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backfiring keeps roasting my exhaust gaskets

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  • backfiring keeps roasting my exhaust gaskets

    So this has got me frustrated. I just replaced my turbo to manifold gasket because I cooked my last one, and 100 miles later. Cooked another. I think this is related to the cars frequent backfiring. No clue on what's causing the backfiring. Already spent a bit of time messing with timing and fuel mapping, and nothing seems to make any difference. Any ideas of where to look to fix the backfiring or where I can get the toughest t3 gasket made? Maybe the gaskets I got were just crap.
    Last edited by josh_s13; 08-02-2012, 06:00 PM.

  • #2
    I'd guess one of the better things you can get would be to get a thin sheet of copper and just trace a t3 gasket on it and cut one out.

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    • #3
      You sure its the back fire roasting them and not the exaust putting too much load on the 4 nuts and studs which are getting a little loose. Back fires usually happen much further from the turbo from what I know. My car very rarely backfires and i had burned a lot of those gaskets until I build a braket from the elbow to the transmission.

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      • #4
        I may try to get some new gaskets tomorrow, while I'm down there I will weld a bar from the exhaust to tranny. I don't know for sure if the backfiring is causing it. Ever since I've had the car it's backfired almost everytime I lift throttle while driving slow driving in traffic.

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        • #5
          Any tips on where and how to connect the two?

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          • #6
            Vband ftw?

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            • #7
              Bov or recirculated? Backfire is often caused by running too lean for the cyls to fire at all. Then the lean unburned mix hits a hot exhaust (turbo) and bang!
              Same can happen with running pig rich, but that usually manifests in exhaust fireballs on shifts and decel. Backfiring happens inside the exhaust.

              As for the gasket failing, use stainless or copper gaskets w good hardware and possibly tack welding the bolts or something to prevent them from loosening.
              Also brace the turbo or exhaust as mentioned to keep mechanical stresses down on that flange.
              Originally posted by SoSideways
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              • #8
                You have an EGT gauge? How are the temps?
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                • #9
                  around 1000 deg F after the turbo, recirculated. I got some material to cut a gasket out of. It appears to be a steel mesh core covered in a hard graphite. I couldn't find any actual t3 gasket in town and I need it fixed before a race tomorrow

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                  • #10
                    do you have a flex section near the downpipe?

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                    • #11
                      i doubt the backfiring is causing the gasket being blown. but yes, you probably have excessive rich condition or unburnt fuel causing the backfiring. separate issue from your gasket issue IMO.

                      regarding the gasket, you need to support the exhaust. i would blow a gasket every event until i got an extra support added near the trans. (Thanks to some advice from members on here!) your downpipe should be able to hang (with the exhaust hangers) in the general vicinity of the turbo outlet without being bolted down. flex pipes can also help with some "give". if you're using the bolts to support the weight of your downpipe and exhaust, those gaskets are not going to last long. Typically the weakest gasket is the one you are blowing. the turbine to manifold gasket. take the weight of your exhaust acting like a level arm on your turbo off.

                      finally, make sure your surfaces are true. if they aren't, get them decked. if the surfaces are good you don't even need a gasket at all. i don't run one anymore.

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                      • #12
                        There is a flex pipe, but the exhuast is poorly supported

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                        • #13
                          Well, it's put back together and not leaking. I am going to baby it home tonight and baby it to Robeling Road tomorrow. I put an exra support from the exhaust to the transmission. Going to see what happens, hopefully if it does break again it will be after I get a few runs in.

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                          • #14
                            I couldn't keep my damn factory Nissan turbine inlet gaskets (T25) to last on my car. I didn't have a flex in my downpipe, but everything was well mounted and supported. Street driving and even moderate track driving it was fine, but go balls to the wall and it'd blow the gasket out in 2 weekends.

                            I finally got sick of it and welded the turbine housing to the manifold. Works like a charm after that!!!
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                            • #15
                              I fixed my issue first and foremost with a downpipe with a flex section supported to the trans. Funny thing was the support was about an inch too short. Hockey puck fixed that.

                              The nuts would still vibrate loose on tracks with a lot of long sweepers though, but because it was supported, the gasket wouldn't blow if caught it when only one or two would loosen up.

                              I used Honda deform locking nuts to fix the vibrating loose issue. I had a shop redo my engine and they put the stock nuts back on and the problem came back. Not blowing the gasket but the nuts vibrating loose. So I'm going to put some new locking nuts back on.
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