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Thread: Exhaust Tip - How Far Should It Stick Out?

  1. #1
    '73_240Z sdaughtry's Avatar
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    Default Exhaust Tip - How Far Should It Stick Out?

    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
    b) 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?

  2. #2
    Registered User MEZZZ's Avatar
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    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.
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    Last edited by MEZZZ; 12-27-2010 at 04:47 PM.
    1977 280Z
    I'm great at taking my Z apart, putting it back together has been a whole different story.

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    Z geek at large FastWoman's Avatar
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    Another benefit to a tip sticking out is that the exhaust won't corrode your bumper!
    My last three sports cars while I still owned all three:

    2001 BMW Z3 Roadster 3.0i soft/hard top (sold)
    1966 Ford Mustang Coupe (sold)
    1978 Datsun 280Z (enjoying very much )

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    Registered User ajmcforester's Avatar
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    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

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    Semi-retired admin Arne's Avatar
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    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.
    Arne - Former owner, HLS30-37705, 7/71, 905 Red
    Car blogs - 240Z - Porsche 911

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    Registered User Oiluj's Avatar
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    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.
    Julio
    1972 240Z (in-progress, 95% complete)
    CZC# 15388

  7. #7
    Registered User ajmcforester's Avatar
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    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

  8. #8
    Registered User Bonzi Lon's Avatar
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    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. 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
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    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.

  10. #10
    Datsaholic Mr Camouflage's Avatar
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  11. #11
    Registered User ajmcforester's Avatar
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    Quote Originally Posted by Mr Camouflage View Post
    I've seen longer

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    Registered User Daishi_GD's Avatar
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    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...
    M@
    78 280Z HLS30-448275

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    Just had a new muffler and chrome extension tip installed. I used a 9" Pep Boys extension, angle cut and turned down. It sits even with the end of the bumper guard, about 3" longer than my previous pipe.


    1973 240Z HLS30-144433 1/73 115 Metallic Blue

    "Whoever said 'the pen is mightier than the sword' has obviously never been stabbed."

  14. #14
    Registered User 5thhorsemann's Avatar
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    This is the setup that came on mine, 10 inch twin tubes. No fume issues, and at appx. 5 inches past the bumper it looks like hell and will punch a hole in your leg if you aren't careful. However, it directs the sound and fumes away from the car and after going to a header I think it runs about as good as any 240 I have ever been in or driven. I thought about changing it but after talking to some british car fans, the consensis seems to be that it is a nice stainless steel system and is designed to do just what it does. So, it will stay.
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