Cats/ Test Pipes

AJ 370ZSC · 07-22-2014, 10:36 AM

hey guys so i was talking to the mechanic at the nissan dealership near me, which is a friend. He suggested i take the stillen cats off my car. (have a 2012 sport, with stillen SC and stillen exhaust). He said i should put the OEM cats on or test pipes, how much will my fuel milage go down? and how will the oem cats affect the sound i get vs. the test pipes? i do like the sound i have now.

ANMVQ · 07-22-2014, 10:53 AM

With the SC you should only run OEM cats. Stillen even says this.

spdandpwr · 07-22-2014, 11:32 AM

yea, they say that you should keep stock cats because you loose boost when you make the exhaust more free flowing on the s/c kit.

I think the problem though is with the cams on the car. Overlap of the cams profiles is the important part. You dont want overlap on a f/i car. (overlap is the length of time both the intake and exhaust valves are open at the same time.) All internal combustion motors rely on cylinder pressure. On f/i cars need only one set of valves open at a time to reduce boost loss out of the exhaust.

What's happening with the Z is you're losing boost with unrestrictive exhausts because of the overlap in the cams. A custom cam would allow you to run more boost, a free-er flowing exhaust and make wayyyy more power.

AJ 370ZSC · 07-22-2014, 11:42 AM

Quote:

Originally Posted by spdandpwr

yea, they say that you should keep stock cats because you loose boost when you make the exhaust more free flowing on the s/c kit.

I think the problem though is with the cams on the car. Overlap of the cams profiles is the important part. You dont want overlap on a f/i car. (overlap is the length of time both the intake and exhaust valves are open at the same time.) All internal combustion motors rely on cylinder pressure. On f/i cars need only one set of valves open at a time to reduce boost loss out of the exhaust.

What's happening with the Z is you're losing boost with unrestrictive exhausts because of the overlap in the cams. A custom cam would allow you to run more boost, a free-er flowing exhaust and make wayyyy more power.

so best bet is OEM cats then, will i lose noticable HP and TQ and exhaust noise?

spdandpwr · 07-22-2014, 12:05 PM

So you'll gain power with OEM cats. But you'll lose sound

njobe89 · 07-22-2014, 01:54 PM

ill be getting test pipes soon, but i'm not FI so yea lol not even sure why i said that but to lazy to erase all of this -_-

07-22-2014, 10:36 AM	#1 (permalink)
AJ 370ZSC Base Member Join Date: Jun 2014 Location: Ontario Posts: 13 Drives: 12' stillen 370Z MT Rep Power: 11	Cats/ Test Pipes hey guys so i was talking to the mechanic at the nissan dealership near me, which is a friend. He suggested i take the stillen cats off my car. (have a 2012 sport, with stillen SC and stillen exhaust). He said i should put the OEM cats on or test pipes, how much will my fuel milage go down? and how will the oem cats affect the sound i get vs. the test pipes? i do like the sound i have now.

07-22-2014, 10:53 AM	#2 (permalink)
ANMVQ A True Z Fanatic Join Date: Mar 2011 Location: Framingham MA Posts: 2,732 Drives: 2014 Q50 AWD Rep Power: 19	With the SC you should only run OEM cats. Stillen even says this. __________________ 14 Q50 AWD, ARK, ECUTEK (SEB), Takda,

07-22-2014, 11:32 AM	#3 (permalink)
spdandpwr Base Member Join Date: Jul 2014 Location: CT Posts: 52 Drives: 370Z Sport Rep Power: 11	yea, they say that you should keep stock cats because you loose boost when you make the exhaust more free flowing on the s/c kit. I think the problem though is with the cams on the car. Overlap of the cams profiles is the important part. You dont want overlap on a f/i car. (overlap is the length of time both the intake and exhaust valves are open at the same time.) All internal combustion motors rely on cylinder pressure. On f/i cars need only one set of valves open at a time to reduce boost loss out of the exhaust. What's happening with the Z is you're losing boost with unrestrictive exhausts because of the overlap in the cams. A custom cam would allow you to run more boost, a free-er flowing exhaust and make wayyyy more power. Zbrah likes this.

07-22-2014, 12:05 PM	#5 (permalink)
spdandpwr Base Member Join Date: Jul 2014 Location: CT Posts: 52 Drives: 370Z Sport Rep Power: 11	So you'll gain power with OEM cats. But you'll lose sound Last edited by spdandpwr; 07-22-2014 at 12:36 PM.

07-22-2014, 01:54 PM	#6 (permalink)
njobe89 A True Z Fanatic Join Date: May 2014 Location: Atlanta, GA Posts: 5,227 Drives: 2013 370z BS 6MT Rep Power: 174284	ill be getting test pipes soon, but i'm not FI so yea lol not even sure why i said that but to lazy to erase all of this -_- __________________ 2 plus 2 times 2 = ? ... hint, it's not 8 Stillen CBE, Stillen Gen 3, TP's, Uprev tuned - 324whp/264tq

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