JasonSed

I am installing a FVD Sport Cat X-Pipe on my 996 C4S and wanted to see if I am overthinking the issue or not. When I install the pipes on the engine hangers first, I am finding the connection between the exhaust manifold and the new pipes is quite a bit higher than what would allow me to screw them in without forcing the x-pipe fitting down to match up with the manifold. If I attach the manifold portion first, then the lower part of the pipe sits a similar distance from the hanger; thus, it probably won't match up with the muffler when I reconnect it. I emailed Rhonda, and she sent me the Porsche instructions attached, but these instructions basically say connect to the manifold, then connect to the muffler, then attach to the hanger. I don't see how that series of steps will avoid the mismatch that I am seeing in the parts. I've not done exhaust work before, so maybe expecting things to line up perfectly is unreasonable, and there is always some amount of force and stress on the system when installed?

996C438

Even though exhaust parts are made on jigs everything has a + and - tolerance . Headers off a pinch , x pipe off a pinch and voila it doesn't line up perfectly . It is not unusual to have to use ratchet straps to tweak things to line up .

JasonSed

Good to know, thanks.

Paul Waterloo

Just a guess, but when was the last time you replaced your motor mounts? If you have an old picture of your exhaust pipes, are they low in the bumper? There is a possibility that they could be extremely worn and adding to the issue.

996C438

Looking at the pic I would get a large C clamp or wood working clamp and slowly pull them together . Keep the clamp in place as you slip bolts in . Tighten bolts and remove clamp .

brontosaurus

The side mufflers move with the engine, as do the headers & cats, so this is unlikely to be the cause. The only thing I can think of where it might make slightly more sense to attach parts from the header onward is that there are bushings in the muffler mounts so there might be a slight bit of play there (unlikely as well).

Just bolt it up IMO.

tommelton

Looking at your first picture - that is a long way off. Forcing those two together, will place a lot of stress into the x-pipe and/or the headers. I would not want that much stress in the steel of the headers. Something seems way off. Can the hangers be adjusted at all? Spacers added?

-Tom
2002 C2

JasonSed

Thanks for all the info. I'll plan to start at the manifold as the Porsche instructions suggest and go from there. I just wanted to be sure this was fairly common for exhaust replacement before I went through forcing all the parts to fit together.

De Jeeper

If u r real careful and think u can loosen the manifold bolts im betting it will line up pretty good. It wont take much of a shift at the flange to change the output position. The issue is if u break a manifold bolt u create a much bigger problem.

dporto

^^^This… loosen anything you’ve already got tight and then insert your bolts - this should give you enough slack to get everything to bolt up correctly. It seems like a lot in the first photo but if everything moves just a little bit, it should all go together. Good luck!