GM Forum - Buick, Cadillac, Olds, GMC & Pontiac chat

- Performance, Brainstorming & Tuning (https://www.gmforum.com/performance-brainstorming-tuning-96/)

- - Aluminum upper intake manifold (https://www.gmforum.com/performance-brainstorming-tuning-96/aluminum-upper-intake-manifold-208524/)

Aluminum upper intake manifold

Did mkaake(I believe he was the person investigating this) ever come out with procedure for the aluminum UIM swap? I remember this being talked about, but as yet I haven't seen anything on it.

The L26 upper. I know there was a topic about it on ClubGP, i think it works if you buy some other adapeter plate.

You just need an adapter plate for the throttle body. Otherwise it just bolts onto the LIM.

So if that's all there is to it, why doesn't each of us have one already? It has to be many times stronger than the plastic one. Is it a cost issue?

less power. You only have to replace the upper intake once in your cars life anyways.

Quote:

Originally Posted by big_news_1

So if that's all there is to it, why doesn't each of us have one already? It has to be many times stronger than the plastic one. Is it a cost issue?

The composite is lighter. When GM designed the Series II engine, they didn't realize the problem until the cars had high miles on them.

But to put the composite intake in to perspective, they are used in the LS1 and LS6 engines, so they aren't that bad.

Quote:

Originally Posted by jr's3800

Quote:

Originally Posted by Sol

Quote:

Originally Posted by big_news_1

So if that's all there is to it, why doesn't each of us have one already? It has to be many times stronger than the plastic one. Is it a cost issue?

I will somewhat agree there SOL...

Mine has given me more than 5 years, and so far it look to have no degradation or warp...

I will say alluminum is a great conductor of heat, I'll bet the Composite keeps the incomming air a shade cooler than does the alluminum...

But at the same time, chances are really good the the alluminum unit will not fail.. :wink:

the plastic one is probably a little cheaper and easier to replace with. You chances are pretty good that it will only fail once in the life of your car.

:) -and as I've said so many times before, if you remove the direct contact of the EGR stove pipe to the composite unit, it would no doubt never fail. :)

-remember, it is the heat from that stupid EGR tube that wrecks the composite over time-

Thanks for all the responses guys. Hopefully you're right Macho and I won't have to deal with replacing the thing again. Well actually I take that back... I hope this car lasts so many miles that I have to go through two more UIMs. If I ever have to replace it again, is it an easy thing to modify the EGR stovepipe? You don't have to answer in-depth; I won't be dealing with this issue for a while, hopefully. Unless it's worth it to get in there and do some modifications right now, that is.

The L26 upper intake manifold is available from GMPartsdirect.com for $106 to your door. I forget who it is that sells the TB adapter, but they do the N* throttle bodies for the SII L67's.
Anyone know if the L26 UIM is portable. Would be nice if it could be ported another 8-10mm and the TB and adapter with it. And with a stroker kit.