Quietest Viper Race Mufflers

[Manny_C]

I posted this in another forum and realize this might be a better place to ask. So here's what I posted:

Hey guys,

Just got back from Laguna Seca for some SCCA racing. There were two of us in Gen 2 Vipers and 2 Comp coupes. All the Vipers had issues meeting the 103db sound limit, and one of the comp coupes got eliminated from all of Sundays races because of continually blowing sound.

The rest of us would have to short shift into 5th or lift a lot when going by the sound booth. This is killing our up hill speed and lap times. I can literally see the car behind me make up about 10 to 20 car lenghts every time I went by the sound booth.

That being said, for those of you that have 600+ RWHP cars, what kind of secondary muffler can you fit into the side sill section of a GTS? All of our cars have side exhaust. We want mufflers that can take a beating, the heat, the power, and that will cut out sound in a big way. Anything to get us around 100 DB when wide open throttle in 4th gear (think of a dyno pull.)

I think most of us have just 1 muffler in there now. I know that I had to add 3 mufflers to my Supercharged viper at 883 RWHP to make it nice and quiet driving around town, but that had rear exhaust -- something my race viper doesnt have.

Any help from somebody who knows of something that will work for sure would be great. I have another race event next weekend and I would love to order a muffler and test it that weeend at Button Willow before heading back to Laguna Seca in 3 weeks.

Thanks,

Manny

PS: These are full on race cars, so no cats. Also, how much HP should be expected to be lost from this?

[kjslider]

Is it true you knuckleheads got beat by a Honda Civic this past weekend?

I was cracking up watching the vid clip you posted on OTR. You had to coast uphill. That costs you time all the way to the corkscrew.

[Manny_C]

Gunter and I took the #1 and #2 position in the first race. In the 2nd race, Gunter wasnt racing and instead testing his car, coming in to the pits, making changes, going back out, etc. My car was broke (transmission) so I borrowed Gunters GTS and started the race from the back. I was pretty far back too -- somewhere around the corkscew when they threw the green flag. It was too much of a deficit to make up in a friends car I didn't want to put at risk. So the Honda and 2 other cars beat me in the end (I passed the other 30 or so cars in the race.) It was fun though running a race in a viper other than my own. I learned about some things his car does that mine doesnt, and vice versa.

You shold break out one of your cars for the Laguna Seca event at the end of this month. I'll be back and hopefully drive better. I doubt there is much we can do about the sound. Gavin has spent thousands of dollars on various mufler combos with no luck. I even asked Skip from Viper Days and he wasnt sure what could be done. We just have to lift and that has to be at least a second lost right there. Coasting sucks.

So hit your garage and pick a car.

Manny

[kjslider]

I've got a GT up on the lift and Mueller's doing his "stuff" to it. We head out to a private track day at Willow Springs this Tuesday.

If it runs well we'll turn it into a dedicated race car and take it racing

[REDSLED]

Originally Posted by kjslider

I've got a GT up on the lift and Mueller's doing his "stuff" to it. We head out to a private track day at Willow Springs this Tuesday.

If it runs well we'll turn it into a dedicated race car and take it racing

I wanna come play on Tuesday.

[kjslider]

Hey Martinez, obviously you would be welcomed if it were my event but it's actually an all GT thing.

Neil Hannemann, the Cheif Engineer of the Ford GT project, as well as the Viper Lemans project, is the head instructor ( I'm hoping to gain some insight into the GTS-R's too) . Mueller knows him. Anyhow there apparently are something like only 6 total GT's going and sadly two of them are mine.

With so many GT's here in the southland would think it would be sold out. They were counting on 20.

[BAD68GTO]

I am runing a Corsa cat back with teh 4 Corsa mufflers and where my cats are, I am running Moroso Bullet mufflers from Sumit $99 each. It has 6 mufflers total and is VERY quiet, prob as quiet as stock I think. :-) I drive it daily too and with this much HP it is nice on the ears, yet still has gogogo power!

[Manny_C]

I dont remember, but I think I had Moroso's where my cats go on my super charged Viper. We went through quite a few different exhaust options to quiet it down and I dont recall what it was I used. The moroso spirals sounds familiar. Is that the kind you have? Did hear your car without the Morosos and just the Corsas? If so, is there a big difference when adding just the bullets ?

[BAD68GTO]

Honestly I only had the Corsa with the Moroso mufflers, as I changed even my headers at the same time.
Old set up on my Roe 2000 GTS:
Stock 2000 GTS headers, high flow 2.5" cats, 2.25" Snake Oil no muffler exhaust, very quiet, I think as quiet as a stock Viper or only slightly louder! Lets say stock as a 5 on a 1-10 scale for noise, this was a 6.

New Set up:
TNT 1.75" Headers, Corsa, no cats, but Moroso Bullet Mufflers
Only slighly louder at idle, and not bad at all even when you get on it. Lets say stock as a 5 on a 1-10 scale for noise, this was a 6.5 or MAX a 7. My side sills are a LOT cooler too!

You can see my car here as well as hear the new system. This was done two weeks ago:
3000GT VR-4, 16Gs, methanol, blah blah blah, getting slautered by a supercharged viper GTS. - Video

Hope this helps! Gary

[THOR]

Greetings Manny:
Long time last time. Although I cannot yet personally speak of the results, I found some vortex cones (from Dynatech) which you install behind the headers for dB reduction w/o a power penalty. I bought a pair - which are waiting for me in my garage - that will be installed when the headers go on.

They are available in 3", 3.5", 4" and 4.5" T-304 SS. Here's a link at Jeg's for them:

Dynatech 72-32520 - Dynatech Vortex Insert Cones - JEGS

Let me know if you end up trying these.



**** If anyone has already installed a pair, I would be curious to hear your comments as to how well these cones work.



Cheers

[sundiego]

Manny, I got by 103 sound in my GT350 there by using large performance car mufflers, pointing the side pipe down, short shifting and driving up the left side of the track. I didn't lose too much speed that way and only got one warning. I'll find the name of the muffler. An X pipe in the system helps too.

Flowmasters.

[Manny_C]

I think I have found the magic combo. I know some guys who have spent thousands of dollars on their exhaust setups to pass sound at laguna without lifting, and it never works.

My car already had dynomax on the side sills, so I bought some 21" Lobak mufflers and installed them before the dynomax. The car lost some power, but it sounds about stock when going flat out down the straight. You can actually hear the wind coming off the car isntead of all roar. I'll be testing the sound capability of the exhaust next weekend at the Laguna Seca SCCA event.

-Manny

[sundiego]

You may still want to do an extension/turndown on the right hand side so you aren't aiming the sound right at the meter.

[Manny_C]

I never came back here to update you on the sound. We ran the exhaust combo at Laguna Seca and went flat out by the sound booth in both 3rd and 4th gear. The loudest reading we could get was a 94Db. On average, it was around 90db.

So for those of you looking to get under the 101db sound restrictions that SCCA has, this is the perfect set up. No lifting!

M

[GTS Dean]

Originally Posted by Manny_C

Just got back from Laguna Seca for some SCCA racing. There were two of us in Gen 2 Vipers and 2 Comp coupes. All the Vipers had issues meeting the 103db sound limit, and one of the comp coupes got eliminated from all of Sundays races because of continually blowing sound.

All of our cars have side exhaust.
Any help from somebody who knows of something that will work for sure would be great. I have another race event next weekend and I would love to order a muffler and test it that weeend at Button Willow before heading back to Laguna Seca in 3 weeks.

Thanks,

Manny

Manny, the problem is that the dB meters are probably aimed at the side of the cars, with the exhaust outlets pointing straight at the dB meters. This is a tough situation. Point them out the back and you have some hope. I think I read Luc saying that his stock GTS wouldn't even pass the noise requirement at Laguna.

[REDSLED]

Originally Posted by GTS Dean

I think I read Luc saying that his stock GTS wouldn't even pass the noise requirement at Laguna.

A stock GTS exhaust will pass the 92db at laguna (barely)
Yes, having side exhaust does play a factor for the Viper race cars as well as Comp Coupes. I hesitate to choke down the race car to the DB lavels Manny's car was running as no one can say if the EGT were too high, due to too much back pressure.

The db levels at Laguna vary according to the time of day and the vent that is being held. For example, when SCCA is racing the max db level is 103 db only during the times that the High HP cars are n track. Smaller displacement motored cars and sports racers have lower db limits.

On regular non-SCCA track days (no matter if during the week or weekend) the db limit is 91-92 db, depending on the time of year.

There is no Laguna Seca mandated sound limit only a handful of times during the year and those are when the ALMS cars run, Rolex Series, Champ Car, and a Christian Rock Concert. Go figure

Unfortunately, many areas surrounding well established tracks are putting preasure on track owners to establish and enforce sound limits.

[sundiego]

And no limit for the Historics! I think it's 7 dates a year they can have no limit.

[REDSLED]

Yep, I forgot about the old man cars! You should come out to play @ Buttonwillow on the Sat & Sun after Thanksgiving. There will be about 5 Viper race cars out there as well as some vintage mustang, Trans-Am race cars. It is with Green Flag Racing.