Hi, first let me start off to explain my story. I have a 2006 Cobalt which I used and abused, well now that the rotors are shredded up and the engine has a blown ring, I figure it'* time for an overhaul. See my thing here is I don't want to put the stock M62 gen 5 back on because I've already hit the limits of the SC. So I've been doing alot of research and figured my cheapest alternative besides going turbo (we own a Turbocharged Cavalier just built) would be to upgrade to a m90.

This is not a daily driver, and is past the point of me just returning it and getting a cheaper car to play with, so I figure this will be my platform. Now I'm not a experienced mechanic (took classes to be certified) but I do know how to make things work. Now I already know I will need an adapter plate that will screw into the stock Intake Manifold, and have the holes for the m90 drilled and tapped in the correct position. Also because I can't find a m90 that runs the boost bypass through the manifold, I will have to block off the current bypass hole with the adapter plate as well.

Also I have found that I will probably need a custom snout assembly made due to the fact I don't know how close any of the m90'* snouts are to the m62. If close but a little short I can just make a spacer for the pulley, but if to much or to little, I'll have to find a custom shop online to do this (which I thought I saw one before.) Another note is I noticed that some m90'* run inverted, intake side being the bottom, and charge side is on the side. My guess is this shouldn't be a problem as long as the pulley is spinning the one way that makes it pull air through the side, and charge side is on the bottom.

Now I don't know what else I might have to factor in with this build, besides which m90 I should go with. I want one that will hopefully be the easiest to make fit, and produce a good gain, obviously newer models use coated rotors and have bigger inlets for bigger throttlebodys and what not. Also I was wondering how the bypass works on the bigger m90'* is it just a vented purge valve, acting like a wastegate on a turbo, or am I mistaken and it does bypass the rotors and go to the charge side. Also because mine is mounted on the intake manifold directly will there be any differences in some m90'*, I assume most must bolt up the same way. And lastly I did read that another good upgrade is a m112 with m90 internals, but I don't want to jump headlong into something without proper research.

If anyone can help me with a few of these or point me in a direction, that would be greatly appreciated. Also thank you in advanced.

There'* no way that 4-cylinder has reached the limits of the GenV blower. That M62 (Gen3) is still matched to a 3.8 liter application for quite awhile. You'll outflow your heads way before you'll every outgrow the '62.

I'll move your topic to the right section.

I'd be willing to take that GenV off your hands, though.

The snout on the M90 applications here is far longer than the 62. The M62 is the inner belt path of the pair, and the M90 is the outer path. Probably a good 5 or 6 inch difference.

what do you mean you've hit the limits? I dont understand.

what are your current mods on the car?

I guess I should go into more detail. First off I'm running a 2.7" pulley on it. I can't remember what the redline was on the SC, but with a 2.7" pulley the m62 is right before the redline at 7k rpms on the cobalt, and a bunch of people who run the 2.5 and 2.6 limit boost in high rpm but get the benefits of more TQ lower in the power band. Also you don't want my SC core lol, Not only are the rotors gouged and scrapped to hell, but the housing it self has a 2 inch stress crack from the heat. and the shaft is not 100% straight due to improper installation of the pulley.

I'll try and find the info about the redline. So going with that info, that is why I want to go to a m90

Well Boost is a measure of resistance really, before I had it breathing with a 2.7 it was at 21psi then after taking of the very hoggish cat it went down to 17-18psi. then after the rings it went down to 15 psi Lol

Copied from another forum
"The Eaton M62 Supercharger'* redline is 16,000rpm

A 2.7" pully at 7000Rpm should give you ABOUT 15,555Rpm at the supercharger."

I did read I might now gain much from it, but at this point it is almost a win win for me, cause I need to get a new core and rotors anyways.

I understand that I might not gain much from the m90 (m62 less CFM but less HP to drive, m90 more cfm but more HP to drive)

Now my old setup was almost at the 300 WHP mark, so I'm upgrading the pistons from 9.5:1 to 10.5:1 Wiseco pistons and rings, New rods just incase, keeping the walls stock bore just to keep the strength without resleeving. And also finding a local shop to regrind my I/E cams and get new springs and valves to hold up to the added heat. So without doing a SC swap I should be putting alot more down. So I will have plenty to move the SC and it should atleast add a few extra HP, or else why would Gm switch the bonnevilles to have a m90 rather than a m62. And if they did it I must be able to He he.

Also I took a few quick measurements while I was visiting my car:
From SC end of snout to the pulley end is 7 7/16"
From SC end of snout to the pulley is 6 1/4"
And I verified the pulley width is 1 3/16"
because the SC is still assembled on car, I couldn't take of the pulley to get a measurement to the end of the snout or a measurement of the hub for the pulley.
but I guess it seems like the snout is shorter than some m90'*.

There are other SC options but I don't want to shell out 1600$ for a whipple and have more problems of getting it to fit.

Thank you for your time

Yea I love it, no traction at all, 2.1 60 foot, but low 13'* all day. The only thing I have heard though even if you spin it higher, Now your multiplying the heat, since it'* past it'* High point on the VE curve.

I know a bit, but again not enough. I tried to research alot (hence why I came here, seeing as you guys' bonnevilles were m62'* before changing to the m90. And yea for the price of a m90 rebuilt (from a personal seller not a website) plus the custom fab of adapter plates, will still run me less then a rebuilt m62 gen 5.

And on the Knock retard, let'* say I have that covered . For one I'm switching to a dual pass cooler, and thinking of upgrading the tiny aftercooler behind my radiator to a bigger one up front, so IAT'* will go down, but my MAIN source that will be helping, is a very powerful program I use to tune OBD2 vehicles. HPtuners. VERY powerful program, it'* one step below having a standalone. Obviously with that high compression I'll have to lose some timing, then once I tune the VE tables and the PE AFR I'll add the timing up till it'* at a safe limit. Unfortunately dyno runs are a bit overpriced here in NH it seems, so tuning the spark on a dyno will have to come later. And if worse case comes, I'll do meth injection. But I hate following what everyone is doing with their Cobalts, since most of them just don't understand the fine art of building a race machine. I don't, but I've been learning the past few years .

I'll find pics and post em up for you

Here is the little beast





Hard to believe this is what it was like new, so long ago feeling, 21k miles and almost 2 years later, and 20k$ poorer Lol (with insurance)


I'm sure you guys know how it works, but maybe it'd help in showing what differences my gen 5 could be from the gen 2 and 3'*


My first time welding, didn't look bad, what a pain though


And while I'm at it, might as well show my work on my gf'* 02 Cavalier
t3/t4 48 a/r turbine side 70 a/r compressor side