Exhaust Leak

siickwrx · 12-01-2019, 03:35 AM

Hey guys,

I'm having trouble with an exhaust leak. I have an invidia downpipe mated to a greddy catback (I believe its the Revolution RS). I put a 3" flat gasket between the downpipe and greddy catback but it seems like there is a gap on top and it's producing a fat exhaust leak. How do I get rid of this leak? Car is an 07 WRX

Thanks

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shadowsports · 12-01-2019, 09:43 AM

3in flat flange to flat flange?

Sometimes the angles don't quite line up.

What can help:

Using different exhaust hangers
Using a spacer
Using 2 gaskets

Soapy water to test the fix. Good luck.

BeastianSTI · 12-01-2019, 11:15 AM

Quote:

Originally Posted by shadowsports

3in flat flange to flat flange?

Sometimes the angles don't quite line up.

What can help:

Using different exhaust hangers
Using a spacer
Using 2 gaskets

Soapy water to test the fix. Good luck.

Quite right.

There are three hangers. I'd try to go into some theoretical thinking like:

If the back of the exhaust (2 hangers at rear) were lower, would that make the angle of the flanges line up better?

Same for the front hanger. That might need to go a little lower to enable the flanges to be parallel to each other.

I've also used Grimmspeed's exhaust gaskets to make things fit better. They're thicker so it makes it a little bit easier.

kopele · 12-01-2019, 02:38 PM

I've good success with RTV gasket maker, it's a little messy but does a good job.

siickwrx · 12-02-2019, 02:53 AM

Thanks for the advice guys! I put that red high temp rtv I had lying around on both sides of the gasket. It's working so far. Don't know how long that will last tho.

MortonCharbo · 12-02-2019, 10:20 AM

I used a remflex 8006. It's just a thick graphite gasket that forms to the two flanges when you tighten them together. I payed 8 bucks for it on Amazon.

I tried the GS gaskets with no luck. I used the rtv stuff and it lasted about a week.

BeastianSTI · 12-02-2019, 10:26 AM

Quote:

Originally Posted by MortonCharbo

I used a remflex 8006. It's just a thick graphite gasket that forms to the two flanges when you tighten them together. I payed 8 bucks for it on Amazon.

I tried the GS gaskets with no luck. I used the rtv stuff and it lasted about a week.

I've used those too. Worked well in my case, but I think it's difficult to fix exhaust leaks if the flanges just aren't lining up.

@OP - if you want to share some pictures of what we're talking about, that could be helpful (of the flange currently, and maybe the tip of your exhaust).

raisingAnarchy · 12-02-2019, 12:26 PM

Stick a shop vac hose in reverse flow setting in the tail pipe to test your fixes. That's how I did the leak troubleshooting on my Tomei expreme catback with those damn slip fittings.

siickwrx · 12-03-2019, 02:59 AM

I'll try the remflex 8006 once my ghetto rtv fix fails haha. I'll try to post pics of the flanges whenever I get a chance to.

shadowsports · 12-03-2019, 11:26 AM

Quote:

Originally Posted by siickwrx

I'll try the remflex 8006 once my ghetto rtv fix fails haha. I'll try to post pics of the flanges whenever I get a chance to.

Soapy water, best way to check for leaks

and easy too.

Jedi03 · 12-03-2019, 06:47 PM

get the seal for good gaskets from autozone...they are super thick and work great!

metalheadsunite · 12-05-2019, 12:42 AM

Quote:

Originally Posted by Jedi03

get the seal for good gaskets from autozone...they are super thick and work great!

I am not sure what the Greddy catback uses but I have Invidia downpipe and Cobb catback and had to use the Grimmspeed adapter with a flat gasket on one side and a donut gasket on the other. Ended up fixing my issue.

Like here: https://www.subispeed.com/2015-subar...5-wrx-2015-sti

siickwrx · 12-05-2019, 02:36 AM

Quote:

Originally Posted by metalheadsunite

I am not sure what the Greddy catback uses but I have Invidia downpipe and Cobb catback and had to use the Grimmspeed adapter with a flat gasket on one side and a donut gasket on the other. Ended up fixing my issue.

Like here: https://www.subispeed.com/2015-subar...5-wrx-2015-sti

I actually have that adapter. Does the cobb catback have a 3" flange or 2.5"?

siickwrx · 12-05-2019, 02:41 AM

Also does anyone think it could be the way I bolted it up? If I were to torque the downpipe to midpipe first, would it eliminate the gap? I'll try that next but I want to see if anyone fixed a leak that way.

MortonCharbo · 12-05-2019, 02:13 PM

Quote:

Originally Posted by siickwrx

I actually have that adapter. Does the cobb catback have a 3" flange or 2.5"?

When I had my Cobb catback, 2.5, it used the stock donut gasket.

As for torque sequence, start at the front and work your way back. Dp to midpipe first. Then midpipe to axle back. That should minimize possibilities for leaks. It should also make it apparent if you need different length hangers in different spots to get everything lined up right.

siickwrx · 12-06-2019, 02:39 AM

Quote:

Originally Posted by MortonCharbo

When I had my Cobb catback, 2.5, it used the stock donut gasket.

As for torque sequence, start at the front and work your way back. Dp to midpipe first. Then midpipe to axle back. That should minimize possibilities for leaks. It should also make it apparent if you need different length hangers in different spots to get everything lined up right.

Thanks for the input, i'll try torquing in that sequence. I would much rather move my exhaust leak to the axle back to save my lungs lol

12-01-2019, 03:35 AM	#1
siickwrx Scooby Newbie Member#: 508913 Join Date: Dec 2019	Exhaust Leak Hey guys, I'm having trouble with an exhaust leak. I have an invidia downpipe mated to a greddy catback (I believe its the Revolution RS). I put a 3" flat gasket between the downpipe and greddy catback but it seems like there is a gap on top and it's producing a fat exhaust leak. How do I get rid of this leak? Car is an 07 WRX Thanks * Registered users of the site do not see these ads.

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12-01-2019, 09:43 AM	#2
shadowsports Scooby Newbie Member#: 446364 Join Date: May 2016 Chapter/Region: BAIC Location: Nor Cal Vehicle: '17 STI LMT '08 LGT DGM / QSM	3in flat flange to flat flange? Sometimes the angles don't quite line up. What can help: Using different exhaust hangers Using a spacer Using 2 gaskets Soapy water to test the fix. Good luck.

12-01-2019, 02:38 PM	#4
kopele Scooby Newbie Member#: 363007 Join Date: Jul 2013 Chapter/Region: MWSOC Location: MO Vehicle: 2008 STI Black	I've good success with RTV gasket maker, it's a little messy but does a good job.

12-02-2019, 02:53 AM	#5
siickwrx Scooby Newbie Member#: 508913 Join Date: Dec 2019	Thanks for the advice guys! I put that red high temp rtv I had lying around on both sides of the gasket. It's working so far. Don't know how long that will last tho.

12-02-2019, 10:20 AM	#6
MortonCharbo Scooby Newbie Member#: 487057 Join Date: Jun 2018 Chapter/Region: BAIC Location: California Vehicle: 2002 WRX Wagon PSM	I used a remflex 8006. It's just a thick graphite gasket that forms to the two flanges when you tighten them together. I payed 8 bucks for it on Amazon. I tried the GS gaskets with no luck. I used the rtv stuff and it lasted about a week.

12-02-2019, 12:26 PM	#8
raisingAnarchy Scooby Newbie Member#: 408438 Join Date: Dec 2014 Location: OH, USA Vehicle: 2016 WRX STi CBS	Stick a shop vac hose in reverse flow setting in the tail pipe to test your fixes. That's how I did the leak troubleshooting on my Tomei expreme catback with those damn slip fittings.

12-03-2019, 02:59 AM	#9
siickwrx Scooby Newbie Member#: 508913 Join Date: Dec 2019	I'll try the remflex 8006 once my ghetto rtv fix fails haha. I'll try to post pics of the flanges whenever I get a chance to.

12-03-2019, 06:47 PM	#11
Jedi03 Scooby Specialist Member#: 491095 Join Date: Sep 2018 Chapter/Region: SWIC Location: New Mexico Vehicle: 2009 STi Blue Blue	get the seal for good gaskets from autozone...they are super thick and work great!

12-05-2019, 02:41 AM	#14
siickwrx Scooby Newbie Member#: 508913 Join Date: Dec 2019	Also does anyone think it could be the way I bolted it up? If I were to torque the downpipe to midpipe first, would it eliminate the gap? I'll try that next but I want to see if anyone fixed a leak that way.