Cat removal???????

[SoCal Rebell]

Just put a set of Balanger tri-y headers and 3" catbacks on. I am looking for h.p.
should I remove my cats? What are the pros/cons, how much extra h.p. can I expect from removal.

 

[LTHL VPR]

Removing cats....

Pros:
1)You should pick up about 8-12rwhp on the dyno throughout the RPM range. I did on mu 98 GTS with the exact setup minus the gears and flywheel.
2) Your side sills will be MUCH COOLER and they WILL NOT DISCOLOE!!

Cons:
1) On a 2000 your check engine light come on and stay on (=annoying). I am not sure if anyone has the made an adpater for the rear O2 sensor to trick it so the Check engine light stays off, but these are available on just about every other performance car out there.
2) Exhaust will be very loud and you will get hear tons of pops and flames shooting out the rear (personally I think the flames are a pro, not a con), but I don't know if the local police authority will agree.

However, you may want to try using Sean Roe's high flow cats or the ones made by Dynomax, Magnaflow, Random Technology or Buschur Racing. they are all good quality pieces. You should gain about 1/2 to 2/3 of the hp, loose the flames, and keep the check engine light off.

Let me know what you decide, and I am curious of the results.
-LTHL VPR

 

[JonB]

Con # 3.......STINKY ! Eye-watering fumes. Was especially BAD on sidepipe cars, idling 20" below your eyeballs !!

Con $4.....in Caluf, YOU coule be the "Con" !!


(PartsRack has 3" cats that flow 560 CFM..twice stock !)

JonB

 

[Paul Fischer]

After spending some time in a catless sidepiped '94 RT I have to add that not only was there no objectionable exhaust odor (which surprised me, I was expecting fumes) the car passed emmisions testing here in Texas. It sounded great, much fuller rather than louder. I was able to hold the exhaust piping where the cat had been in my bare hands five minutes after the car had completed a hundered mile drive on a 80 degree day (that's how long it took to pull the sills). Sidesill heat was non apparent, completely gone.

 

[Kid97GTS]

The sound of a cat-less car is quite a bit louder (especially during WOT - something John Q. is sure to notice). The "pop" on decel is not something that bothers me, but I am also coming from driving a catless, and at times muffler-less, muscle car on a daily basis. As far as harming the environment, as I have detailed in earlier posts, the marginal pollution that a cat-less Viper will produce, especially given the frequency that most Vipers are driven, will not be significant. If you are really worried about it, don't eat beef for a month (the methane and water associated with raising one cow will outweigh the damage your cat-less Viper does to the environment - or you can pull your cats and drive around eating a hamburger in a styrofoam container while spraying aerosol hairspray out the window

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).

You will, however, NOT pass the sniff test in CA. Easiest solution to this is to have a flange put on your pipes so you can put your cats back on every two years to get smogged. Or, given the relatively small loss in hp, go with the high flow cats to avoid the annoying check engine light and cost and effort involved in the cat swap via the flange route. Only question I would have there is whether the aftermarket high flow cats will stand up to repeated use. Anyone have any first hand experience, or better yet, number of miles used since putting on the high flow cats?

 

[ACR Joe]

The effectiveness of catalytic oxidation (HC and CO) and reduction (NOx) processes is a function of many operating parameters including exhaust gas residence time. High flow catalysts would seem to decrease residence time with a corresponding decrease in conversion efficiency.

How is it then that high flow catalysts are able to reduce emissions to (presumably) mandated levels yet offer a significant enhancement in performance. I can understand how that would be acceptable in the days of the idle test, but now that a modified LA-4 cycle is run with the car on a chassis dyno, it is a very different situation.

RSVP as appropriate!

 

[SoCal Rebell]

Thanks for the responses, I went with a high flow "Bullet Cat" from JonB at Parts Rack. 3" in, 3" out double the volume of a stock cat. I will post observations as well as dyno and drag #s soon.

Motorful Ron (yes I got my motor back)

 

[JonB]

PartsRack backs up our Hi-Flow Cat, with a 2yr/24,000 mile emissions guarantee, and a 5yr/50K mile on structural integrity (ie rattles.) We also can avoid down-time, by sending "Up Front" warranty repacement converters.

Exceptions: Owner neglect (ie physical damage, overheat due fuel mixture tuning,) is not warrantied.

Important ps: We have had ZERO warranty claims!

JonB PartsRack

 

[Chuck 98 RT/10]

I side with Kid97GTS. Also what happens to all these cats when they are used up? Is there a place that recycles them?