High flow cats

christian370z

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.

__________________
-320whp / 259wftlbs-
SP Rays -- RE-11s -- SpecialtyZ Tune -- Swift Springs -- Stillen 25R Oil Cooler -- Stillen G3 Intakes -- Berk HFCs -- F.I. 12" CBE -- Stillen Sway Bars -- Es14 Spring -- INGS+1 lip -- CF Spoiler -- GTR Start Button -- VLED Parking Lights -- PWJDM V2 shift knob

bigdog1250

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.

__________________
350z / 40th 370z / C6 Z06 / BMW M4 / V10 R8 / C7 Grand Spot / 997.1 GT3 / S2K / Camaro ZL1 / 718 GTS / 991.2 GT3

christian370z

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:

__________________
-320whp / 259wftlbs-
SP Rays -- RE-11s -- SpecialtyZ Tune -- Swift Springs -- Stillen 25R Oil Cooler -- Stillen G3 Intakes -- Berk HFCs -- F.I. 12" CBE -- Stillen Sway Bars -- Es14 Spring -- INGS+1 lip -- CF Spoiler -- GTR Start Button -- VLED Parking Lights -- PWJDM V2 shift knob