Well, installed my HKS DP and now I must replace the stock Cat. What are some the recommendations for a straight bolt on.

I have the HKS DP and HKS Carbon Ti exhaust. What bolts directly on?

I live in So Cal, but have access to get Fix-it tickets written off. I'll take my chances with the straight pipe if no hi-flow cat is available...

Thanks.

 

no cat is more than a fix it ticket in ca player...FAT fine. just fyi.

 

We've had this dicussion before, if you want to stay legal, High Flow if you don't care Straight pipe. Its only a 1-2whp difference between the two (from what I hear).

Also you get the benifit from not smelling a ton of fumes at every stop light if your running a High Flow opposed to the test pipe.

I'm running a UR 3 inch cat with a B&B turbo-back and I have no complaints.

 

Great...Sounds like I will go with the Hi-Flow...Any idea who make a direct bolt on replacement? Buschur?

 

I would go with buschar only 150 bucks cant beat that about the same price as a cat delete.

 

Justin1933 ,

Is there a reason you need to replace the cat after installing the HKS dp, or is it just an upgrade thang??

Just wondering because I just installed the same with the standard Hi pwr cat back.

 

I dont see why there would be a problem with that.

 

Nope, no problem with the stock cat...I just want the car to breath better. I know with my Type R, when I switched the Cat to a straigh pipe, the car made better power...

Just an upgrade thing...

Now, I sit and wait till January for the DynoFlash...

 

Ok, cool thanks.

After I installed both the dp and the exhuast, it seemed to spool a bit quicker, but I really didn't see much of a difference. How about you?

 

jsut remember your not driving a type R, turbo'd cares make different types of power with and without cats.... luckly the evo has a somewhat high flowing cat stock so it flows decent compaired to previous dsm cats... A test pipe is best for performance jsut make sure there is no cel, however running a high flow aftermarket cat will drop your power gains by a few whp. If your car isn't heavily modified then I wouldn't worry about a test pipe over a high flow cat, if it is then i'd strickly stick with a testpipe... Another thing to remember, if your running a test pipe and tubo back exhaust and have no fuel controller your car will throw nasty flames.. Cop's aren't going to be impressed by that... there is a video of one throwing flames at a track.

 

fine in CA is about 3K for no cat. Get a carsound highflow cat they just came out with a highflow OBD2 cat

 

woah! Is this a 100% sure thing? Cause I have a tb w/o a cat and no fuel control yet like you mentioned. Does it do it at WOT only? I'll have to have some friends help me check it out

 

From what I have read it looks like the cat is probably the most restrictive part of the exhaust. It also looks like the Random Tech cat is the only one that flows significantly better than the stock cat.

Silver Surfer did some dyno runs, and here are the results:
https://www.evolutionm.net/forums/sh...threadid=37340

 

1.) run the testpipe. Remember, despite being smog illegal in CA, new cars gets 5 years before they have to be smogged. And EVO being 2003, you won't have to worry about smog until 2008.

Of course this doesn't cover you speeding down the street and getting pulled over by the cops after seeing you spit out flames. However, if you behave, i don't see this being a problem.


2.) Gut out your current CAT. That way, even if you get pulled over and cop looks under your car, he will see the cat. And if he asks why it smells, you can simply said perhaps something is wrong with the car or any excuse outside of I use **** for gas.

 

Get the Ultimate Racing 3" High Flow Cat. I have a similar setup as u with HKS DP and HKS CB. Ultimate Racing's 3" test pipe guarantees no CEL as well. Check their website for prices.