you're on the right track.

If your intent is to really find an answer.. you need to follow suggested advice to get on a dyno. Scientific answers come from a scientific method, not by asking others opinions and hoping one of them convinces you better to the truth without doing your due diligence.

Hard to find reputable articles now a days online with so many blogs postings that don't provide proof. I'd also be curious to actual differences but waiting for someone to post dyno numbers to prove any power differences.

Edit:
actually I just remembered and confirmed that APR has scans of their stage I & II tunes with both 91 & 93 octane fuel scenarios on their site. That's a great starting reference.

HackDevil

Thanks for this and I appreciate everyone's attempt at interpreting and answering my question.

Yes I did see the graphs on APR about the performance gains from a 91 tune to 93 octane tune. There's an impressive HP/ TQ gain the higher the octane tune is.

Someone had mentioned that there are zero benefits of using higher octane than what the factory recommends (true). The manual states use a minimum octane of 91. So I'm curious, since we have a supercharged engine, does higher octane affect the engine performance at all.

In my search (as you mentioned) I found a lot of bloggers and forums member stating opinions but no facts. Maybe scientific is the wrong word. So I thought I'd ask and maybe I learned something.

Yes 89vs91 didn't help, but I appreciate the that someone tried. As a matter of fact, in my search there are tons of data showing 89vs91 but nothing like 91 vs 93.

And the other poster didn't answer my question right away, but opened up the discussion that could potentially lead to an answer.

Dyno would be the answer, but I'm very surprised that this hasn't already been done.

Considering 93 is an option out there, and more expensive, wouldn't someone want to know if there is a benefit.

Like 91 is my minimum required gas, but this weekend I'm going to the track so I want to use 93 to maximize my lap times etc.

Edit:
I finished reading that link. That was an excellent read and very informative. Thank you.

lectrolink

You CAN actually get higher octane fuel commercially in California. There is a 76 station near me in West LA/Brentwood that sells 100 0ctane racing fuel from one of their pumps. One time I decided to test it out on my Neuspeed stage 1 A3. As I recall, car felt perhaps a little bit faster, but somehow SMOOTHER, like the whole drive train had been drenched in a fresh batch of synthetic lube. To the car, it was like having a highly nutritious meal versus the usual meat and potatoes. Interesting, but not worth the $8-10/gallon unless you have a tune specifically geared to that fuel and plan on doing some competitive challenges.

IknowHuhA6

There is a "theory" but one I cannot confirm since I don't have access to a fuel testing method.
For many years, Hot roders believe that for us Californians.. you can mix half portions of 97 octane and half 91 octane; And this will result in increased 93 octane due to way each fuel octane is blended.

I can neither confirm nor deny this theory.. but leave you all to investigate on your own.

bhvrdr

There are stock Data logs floating around showing 91 California cars retarding as much as 10 degrees of timing. Yes 93 octane can help alot. Log your knock correction on 91 octane and log it on 93 octane. You could gain 4-5 degrees of timing.

Mike