I don't understand why people change the pulley. Sure you increase the boost pressure by a small amount, but the supercharger then spins 2000-3000rpms faster. I estimate this would probably produce around 30% more heat. When air is heated it expands, just like anything else. If the air expands, you have less density in your engine, thus decreasing the performance gain, that explains the use of an intercooler. I think an intercooler beneath the supercharger is one of the best mods you can do to your car. Installed beneath the supercharger, it would cool the superheated air comming from the supercharger to a nice cool temperature, which is good... Most people probably have noticed that their cars have a noticeable HP gain when it'* cool and damp out.
Back on topic though.. The supercharger will also draw more engine power to power itself, thus negating the performance "gain" you hope to achieve. A pulley "upgrade" is not something that I plan on doing, and i am not sure why my info says i have a 3.4"pulley, because we have the stock pulley.
Just my $0.02
I understand your thinking here, and that is why you can only run so small of a pulley. Obviously a smaller pulley is going to increase boost & heat, but the increase in air at a hotter temp provides more of a gain than less air at a colder temp. More air = more fuel = bigger boom = more horsepower. After a certain point the superchargers get inefficient and you have to run a bigger supercharger or a turbocharger to see a gain. These blowers (M90 & M62) like to make 12-15psi, but any more than that and they are really inefficient. A 3.4 pulley on the M90 is the BEST modification you could possibly do to an L67. It provides PROVEN gains of 25hp & 50lb.ft of torque.
The intercooler does help tons though! It is the only way to go IMHO if you want to get serious with your L67!
1990 Maroon Grand Prix STE McLaren 3.1 Intercooled Turbo, 14.695 @ 94.49 on 12psi before cam/heads/etc.
1990 Bright Red Grand Prix McLaren 3.1 Intercooled Turbo, 14.819 @ 92.72, 189whp
1999 Grand Prix GT 9.75:1|K&N|160 tstat|No Ubend/Cat/Res|UD Pulleys|Ported M90/TB/Heads|XPZ|2.55"|Pacesetters|Stage 2 I/C. 12.442 @ 112.78
2000 Blue Bonneville SSEi Supercharged Gutted Airbox|K&N|3.4"|1.9'*|WP Pulley|Custom DHP|180*stat|41932'*|No Cat. 14.681 @ 94.80
2002 Dark Cherry Grand Prix GTP Supercharged & Intercooled
12.084 @ 114.38 w/1.743 60', 315.6whp, Fastest Stock Cam M90 GTP!
NOW XP CAMMED, 340.6whp with XP, stock heads, Gen 3 M90, 11.984 @ 115.84 w/1.750 60'!
Most HP Stock Heads Gen 3 M90 GTP!
2004 Red Monte SS Supercharged K&N|3.4 Pulley|1.9'*|180*stat|41919 plugs|3" dp|No cat/ubend|DHP|Shift Kit. 14.2 @ 98
GOT BOOST??? Friends dont let friends drive stock!