lx9 to LG8 TB adapter

[1988GTU]

In the past I purchased a TB adapter for my motor (see title for specifics) and after much effort in trying to find my vacuum leak, it ended up being the flange.

I swapped TB's one after another and the problem never went away. The problem seems to be the groove for the o-ring. It seals on the back side to manifold fine, but it would not seal on the TB side. I tried stacking gaskets, copper spray and sealants with gasket. The sealant only works temporarily since as soon as I hit target psi, the sealant over time, pushes out and leaves me with a vacuum leak.

Anyone else have this issue?

[LZeppelin513]

Try removing the o-ring and using a very thin layer of gasket maker on the flat aluminum.

[1988GTU]

Try removing the o-ring and using a very thin layer of gasket maker on the flat aluminum.

The O ring on the TB side has always been removed since it would not be possible to use it with the 3400 TB due to the IAC port.

[IsaacHayes]

When I had one mine was fine, but I was not boosting.

If I were you I'd upgrade to the LX5 TB & Adapter. Then you use a flat gasket to the manifold, and an OEM gasket to the TB and you are done.

[1988GTU]

When I had one mine was fine, but I was not boosting.

If I were you I'd upgrade to the LX5 TB & Adapter. Then you use a flat gasket to the manifold, and an OEM gasket to the TB and you are done.

I kind'a welded the adapter to my manifold though.. lol I will more than likely go with another uim and just do the "buy more parts" fix.

[gar70614]

i have the aluminum insert that is from inside a lx5 intake. u could weld that to ur uim and use the 65mm tb from a lx5? e mail me if ur interested.

[IsaacHayes]

That's an idea. I knew there was some sort of adapter on those stock, as there is a gasket that goes between the TB and the adapter, then adapter to the plastic manifold... I've never seen one in person though, just know this from trying to get a TB gasket. I wonder if you could just drill holes and bolt it on? I think it seals stock with just an o-ring, which would work on the LX9 manifold... Then use the gasket for the TB and it would be basically like GM made it.

Bonus with the LX5 TB is 65mm... that would be same diameter as the charge pipe...

[1988GTU]

i have the aluminum insert that is from inside a lx5 intake. u could weld that to ur uim and use the 65mm tb from a lx5? e mail me if ur interested.

Can you post up a pic? I might be interested. :shrug:

[gar70614]

ill try and grab a pic. i think i wasent able to drill holes because there wasent enough material to reach the uim holes. the other problem was because there was a hole in the top half of the flange that would need to be filled.

[1988GTU]

I C..