ozzypriest

iTrader: (2)

Hey - has anyone seen or gotten any before and after dyno numbers for the addition of just an HFC? I'm just about to pull the trigger on a pair, and I cannot find any numbers - I could have sworn I've seen some graphs in the forum but I can't pull anything up.

Anyway, my concern is that i'll lose torque down low (<3.5k) - I am not sure if this is true, but I could have sworn that I have seen some dyno graphs with a low torque loss - can anyone talk about this, or point me towards a thread?

ozzypriest

iTrader: (2)

So nobody knows nothin', huh? Bump for knowledge.

hispeed-lowdrag

iTrader: (7)

just from my butt dyno I'd say you don't lose any torque but I haven't seen any dyno's, I'll keep my eyes open though

amf25

iTrader: (3)

do HFCs keep the infinity exhaust sound except louder? on the search for forum and youtube clips...

hispeed-lowdrag

iTrader: (7)

lol here you go...https://www.myg37.com/forums/media-s...-berk-hfc.html

amf25

iTrader: (3)

thats perfect, sweet thx

TheLocNar

iTrader: (5)

Our cars are goofy. It really depends what mod(s) you add first. If HFC is your first mod, expect 10-12ish HP and 5-9tq. But every mod after that (intake/exhaust etc.) will only give you a few more hp/tq.

Q8y_drifter

yup ^^
I installed a CBE and CAI first. then after adding HFC's, i strapped it on the dyno and gained 7whp from them.

ozzypriest

iTrader: (2)

Yeah, but do you lose it down low? I don't know, and I can't find anything, so that's why I'm asking - sometimes with HFCs, the toque curve gets all screwy - another worry is that godawful hiss I hear on some of the videos - is there a particular HFC /exhaust combo that avoids the hiss? Or, a particular HFC that is less hissy than others? Lord, I am making this so complicated.

TheLocNar

iTrader: (5)

My car's been punchy down low actually... from a stop that is. I still have a bit of that lag from 20-30ish or so, but it's not as bad as it was when I was stock.

You will get hiss with any HFC. That's just the nature of them. But with intakes and CBE, you just won't hear it anymore.

ozzypriest

iTrader: (2)

^^ ha ha good point. The G8s I know with HFCs didn't have any hiss (that I could tell) - nature of the V8?

daveinli

stillen Gen 3's, everything else stock
272.7 HP on Dyno

Stillen Gen 3's, Invidia HFC and Invidia gemini Cat Back Exhaust
283.9 HP on Dyno

Stillen Gen 3's, Invidia HFC's and removed Invidia Gemini Cat Back Exhaust
301.1 HP on Dyno Consistantly for a few runs

2009 G37X AWD 7AT Coupe

quieter car with more HP
the Cat back Gemini exhaust is still for sale 600 plus shipping if anyone is interested PM me

Q8y_drifter

try to tune the G with the exhaust on and without the exhaust on. I'm willing to bet it will make more power with the CBE on.

TreSe7en

iTrader: (2)

^^hmm those numbers don't make any sense, lost of 17 hp from a CBE?, you sure there wasn't any leaks?

Q8y_drifter

either the conditions were very different (maybe the correction factor was not the same?) or the stock exhaust limited airflow which made the AFR richer which reduced detonation (assuming it was lean and was pulling timing with all the bolts ons)