How much boost can I run on my t78 with 91 octane pump gas. I have all the fuel, ignition, porting, etc that is required to run the t78. I've heard 15 lbs. what can you guys tell me.

Thanks,

Chris

 

I've gone as high as 18-19psi on 93 cause that's what super is here on the east coast, don't know about 91 though.

 

I've done about 18 psi on 91 octane with no problems running conservative timing and fuel...

 

i run 16psi all the time on 92-93

 

I see you are located in SoCali where we get the shittiest of gas. How much boost you can run depends on how "conservative" exactly your timing is. Even then, I wouldn't run much over 15psi on our 91oct gas.

 

i wish we could get 100 octane at the stations lol. Does any1 even know how to get 100 octane around the burbank/ san fernando valley area?

 

KDR says I can run 20psi on 93 octane no problem with their anti detonantion device.

 

I run 19psi on the street with my HKS T51R KAI

 

Its all about tuning and fuel delivery capabilities.

 

You can get 100oct at a 76 station in Pasadena. Something like $5/gallon though.

 

As others have said it really depends on your timing and afrs. I asked both tuners that dialed in my car (on two seperate occasions) where the cutoff is on 93 assuming I want a good safety margin. The first said 15psi is fine with 11.3afr and 13deg of advance around torque peak. The second said 14-15psi with 11.3afr and 14deg of advance.

 

I run 14 psi. on 91. with 5 gal of 100 . I also premix my gas, 4 oz to full tank


The problem of pump gas. they are not reliable. differnt gas station's gas got different rate. even though they are all rate 91. but they are not the same all the time. you never know the GAS you put in . until It start to knock. on my friend Z06 one time he put a COSCO gas into it. 92 octane. and during high gear up hill drive( the load is big, but speed is not too fast) I heard two pin from the front. and suddenly the car slow down by itself. That is call KNOCK and GM ECU is retard the timing to save the engine . Turbo Rotary dont like this thing. Few pin you Apexi seal will be over and you wont heard the pin like piston do because the Rotary simply too loud to heard by the time you feel it, it could be too later. and plus if you are running PFC good luck. the PFC dont got retard on timing function . so.....

you should be fine under 14 psi I would not boost over it. if you really want to play with boost. got C16

 

I run 15-16 PSI all the time on 93 pump gas with 15 degrees timing around that boost. AFR is 10.8-11.0 according to my Techedge DIY WB.

Brian

 

And I run 15 psi on 91 with Wargasm's timing map and similar afr's, except I pulled two more degrees of timing to compensate for the less octane gas (so I'm at 13 deg's at peak torque).

Thanks again, 'gasm!

Beast