Dodge SRT Viper Forums : ViperAlley banner
1 - 20 of 39 Posts

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #1 ·
Guys, as some of you know, I fried up my set of cats on my 883 RWHP DLM car -- either during the 7 pulls on the Dyno, or the 7 races against the Busas in one afternoon. Either way, they were melted, chewed up and spit into my tail pipe. This was not surprising and Doug told me this would most likely happen. No big deal, as I was going to pull the cats anyway. THe interesting part is whether they were fried before I raced the Busas or got fried sometime during one of the races (I am thinking it happened during the races.)

So, I went ahead and had the cats pulled, and holy shit my car got L O U D ! ! ! Now, I like loud cars to an extent, but this is ridiculous. My car has Corsa exhaust, and from what I can tell, the side muffler does nothing, and the rear muffler is straight through for the most part. Yellow Fever (Jeff) came over to my house and I showed him, and I could tell by his expression that my car was insanely way too loud. My neighbors looked at me weird before when I had cats, so now they probably HATE me.

I knew something was up when Moundirs car was running with no cats, and his car was MUCH quieter than mine was WITH cats. Main difference between our cars at that time was that he has Borla and I have Corsa.

Sooooooo, I could quiet my car down (most likely) by swapping out the Corsa with the Borlas, but I already have Borla on my RT/10 and want something different on this car. Besides, I would like to go even quieter than the Borlas. After thinking about it for a while, I have decided that I want to have as QUIET of a supercharged viper (with a 1000 hp) that I can, without having to give up much horse power. So after talking to 1Tony1 and a couple other people, I have decided to do the following:

The cats will be replaced with Moroso mufflers
The side sill Corsa mufflers will be replaced with Dynomax Ultraflow mufflers
The rear Corsa mufflers will be replaced with 3 chambered flowmaster mufflers

I am told my one of my local tuners that I should lose MINIMAL HP with this setup as the 1st two mufflers are very non-restrictive. I am guessing I may lose about the same amount of HP that I did when I had the cats on.

Now I love the way Flowmasters sound on a Mustang GT -- that metallic growly kind of sound (you know what I am talking about.) It is the best sounding exhaust I have ever heard. I am not sure how the flow masters will sound on a Viper, but Jason at WCV tells me he had them on his car and they were awesome.

My thought process behind using 3 different muffler set ups is that each muffler is set to eliminate various sound waves/frequencies, so as each muffler does its job, less and less noise (and less fequencies) will move into the next muffler. What should come out of my car in the end is something very quiet, at least for a Viper with as much power as mine is putting out. Jason did mention the flowmasters sounded awesome, but we're not sure what the sound will be like once it has passed through two mufflers and then goes into the flow masters.

Anyway, I am experimenting with sound volume and sound tone on a viper exhaust.

Please post your comments and suggestions, as I am having this done next week. If I am making a mistake in terms of logic, please point it out. I'll still have my very loud RT/10 with the borlas and hiflow cats to drive around in as well.

Manny
 

·
Registered
Joined
·
3,999 Posts
Flowmaster on the truck V-10 sound odd. But that may just be the v-10 sound. You could however, still get a hint of that trademark flowmaster sound. It doesn't have the sound of a 302 (of coarse never will), but you could tell they were flowmaster over something else.

I'd go for it, always wondered what flowmasters would sound like on a viper.

Which ones, two chambers, three chambers.........
 

·
Registered
Joined
·
5,099 Posts
I would use more of a process of elimination. Start with the FM's and see how it sounds. Then, add one of the other muffler pairs and compare. Does it affect drone? Is it louder at certain rpm's than others. Then either remove those and try the others or just add the others if you are in a rush and see the difference. Hopefully you will not need all three pairs.

Chad
 

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #4 ·
Besides driving around, I would like to quiet it down under WOT as well, as that is when I LEAST want to attract attention from local law enforcement.

-M
 

·
Supporting Vendor
Joined
·
4,047 Posts
Put a stock exhaust system, less the cats back on the car. You will probably lose 50 rw hp. But you will still have 800+ rw hp and something you can live with. Good luck with it.
 

·
Donald Trump's Landlord
Joined
·
8,621 Posts
Isn't there a Corsa cat back system with dual rear mufflers? (4 total) Sean Roe used to have them. They're somewhere between stock (with cats) and the standard Corsa system (with cats).
 

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #8 ·
Not sure about those Corsas. Mine have mufflers in the side sills and mufflers in the rear, both of which seem to be on there for looks more than anything else. The previous owner said the car was loud when it was stock with this set up. Unless somebody tells me why my set up above (using 3 different mufflers) is a bad one, I am going through with it and see what happens. The mufflers are pretty cheap (less than $100 each).
 

·
Registered
Joined
·
3,474 Posts
Manny, the easiest way to quiet down the car to a stock leveland have way more power is to go twin turbos! LOL!

I have to tell you the Dynomax welded ultraflows to your car will be loud! I had those on my car when it was stock and it was loud as hell. I do not know what to tell you.......
 

·
Registered
Joined
·
1,251 Posts
I have the B&B's on my car with the stock cats (they were cut in half and re-welded I believe). I make mid 800 horsepower and have never had any problem with this setup (in terms of making horsepower or burning up cats). The Corsas are really loud and to my ear they are somewhat raspy on the Viper. I know a lot of people here have them and love them, but I like the deeper tone of the B&Bs. You might want to check this setup out.

Also, I've been thinking about your cats burning up. I've seen a bunch of cars that make the kind of HP we do and they did back-to-back-to-back dyno pulls and trips down the track. I've never seen this problem. Is it possible that the methanol is burning up the cats? I know you said you were injecting methanol and I know that cats can be adversely affected by different kinds of fuels. Just a thought.
 

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #11 ·
Gary, I'm in California with 91 octane, so my car is probably running a bit richer than most DLM cars do, for extra safety. That and the fact I did 7 back to back races with almost no cool down most likely fried them. Plus, I went an extra 40 MPH faster than most people do on a track, even if they were going back to back to back.

Paolo, would adding the ultra flows in addition to the other two types of mufflers quiet the car down vs not putting them on? For example:

2 Morosos + 2 flow masters
vs.
2 Morosos + 2 Ultraflows + 2 flow masters

The scenario with the 6 mufflers should be quieter than the 4, right? Is it a linear thing like this, or is it one of those cases where 2+2+2 doesn't always = 6?

-M
 

·
Registered
Joined
·
7,245 Posts
There would have to be a fair bit of methanol injected with the water to toast a pair of cats, but it is possible at WOT racing in back to back races. It's probably more likely it was just the unusual combo of 7 back to back runs and heat soak combined with a lot of unburnt fuel burning out the exhaust.... that'd make any system hot!

In theory 6 mufflers must be quieter than 4, but the tone may be different and that can mask it. 6 can't be louder than 4 however (using same mufflers) so you can't make it worse by adding 2 more.

It'd be fun to start from front to back and fire it up at each stage leaving the rear Corsa's on till the end when you swap them over for the F'masters. I think the final addition of the rear flowmasters will be the most significant change - but keep us posted - sounds fun!

the further away from the header collector you mount the first muffler the better for flow - for that reason if you dropped any pair it should be the front pair as they'll make the least difference to noise reduction and the most to power reduction given the same cfm rating.

You can help the front mufflers perform better by coating them with a ceramic heat coating and wrapping them... this will help noise a little but mainly will keep heat in and therefore aid flow. It will also shorten the life of the muffler but if made in quality material of adequate thickness - should be long enough.
 

·
RIP - Gone But Not Forgotten
Joined
·
18,149 Posts
Manny which Moroso mufflers do you want to use? The "screw" type?

If so they are a nice restriction. A gauge in the exhaust will tell you this. :nod:

I would run multiple Borlas in the sill or maybe a Spin Tech into a Borla.

Remember that the Borlas are straight thru and by using more or using a longer one will only help reduce the sound, not add to backpressure.

:twocents:



Never pay again for live sex! | Hot girls doing naughty stuff for free! | Chat for free!
 

·
Registered
Joined
·
1,251 Posts
Torquemonster said:
There would have to be a fair bit of methanol injected with the water to toast a pair of cats, but it is possible at WOT racing in back to back races. It's probably more likely it was just the unusual combo of 7 back to back runs and heat soak combined with a lot of unburnt fuel burning out the exhaust.... that'd make any system hot!
Thanks, B. That answers my question. I've always been concerned about race fuels and such and their effect on cats (in particular).
 

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #15 ·
Paolo Castellano said:
Manny, the easiest way to quiet down the car to a stock leveland have way more power is to go twin turbos! LOL!

I have to tell you the Dynomax welded ultraflows to your car will be loud! I had those on my car when it was stock and it was loud as hell. I do not know what to tell you.......
Paolo, which muffler would you put in place of where the Ultraflows will go?
 

·
Registered
Joined
·
2,657 Posts
You might have a lot higher temps inside your car with all that other restriction (compared to a straight through setup). Be prepared for a little more heat.

But hey, there's always a tradeoff.
 

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #17 ·
From what I am told, the restriction when done should be no more than what it was when the cats were on the car. I guess we will see after it is dynod.
 

·
Registered
Joined
·
1,344 Posts
If you hate drone, keep the Corsa's.

In my opinion, you are thinking way too much. Keep the Corsa's, and just put a muffler in front of them. Now what muffler, I do not know. I would talk to Summit racing about a tube-like muffler that will really reduce the volume, but not hurt the flow too much. Think about it, you have a lot of room between the header flange and the first Corsa muffler in the side sill. Your best bet is to probably get the longest tube style muffler in that area that is designed to reduce sound, but not hurt flow too much. Make sure it is a muffler that can withstand you massive flowing motor, and a quality unit that will not deteriate over time.

Why chop up a Corsa system that is specifically designed for the Viper to reduce drone and give a great sound? Don't do it...

My .02
 

·
Premium Member
Joined
·
1,338 Posts
Discussion Starter · #19 ·
Onerareviper, where is Summit racing? They do custom exhaust?

As for adding one muffler, my thought process was that adding just one muffler in place of where the cats were would simply bring the noise level back down to what it was WHEN I had cats, and that to me was bearable, but still louder than I wanted. So adding another set of mufflers in the side sills (replacing the corsas in there that I think do almost nothing) should fix the problem (I hope.)

Do Flowmasters give you drone? I know Borlas do, as I have a pair on my other car, but that is a different beast since it is side piped.

-Manny
 

·
Registered
Joined
·
1,344 Posts
Summit racing is a HUGE parts distributor. Either the biggest, or one of the biggest in the World. Jegs racing is great as well. The links are:

www.summitracing.com
www.jegs.com

OK. First off, I truly believe a muffler will reduce the sound a good bit more than a high-flow cat. To be honest, I feel at full throttle a high-flow cat does virtually nothing to reduce the sound, and reduces the emissions minimally. Now at idle and part throttle, they do seem to reduce the volume and emissions a bit more....

What you need to do is measure (precisely) a OEM cat. This is probably about the size of the largest muffler you will be able to use. A bit longer may be possible, but not much (Look at the picture below). Make sure you measure the length and circumference. A muffler that is too fat will not allow the side sills to be bolted back on the Viper. Once you have the size measured, give Summit and Jegs technical support a call and see what they recommend. Let them know you have a massive flowing motor. See if any Viper folks have already used the mufflers they recommend. They will probably recommend a tube style muffler that actually looks like the OEM cat, and is designed to reduce volume. As a matter of fact, they do sell the Moroso Spiralmax 3' in 3' out for $47 bucks.

If you ever heard a straight pipe Viper, you would realize how much those Corsa's do reduce the volume. Trust me, it is significant. I just think chopping up the Corsa system to use univeral Flowmasters, etc... is not a good idea. Could it work? Maybe. But most who have tried (and many have) end of scrapping there homebuilt system.

Why not try in steps:

1.) Put the recommended sound reducing muffler where the cat was - see if you like it.

2.) If it is still too loud, remove the side sill Corsa Muffler and put another sound reducing muffler in its place.

3.) If still too loud, replace the rears with another sound reducing muffler.

** My take is you will be happy after the cat-muffler replacement, but if not, nothing lost. Just keep adding. But I wouldn't try everything at once...

[image]http://www.viperclub.org/instructions/CorsaInstall_files/image018.jpg[/image]
 
1 - 20 of 39 Posts
Top