Exhaust Tip - How Far Should It Stick Out?

[sdaughtry]

I see lots of posts regarding exhausts / cabin fumes, but no real consensus on how far the exhaust tip should extend from under the car. the 3 possibilities are:

a) Stop short of the rear bumper

Flush with the rear bumper

c) Extend past the rear bumper

I am redoing my exhaust system at current - the Flowmaster I had installed two years ago was so boomy that I grew tired of it and had a turbo muffler installed. I have a chrome tip (angle cut) picked out for it, but would like to ensure I have it welded on at the optimum length to not aggravate cabin fume problems while I have the opportunity.

Thoughts anyone?

[MEZZZ]

Mine sticks out well past the rear bumper. I installed a Pacesetter Monza exhaust on my 280. Then I replaced the rear bumper with one off a 240. Since the bumper is in tighter, my muffler sticks out further. It has taken me awhile to get used to it, still not sure I like it that much. One benefit to a tip sticking out further is less fumes into the cabin.

Edited December 27, 2010 by MEZZZ

[FastWoman]

Another benefit to a tip sticking out is that the exhaust won't corrode your bumper!

[ajmcforester]

I'd recommend just a little past it pushed the gases into the slip stream and not under the car. Even with the bumper not good for this. So my answer is C:classic:

[Arne]

I have a factory-built Monza rear muffler replacement (dual vertical tips) on my 240Z, and the pre-attached hangers locate it with the top tip extending beyond the bumper, even a touch beyond the bumper guard, in fact. I can't say that this has eliminated the fumes, but it did cut way back on them.

[Oiluj]

Mine sticks-out about 1.5" past the bumper bar. Used to have more fumes in the cabin before extending the exhaust tip past the bumper.

Still have a small amount of exhaust smell with the window rolled down, but almost none with windows up. I'm thinking of moving the tip out an additional inch.

[ajmcforester]

Vacuum pulls exhaust under the car, this is very common with hatchbacks. If you look at later hatchbacks they flatten out before they reach the back unlike the Z to fix this problem. Now when you open the window you create a vacuum in the cab to you have a rear vacuum and the cabin, not good. I try when driving to just use the floor vents for air they seem to have a positive feed and it seems like they reduce exhaust fumes

[Bonzi Lon]

When replacing the exhaust on the 73, I was there and showed them where to weld the flat cut tip. It extends about 2" from the bumper, only photo. The old system had a slant cut which I think helped drag fumes under the car, and unwelded connections. :stupid: The combination of a new system and the flat cut end has reduced fumes 98%, but still get a whiff now and then.

Bonzi Lon

[ezzzzzzz]

There's no magic length. Mine sits about even with the bumper and I have no fume problems. Good seals are the answer and that includes the drain plug in the spare tire well, the antenna drain tube hole, larger plugs in the bottom of the hatch and the fuel tank hose seals. I also have a BRE spoiler that maybe helps some(?). The vortex behind a S30 is horrible. I plan to apply some vortex tabs like those found on the Mitsu's to improve airflow down the hatch.

[Mr Camouflage]

this is too long http://scene-media.com/blog/wp-content/uploads/2010/04/bozo2.jpg

[ajmcforester]

this is too long http://scene-media.com/blog/wp-content/uploads/2010/04/bozo2.jpg

I've seen longer

[Daishi_GD]

I think it's personal preference. But just don't burn your leg on it if you choose to have it sticking out. I've heard too many stories...