Octane question

[JimG]

I have been offered to share in the cost of and the usage of a 45 gallon drum of higher octane unleaded. What octane it will be, I am unsure of, but talk of 110 was heard.
I have been running 94 octane with a TT street chip for that octane level normally and regularly, and I wondering if there would be any downside to running this high test on the occasion without any other mods?
Any feedback would be appreciated.
thanks
Jim

 

[TurboDave]

Well, unless you have a way to bump the timing in the chip to match the higher octane, you wont gain much by running it (assuming you're not have a knock problem now). The advantage of the higher octane is to be able to crank up both the boost and timing to take advantage of it.

 

[JimG]

Thanks Dave,
I do have a little first gear knock, that I have been told I could reduce by retarding the timing on the TT chip, so you are suggesting that I would likely need to advance it again once running with the high test?
Jim

 

[RUQWKNF]

Here is what I've found with my old TE60R PTE Stock Location, 60# Mototron, TT Race chip, 3" THDP, 2 3/4" cat back with dump, fuel pump, regulator and hot wire combo.

93 octane, I ran 20-21* timing with boost levels of 19-20psi. Zero KR and good O2 numbers.

100 octane Rocket Brand unleaded race fuel, I ran 22-23* timing with boost levels of 24-25psi. Zero KR and good O2 numbers.

117 octane VP C-16 leaded race gas, I ran 27* timing in all gears with boost all the way up to 29psi. Zero KR and middle of the road O2 numbers.


With my current combo and a recently upgraded TT chip, right now, I have the timing on 21* in 1st and 2nd and 20* in 3rd & 4th, with boost on 20psi and 93 Shell V-power unleaded in the tank. My last blast showed .812 O2 and Zero KR with ambient temps of 75* this past Sat.

100-104 octane unleaded gas is typically good for timing in the 22-23* range under WOT and boost levels of 19-25psi on pretty much all combos except for extreme turbo sizes and higher than stock compression ratios.

Very similar to what alky injection users typically run to start with until they realize they can run higher boost and higher timing levels due to the extra cooling effect that the alky gives them.
Hope some of this helps a little.

Patrick

 

[Blown&Injected]

better check on the 110 NO lead

104 is the highest R+M/2 unleaded race fuel I know of.

Octane is great just for more boost even with no other changes!

 

[TurboDave]

Thanks Dave,
I do have a little first gear knock, that I have been told I could reduce by retarding the timing on the TT chip, so you are suggesting that I would likely need to advance it again once running with the high test?
Jim

I'm not saying you "have" to , it's just that the higher octane "allows" more timing and more boost, as you can see from Pat's post.

I'm not quite able to reach boost/timing levels he is, but I'm presently running 20# of boost and 17° of WOT timing in 3rd and 4th, with 19° in 1st and 2nd. I think I'm running a little leaner than he is though, and he's got a good bit more turbo than I (that also makes a difference).

 

[FastGN007]

VP has recently came out with a 109 unleaded. It was in the most recent issue of performance racing industry magazine. it is available in quite a few different amounts as well.

Scott

 

[Blown&Injected]

very cool on the 109

bet that will hold 25 psi easy for me