Mopar race exhaust modification

[Schulmann]

I got my lazy 06 Coupe in July and it didn't stay stock for more than a week.
I installed a Mopar race exhaust on the Viper.

Unfortunately it is very noisy and don't pass the federal 92db noise restriction.
Yes in Canada each track has now two inspectors to check the noise. One from the Federal office and the other from the track. The two usually report the same noise level. So the guys who are kicked out can't complain because there were too noisy. Naturally those federal inspectors don't stay on the track the entire day. They arrive at 7AM and leave usually at noon. The afternoon is open for fire !

I have made an exhaust plug to pass the noise inspection. It restricts the exhaust from 3'' to 1''. The Viper makes 85db instead of 98db. It takes 1 min to install or remove it. It works fine but it needs some tuning to improve the sound on hwy. One of the problem that I am having is the ring inside the Mopar exhaust tip. It prevents me to install a better plug.

What is this ring for ?
If I remove it what issue might I encounter ?

[viperflex]

Can't help you with the ring, but looks like your burning the paint around the openings. Its doing the same on mine..

[Schulmann]

The paint is an easy fix for $20 ...

However I don't want to loose $500 if I am kicked out of a track because my Viper is too noisy.

[fqberful]

Originally Posted by Schulmann

I got my lazy 06 Coupe in July and it didn't stay stock for more than a week.
I installed a Mopar race exhaust on the Viper.

Unfortunately it is very noisy and don't pass the federal 92db noise restriction.
Yes in Canada each track has now two inspectors to check the noise. One from the Federal office and the other from the track. The two usually report the same noise level. So the guys who are kicked out can't complain because there were too noisy. Naturally those federal inspectors don't stay on the track the entire day. They arrive at 7AM and leave usually at noon. The afternoon is open for fire !

I have made an exhaust plug to pass the noise inspection. It restricts the exhaust from 3'' to 1''. The Viper makes 85db instead of 98db. It takes 1 min to install or remove it. It works fine but it needs some tuning to improve the sound on hwy. One of the problem that I am having is the ring inside the Mopar exhaust tip. It prevents me to install a better plug.

What is this ring for ?
If I remove it what issue might I encounter ?

According to Borla these rings help attenuate sound waves and improve velocity. This is pretty typical of Borla construction, the package for my Vette had these in 3 places.

--Ed

[Vipermann]

I had the 3" Random Tech cats in front of my Mopar Race exhaust (instead of the open flex-pipe) and it wasn't too loud at all ... also, probably better flowing than that pipe insert you have there

[06blueviper]

So the Mopar exhaust burns the paint and that's considered normal?

I was planning to buy the Mopar exahust, but not if it will create a paint issue.

Originally Posted by viperflex

Can't help you with the ring, but looks like your burning the paint around the openings. Its doing the same on mine..

[Schulmann]

Guys this thread if about noise reduction not paint burning.
Never had any paint issue related to that Mopar exhaust .... In fact it is the best protection againts heat issues.

Should you have any paint issue it will be caused by the Cats ... You make me laugh guys. Are real Viper owners ?!

[Vipermann]

Originally Posted by Schulmann

Guys this thread if about noise reduction not paint burning.
Never had any paint issue related to that Mopar exhaust .... In fact it is the best protection againts heat issues.

Should you have any paint issue it will be caused by the Cats ... You make me laugh guys. Are real Viper owners ?!

Any comments on paint burning are only because of your posted pictures. It kind of looks like your tips are too far in (I had my Mopar tips sticking out by about 3/8"), and thus burning the paint around the opening ... at least that's what the pics appear to show

As for the sound reduction, your mod really doesn't look that practical to me, IMO (and I experimented with 4 different exhaust systems on my '05)...

[Schulmann]

Pratical ?! You make me laugh. It is a necessity to pass the 92db test.
It takes 1 min to install it and 1 min to remove. Beside I drive a lot on hwy and it is more pratical to have a quite cockpit that a noisy one.

Go to a race tracks and check what is going on regarding noise reduction on the cars. Then ask the Managers what they think about the layers who sue them for excessive noise ...

[Vipermann]

Okaaaay (yikes)

... are you triying to sell this new mousetrap or something?

[Fast Viper]

I think thats funny, but if it works to reduce noise, then excellent! Hopefully it's a temp mod? My mopar race does the same with the back, it makes a little scuff mark against the sill cause it moves a little, no big deal, nothing some 1200 degree paint cant fix

[Copperhead245]

Schulmann,

I've only been to one track where there's a noise limit, and that is only certain days/times (and that didn't apply to me).

How do the inspectors determine if you exceed the 92dB limit? Obviously, using an SPL meter, but what distance are they measuring from? What is the reference point for the distance - one of the exhaust tails, the center front most point, etc?

Is it measured in open space or in a paddock/etc.?

What weighting do they use (dBA or dBC)?

Is it a specific RPM or do you have to run it from idle to red-line?

As I'm sure you know, each of the above makes a very big difference, so I was just curious...

Ron

[JonB - PartsRack]

Originally Posted by Schulmann

The paint is an easy fix for $20 ... However I don't want to loose $500 if I am kicked out of a track because my Viper is too noisy.

Virtually every bona-fode race venue measure from the side, at 50 feet from track centerline, at a point on the track where competitors are ON THE THROTTLE FULLY.

A side-outlet racer therefore has an inherent penalty. Many VCCs and other sidepipers simply add a right-angle diverter to the tip, that elbows the exhaust stream REARWARD. This collar can go on w/ 4 allen-set screws and be FAST on-off, assuming the outlet is not too far inside the sill.

The elbow pipes cannot exceed about 4"-5" outside the body, or some OTHER tech rule might be violated

[Copperhead245]

Hey JonB, its Ron R (Copperhead in NJ)...

While I don't expect to be on a track that matters anytime soon (I'm mostly @ Pocono), I will get a friend to take some dBA readings @ 50' from center of road while full open throttle. I'd imagine the Corsa Track I just got from you will pass, but I'm just curious (the geek in me)...

If it is above 9XdB, do you have (or can you get) elbows that'll fit the 3" Corsa?

Thx,

Ron

[Nader]

Ron I ran at both Pocono and Limerock and no one said anything to me. Well I take that back, one of the race instructors at Pocono, while in the car, asked what exhaust i was running and how did i pass the sound limits...