So your not worried about the fact that you are probably getting massive knock retard, and are risking blowing up your engine? Just making sure. If you want to run 17psi boost effectively you will need a bigger blower, an intercooler, a really good exhaust system headers and all, and a lot of nice internal engine mods. But anyways, have fun with your 17psi!!!

hmmmmm, sounds like jeffrey just got shut down

i was just playin' jeffrey
you seem to know what'* going on

The stock SC motors come with stronger crank, rods, and pistons, the engines really aren't all that much stronger, and the things that were strengthened didn't need to be. The heads still suck, the pistons still aren't that great and with too much boost will break, and that is the Series II, I don't even know how much stronger that is than the Series I. With the GTP we are running 14.96psi at WOT on race gas with an Intercooler, Headers and Full Exhaust, High Ratio Rocker Arms, Intense Pushrods, Comp Cams 85lb. Valvesprings, and a lot of other goodies, besides the fact that it has the M90 insted of the M62 (or whatever it is) so it is much more efficient anyways. We only run 14.3psi boost on the street. Any more boost and we would have major problems even on the Series II with some built up valvetrain parts. The guys running 11'* are only running around 12psi boost, so our 15psi is stretching it even. Yes, the pcm takes care of the knock, but it does it by pulling a bunch of timing so you lose power by raising your boost, so what is really the point, besides the fact that if it starts seeing big problems it uses the wastegate to drop the boost so the engine doesn't blow up, so you are ridding of a major safety device the factory installed. The 3 range colder plugs may be helping you a little, but we have 2 range cooler in the GTP so its not much of a difference, and yes you have a water/alcohol injection system, but those aren't nearly as effective as an Intercooler, which the GTP has, so this doesn't give you any advantage that would allow you to run more boost than we do. Our CAI, and the air tube are completely insulated also, so its not like that is giving you an advantage either. You don't really have any systems that are helping you run that much boost, yeah you can run that boost for a while, and it MAY give you better performance depending, but in the long run you will end up replacing pistons, valves, head gaskets, and things like that, and the M62 is SO inefficient at 17psi that you may not even be making more power than the 15psi or whatever you usually run.

But it is your car, do whatever you want to it, I'm not gonna stop you.

dbtk2, the only REAL difference between the M90 and the M62 is the CFM rating. At 90CFM per revolution, the M90 on your Dad'* car doesn't have to spin at the same rpm level as the M62 to produce the same boost. This means that the M62 produces more heat because it has to spin faster. How much more heat? Beats me, but we could probably do a comparison between them sometime.

So the M62 has a smaller pulley to fill the greedy cylinders, where the M90 doesn't need to spin that fast.

Both are over-capable of supplying the L67.

As far as water alcohol injection is concerned, I'd love to see an effieciency comparison between one and an intercooler. The injection has added benefits that the intercooler can't provide, but I'm sure the intercooler is more efficient at cooling the intake charge.

As a point of comparison, my water alcohol injection gave me an additional 2 psi of boost with the stock pulley last summer. How much boost did you gain when you installed it on the GTP? That might be a starting point for the comparison. BTW, that was WITHOUT alcohol. Just water injection.

Jeffrey, how much boost difference do you see, and what ratio are you running in the mix?