bman Posted May 30, 2007 Share Posted May 30, 2007 This might be a better forum for this question. I recently finished a UP and DP upgrade. I'm noticing an exhaust leak in the connection from the mid to down pipe. I'm using the included (flat) gasket from Invidia and the stock spring bolts. I didn't use the doughnut gasket (I didn't realize it was mashed onto my stock DP when I removed it). So my question is now: Should I order a another doughnut or should I go to AutoZone and pick up a tube of some exhaust sealant? Is one better than the other? Since the stock DP fits into the mid and the new one doesn't (it just butts against the mid) would one type of sealant be better? Thanks, Brian Link to comment Share on other sites More sharing options...
GTTuner Posted May 30, 2007 Share Posted May 30, 2007 Do it right. if you use new seals and torque them properly there is no need for sealant. Link to comment Share on other sites More sharing options...
bman Posted May 30, 2007 Author Share Posted May 30, 2007 Anyone know the part number for the spring bolts? The ones that connect the DP and the Mid. Thanks, Brian Link to comment Share on other sites More sharing options...
TravisS Posted May 30, 2007 Share Posted May 30, 2007 If you're gonna use the flat gasket, don't use the spring bolts. Donut gasket + spring bolts are there to allow flex. Flat gasket + flex = leaks. BTW, the donut gasket isn't cheap. Link to comment Share on other sites More sharing options...
Balrock Posted May 30, 2007 Share Posted May 30, 2007 BTW, the donut gasket isn't cheap. +1 and neiter are the stupid spring bolts Link to comment Share on other sites More sharing options...
twisted Posted May 30, 2007 Share Posted May 30, 2007 i cleaned the donut and re-used it with some sealant and mine's fine....worst case if things go wrong that gasket is easy to change anyways. Link to comment Share on other sites More sharing options...
bemani Posted May 31, 2007 Share Posted May 31, 2007 A $5 tube of exhaust silicon can make a lot of gaskets. Link to comment Share on other sites More sharing options...
Mr. Ed Posted June 6, 2007 Share Posted June 6, 2007 i cleaned the donut and re-used it with some sealant and mine's fine....worst case if things go wrong that gasket is easy to change anyways. +1 and no leaks i catually bought a new one thinking mine was bad and it wasn't......bought a second exhaust set up and the guy sent me his...sooooo if you need on let me know..I have 3 i think i might have a spring bolt set laying around here as well Link to comment Share on other sites More sharing options...
f85stealth Posted June 9, 2007 Share Posted June 9, 2007 +1 and no leaks i catually bought a new one thinking mine was bad and it wasn't......bought a second exhaust set up and the guy sent me his...sooooo if you need on let me know..I have 3 i think i might have a spring bolt set laying around here as well can the spring bolts be reused that are factory on the car? with aftermarket mid and down pipe can the donut gasket even be used? Link to comment Share on other sites More sharing options...
qikslvr Posted June 9, 2007 Share Posted June 9, 2007 I just got done putting an SPT CBE on to an Autospeed DP and I used a flat gasket with about an 1/8" of hi-temp silicone on both sides and straight bolts with washers and a lock washer to bolted it up loose unitl I hung the mufflers. Then I adjusted the cans and tightened down the DP->MP bolts snug and let it sit for an hour while I removed jackstand and cleaned everything up. It sealed great with NO leaks. With the 3" DP and OE MP; I tried the flat gasket with no goo and it leaked, the doughnut with no goo and it leaked, the same used doughnut with goo and it leaked. This is the first time since I did the UP/DP a couple weeks ago that I'm not sucking exhaust fumes! It's great! Oh and it sounds nice too. Let's kick this pig! Link to comment Share on other sites More sharing options...
f85stealth Posted June 9, 2007 Share Posted June 9, 2007 I just got done putting an SPT CBE on to an Autospeed DP and I used a flat gasket with about an 1/8" of hi-temp silicone on both sides and straight bolts with washers and a lock washer to bolted it up loose unitl I hung the mufflers. Then I adjusted the cans and tightened down the DP->MP bolts snug and let it sit for an hour while I removed jackstand and cleaned everything up. It sealed great with NO leaks. With the 3" DP and OE MP; I tried the flat gasket with no goo and it leaked, the doughnut with no goo and it leaked, the same used doughnut with goo and it leaked. This is the first time since I did the UP/DP a couple weeks ago that I'm not sucking exhaust fumes! It's great! Oh and it sounds nice too. I still dont understand why everyone has such a problem with leaks....what are these manufacturers doing wrong on our cars that we cant get these things not to leak.....i have never heard of this severe of a problem with other vehicles aftermarket exhausts Edit: By the way congrats on it being done with no flaws! Link to comment Share on other sites More sharing options...
qikslvr Posted June 9, 2007 Share Posted June 9, 2007 The issues is the mismatch in the pipe size and the size of the OE doughnut. When you out a bigger DP on; most are designed to mate with a larger mid-pipe. When using the OE MP; the doughnut mates with the OE MP but is too small for the 3" opening on the DP. If you use the flat gasket; it won't mate properly because of the difference in pipe sizes also. The flat gasket will mate fine with the 3" pipe, but the hole in the gasket isn't small enough to mate with the OE pipe properly. It's fine when you do the whole exhuast at once from the turbo back. The problem is in matching up the two different sized pipes and flanges. Let's kick this pig! Link to comment Share on other sites More sharing options...
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