High flow cats
 

Which HFC'S show best performance?

Berk hfs are the more popular and as for gains? They are all pretty close all depending on what center core is used. Fast Intentions are also a good choice. Hp gains are in the 5-7 hp range? Someone could correct me if I'm off.

I have to put in a recommendation for the Berk HFCs: I feel like they have fine tuned the rear o2 bungs to produce the least chance for a check engine light. They also show very good gains, increases the exhaust sound, and are very high quality in terms of fit and finish.

That's my thought on it, but most of the popular choices here such as Fast Intentions and ERZ will be similar in most respects.

Sigh. This is like going to a library and asking where the books are.

So by getting HFC'S, the check engine light will go on in my car?

Not typically. Most HFC are built with an extended pipe to fool the O2 sensor.

hahaha

I don't feel cats are worth the 4hp gain, never seen a dyno sheet with more gains than that

I have no dyno sheet, but the stock cats are the single largest restriction in the entire exhaust system so I don't understand how that is possible. I installed Berk HFCs in my car with a Tanabe Y pipe and the stock exhaust and put down 309rwhp which is the same or even a bit more power than what other Zs with CBEs put down on the same dyno.

After installing my FI CBE, I felt an additional bump in power and will be going on the same dyno to see what I gained soon.

I know Cats are the main restriction in the exhaust, that is why I don't think High-flow cats help too much. Its the removal of cats that makes power. Saying "high-flow" cat to me is like saying "fast snail"... I think its has more of a placebo affect on power.

Sure, I guess you can convince yourself it is a placebo effect. The gains with HFCs are proven and while they may not make as much power as test pipes (duh), at least they don't smell, decrease rasp, have a hope of passing emissions, and are one of the best legal power adders. The most I have seen anyone gain here using test pipes over HFCs is 4-6rwhp. If your car puts down say 300whp, that is not an appreciable difference. You also lose torque with test pipes vs. HFCs.


High flow cats have a much less dense cell count, as well as a smaller catalyst which is why it is significantly less restrictive than the OEM cats. I think this picture makes the difference quite obvious:


http://i648.photobucket.com/albums/u..._0014_1031.jpg

Christian thanks for your input, I guess if you can get them for a good price they are useful. I wasn't quite sure how well they performed, I just knew everyone claimed they had them but never really backed them up. Hard to tell how much bigger the stocks really are with that heat shield, but you can definitely tell they are in-fact larger.

If you are looking into performance I would go the Art Pipes.
Best Gains for our vq's.

Here's a nice review of the Berk's:

http://www.3 7 0 z.com/MagazineArticles/tabid/57/ArticleType/ArticleView/ArticleID/43/Default.aspx

(get rid of spaces)

Dyno is on page 5. The results seem a bit...ambitious, but nonetheless gains are MUCH more that 3 or 4hp. I think it was test pipes that showed minimal gains over HFC's. I believe FI had a video of their dyno sessions a while back to compare stock, HFC and test pipes.

There is someone that gained around 20whp with just the Berk HFC and everything else is stock.