Gen 3 M90 pulley size VS. Gen 5 M90 Pulley

[Pure2sin]

If a Gen 3 M90 is running a 3.4 pulley and the Gen 5 M90 is more efficient. What would the 3.4 equivalent pulley be on a Gen 5 M90? Would it be a 3.6?

[99prixgt]

yeah, something like that

[SilvaMan61]

i believe that for the most part you add .2 to the gen3 pulley size and come out with the gen v. sooo...

gen 3 gen v
------ -------
3.4 3.6
3.2 3.4


im not sure if it is true across the board but yes the gen3's 3.4 is roughly equivelant to the genv's 3.6

[blueguy]

oooooooooooooooooooooooohhh...I've typed this a few times...here goes.

The reason people upgrade from the GenIII to the GenV is a couple reasons...one being efficiency...you can get away with smaller pulleys on a GenIII but your yanking more power off of the motor to do so...where as the GenV...you can make the same power with a larger pulley and take less power off the motor to do so. The other reason being the rotors never flake apart from what I've seen...GM skimped on the GenIII's and it shows...the coating on the GenV's rotors are tits. The inlet to the GenV also doesn't "ramp" up like the GenIII's do...so you don't have to worry about the air having to run up to get to the rotors...guess you could call it an obstruction. Typical rule of thumb...I don't really say .2"...because some people will have different results. I will say that most 3.4"/3.25" setup GenIII cars are the same on GenV cars with a 3.6"/3.4" setup. You've just gotta mod more to drop pulleys on the GenV's. Also...according to Eaton...anything lower than a 2.8" on a GenV makes it spin WAY too much...causing a big break in inefficiency...only thing I would do...if you were GenIII and just kept running down in pulley sizes is this...when you get to a 2.55" on a GenIII, go to a 2.8" GenV...and be happy.

Hope this helps.