Who's using a test pipe, I need some info

[transampacecar]

I just received my test pipe in the mail. I plan on putting it on in April. In the meantime, I figured I would order a flange gasket as a spare that goes between the rectanular flange on the test pipe and the exhaust. The other end of the test pipe is a slip joint.
The flange is somewhat rectangular shaped and no exhaust shops I went to have them
Looking at the schematic, there doesnt seem to be a gasket, only part number 23 and not sure if I need that or not.
I went GM and the looked it up and said that is called an adapter, that it is discontinued and the GM part number is 12396773
I am going to try and attach a photo here of number 23 in the schematic.

Questions are, Is there a gasket at all ? If there is a gasket, when you installed the test pipe did you need to replace it ? If a gasket is needed, any ideas where to get one ?

 

[ALXTTA 1]

There is no gasket there.

Part #23 is a thick metal adapter piece. You can't tell just by looking at that parts diagram, but the intermediate pipe of the exhaust (#25) has a flared end. The end of the test pipe, as you say, is flat. So #23 goes between them and is flat on one side, and the opposite side (not visibile in the diagram) has a ball-shaped flare.

Other third gens also had this adapter so you might be able to find one from a junker; I know this topic has come up before.

If not, you'll just need to swap the adapter over from the cat when you put the test pipe on.

 

[pacecarta]

no gasket there , if you want to put some high temp silicone on it.

the adapter is to steel plate that bolts onto the back of the buick converter which has a wide 4 bolt flange , the adapter has studs to attach to the two bolt ball style exhaust of the TA

if the test pipe is like the one for the GN they have a 4 bolt wide flange like the converter end in which case youll need to unbolt the converter from the adapter . if you dont require a converter you can just cut it off the downpipe close to the body of the converter and split the neck off the down pipe but if you need it for emmisions it is a slip fit onto the downpipe and clamped and even with the clamp taken off they usaully dont like to slide back off without a lot of heat from a torch or cutting a slot (or two) into the neck of the coverter with a whizzer wheel ,

, the cat has studs so to attach the test pipe youll need to get 4 pcs of 3/8" bolts about 1 1/2" long, lock washers and nuts,

 

[Jan Larsson]

I got a test pipe with the correct flange style to be able to eliminate the adapter #23. The test pipe I got is a standard for a 89 GTA (with the V8) all I had to do was shorten it a bit to fit the TTA.

 

[transampacecar]

Ok,
Are you saying then, that the adapter in the above schematic is a separate piece and can be re-used with the test pipe I bought ?
I have attached a photo of the test pipe that has the 4 bolt flange. Are you saying that once I disconnect the cat, I will be able to use the factory adapter (part #23) with this test pipe I bought or is the adapter welded or attached to the factory Cat thus needing to get another adapter.
Sorry for my stupidity, just trying to find out what else I will need to buy to use this test pipe I bought that is flared on one end and 4 bolt flange on the other.

 

[pacecarta]

the pipe you have is similar to the GN and replaces the cat completely and as mentioned has the bolts youll need to bolt it up

just remove the cat , leave the adapter on the car , ithe adapter is seperate just slides off the studs on the converer

 

[transampacecar]

Last dumb question. Can you tell me what size diameter the stock exhaust pipe is on the TTA. What my concern is, the test pipe I bought above is a 2 1/2 inch and is flared at the end to slip on and over a 2 1/2 exhaust. Is this the right size test pipe I bought, or is it to small in diameter for the stock exhaust. I know they offered a 3 inch pipe. Since the car is in storage and hard for me to get to where it is, I cant measure it.

 

[hiballin]

the test pipe you have pictured will work for you car with the stock size down pipe. the test pipe with the expanded end fits over the down pipe that is 2 1/2" . the end with the flange is what you put your adapter on and then the intermediate pipe bolts to that.

it will all become apparent when you see your car again. the 3" model that guy offers is for folks with 3" down pipes.