New exhaust leaks

[Vukodlac]

Looks like I'm the only one with this problem.

I just installed the Motiv Overpipe and HFC. Pretty easy install, but as soon as I started up the car I was leaking exhaust out of every seem.

I've installed exhaust systems before and followed the directions from front to back. I used the gaskets supplied and found they leaked so I switched back to factory. I checked for leaks on the overpipe and they seem to have dissipated.

The main problem area is the doughnut gasket from the HFC to the midpipe. I installed the HFC to the Overpipe as instructed, secured the HFC to the hanger under the chassis then proceeded to tighten down the spring loaded bolts/nuts on the HFC to the Midpipe.

I started the car and had a huge leak, drove the car and let it warm up, leak still there. Went out and bought all new hardware for the HFC and Midpipe connection, STILL leaks... The spring loaded nuts and bolts are tighted down as far as they can go. Any farther and I will break them.

What am I doing wrong, this should be pretty simple simon.

[Captain Insano]

Did u not align the donut properly and smash it up? Just guessing.. really hard to diagnose without seeing the car or pics.

[Vukodlac]

Alright I'll take some pictures and get back to ya. Sorrys

[Vukodlac]

Alright a made a raw video of the issue. I'm not a video editor and sorry about the compression software logo.

I talked to a couple friends about this and it sounds like the HFC might be under spec. I'm not really sure, I've never had this problem.

Enjoy

[jpit]

I have the same problem with the donut gasket although I have the motiv test pipe. Tightened the spring bolts as tight as possible and then did some research and apparently they are only supposed to be torqued to 15 lbs. I have not readjusted them but I haven't seen any more residue on the garage floor so I don't think the gasket is leaking anymore. Maybe carbon build-up has helped.

[Vukodlac]

Wow 15lbs? Yeah I've got mine down tighter than that.

Well today when I put my bare hand down there I couldn't air like I did yesterday, I have driven it since then and got it up to normal temp.

Unfortunately my work hours really don't allow me to play with the car for another week. So I guess I'll end up getting a stethoscope and checking for leaks, if it still leaks I'll probably return it.

Did you notice any gains with your test pipe?

[Beyer Subaru]

Yep, you don't want to tighten these much past 15lbs. If you do, you can shear the bolt (I've done it) or bend the OE pipe.

The only fix I can see is putting some exhaust gasket material behind the donut to space it off the new pipe more. You can get gasket material from any "real" auto parts store. Not your advance, pep, autozone kinda stores. Sometimes it will be listed as header gasket material and it is cuttable to the shape that you need.

[Vukodlac]

No shit..

What a PITA. Errh, is this normal? I'm guessing the after market pipes and the stock pipes don't match up very well.

[Beyer Subaru]

I had something like this happen to me with a bs flat flange downpipe on my STi. That's why I have experience with the cuttable gasket material. I've always got a small sheet in the garage for any kinda leaks.

I wouldn't say what you are experiencing is "normal". The new pipe looks to be butting up to the old piece just fine and it looks like you actually might have the bolts a little over tight.

You just will have to wiggle em a little bit until everything mates or fill the gaps with some new gasket material. Donuts are generally a set-it and forget it affair.

[Vukodlac]

I got ya, yeah obviously first time for me.

With the gasket material you can simply make your own custom gasket, and set it behind the doughnut, thus making the doughnut gasket push closer to the downpipe and make a seal?

Next time a have a chance to get back down there I'll mess with it some more.

Thats also what I heard about doughnut gaskets, which is why I thought this hole thing was strange.

Thank you for the help though.

[Beyer Subaru]

Originally Posted by Vukodlac

I got ya, yeah obviously first time for me.

With the gasket material you can simply make your own custom gasket, and set it behind the doughnut, thus making the doughnut gasket push closer to the downpipe and make a seal?

Next time a have a chance to get back down there I'll mess with it some more.

Thats also what I heard about doughnut gaskets, which is why I thought this hole thing was strange.

Thank you for the help though.

Yep. It comes in sheet form about a foot square or oddball sizes. It looks like a thin, white cardboard. It is made of some nasty, heat resistant materials. When it gets hot, it swells up a bit.

So you could cut a round, oval, etc size gasket with holes and all. Then put it behind the donut to push it out a little further. This would hopefully make the pipe and donut seat good.

You should also check your donut really good for tears, dents or any other irregularities. Donuts are usually pretty hearty and can be manipulated to some degree to fit bad pipes connections.

[JoeBoxer]

Bolts are too tight for sure you may have damaged the donut gasket.

[Vukodlac]

Yes. I understand they might be a little tight.

The issue I'm experiencing is that my dounut gasket isnt tight enough against the downpipe.

[Jacob G.]

I have the same issue. I don't see or smell fumes but I do have condensation forming. Same HFC. I'm going to get a torque wrench and see where I'm at. The worst part is I paid someone $60 to do the installation bc I don't have a lift and now I have this