2-1/2 down tubes?

[Ryan A Harris]

Ok, I'm FINALLY getting my exhaust fixed(blocked cats for about 1-1/2 months :rolleyes: )

But at the shop, the guy was saying that 2-1/2 might not fit. I'm sure about 2-1/4, but want to see if anyone is running a set of 2-1/2 down tubes? At this point the manifolds are stock, and not ported, so there is a good size lip to seal up against.

Thanks.


P.S the exhaust shop is RIGHT ACROSS the street of my new house, I can drink beer while my car is getting worked on! Pretty sweet eh. ;)

[fast Ed]

Ryan, I don't think there is enough material on the ball flange of the factory manifolds for a 2-1/2 diameter pipe to seal up properly. Even a 2-1/4" can be a bit dicey.

cheers,
Ed N.

[BlueThunder90]

I had 2.5" on my SC. Rick @ Pipes seems to be able to do them without a problem :confused:

[SeanMatteson]

I'm running 2.5" downtubes, and since the first day the exhaust was installed, I've been living with the problem of getting the downtubes to seal against the underside of the flange on the manifolds. The leak is slight, and is more prominent when the car is started cold. Once things heat up, the gap seems to decrease a little and it's hard to notice. I've had the exhaust off the car a couple of times since it was originally installed, and the downtubes are not flared at all at the ends. They are simply cut off straight, with a little pipe left sticking up above the bolt flange near the top of the dowtube. I don't know that I'll ever get these to seal properly against the stock manifolds.

Ryan, my manifolds are ported, but that makes no difference at all. The ball part of the manifold is less than 2.5" in diameter, so it ends up sitting fully within the downtube.

For the future, I'm considering swapping in a modified set of the Mustang shorty headers in the hopes I can finally get around this problem.

Good luck!

Cheers,

Sean

[Tazer999]

Runnin 2.25 with no problems. My guy said 2.5 would be really hard to do on stock manifolds

[Ryan A Harris]

Well, I just thanks guys. But it seems if I had measured up a set of manifolds I had here, I could have answered my own question.

The ball flange is not 2-1/2, its under that, measuring 1.465, thats .035 smaller, or 1/32. So no looks to be the answer.

BUT, with maybe a small flange on the tube, making the 2-1/2 flange down in size, this can be done. I'm pretty sure this can be done with tubing, it can be flanged either way, right? Not being a fitter makes this hard to tell......

Anyway, thanks guys, I'll post what we got to work some time on FRIDAY.

[SkunkWorks]

Just JB the bastard and you are good to go.. :D :p

[Ryan A Harris]

Do you mean JB weld? I had to use that to seal up a leak in my EGR tube, I couldn't get it off to be welded up propperly, so that crap is on there as a cheap azz HACKER fix. I'm not a big fan of that stuff, and when it comes to exhaust, I'm not sure how long it will last. :rolleyes:

[Kirk Bryan]

Ryan,
Go to Brullen. Richard will make you a stepped down tube no problem.

[Ryan A Harris]

No way man, BRULLEN made quite the mess of that sytem I have now. Hack this, cut that, oh don't tell the guy about that.....

When they were fitting that sytem, things went well. So one the hoist I hop in the car, they lift me up, I start it and they find the leak. They didn't tell me that they used 1-3/4 for the downtubes! then that goes into the 2-1/2 for the cats, thanks guys. I never really looked at it, until a while ago. Oh well live and learn.