Hi all,
What did they change to get an extra 30 HP out of the series II engine? I know the PCM calibrations are different....but what else? Heads? Cam? Exhaust?

Valve sequence, heads, cam. You pretty much got it. They develop more hp and tq, but at a higher rpm.

I've driven both now, and I'm impressed with the way the Series 2 winds out on the top end, but I like my low-end grunt. Tough choice, but I have to give the nod to the S2.

I think the S2 has lighter internals, so the engine can spin up faster. It also has a higher redline than the S1 engine. It does make more power up top, but it still keeps its share of low end power.

I would trade for a series 2 in a heartbeat. Unlimited amounts of mods. I like mods.

Seems like the SER2 has a smoother rev band, I agree with SOL feels like lighter internals....But I definitaly like the sounds of my intake scream on my SER1 much better than the quiet hush of the intake on my SER2.....different types of intakes but I still think the SER2 intake would be quieter with a similar setup as my SER1.......but theres something to be said about quiet too!

I would also assume that the SER1 blower turns at a higher RPM and therefore forces the air in with a bit more pressure than the SER2. But thats just speculation

Yes, when it comes to the supercharged engines, the S1 is way louder, because it does spin faster.

Although with the right intake, the S2 can really whine. My Thrasher intake turns heads when you step on it.

the M90 is more efficient, thats why it doesnt have to turn as many times as the m62. The pressure is pretty much the same on both. The m90 just takes less force to do it.

I have driven both myself and I would just have to take both of them.

I wanna do a Series II engine and tranny swap all brand new when I save up enough dough so I can throw a turbo on that ****. And now that AEDCEntral is making a body kit for our cars this car will be off da hizzie. lol

And off your budget hizzle also. Just get a S2 SC and build it up instead of a turbo, or maybe add a M112 supercharger instead?