above 15 on pump gas??
 

If your afr's are right , and you are running rich, can you run 17-18 psi on pump gas???? Would it be safe to run that psi with octane booster???

can you do it safly???

There have been some discusions here recently about this topic, you'll have to search the single turbo section to find them.

I ran 22psi and made near 500 to the trreads :D

Would you mind me asking a few questions about your set up???

What a/f ratio was that at?
How much L and T timing are you running (roughly)?
What intake temps and outside temps was it at?

This would be a huge help to me...

Thanks man,
STEPHEN

Also, what is your definition of "pump gas". I can get 100 Octane, sold at Sunoco and it comes out of a pump. :) I have no fear of running 18psi maybe even 20psi on that. But I wouldn't call it "pump gas" though, it's $4.19/gallon. :D

Max "pump gas" around here by my definition is Sunoco 94 Ultra, ~$1.59 - $1.69/gallon.

K

hey you're across that big puddle called the Pacific, and don't you guys readily get like 97-100 octane at the stations......if i can find 93 octane here i start giggling. Airports and racetracks/shops are the only places that i can get 100+ at. So your pump gas may not apply to us.

To run over 15lbs on the street, you should get a water injection kit to help prevent detonation.

I've been using knock as my indicator for detonation.

As I've slowly raised my boost on the street (have been up to 16.5psi with 50/50 mix of 94 octane and 100 octane) with the GT35/40 I've been watching my knock (and AFR via in car OZ-DIY WideBand) to determine if I'm nearing a "dangerous" point. Are there other indicators I should watch as well? I don't want to be surprised ...

Thanks for any additional insight on watching for detonation indicators.

K

SPAutos - I run bugger all timing, well I should say HITman puts bugger all timing into it :D I think around 10 degrees at 15psi.

A/Fs are around the mid 11 mark. Intake temps were around 30c and outside temps were 25ish.

nocab & fast - Yah we get 98 octane at the pump here and its everywhere :D

i wouldn't go above 16....but watch for detonation. It likes to eat seals!

I guess it depends on what motor as well, and S4 could probably handle a little more boost before detonation due to the lower compression ratio. I think outside air temps are another factor, a rotary running 18 psi in California is probably more of ticking time bomb than a 18 psi running car here with 65 deg outside air temps given the same quality of fuel , a/f ratio and intercooler efficiency.
I would think altitude plays a factor as well, unless we start talking about absolute values..Max

I used to run 17psi on 91, and 20 psi on 100 octane... until one hot summer day... my a/f was in the mid 11's and timing was at 12. I was running 20 psi on a fresh tank of 100 and bammo! I had done it many times before but not on a 100 deg day. I decided then I was not going to play with my engine's life anymore.
From now on I will be running 15 psi on pump gas, which is 91 here in Ca., and as much boost as I want on C16. No more of that 100 octane pump gas for me. You just never know how long that gas has been sitting around and personally, IMHO its not worth it.
For almost the same price you can get some real race gas and be done with it... plus you get that nice race gas smell!

What compression rotors? FD or TII?