Write-Up: M90 Blower Installation

Old s/c on my Riv was making a worn bearing sound, sounded almost like a diesel idling. So I bought a refurbished supercharger off eBay and installed this weekend. Not too hard of a job, but a bunch of small things, screws, bolts, plugs..

I knew I had to take the fuel rail off, so I bought new o-rings for the injectors too.


Taking parts off. On the fuel rail be sure to depressurize before you undo the fuel lines. You'll need a special tool to pull the fuel lines off the fuel rail. It's a 3/8" size too.

Fuel rails off, injectors cleaned and new o-rings installed.

UIM cleaned up. Cleaned with throttle body cleaner. There's two rubber yellow o-rings (not seen) on the drivers side of the UIM. They go over the coolant ports..

Good time to clean the throttle body.

The "new" s/c from eBay. I cleaned it up quite a bit before install. Sprayed throttle body cleaner all over it. HOWEVER, in doing so, the teflon coating on the impellers bubbled up and came off quite easily. So I spent like an hour scrapping off as much of it as I could. Did some google searches and didn't see any downside to not having it. It's really just used for tolerances.. The impellers are aluminum so they won't rust. But I did spray a liberal amount of a lubricant on them to coat them.

All installed. Double Double checked all connections and plugs and vacuum lines and fuel injector connections, and fuel line connections... Started her up and it's amazing! Sounds like a new car, no diesel idling!!!!!!!


Good as new!

I did discover that I had my evap purge solenoid on backwards (according to the shop manual drawing), so I reversed it and we'll see if I get that CEL again...

Car sounds so much better, no rattle, no underlying noise...I love it!

Next, fix the ABS/TC lights and check the HVAC system to make sure all the air flap motors are working...

whew!

nice write-up, but im almost positive you need that teflon coating on the rotors or you might be having some problems soon.

97 park ave wrote:

nice write-up, but im almost positive you need that teflon coating on the rotors or you might be having some problems soon.

nope you just lose like 1lb of boost.

coating is gone... the throttle body cleaner made it come right off.. It just scrapped off with my fingernail.

Runs fine, no noise. The teflon is just that final tolerance coating. The impellers are aluminum so it won't rust, and I sprayed a lubricant coating on them too.. I had originally thought they were steel and would rust...but aluminum doesn't rust (it does oxidize)

Runs like a top!!!

Thanks for the write-up. What you lost is some power/torque. Like Travis said, the ~ 1 PSI boost = losing about 10 HP in most cases. Your car will run fine, but the blower will be less efficient. You could do a pulley swap to overdrive the SC and reclaim some boost, just be sure to monitor KR, as removal of the coating could increase the air charge temps into the LIM. Imo, there will be more friction now as the air pushes against raw aluminum vs. the Teflon coating.

no way to not remove the coating...it just bubbled up and came off. I'll keep an eye on the MPG and performance. I also coated the impellers with a surface lubricant...so, we'll see how it holds up..

BTW.. my OEM s/c has areas on the impellers which have worn off teflon as well...

Thanks for the write up. If anyone else has to do this, you don't have to remove the fuel rail from the fuel lines if you don't want to. The lines have enough play that you can move the fuel rail out of the way. Good job on changing the injector o-rings. Cheap insurance to help prevent a fuel leak and possible starting your car on fire. Also for anyone that has to remove the blower, it would be a good idea to check your lim gasket for leaks. If you don't have the new version, you will be repeating this process in the future to change the gasket. Here is a write up https://rivperformance.editboard.com/series-ii-engine-transmission-f4/write-up-lower-intake-manifold-gaskets-t2283.htm#24393

I wouldn't worry about the coating too much. If you keep it stock, you won't notice much difference in power. Especially if your old blower had bad bearings. It just serves a warning to others to not get cleaner on the coating. The surface lubricant probably won't do much. The blower spins really fast and there is so much heat, that it will probably be spun off or melted.

Few tips for others:
Use plastic sandwich bags to hold the bolts and nuts. Use a sharpie to mark on the bag where the contents of the bag goes.
Make sure to depressurize the fuel system before you try to remove the fuel rail. If you don't, fuel will spray everywhere.

Natesriv wrote:

no way to not remove the coating...it just bubbled up and came off. I'll keep an eye on the MPG and performance. I also coated the impellers with a surface lubricant...so, we'll see how it holds up..

BTW.. my OEM s/c has areas on the impellers which have worn off teflon as well...

yes there is, dont touch them or remove them for cleaning the case. the rotors shouldnt be touched with anything that will remove the teflon coating and they can never be re-coated. the specs on the rotors is within millimeters, and the coating is taken into consideration. when the teflon coating is removed it leaves more space between each rotor and more space between the rotors and case, allowing air to move somewhat freely. it may not seem like there is anything wrong but without that coating youre just asking for trouble it doesnt matter what you put in its place. IMO if it was just the bearings that went bad in your old blower, swap out the rotor pack along with the rotors into the blower you just put on and youll be good to go.
by the way, "areas" of the coating that were worn off from age compared to all of the coating removed by cleaner are 2 seperate things. your old rotors may have been going bad and may have been letting a bit of air by, but it is nowhere near as bad as absolutely no coating especially if the blower is pretty much new.
if the blower isnt near air tight than its not good anymore, but whatever you do is up to you...

One way to know how much efficiency has been lost is to measure boost with a gauge or scan device. Also measure KR. It may be that the theoretical disadvantage of losing the coating isn't as bad in reality. Something I'd check into - if it were my engine.

I've seen online other M90s without any coating. I don't think the teflon coating is too vital. I think it's just another little edge towards greater efficiency. I wouldn't doubt I've lost about a pound of boost.

I can't change the impellers from the old to new since the bearings by the front gears are what was worn. The needle bearings in the back I don't think were bad...I don't see how them being bad could make the front impeller bearings sound like a diesel...

I wouldn't have sprayed the cleaner knowing it would take it off, but not much I can do about it now. It came off with just a fingernail and I used a wire brush for the deeper stuff...no scratches.. Not a lot I can do about it now. The 20 minute drive I took afterwards felt fine, no noise, or loss of performance I could detect. But I"ll keep my eye on it...

I need to snap a few more pics and update my original post to have some more info. I'm not sure it's good enough for a write up since I left out some key steps & such..

This is a cool site I found
http://www.aerospaceboy.com/384/cad.htm

ALSO...

CAN YOU REMOVE THE ROTORS FROM THE FRONT SPACER? IF SO, THEN PERHAPS I CAN TAKE MY ROTORS FROM THE OLD ONE AND PUT IN MY NEW ONE? IT TAKES ABOUT 1/2 HOUR TO GET IT ALL OFF BUT THAT'S A SMALL PRICE TO PAY TO HAVE IT LAST!!

Natesriv wrote:

This is a cool site I found
http://www.aerospaceboy.com/384/cad.htm

ALSO...

CAN YOU REMOVE THE ROTORS FROM THE FRONT SPACER? IF SO, THEN PERHAPS I CAN TAKE MY ROTORS FROM THE OLD ONE AND PUT IN MY NEW ONE? IT TAKES ABOUT 1/2 HOUR TO GET IT ALL OFF BUT THAT'S A SMALL PRICE TO PAY TO HAVE IT LAST!!

that was my next question, can you change the rotors between the packs. it may seem fine but something tells me with that little bit of extra play between the rotors and case with them spinning at high rpm might cause the bearings to wear prematurely.

I'm not sure. i'm going to take the front snout off my old one and see this weekend. Been driving with the new one for a couple of days...lovely!

I'm not convinced the teflon was there for more than an extra squirt of boost. there are other M90s in other apps which don't have that coating... and those impellers are the same..

Honestly, I'm going to fix the ABS and I need a new pearl white hood and that's about it.. Eventually i'll reach a point where the car is just Kaput...and I'll part her out... BUT THAT'S NOT TODAY!!