Max boost for 03/04 cobra in so-cal with 91 octane?

[ret_junior]

i have a 2.3 whipple and mine hit 18psi

 

[svtleen]

I have a 2.3 Whipple and pushing 15psi with 91 octane, wouldn't go more psi with 91.

 

[HighPSI]

Well I'll throw this out. IT'S ALL IN THE TUNE!!!!! It's great that people want to blame thier motor blowing on 91 octane. Fact is there are quite a few people running 18lbs on 91 with no problems. I even know a guy out here that runs 21lbs on straight 91 octane. I believe his SN is NITROSCOBRA. Talk to him, I personally wouldn't run more than 18 but he has a ton of miles on his setup running 21lbs on 91 octane with a 3.4 whipple. There's no doubt that the motor is on the edge now, but he runs 91 just fine right now.

Just my .02

I would imagine he's pulling a crap load of timing though? I would be curious to know his numbers and would bet he'd make more power and the car would run better on lower boost.

OP, it's generally 16-17.5psi max that I would run on 91. My tune is to 16.5psi on 91.

 

[Impact 5.0]

Talk to a reputable tuner and go with their recommendation. I've read lots of posts of people running tons of boost on low octane fuel, but I wouldn't do it! My shop (AED in Sacramento) installed a 3.5" upper (stock lower) on my Whipple for 91... I don't remember exactly, but I think it is somewhere around 13 or 14 pounds. Hopefully my engine will last a while and I don't have to worry about getting a bad tank of gas.

I use a 2.75" upper for 104 octane, which I believe is around 18 pounds. I also would not recommend using 100 octane from a pump- it sits down there a long time so there's a high risk of it going bad.

3.5 is 15 PSI until the blower breaks in, then your going to see 13-14.. I just found that out the other day. :fm:

Shaun AED said he doesnt like to tune over 15psi on 91, some guys want 16.. when he says 15 I take his word for it.

 

[FAsnakes]

Just had my car retuned 12 - 13 lbs for the street.. BTW That's at 15 degrees of timing.
Very happy with that.

I know how much motors cost:nonono: