High-flow cats?

[Boofneenee]

Originally Posted by BC-Boy

i went from a resonated front pipe to a HFC and it was louder with my header and had more drone, i couldnt take it anymore so i put my oem frontpipe back on and now the car pulls way better , maybe because i didnt have enough backpressure ? but the low/mid range pulls really good. i did have it go lean a bit had to get it retuned but it wasnt much.

If i am reading this correct your saying a front pipe with highflow cat is louder thN front pipe with no cat and resonator? Thx

[BC-Boy]

Originally Posted by Boofneenee

If i am reading this correct your saying a front pipe with highflow cat is louder thN front pipe with no cat and resonator? Thx

i had a invidia resonated frontpipe, with my overpipe and catless uel header(jdl) i also have a borla catback which i love it has no rasp just brute sound. i wanted to quiet it down a bit and remove the stench because catless does stink, i went with a custom frontpipe that used a 200cell Vibrant HFC, the car got louder, it droned like mad too, the frequencys that the resonator removed were the droney ones i quess, there was no difference in power and the logs were the same, i got headahes from the drone and the car was stupid loud, so i went back to my stock frontpipe, the car has a beautiful exhaust note now , no drone, much more quiet and to my supprise pulls alot harder from 3000-5000 before it felt a little dead, althouth i have a great tune, but that is prob because of back pressure , a lack of to be exact. im very happy now with my setup i couldnt ask for a better exhaust note, and now that i solved my gas problem my car runs super strong. when i went back to stock front pipe it did go lean a bit at in that range where it pulls harder and it knocked a bit but got that dialed out easy from my tuner.

[BC-Boy]

i highly recomend if you have catless header, dont even change the frontpipe unless you have a very quiet exhaust, i had a greddy spelite and with my catless setup it rasp like mad it was embarassing. then my borla didnt rasp but was way loud, so i think that you have to either keep the oem header or frontpipe , or else it will be either too loud , or sound like garbage with a rasp. it sounded like slapping steel sheets together , it was gross, cold starts were horrific.

[Boofneenee]

Originally Posted by BC-Boy

i highly recomend if you have catless header, dont even change the frontpipe unless you have a very quiet exhaust, i had a greddy spelite and with my catless setup it rasp like mad it was embarassing. then my borla didnt rasp but was way loud, so i think that you have to either keep the oem header or frontpipe , or else it will be either too loud , or sound like garbage with a rasp. it sounded like slapping steel sheets together , it was gross, cold starts were horrific.

Ofh and q300 all else stock and is just too quiet. I used to hear the UEL rumble but not since the q300. Was sort of hoping a catted front pipe would help. Interesting to hear urea got louder

[BC-Boy]

Originally Posted by Boofneenee

Ofh and q300 all else stock and is just too quiet. I used to hear the UEL rumble but not since the q300. Was sort of hoping a catted front pipe would help. Interesting to hear urea got louder

humm my guess is that youll get alot of rasp. its gonna rasp bad with that kind of muffler. i know when i put my overpipe it made it louder too. it made the cold starts rasp way more. maybe tho with the OFH it wont be as bad as my JDL, maybe the invidia resonated frontpipe would be better for you, i know for me it was quieter and keept down drone compared to hfc

[gabeg86]

Originally Posted by ATL BRZ

No drone at all. Just a little bit throatier exhaust note.

Do you have any idea the piping size? Looked and couldn't find it listed. It's supposed to be an OEM replacement so idk if that means same piping size too?


Edit: read your build thread

Sent from my HTC One using Tapatalk

[chas3wba0]

Originally Posted by BC-Boy

i highly recomend if you have catless header, dont even change the frontpipe unless you have a very quiet exhaust, i had a greddy spelite and with my catless setup it rasp like mad it was embarassing. then my borla didnt rasp but was way loud, so i think that you have to either keep the oem header or frontpipe , or else it will be either too loud , or sound like garbage with a rasp. it sounded like slapping steel sheets together , it was gross, cold starts were horrific.

Thread revival, but stellar info, mate. I recently put the stock front pipe back on too (replaced a catless front pipe), cus I couldn't stand the rasp (even with catted header). It sounds nearly perfect now, albeit a little quiet, and I also noticed that I got my low-end torque back, but I'm just concerned that the front pipe diameter doesn't match the rest of my exhaust, which is 2.5"... typical forum knowledge would say that's bad but my butt dyno says otherwise.

Was tempted to drop another couple bills on a HFC 2.5" front pipe but good to know I'm not the only one who thinks the stock front pipe is decent.

[unsurety]

Originally Posted by chas3wba0

Thread revival, but stellar info, mate. I recently put the stock front pipe back on too (replaced a catless front pipe), cus I couldn't stand the rasp (even with catted header). It sounds nearly perfect now, albeit a little quiet, and I also noticed that I got my low-end torque back, but I'm just concerned that the front pipe diameter doesn't match the rest of my exhaust, which is 2.5"... typical forum knowledge would say that's bad but my butt dyno says otherwise.

Was tempted to drop another couple bills on a HFC 2.5" front pipe but good to know I'm not the only one who thinks the stock front pipe is decent.

Wouldn't the OEM FP just cause a bottleneck?

I was going to get the FT86SF catted UEL but the wait and cost turned me away. I'm going with a quiet catback (Corsa), the Magnaflow catted and resonated FP and gonna get a 2.5" OP and the OFH. Should sound really good. Just broscience, no proof behind it... but I think when the pipe diameter is uniform throughout, it generally sounds better.

[chas3wba0]

Originally Posted by unsurety

Wouldn't the OEM FP just cause a bottleneck?

I was going to get the FT86SF catted UEL but the wait and cost turned me away. I'm going with a quiet catback (Corsa), the Magnaflow catted and resonated FP and gonna get a 2.5" OP and the OFH. Should sound really good.

That's what I'm thinking, but what would be the noticeable result? Loss of power? Because all I noticed was more torque when I replaced the 2.5" straight pipe

What I have now is:
Header post-cat 2.5" > OP 2.5" > FP + cat ~2.118" > Catback 2.5"

I would think that the cat in the FP makes the diameter kind of trivial since flow is already disrupted anyway?