High Flow Cat and Back Pressure

[98-Eclipse-GS]

Ok Here it goes, I am new to this But I have a AEM CAI, DC Sport Headers, and a 5Zigen catback Exhaust on my 98 GS. Should I put a High flow Cat on, and if so what will that do for my backpressure??? I know that backpressure is a more important when you are working with a turbo, but I just want to know if I should even bother with a high flow Cat and if so Which one????

[kjewer1]

I recomend highflow cats on all types of cars, as a strategic part of a complete exhaust system upgrade.

[Whathits14]

The cat is generally the most restrictive part of the of the exhaust system, so a high flow cat can really open up the airflow, especially if you already have header and catback.

[98-Eclipse-GS]

I know that the OEM Cat is Restrictive, But what about the Back pressure, and how will it affect my performance???? What Cat should I get and from where???

[gen2gst95]

depends on where you live, but i would recomend a test pipe instead of a high flow cat. In Illinois, where I live, the cops are too busy hunting for potheads to notice. As for the backpressure thing, I'm not too sure about how much it helps. All i know is ive never seen a smaller exhuast system give more power than a larger one.

[scottsee]

i recomend getting a downpipe with cat elimnator (meagan). the less back pressure you have the more effecent your exhaust stroke will be, wich in turn will help vac pressure let more air into the combustion chamber durring your cam overlap. it wont help alot but any help is better then none!!

[Kuhn]

From everythings I've read, a high flow cat is only slightly more restrictive than a test pipe... with the benfits of being legal and not destroying the environment. ...The fine in CA for a test pipe is around $2500

[98-Eclipse-GS]

Originally Posted by gen2gst95

depends on where you live, but i would recomend a test pipe instead of a high flow cat. In Illinois, where I live, the cops are too busy hunting for potheads to notice. As for the backpressure thing, I'm not too sure about how much it helps. All i know is ive never seen a smaller exhuast system give more power than a larger one.

I live in NY, and there is no way I could use a test pipe. Also our inspections just changed and when you get an inspection they hook your car up to a computer and run a diagnostic and check emmisons, I am not even sure if a High flow Cat will pass.