Simple cat/exhaust question

[JohnnyBravo]

I have a 1998 GTS. The temperature from the factory cats is killing me.

I have read perhaps every possible thread on this topic, but haven't been able to piece together an answer to my question.

I have a few options available to me (because I live in a non-emission state).

I can:

(1) cut the factory cats out and replace them with a small piece of 2 1/2" pipe, and leave all of the other factory stuff in place;

(2) cut the factory cats out and replace them with 2 1/2" high flow cats;

(3) cut the factory cats out and flare the end to 3", ditch the cats completely, but add a cat back exhaust; or

(4) cut the factory cats out and flare the end to 3" and install 3" highflow cats and a cat back exhaust.

Obviously, option one is the cheapest. Just a cheap piece of pipe and some clamps. Option 4 is probably the most expensive.

Would one be quieter than the other?

Would one yeild better performance gains than another?

Aren't most of the HP gains attained just by ditching the cats?

I know bits and pieces of this have been discussed, but I just want to make a decision and get the most cooling/bang for the buck I can.

Thanks in advance,
JB

 

[sbkim]

JB - what's up! hope you are enjoying the Viper over the Supra

I chose option #2 from Sean Roe. I have the 3" Borla cat back as well. Sill temp have improved some what but the car still gets pretty hot. I didn't want to run without cats b/c of emmission and having to run 02 emulators. I didn't gain ton of power from doing this (may be 10rwhp?). I heard some guys with no cats and aftermarket exhaust and sounds great. Also look into exhaust wraps sold by Roeracing.com. Good luck and hope all is well in KC

 

[Anaconda]

(5) Side sill insulation kit. It would be the quietest, but offer no increased power....

http://roeracing.com/ProductCart/pc/viewPrd.asp?idcategory=9&idproduct=203

 

[PDCjonny]

I had Roe Hi Flo cats installed recently, along with the side sill insulation kit, to go with my previously installed Corsa cat back exhaust. I must say I have not noticed any real decrease in cockpit temperature, it was still an oven last weekend. Don't know about any HP gains. I like the sound, it's certainly louder than with the factory cats. But if you are doing it just to reduce the heat, it is marginal.

 

[LETHAL GTS]

Go 3in all the way back from the 90o (no cats) near the headers and don't plan on sneaking around after.

 

[PhoenixGTS]

(5) Side sill insulation kit. It would be the quietest, but offer no increased power....

http://roeracing.com/ProductCart/pc/viewPrd.asp?idcategory=9&idproduct=203

Helps but is not a solution to sill heat issues. Of course When I drive in 100F+ temps nothing helps much. If I am not mistaken, it looks Roe reduce the price drastically though so worth a try.

 

[Matthew Klinger]

I just recently did the CAT delete on a stock exhaust. Cockpit is alot cooler, it is not much louder (maybe 20-30%), and I assume I gained some horsepower.

Its pretty simple, you can either get a a 2.5" 2 foot pipe at NAPA (6.99) when you pick up the clamps or you can get a 3 footer at pepboys (11.99). I had to get one of each cause each place only had one. Hardest part is pulling the old cat off. I flared out the input to the resonator alittle and pushed the 2.5" pipe about 2 inches into the resonator. Used the flared end in the front and used the NAPA clamp there. I also had to buy a new facory clamp cause one of my old ones were stripped. I need O2 sims now.