Dougs951S

Edit: I'm an idiot.

OK another question, were there two different styles of flanges Porsche used on the 2 piece crossovers? I've seen pictures of some where the flare is on the elbow pipe, and others where the flare is on the crossover. Did this change at some point? I purchased a really nice condition crossover from an 89, and it has the flare on the crossover. My elbow pipe is from 87 and also has a flare (I assume its meant to be paired with a non flanged crossover). Will this still seal correctly with the proper crush donut, or do I also need a later, non flared (89 only?) elbow pipe to match? If they are mismatched and therefore wont seal with the factory crush donut, is there a flat triangular gasket I can at least put between the two flush faces of the flanges to help them make a good seal?

Just to clarify, I'm talking strictly about the wastegate inlet, I'm not running a wastegate outlet to main exhaust pipe since I dump to atmosphere and I am running a 40mm WG.

Dougs951S

Paging Lart? Help me, I think I have the dumb..

Dougs951S

I can't be the only person to have come across this, does nobody know what I'm talking about? Bueller....

lovemyp-car

Any pics you can find of what you are talking about? I'm having a bit of a hard time picturing it in my head...

I know what the crossover setup looks like on my 89TS engine, but I'm less familiar on the early ones, so any pics would help a lot.

Thanks,
Ethan

Dougs951S

Ethan, this is what the crossover I just bought looks like, see how it has that lip or bulge or whatever you want to call it in front of the flange?







Do you see how on this elbow pipe, it also has that same bulge in front of the flange?


Some crossover pipes though (and some elbow pipes as well I think) like this one, do not have that same bulge and instead are flat after the flange..






So my question is, are the two pipes meant to go together so that only one of the two is flared, or are they both meant to be flared? In my case both pipes are flared and I want to be sure they will seal with the factory crush donut. The reason I'm even concerned to begin with is because I think (and I could be wrong) that my original early 2 piece crossover did NOT have the lip on the crossover side, so since my new once does I wanted to be sure this was ok. Hell for all I know my original has the flare too and I just didn't notice because its bolted up, in which case this is all a moot point... But I dont think so, I think only one of the two pipes is meant to have that flare, else how do you get the crush donut to slide on...its supposed to slide onto either of the two pipes, whichever is not flared.

lovemyp-car

Hey bud,

I believe this is what you need. http://www.ecstuning.com/Search/Gasket/ES1428240/
Part #93012313404
Number 3B in the diagram below.

It's a double-chamfered (right word?) crush gasket that goes in between the two flared ends.

Travis at Rennbay should have one for you cheaper than most other places!


Ethan

lovemyp-car

It should look like this when bolted up...see how there's a bit of a gap? That's because of the double flare design, the donut seals in between the double flare and is squished into place by the two 3 bolt flanges

Dougs951S

OK...double flare is good. So how does one get the gasket on (I have a new one here) over the flare? Am I missing something obvious?

lovemyp-car

The gasket doesn't go over the flare, it goes in between the two flares when you bolt the elbow to the crossover.

Like this: FLANGE<FLARE<donut>FLARE>FLANGE
Bolts go from FLANGE____________to FLANGE and pinch everything together...

Make sense? I'll see if I can take some pics when I get home of this stuff
Ethan

Dougs951S

Ethan, I got it now, my brain finally engaged the "common sense" drive. I knew it had to be as easy as me being dumb!

Thanks a bunch!

Paulyy

I bought a generic one from an exhaust shop. it was slightly smaller which was a nice tight fit. works well.

lovemyp-car

No problem man! Glad I could make it make sense lol! You definitely weren't being dumb, some of the variations on these cars don't make sense to me, you just picked one I was familiar with...I just did put my turbo together last year and unfortunately because of my clutch failure I had to just undo everything, so it's fresh in my mind!

This sounds like a great idea! Would you happen to have a part number or manufacturer? It would be nice to know what generic parts fit in case one gets stuck in a jam or if you don't want to spend 20 bucks on a gasket :-/ LOL!

Dougs951S

I second this, good tip Paul. I have a new OEM gasket in hand but I'd love to know more about the generic one. I'm going to measure the OEM donut and find out the ID/OD. (can you believe those things are really 20 dollars almost? same thing with the 3 sealing rings between the crossover/turbo and the header/crossover! I spent ~100 bucks just on pre-turbo gaskets!!)

Dougs951S

quick bump for a long dead thread, but how does this arragement seal properly on earlier cars when the crossover is not flared and the elbow pipe is? My understanding is that the double chamfered crush ring is meant to be sandwhiched between two flares to seal correctly, so if the early crossover pipes were not flared how does this work?

edit: I think this is possibly where my earlier confusion stemmed from? It appears on the early straight crossovers the crush ring slides onto the straight section and is then compressed when the elbow is torqued on? Does anyone know why Porsche updated this part? Also does anyone know when Porsche went to the 2 piece design? My buddy's car is an 86 but it has a two piece crossover with a straight end, just like my 86 did. I don't think that was the original crossover in either case; unless they switched in mid 86?