Exhaust Question: Weld or Self Tapping Screws?

[xRUSTYx]

Hey Guys,

Posted this on my Jack Stand thread, but figured, it might get a bit more attention if I started another thread.

I've read I can either tack weld, or use self tapping set screws. Thinking about going with screws for a couple reasons

1) The car is still on jack stands, and I've been unable to find a mobile welder locally
2) I don't feel like grinding off welds should I decide to change something.

So ... I figured a single set screw through each Band Clamp ... Anyone know a good length/size to use?

I was thinking about the below. 1/2" Self Sealing ... Although not sure how well the rubber would hold up over time. Perhaps just hex screws?

http://www.mcmaster.com/#self-tapping-screws/=id8q47

http://www.mcmaster.com/#self-tapping-screws/=id8n5u

 

[Wiretech]

You can't use sheet metal screws because going through stainless steel when you torque it down the head breaks off then you have drill it out. You have to drill hole tap the thread and use stainless steel machine Imperial or fine thread.

 

[xRUSTYx]

Thanks Wiretech!

I'm assuming, there should be no ill effect from having a small screw hanging down within the exhaust system? Would you got with 1/2" screw or something longer/shorter?

Lastly ... Would you use locktite, or something similar so there are no tiny exhaust leaks?

 

[Jeebs]

Are the band clamps just not holding tight enough? I just put an exhaust on mine and just used clamps. Re checked everything after a good ride and all is good.
If you are still going to do this, i'd use no longer then 1/2 and use RED locktite.
Good luck

 

[mjorgensen Woodhouse]

If you are installing a Corsa catback you definitely want to tack or screw it in place, over time and heat cycles they ALL move and tend to ruin the paint at the exhaust opening. We have done hundreds of them and tack all of them, after enough slips and pay to repaint jobs it is just a good security item.

Are the band clamps just not holding tight enough? I just put an exhaust on mine and just used clamps. Re checked everything after a good ride and all is good.
If you are still going to do this, i'd use no longer then 1/2 and use RED locktite.
Good luck

 

[JPUConn]

If you are installing a Corsa catback you definitely want to tack or screw it in place, over time and heat cycles they ALL move and tend to ruin the paint at the exhaust opening. We have done hundreds of them and tack all of them, after enough slips and pay to repaint jobs it is just a good security item.

Does the same apply for '08 OEM catbacks intalled on '03-'06 cars?

 

[mjorgensen Woodhouse]

No OEM have tabs to prevent this.

Does the same apply for '08 OEM catbacks intalled on '03-'06 cars?

 

[xRUSTYx]

I ended up going with the Mopar Exhaust. Had a corsa on my CTS-V ... A bit too quiet for my tastes.

What tabs do you speak of Mark? The cutout on the cat side for the set screw near the exit of the cat's? The Mopar exhaust does have these tabs and the set screw goes in to them.

Wondering if I'll be safe or if I should still tack/screw

 

[mjorgensen Woodhouse]

The stock system slips together one way only so it doesn't move, the Mopar one is not the same so you should use a screw or we prefer to tack them, you really won't be removing this often unless something is wrong.

I ended up going with the Mopar Exhaust. Had a corsa on my CTS-V ... A bit too quiet for my tastes.

What tabs do you speak of Mark? The cutout on the cat side for the set screw near the exit of the cat's? The Mopar exhaust does have these tabs and the set screw goes in to them.

Wondering if I'll be safe or if I should still tack/screw

 

[klamathpro]

The clamps these come with must be subpar for the exhaust to come loose like that over time. The clamps I got from Roe for my sidepipes from 5 years ago are on so tight you could tow my car from my exhaust. I do have them torqued down beyond the recommended spec though, as they always unrate that.

 

[xRUSTYx]

The stock system slips together one way only so it doesn't move, the Mopar one is not the same so you should use a screw or we prefer to tack them, you really won't be removing this often unless something is wrong.

Thanks Mark!

The clamps these come with must be subpar for the exhaust to come loose like that over time. The clamps I got from Roe for my sidepipes from 5 years ago are on so tight you could tow my car from my exhaust. I do have them torqued down beyond the recommended spec though, as they always unrate that.

What did you torque yours down to klamathpro? Mopar states 35 lbs, the Corsa states 45 lbs. I went about 40 lbs.

 

[Flexx91]

The issue is not really the clamps but the 45lb. torque spec. They obviously don't want you to tighten it to the point where it makes the pipe ends elliptical instead of round - thus causing the connection to leak.

 

[xRUSTYx]

The issue is not really the clamps but the 45lb. torque spec. They obviously don't want you to tighten it to the point where it makes the pipe ends elliptical instead of round - thus causing the connection to leak.

You really shouldn't see that with band clamps though Flexx? I've seen that happen with old style U Bolts, but not band clamps

 

[dantelisky]

I would tack the mufflers in place... Just make sure you are happy with the alignment and account for significant growth when they heat up. I did the corsa race catbacks on my 04. The bandclamp does not hold guarenteed! I had to redo mine twice each side because they rotated and contacted the bottom side of the hole. It will tear up the aluminum. I finally tapped a inserted a set screw thru the clamp to fix. Be careful not to break the tap off do to the gummy stainless. If i had a welder I would have tacked them in place. My 2 cents

 

[Flexx91]

You can when you're clamping metal while trying to maintain practically an air-tight (exhaust-tight) seal. Band clamps are excellent on softer materials for obvious reasons but in this particular case, too much force can cause the metal (stainless steel) to deform and 304/304L stainless steel doesn't "spring" back once it deforms.

 

[Viper X]

Even the stock clamps don't always hold the exhaust tip as well as they should.

Have to repair one twice at Laguna Seca two weekends ago.

After the last session, we just gave up and will have it welded.

Dan

 

[Allan]

I got tired of pulling the sills to re-adjust, so I tack welded mine and haven't had an issue since.

 

[xRUSTYx]

Got my sills back on (partially) ...

Will drive it slowly to the exhaust shop tomorrow after I put the wheels on, double check to make sure when fully heated up, they are where I want them, then remove, weld, then put back on

 

[Shandon]

Tack it in two spot on each side. Easy to grind back off if you change the exhaust later.

 

[Flexx91]

Corsa even advises you to tack weld the connections. I wouldn't do anything different (the reason why I tack welded mine).

 

[xRUSTYx]

Ended up getting it tack welded.

Put the side sills back on (only half the bolts/screws) and headed to the exhaust shop. An hour later (side sills on/off) and tack welds + $0 and was good to go.

It helps when you do all the work yourself at the exhaust shop

Thanks for all the feedback guys!