What is the difference between the Gen 2 & Gen 3 Eaton M90 Superchargers?

How can you tell the difference by looking at them?

Thats an interesting question. Why difference between a Gen2 and Gen3? :confused:

Most GTP owners are more interested about the differences between a Gen3 and Gen5 Eaton M90 blower. The Gen5 is what the '04 and up have.

I came across a 96 Buick Park Avenue Ultra 3.8 S/C that was hit in the rear and has less than 60K on the engine. I was thinking about buying it since its literally being given away for the price. But I didn't know what generation M90 blower is sitting on the 3.8 and want it for the gen 3 set up. :dunno:

I would love to know the difference between all three! :wink: I have a hunch the answer is in here. I will be reading through this forum soon.
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Without confusing matters the only Eaton M90 blower applicable to '97 and up L67/L32 Grand Prixs (GTP/Comp G/GTX) are the Gen 3 and Gen 5. '97-'03 GTPs have the Gen 3. '04 and up the Gen 5. Undoubtedly the Gen 5 blower is the best since it gives more power based on the redesign.

As to the history of the Eaton M90 supercharger Gen 1 was used in various make and model cars from 1989-1993. Gen 2 only in 1994-1995. All GM cars with the L67 SII 3800 from late '95 and '96 were supposed to be delivered with the Gen 3. Therefore, a '96 PA Ultra should have the Gen 3. On previous PA models the blower was not an Eaton M90 but a M62 which had less boost and overall performance. The SC pulley used was a 2.2" and not a 3.8" stock. The engine was a Series I 3800.

The blower on the 96 has a vacuum port that faces the front of the car (located towards rear of the blower nearby the T-stat housing area) while my 98 GTP's M90 pick's its vacumm off the intake port located on the front side of the engine. That was one of the glaring differences I saw between the two M90s (96 vs 98) that made me curious if I was looking at a different GEN M90.