ok well i obviously know these things suck and are like always bad(like i'm sure mine is), but what is their purpose? i don't mean to sound like an idiot, but why can't you just weld in a piece of pipe instead of the flex bellows?
You need flex bellows in order for the pipe to be able to flex and not crack when it moves (slightly) as the temperature changes from air temperature, to 1200*+ exhaust temperature. If you didn't have flex bellows, the replacement pipe wouldn't be able to flex enough and would just crack instead of flexing. Make sense?
yeah that makes sense, but how come i've never seen a part like this on other cars?
That I do not know... my TGP is my first car :laugh:
I believe N/A 3.1 have one on the crossover from the front to the rear exhaust manifold. I've never pulled off the heat shield to check though.
The flex bellows are there so that the crossover can withstand the expansion and contraction of our aluminum cylinder heads.
Quote from: mfewtrail on July 22, 2007, 04:05:41 PM
The flex bellows are there so that the crossover can withstand the expansion and contraction of our aluminum cylinder heads.
With the slight torsion that the turbo puts on it when spooling.
Quote from: pontiac6ksteawd on July 22, 2007, 05:32:37 PM
Quote from: mfewtrail on July 22, 2007, 04:05:41 PM
The flex bellows are there so that the crossover can withstand the expansion and contraction of our aluminum cylinder heads.
With the slight torsion that the turbo puts on it when spooling.
Do what??
I have been told with big turbo aplications, that the turbo can actually move from the turbine spool. Causing a slight sideways motion. And since the turbo is mounted on the brackets above the tranny, instead of hard mounted to the exhaust flange (like most turbos that I know of are), that thru the engine heating, tranny heating, etc, there is sideways motion, and longways motions from everything heating and cooling at diferent rates, diferent metals, etc.
i just wish it wasn't cracked. that would be cool
Replace it. Make a fun afternoon project, trust me it sucks. But after you take it out once, it makes it easier the next time you work on it.
Quote from: grinders_18 on July 24, 2007, 04:03:52 AM
Replace it. Make a fun afternoon project, trust me it sucks. But after you take it out once, it makes it easier the next time you work on it.
did you do the repairs yourself or have TGPilot do the welding?
Kenny (TGPilot) welded mine for me, and I removed and re-installed the finished product.
I might have a spare crackless crossover. PM me if interested.
ordered a brand new one from my buddy at the dealer last year. i paid $180.00 for it last summer. so far so good it runs fantastic.
I checked a few months ago and it said.. 1239. The part numbers you seek have either changed to a new part number or no longer available from GM. So I called them up to find it discont. :icon_sad:
Inline 4s and 6 can get away with not having flex bellows because the head expands together with the pipes. Even so, they'll get some cracks. Even the Cast iron units get cracks because of heat expansion.
On V engines like ours, the heads expand at different directions and the block doesn't expand as fast/as much as the heads do. The pipes expand at another rate and size too. SO those flex bellows are needed. Even having one flex bellow is enough.