hey all... I have a 93 T04S turbo that I've tuned myself to just over 400 rwhp at 14 PSI....



I've run the car up as high as 15 or maybe even 15.5 PSI many times on 93 pump gas with no problems at all.



Here's my question... assuming my fuel system can do it, do you guys think I'm pretty safe going to 18 PSI on a mix of 20% Xylene and 80% 94 octane? That should be right around 98-99 octane. Obviously I've got the wideband and stuff and I'd also be putting in a 3 bar MAP sensor before starting this little project....



So.... 18 PSI on Xylene/Gas mix possible? 20 PSI???



Thanks!



Brian



P.S. Anyone reading this with "only" 300 rwhp... DON'T upgrade! It becomes more and more addictive and you're never happy https://www.nopistons.com/forums/pub...IR#>/smile.png

Dude I ran 18psi on pump 93 for a few years and 25k miles, another 10k were put on by the second owner before it blew.

https://www.nopistons.com/forums/pub...#>/biggrin.png yes you could run that. I've got a friend running 18 psi (low boost) on 91 pump gas.

Which blew by the way driving it easy. I believe a coolant seal is what caused the failure.

I wouldn't do it. Theres not enough of a safety margin. The most I run on 93 octane without water injection is 16 psi. Its just not worth the cost and hassel or replacing the motor for a few more horsepower.

My friend runs 20 on pump. I'm not sure what his timing is like.

on a rotary?

19 psi and 95 octane with W/I(aquamist 1S) and still going strong. Still needs more loving...er...tuning.

I agree, check out the water injection for the safety margin, although the pump says it is 93 octane, it does not mean you got a quality product. Also gasoline as it sits will drop in octane. My uncle hauled gasoline for years, the Sunoco Ultra 94 comes out of the plant @ 108-111 Octane, but with it being mixed with the gas in the tanks that has been sitting, you are getting an average minimum of 94. If you have a few extra bucks, have a private company check the pumps you frequent, some of you might be surprised how high the acctual rating is on the gasoline you are pumping in your cars, the octane rating on the pump is the minimum the gasoline has to be be to meet state testing. My uncle said he had delivered a few loads to the stations and their high octane tanks were not low enough for the full load, and the managers just had them dump the excess into the lower octane tanks. This is something to think about the next time you go to the pumps...

Interesting.