[PEREMOTION]

Imo the best sound for the GT!!!
Roush axle-back + Borla over-axle pipe

I think to remove the cat, should bring about
+ 20 hp

https://www.youtube.com/watch?v=iOJRa5XpR9k

 

[Beechkid]

"I think to remove the cat, should bring about
+ 20 hp"

1. Removing the cats will really not gain much power.
2. Even though you are exempt from inspections, you are not exempt from the requirement to have them- all law enforcement & pollution enforcement officers at local, state and federal leveles carry a manual that identifies each vehicle and the required smog equipment, illegal engines changes, etc with pics of how to ID.
3. Any law enforcement officer (including fish & game), EPA inspector, etc. can impound the vehicle and cite it as a gross polluter
4. Once cited, a judge will decide if the vehicle is to be scrapped or returned to the owner- and you do not have any opportunity to speak in court- just required to sit & listen.
5. If the vehicle is returned- guess what, now you have to repair and take the vehicle to a federal referee station for the rest of "its life" for a smog inspection & test.

IMHO, it's not worth the risk versus the little gain.

Here's a link to a "Real Test" that verifies....on a 700+ hp engine......no gain or loss of with or without the cats!

http://www.kennebell.net/KBWebsite/C...aust_tests.pdf

 

[jlee910]

I believe you'll see a marginal increase, but not enough to even notice by removing cats, and as Beechkid stated, it's a heavy risk. I ran catless on my 85 F-150 with a built 302 and couldn't tell a difference around town or in the 1/4. The only time I've ever seen a difference was my Honda VTX 1800 motorcycle. The cats were incorporated into the muffler and were extremely restrictive. I picked up a good bit of gas mileage and power after removing them on it, but this is a totally different design than a modern sports car exhaust system. I put headers and eliminated cats on my 2001 Dodge 4x4 (that had 3 cats) due to exhaust problems, and I can't tell a lick of difference in power, and I'm still getting 11mpg with my 35" tires.

IMO, unless you're having major problems as I was with the Dodge and are exempt from inspections, don't pull the cats. Under any circumstances, I wouldn't pull them strictly for a power gain unless you're running a 1500 hp forced induction monster that may have cat failure due to flow rates, temperature, and A/F mixture. Even when I build my engine and throw on FI, I intend to keep high flow cats with my 800hp goal.

 

[JonR2006]

This is forum, in general, is all about keeping cats on...it's kind of funny...remove them if you want. In a non-inspected area you will be hard pressed to find anyone who could give a rats a$$ (law enforcement or anyone else) if you have cats on your car...

I do agree, power gains are minimal, but hey, arent we all out to get as much as possible out of cars (at least most of us who are on this forum are).

I have a catted mid-pipe because I have to pass inspection...if I didn't have to, off-road it would be

 

[Mustangfreak196]

The cats on new cars flow really well. Its not the the early 90s where they really plugged up the exhaust system.

 

[elsuave]

i had to many exhaust systems on numerous v8 cars and trucks i owned over the years. im still young in my late 20s but i just got tired off the smell. im not removing them at all on my 5.0 if later i do run LTs im running a set off kooks LTs with there green cats to pass emissions.

 

[devildog1679]

Go ahead and remove the cats. They are definitely worth it if your staying NA and want to squeeze out every HP you can. I saw a 11 HP and 9FT/lb gain. Though the smell does suck\.

 

[PEREMOTION]

i had to many exhaust systems on numerous v8 cars and trucks i owned over the years. im still young in my late 20s but i just got tired off the smell. im not removing them at all on my 5.0 if later i do run LTs im running a set off kooks LTs with there green cats to pass emissions.

I'm thinking about getting some LTs from stainless steel works or kooks. I need some high flow cats, because I don't want the smell as well. Also the black smoke sucks-.- If the police realize that, it's over :O That's tax evasion -.- Therefore you can go to jail. Stupid german law-.-

But stainless works does'nt offer h-pipes, only x-pipes.

That's why I think i would buy some kooks. LT's + h-pipe is 1700$

I have to safe some money