Maximum boost thread (93 oct > pump petrol/gasoline only!)

PSI · 03-30-2013, 03:43 AM

I've managed to get up to 40.5psi so far, still on 98 octane pump fuel (93 octane USA) and water injection. Still running inductive ignition and $3 sparkplugs with a massive 60" plug gap with no sign of misfire. The dyno says 740rwhp at 38psi. Whether it's accurate or not at that hp level I don't know. What I do know is that 40.5psi from a 75mm turbo is a fair amount of power. Enough to trap almost 156mph on the 1/4 mile anyway. I'll be going back on the dyno soon to try another couple of ideas I have, and probably more boost. It's at the point of diminished returns now though, we're almost out of compressor and I believe the turbine is starting to choke now also. We'll be fitting a larger turbo in the off season I think. Still sticking with the Series 5 engine/intake (TII) at this point.

03-30-2013, 03:43 AM	#11
PSI The Newbie Join Date: Feb 2012 Posts: 18 Rep Power: 0	I've managed to get up to 40.5psi so far, still on 98 octane pump fuel (93 octane USA) and water injection. Still running inductive ignition and $3 sparkplugs with a massive 60" plug gap with no sign of misfire. The dyno says 740rwhp at 38psi. Whether it's accurate or not at that hp level I don't know. What I do know is that 40.5psi from a 75mm turbo is a fair amount of power. Enough to trap almost 156mph on the 1/4 mile anyway. I'll be going back on the dyno soon to try another couple of ideas I have, and probably more boost. It's at the point of diminished returns now though, we're almost out of compressor and I believe the turbine is starting to choke now also. We'll be fitting a larger turbo in the off season I think. Still sticking with the Series 5 engine/intake (TII) at this point. Last edited by PSI; 03-30-2013 at 03:55 AM.