I have this mod in my car

TBE w/3inch
Hallman MBC 21psi
HKS RS Intake
walbro 255 fuel pump
octane 92
with dynoflah

here is question

* if iam using 112 octane race fuel
how much can i turn up my boost without too much risk?
ill probably have almost empty gas in the tank and feel up 2gallon
and race

so any advice?

thanx
Min

 

I have been at the track with nearly identical mods as the one that you have.
That type of race gas would help you a little bit but not much because you are not tuned for that kind of fuel.

You don't have to go much higher than 99-104oct. It gets to a point were too much of racing gas might work agaisnt you. I would put just a few gallons of 99oct into the existing tank, you will drop a couple of tenths or ore and increase your trap speed another 2MPH.

Also, I don't know how much boost you are running now, I got worst HP/TQ on my car when I exceded 28PSI on the Dyno. Don't overkill it


MY .2C

Carlos

 

oh so i guess my car have to be tuned for certain oct. level

right now my car is at 21psi

i guess i have to get 110 oct instead..

but can i stilll raise my boost little bit with higher oct ? (ex. 110, 112)?

im just asking

thanx
Min

 

Sure you up the boost a bit more, but like fromWRXtoEVO said, it will work against you. The great thing about race fuel, is you can adjust the timing by advancing it, and it will create a big difference. You will incrase boost, and thus you will have some power increase, but not a significant amount. If you were able to modify your a/f ratio aloing with timing, then the higher octane would be worth it. I'll say 24psi is the max with race fuel, but you honestly can't tell until you havea wideband installed on the car.

I prefer to be safer than sorry, so I'll just increase the boost a few pounds, nothing more.

 

Not only tuned for certain octane level, but also tuned for certain boost level.

 

My estimation is that if you are at 21PSI now on 92oct then you can probably add up another 3PSI. Each car and each location is different, for me cracking the boost here in Tucson makes my turbo work harder than if I was cranking up the boost in Baltimore(sea level) at 30 degrees.

There are many variables but I really don't recommend making the mixture higher than 94-95 oct without tuning. Very High octane gas can make your car slower.

Take my advise as I had taken my cars to the tracks hundreds of times and I have recorded all the updates.

Carlos

 

ill do that carlos~!

ill just put 100ct in almost empty 92oct

which will give me around 94-95?

ill only give 2-3more pounds of boost

thanx
Min

 

I think the formula to figure out how much octane the fuel you have is something like this.

A=gallons of pump gas
a=pump octane level
B=gallons of race fuel
b=race gas octane level

and the formula would be:

(A*a+B*b)/(A+B)=

So, lets say you have 3 gallons of 93 octane gas and you had 3 gallons of 104 unleaded to the tank, you would have an equation like this

(3*93+3*104)/(3+3)= 98.5 octane.

I believe that is how you do it, someone correct me if I am wrong.