My Superchargers snout has decided it does not like it's bearings anymore.

I have decided to just remove the whole SC and gut it, powdercoat it and rebuild it since it looks a little tired.

The question I have is does the gasket between the SC and LIM need a sealant on both faces or is the gasket as is out of the box sufficient? I will be using the felpro gm #24503911 gasket.

thanks ahead of time!

No additional sealant should be necessary. Make sure you clean all of the old gasket material, corrosion, and buildup off the lower intake manifold and the bottom of the supercharger housing prior to installation. Make sure no old gasket is clinging onto the bottom of the snout portion of the blower housing where the single bolt passes through it (to bolt it to the lower intake).

Also make sure you replace the two coolant passage o-rings that rest on the lower intake manifold at the throttle body end, prior to installing the supercharger.

Torque the supercharger to lower intake manifold bolts to 18 ft/lbs. Start at the center bolt on one side and alternate from side to side, working your way outwards in a circular pattern to evenly torque down the blower housing.

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More is more. Less is not enough.

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

[This message has been edited by Darth Fiero (edited 08-06-2015).]

Sorry to jump in here but are the two coolant passages that you speak of for the throttle body the ones that some guys block off with a couple dimes ? Is this a good idea ? I thought I would mention it now because if it's a good idea then it can be done before the SC gets put back on.

quote Originally posted by Adjustso3: Sorry to jump in here but are the two coolant passages that you speak of for the throttle body the ones that some guys block off with a couple dimes ? Is this a good idea ? I thought I would mention it now because if it's a good idea then it can be done before the SC gets put back on.

How do dimes seal up passages? I think I would rather tap and install proper threaded plugs to do that job - if I was going to do it and if it was necessary.

Hey Darth, I have not done this job myself yet but was told that there are 2 passages that should be blocked off under the supercharger. I was told to block them off with a couple dimes and some RTV. I was hoping you would chime back in and comment. From what I was told it is where the two yellow o rings you see when you pull the supercharger off. I guess a little grinding may have to be done to the dimes. I just wanted to point that out since he will have the SC off already. Do you recommend this or is it better to tap the holes and plug them or just leave them alone. I don't mean to hijack this thread but since the supercharger is off I wanted to point out what I was told. I know Darth will recommend if this is a hack or not and is a good idea or not.

quote Originally posted by Darth Fiero: No additional sealant should be necessary. Make sure you clean all of the old gasket material, corrosion, and buildup off the lower intake manifold and the bottom of the supercharger housing prior to installation. Make sure no old gasket is clinging onto the bottom of the snout portion of the blower housing where the single bolt passes through it (to bolt it to the lower intake). Also make sure you replace the two coolant passage o-rings that rest on the lower intake manifold at the throttle body end, prior to installing the supercharger. Torque the supercharger to lower intake manifold bolts to 18 ft/lbs. Start at the center bolt on one side and alternate from side to side, working your way outwards in a circular pattern to evenly torque down the blower housing.

Thanks! Is there a gm part# for these o-rings? I really want to have my ducks in a row when I Go to put this thing back on.

They should come with the gasket. If you look on rock auto they will be in the picture of the gasket. Sorry if I confused anything or gave out wrong info. I'm going to be replacing my LIM gasket from the plastic to the new metal ones and was told by a member to plug the two yellow o rings with a couple dimes and RTV to prevent warm coolant from flowing through the throttle body. I am by no means an engine wizard like a lot of the members here. I'm learning just like you. I was just passing on info before you put your supercharger back on. Hopefully Darth will chime in and clarify if this should be done or not. Once again, sorry for the confusion.

There is more to plugging the holes, if you go that direction. You also have to remove the "front Cover" and grind a flow passage ( since you have now blocked it off).

Couldn't find the thread that has pictures of this mod in the LIM Cover, but here's a short blurp from another thread

"The coolant passages to the throttle body keep the body from icing in extremely cold weather. They also flow coolant to the rear head. Granted it is a small amount of coolant but it is still engine coolant. I run them blocked but opened the cover on the lim under the throttle body and channeled it so coolant could flow to the rear head."

Basically you are blocking some flow through the head by blocking off those two ports, and "opening up" the front cover allows that flow to be restored.

BTW, 1/4-20 NPT allen head plugs will also work. Tap the LIM and use some thread sealant on the plugs. If you can find aluminum plugs, even better. Summit racing has them.

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'87 GT in process, including GA / Seville brakes, Poly Suspension, '95 3800 Series 1 SC ( 225 hp ) T460e.

I'm not blocking off anything?

Thanks for the info Darbysan. Definitely more detail than what I was told. It doesn't sound like it's worth the trouble.

I have never seen any definitive hp gains from dyno or track testing that prove blocking off the coolant passages to the throttle body actually helps.