Cat removal??

[grayman]

Just got 2000 GTS with Mopar cat back. Im in a non-emissions area and am considering removing cats. This made a significant difference in other cars Ive had and was wondering anyone's experience with this on 00 vipers? Can I buy a "test pipe" kit for cat replacement somewhere or just go with the "weld shop special" piece of pipe with mating flanges welded. Would be nice to jsut buy an easy fit kit somewhere. Have read threads about the check engine light as well. This doesnt particularly concern me but any other adverse impact on the engine would. Any pointers appreciated.

 

[Joel]

Think that engine light is a BAD thing which will affect mixture. Also no cats means big fumey smell, do a search on the forum, theres loads of posts on this topic. And have a good Christmas

 

[Sean Roe]

For "off road use", you can replace the cats with straight pipe (you'll need 25" of 2.5" o.d. pipe with one end expanded to 2.5" i.d.) and add two downstream O2 sensor simulators. No check engine light, engine will run properly, lower side sill heat, more power (though good high flow cats are very close to the same), but you will have a fuel smell (Vipers run rich with the stock PCM calibration) and your back bumper will get stained from the fuel in the exhaust.
We have the downstream O2 simulators on our website under engine / performance if you need them.

 

[LTHL VPR]

We have done some cat and cat-less testing (with my 98 GTS and 2001 ACR) using our in-house dynojet. While removing the cat may sound like a great idea, we did not observe noticeable power gains until we upgraded the headers as well.

My recommendation to you would be to use high flow cats which will reducr backpressure and improve flow, but not too much with the stock headers...If you need great 2 1/2" high flow cats, we stock them.

If you decide to go cat-less anyway (for max sound level reasons,etc..) we make a 'plug-n-play' kit called Snake Boxes that allows you to do this in a few minutes. We have sold over 35 kits to happy Viper owners. The kit includes EVERYTHING you will need for a quick and clean installation.

Hope this helps!
Happy Holidays!
-Wayne (LTHL VPR)

 

[bad viper]

If you do remove cats...I went with stainless steel Borla Sportsman mufflers in their stead. 14" long 3 " inlet,3" outlet ,3 1/2 " in diameter.
Distinct mean sound.

 

[Chuck 98 RT/10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by LTHL VPR:
While removing the cat may sound like a great idea, we did not observe noticeable power gains
<HR></BLOCKQUOTE>

How unnoticeable were they? I removed the rear muffler and gained 10hp. I would think a high flow cat or a straight pipe would produce at least another 10hp. Just a guess right now.

How much is your "plug n play" kit?

 

[Tom and Vipers]

Righto Wayne!

What I really like about Bad Viper is that you can stand 4 feet from the exhaust and it flaps your pant legs!!!!!

Stock Viper exhaust is a pathetic drool when compared....

 

[ACR Joe]

Install headers and high flow cats instead. Best sound, no fumes, no staining rear facia, etc.

I did the no cats thing for a while. High flows are much better. With factory headers, I doubt you gain very much by simply removing the cats anyway.

 

[Kid97GTS]

Jack the cats, go with a Borla "cat-back" (can be had for less than $1,000) and get some niiiiiiice headers. Word around town is that when this combo goes a'huntin' on the toll road, little Ferrari 550's run and hide behind the gates of Casa de ******.

Seriously, I am totally pleased with the above combo and the noise/smell concerns raised by some of the ladies here aren't that big of a deal. First, while the noise may be pretty harsh while standing outside or watching the car go by, the noise inside the cabin really isn't that bad, especially at freeway speeds in 6th (with a 3.54 gear set). Secondly, unless you plan on camping out with the car in your garage, I don't think you'll have a problem with the smell, especially while driving. If you can smell the fumes in the cabin, cats or not, I'd be thinking exhaust leak. As far as staining the rear bumper, thanks, but that job was taken care of by the stock system and the niiiiiice little black specks it liked to throw. I haven't noticed any further problem with the no cat/Borla/Hennessey header combo.

As far as I am concerned, the only time the cats should see the car are when the smog man needs to do his thing. I'm not real big on the idea of spending $300+ for aftermarket high flow cats and then watching the packing from said cats blow out the back of the car at the track - as witnessed trackside by PMUM and several others. Anyway, speaking from experience, my opinion is in favor of the cat-less approach, especially in combination with any other exhaust mods.

WAR FLAMING, STINKING, ROARING, BELCHING SNAKES!!!!!!

 

[Richard K]

I've got SVP's and a Borla cat-back. I removed the cats and made up some test pipe segments right from the start. The sound is louder but in my opinion not over powering. I have hi-flow cats on now, but also believe I lost a good bit of power by putting them on. If you stop at lights (I assume you do) with windows down/top off, you WILL smell the fumes, or in stop and go traffic. I had a number of people comment that the car was awesome but smelled terrible. Of course if you can deal with the fumes when the car isn't moving, and don't mind that the guy behind you is turning shades of green, then go without.

 

[ACR Joe]

The weird part is both Sean and I get the fumes at speed with the window(s) part way or fully open. No leaks for sure ..... weird aerodynamics!


.... oh, and as far as being a lady? That brown residue that accumulates on the rear facia also accumulates inside one's lungs. Lady? No! Smart? You bet! Do what you will.

 

[Kid97GTS]

Maybe those fumes you and Sean smell are coming from the brakes. As far as the residue ending up in my gills, I'm not in a habit of putting my grill near my rear bumper while driving, so I guess it's not really an issue for me. But, I do see your point - a lot of older guys don't really like the marginal increase in noise/smell. Just gotta go with what you like.

 

[Sean Roe]

It seems to depend on the car a bit. Some run richer than others and those are the ones you notice the exhaust smell in. We had one GTS without cats at the Justin Bell School that would almost make your eyes water to ride in (though this is not the norm). That same car even had it's rear bumper catch fire decellerating from the top of 3rd gear (I was riding with a student and we were right behind it). You know how you can get those little flame bursts on shifts with no cats and a hot exhaust? This one started like that and kept getting bigger. Kid, your '97 does not run as rich. Pulling the cats won't change the air / fuel ratio through '97 and the '97's in particular seem to run a better (read leaner) air / fuel ratio. Might have something to do with that big stick you were bragging about.

<FONT COLOR="#ff0000" SIZE="1" FACE="Verdana, Arial">This message has been edited by Sean Roe on 12-26-2001 at 08:24 PM</font>