New exhaust, one side hotter

[Snakester]

I just had Sean Roe, high-flo cats, and a Corsa cat-back exhaust installed and it sounds very good.

But two things that I noticed were when I let off of the throttle after revving the motor it pops/backfires somewhat.
The Corsa in my Vette does that too, but not as much of a backfire pop explosion as in the Viper. I do have older gas as the car hasn't been driven for months.

And the other thing is that the temperature of the side exhaust covers are different. The driver's side one is much cooler. so much so that I can pretty much touch it on the door hinge (front) end after running the car for a while.

But the passenger side is considerably hotter,and much to hot to keep my hand on it.

I just repainted my car (2000 R/T), and I don't want to burn off the new paint,or have it burst into flames.

-Dean.

 

[treynor]

Is it possible that one of your two high-flow cats was installed with the heat shield facing the wrong way, or that the heat shielding on the inside of the rocker panel was damaged? It doesn't seem plausible that your engine would run lean on one whole side...

 

[Bill/APEX Motorsports]

Barring a mechanical problem (such as the car needing a tune-up), either one heat shield is facing inward and one is outward, or the "hot" cat could have been installed too close to the side sill.
I'd take it back to whoever did the work and have them check it out.
We always install our 2.5" and 3" cats with plenty of clearance to the heat shields to ensure low side sill temperatures. We've had Vipers come in here with completely burned-through heat shields because of improper cat installation or simply bad-quality cats. In fact, on one car, the side sills were burned black.

We'll be in the shop all day tomorrow (Saturday), so if you want us to take a look at it, feel free to stop by!

 

[Snakester]

Thanks for the tips guys. I have a friend who is putting everything together. He is an expert mechanic, but new to Vipers, as I am.

He noticed the heat after we put everything together, and he doesn't want to run the car on the street until it gets sorted out (especially since he just painted the car).

He pulled apart the exhaust and the welding is good, no pinholes, and the cat orientation is correct. The band clamps were tight, the insulation is in good shape and positioned properly (same on both sides).

The car hasn't been running for several months, so it could be out of tune, and probably has bad gas, but it idles fine.

-Dean.

 

[99 R/T 10]

Dean,
remove the cats all together. Problem solved!

Mike

 

[Snakester]

Thanks Mike, but I still gotta pass the California smog tests.

We worked on the exhaust a little more tonight and two things showed up.

First, the Corsa exhaust tube was slotted to fit over the exhaust tube, and the band clamp didn't fully cover the gap.
We ran the car with the side sills off and could hear a small exhaust leak, and rotated the band clamp until it covered the hole.

Also, we just fit both side sills with their insulation over the exhaust before. The driver's side was still glued in and the passenger side had separated.

We noticed that the insulation was difficult to fit between the cat and under the sill, and we were guessing that if it just moved around in the side sill then there would be an unshielded section right above the cats.

So we put the insulation around the cats first, and then put the side sill covers over them. It seems to run cooler now, but we will do some more testing.

-Dean.