Nickshu

In my area we only have 91 octane. I used to run 100 octane in my Lotus race car and there's a 100 octane pump in my area, about 30 miles away from my house. So I put about 1/4 tank of 100 octane on top of the 91. The car runs so much better, feels like 25 more HP.


I guess I shouldn't be surprised. I'll be keeping a couple fuel cans of 100 octane to top off the top 1/4 every fill up from now on!

gobs

You can try Race Gas http://race-gas.com/.

Nickshu

I have read about that stuff, my understanding is it's nowhere near as good a real race fuel.

LexVan

Placebic.

JayG

You know this how?
Calibrated butt dyno?


Unless you reprogram the ECU, putting 100 octane gas in won't do squat

DTMiller

Ehhhhh.. If the car is tuned for 93 and you don't have 93 available you can do the math and combine 100 and 91 to get to 93.

Will the difference be butt dyno detectable? Dunno, but it's not impossible that there is a difference. Is it worth the hassle? Probably not.

Would going to straight 100 make a difference? Almost certainly not. Especially in street driving conditions.

AWDGuy

never noticed a difference running race gas in my cars. Only added race gas for safety measures, not for upping my power. Would need a tune for that.

Nickshu

That was my thinking. By adding a bit of 100 I am getting to 93-94 which according to the manual is what the car was tuned for. Running 91 and at altitude (5000 ft) has to take its toll.

Nickshu

I do have access to a dyno at my local race shop, might be interesting.


And yes my a** has been calibrated.

Nickshu

Agreed. If the car is not tuned for it then the benefit will only be up to what it's tuned for. In this case raising from 91 to 93 by adding a bit of 100.


I ran straight 100 in my Lotus track car, but it was supercharged and I tuned the ECU to run on 100.

JayG

And you can actually feel a difference between 91 and 93?
The ECU adjusts for 91 and I seriously don't think you could feel any (if any) difference

Will you think its better, absolutely!

I have done the octane dance at the track and in reality, no difference, at least for me

Nickshu

Well is sure feels much more responsive on the low end. High end no difference.

Mike Murphy

So, the title could have been, "Wow, 91 vs 93 octane makes a difference!"

Kalashnikov

You think you can keep up with a viggen now?

I suggest you also add couple of cans of NOS to your fuel tank. That should definitely give you top end boost you are looking for. Probably extra 50 WHP from octane and NOS booster alone. Not bad.

ditto

If you are comparing it to fuel with 10% ethanol then replacing the low energy content ethanol with gasoline will certainly make a noticeable difference. I hate ethanol.