70% Isopropyl or 91% ?

[rb68rr]

Which works best with stock turbo and stock injectors while using 92 or 93 octane pump gas? 70% isopropyl or 91% isopropyl? Will I be able to run 21 lbs. of boost using a 100 or 108 Thrasher chip?

 

[Joe 1320]

The higher percentage number means the more alcohol. Ideally, denatured is the way to go. Most people don't realize that isopropyl emits small amounts of poisonous fumes when burned. Since it is going through the motor and out the tailpipe, you are generally safe, I still won't run isopropyl.

 

[RobR]

I used to run the 91% when I first got my SMC kit. I could never run more than 18psi of boost. I then switched to denatured and can run 22-23psi of boost. Denatured is more expensive but its definitely worth it.

 

[YGETV8]

My $.02: I ran 21 psi boost with no prob on 70% Iso and a 93 chip with my stock turbo on my GN. Now, with 70%, my PT51, and Blue Tops I am at 22 psi and a Thrasher 108 and it feels great!

 

[TR Custom Parts]

Running the 91% here with 93 Octane gas. At the track on May 24th was running 24 lbs of boost with NO knock retard as verified with both a Caspers knock gauge and Scanmaster. 02 readings were in the high .750's. Was 80+ degrees out and a higher elevation track (Lebanon Valley Dragway)

So what step is next? Have I reached my system's full potential? Little leery of running any more boost than that!

 

[YGETV8]

Hi Mark,

Have you played around with different chips and timing? That's where I'd look next. I'm NOT gonna go above 25-26 psi and only tune for ZERO knock after popping the headgasket on my WE4 because of my own stupidity! I must say, my GN feels as strong if not stronger at 22-23 psi and a high timing chip than my WE4 did at high boost and low timing. They both have fairly similar combos now.

 

[TR Custom Parts]

I'm using the Extender chip with the Translator Plus but haven't had the time to experiment with different timing as of yet.

 

[YGETV8]

You've got all kinds of timing and fuel adjustments you can play with then, eh?! Have fun! Jay