I'm currently running a test pipe and hate the smell that comes with it. I wanted to know which highflow cat such as ams/ur/spec-x is the least restrictive and loses the least amount of power.

 

Bad smell? Guess I've been around catless cars for too long

Sorry I can't be of more help. I haven't checked into highflow cats for anyone. Hopefully won't have to either

 

I havent heard of many people going from test pipe to hfc, so its hard to tell you which brand is best, you should just check into hfc that people gained the most power from and my guess would be that thats the one you would lose the least amount of power from. It should be minimal either way.

 

Here's a back to back dyno of our Metal Substrate High-Flow Cat versus our Mini-Muffler Test Pipe (straight through). Special thanks to mad_viii for dyno'ing these parts.

http://s331.photobucket.com/albums/l...SSC_HP_AFR.jpg

Darryl
www.ultimate-racing.com

 

If the boost was identical, then the catless pipe made more power everywhere except for the upper-end. Stock cat vs straight test pipe, we observed the difference between 345-375whp but the boost jumped up nearly 1.5psi.

I'd say live with the smell and stay catless. Drive a Prius to work

 

There are a few brands out there, but I dont understand why these cats are not as expensive as the stock Cat. Cats are expensive because of the Platinum inside them. I have not seen till date any aftermarket HFC manufacturer state what metal it is exactly that they use. check the following link to understand a CAT.

http://en.wikipedia.org/wiki/Catalytic_converter

The reason I bring this to attention is because there is a good reason why these expensive metals are used in CATs. They are long lasting and are hence used to comply with the legal requirement in the US to last for long (100000 miles/10 yrs whichever is earlier I think). A bad HFCs may not long last due to the material involved and might be a recurring expense. I have no experience with HFCs whatsoever, if anyone with more knowledge in this matter can shed some light, the OP might be able to make a more educated choice.

 

I don't really see your point here.

Historically stock OEM parts are more expensive and are usually not of the same quality as you can get as aftermarket. Where the OEMs really rape you are on parts no one else sells. It's all about profit.

The main reason people change out their cats on cars like the Evo is the fact that aftermarket cats flow better...hence more power.

 

I couldn't agree more with you about the build quality being better. My concern is the fact that other metals can also be used in a Catalytic converter, which may not last as long as the OEM one. Are the aftermarket CATs also subject to the same law of having to last that long?

Again, I wouldn't dream of disputing your statement here, but one needs to consider all that is going into these after-market HFCs to ensure a sane purchase. That's all I am saying. Also, passing emissions is a big deal. The CAT also needs to do its job of oxidation while allowing for a free flow of exhaust fumes.

 

MIL-Spec. If you dont want smell but still great performance, the Mil- spec is out flows as far as i know everything in the HFC world.
Do a search button and you will see it. They are here in the forum too. Its a true 100 cell metallic converter. Less longer etc.

I running one of they product and i love it. Also no smell what so ever. Unless you are running on race gas

i have picture from my set up if you need it.

 

I've heard of milspec but was hesitant of welding the cat to my exhaust. Although it does seem like the least restrictive which is what I'm looking for. Pics of your setup would be great

 

quick question, is it ok to use high flow cat or test pipe with out a retune?
Thanks

 

I'm running the CP-E quickpower pipe with the cat. I felt noticeable gains from stock, but no idea what you would feel going from a test pipe.

I can tell you that when the car is warming up you will still get the gas smell and you will still need the 02 fix as i was throwing CEL's without it.

 

AMS's HFC is really good but a lil pricey!!

 

^ and whats so good about vibrants cat?

 

Its not gonna smell that much different.