Track day this weekend at Big Willow, want to throw in some race fuel to get ~93-94. Searching locally I can only seem to find leaded 5gal cans (VPR, 110, C12). No one seems to carry 100 at the pump anymore. If I have a HFC, is there any danger from putting 3 gallons in?

 

Yes leaded gas will kill your cat.

They don't have 100oct at the pump at Big Willow?

 

Good question. It used to be much simpler. I had a Mustang w/ high compression and could only run one brand of 93 when I lived back east. I threw 2 gal's of 105 in all the time. Anything to keep it from knocking.

With as edgy as tunes are with this advanced hardware, I would put my money on testing the fuel mix with a stock tune over a base map or otherwise. If you're a 91, mix for 93/4 at first. The cars are factory tuned for either technically.

 

Steve:
The track carries 91oct/ 100oct/ & 110oct

Its a good idea to pump a few gallons of 100oct at the track.

 

They do have a pump there! I had heard as much, but couldn't find any info on prices, etc. Kinda like you can rent a snowboard in town, or you can rent one on the mountain....for 3x' as much
Every time I've gone I fill up at the gas station off the freeway next Jack's.
Thanks!

 

Just don't run a higher octane than you are tuned for. It is a waste.

 

Not true... Throwing in a couple gallons of 100 (with a tank of 91) when you're tuned for 91 can help with knock issues on track.

 

^That does not make sense to me...

The computer will advance timing and a/f ratio for a 91 octane setting. The knock sensor will pull timing if knock is sensed.

The computer will not advance timing past a 91 octane setting just because no knock is sensed...

So, tuned for 91 octane means 94 octane has no benefit (over 91) nor would 100+ octane or...

What am i missig? I admit - it is my first FI car - so i am eager to learn.

 

You are missing the point that 91 oct is horrible and is very sensitive to heat. Adding some 100 oct for track use is a very good safeguard and insurance.

 

Ah! To ensure it 'keeps' the 91 octane properties.

Thank you for 'splainings that!

 

This.

Also, just because it says it's 91 octane doesn't mean it is. Every gas station gets a bad batch once in a while. Insurance, like razorlab said.

 

Bingo!
$15-20 insurance against $1000 error.
Plus I'm going to add a degree or two from 5500-redline

 

Okay. Just from previous experience 'some people' on other forums* have said [quote] Iahma gonna' put sum 104+ octane and really put donw sum mad powah, yo.[unquote]

and i have had to gently disabuse them of that theory.



*Mazdas247.com and every honduh forum

 

Very very sneaky!!! LOL!
Good stuff. Can wait for Saturday!

FYI: Gas prices at the track are usually $4.50 for 91oct & $8.50 for 100oct & 110oct

 

when the time comes to get my tune, I wanted to run 2 tunes. one for 93 and the other for c12. i have a station by me and even tho its pricey i would like to run it when i race. i have no cat on my car. besides that, would running c12 be a safe race fuel? if its not worth it i will stick with 93