I know this topic has been discussed but I want some more feed back. Putting aside the fact that the cat delete is illegal and that the cops can jack you for it, what would you use for your evo? A cat delete or a high flow cat?

What are the positive's and what are the negatives? I am putting together my entire ehaust system in a few days and I am looking for input on which brand and what type of cat (or non-cat) I should get and if it is even worth it.

Any advice and opinions are welcomed.

Thank you in advance.

 

Testpipe/Cat-Delete
About $75-100
Produce a different kind of smell some don't like.
Illegal, also polluting the earth
Will free up the flow better than anything else


HF Cat:
About $150-175
Not sure about a smell
Legal and safe.
Will free up the flow better than stock


There's posts that say AL did back-to-back tests and the HF cat from Ultimate Racing is nearly identical to their testpipe. The testpipe did give a few more horses, but was very close. I know several running the Pruven testpipe, I can't speak to it.
There's also a company out of like Arizona (not Vivid Racing) that produces a fake straightpipe that looks like a legal cat. Just do some searches to find out.
My advice is if you decide on a HF cat, go with UR. If you decide a testpipe, go with whomever.

 

One thing that factors into the HP differences between cat and catless cars is the level of mods. Once you get into cams, headwork, turbos, etc. going catless will give you a bigger gain.

The reasons I run a high flow cat are noise and the rotten egg smell. Too much of either is great reason for a bored po-po spend some time with you.

 

When I did my dyno testing out at Axis racing I finalized my tune on pump gas and race gas, and then swaped in the high flow 3" cat from Buschur Racing. Putting on the CAT caused a 1 psi drop in boost pressure and resulted in 20 HP drop. After raising the boost back up to compensate for the lost pound I gained back 10 HP for a total net loss of 10 HP when putting on the high flow CAT. This is with every mod other than upgraded turbo, head work, or increased displacement.

One of the advantages not mentioned so far is how much quieter my car is with the CAT, I love having the car be quiet and still being able to run a 12.5 sec 1/4 mile at 110 mph on pump gas

Keith

 

Smokey-

If you decide on a testpipe, I have the Perrin pipe available. It was used for about 2 weeks (for testing). I also still have the CEL eliminator which was never wired. So, if you would like it then PM me.