Why a high flow cat?

Post by **ugaexploder** » Tue Jul 10, 2007 9:02 am

I was wondering why you would use a high flow cat if it's for "OFF-ROAD USE ONLY" when you can just replace the catalytic converter with a downpipe or something of that sorts.

I'm wondering because I live in atlanta, but my car is registered in columbus and i wanted to do something to the exhaust system.

Post by **AZhitman** » Tue Jul 10, 2007 9:43 am

You might mean a testpipe, not downpipe.

Adding a high-flow cat will keep you in compliance with emissions laws, while providing the same flow characteristics as a testpipe.

Honestly (and I'm certainly no environmentalist), I don't like the idea of testpipes. Cars were built with catcons for a reason, and eliminating them is just irresponsible.

Post by **bone_stock_240** » Tue Jul 10, 2007 9:47 am

AZhitman wrote:Honestly (and I'm certainly no environmentalist), I don't like the idea of testpipes. Cars were built with catcons for a reason, and eliminating them is just irresponsible.

+1

Cats make a huge difference when it comes to NOx and unburned hydrocarbon emissions. Both of those things are highly bad.

Post by **joe603** » Tue Jul 10, 2007 9:48 am

Its off-road only because it will no longer pass an emissions test. The aftermarket CATs will not be as effective as stock...but better than nothing.

Post by **ugaexploder** » Wed Jul 11, 2007 9:13 am

but wouldn't it be ideal to get the maximum amount of hp to use a test-pipe instead of a high flow cat? or are the gains in hp very minimal between the test-pipe and high flow cat?

thanks for the replies

Post by **joe603** » Wed Jul 11, 2007 9:23 am

The gains would not be a much as you think. Our cars were designed with a certain amount of exhaust restriction in mind. In fact, some FI systems will not perform as well with free-flowing exhaust (Stillen roots type blower).

I would look for HP in other areas...I think you'd need O2 sims to fool the computer, or get a tune.

We're not talking about a top fuel drag car...

Post by **ugaexploder** » Wed Jul 11, 2007 9:34 am

yeah that's understandable, thanks for all your knowledge joe. i remember reading stuff about the exhaust system on m3's and they said the stock exhaust was actually the best for the car. i might just go with stillen, i know they've been aroudn for a longtime. thanks again guys

Post by **AZhitman** » Wed Jul 11, 2007 9:46 am

I like the Stillen and NISMO exhausts on the sedan...

Post by **DJButton** » Wed Jul 11, 2007 10:00 am

The Nismo sounds and looks fantastic, I haven't seen a Stillen, but I'd imagine similar quality.

Post by **ugaexploder** » Wed Jul 11, 2007 11:05 am

i didn't even know there was a nismo exhaust out for the sedan. thanks hitman

Why a high flow cat?

Why a high flow cat?

Re: (AZhitman)

Re: (joe603)

Re: (joe603)

Re: (AZhitman)

Re: (DJButton)

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums