what is the size of the stock exhaust pipe

timSSmokedGT1 · 01-31-2005, 12:51 PM

i am looking @ getting a borla exhaust system for my car but i wondered what inlet and outlet i would need ?

Kdawg207 · 01-31-2005, 12:54 PM

too small...

if you are getting a borla cat back...no worries....

you are just getting the muffler i would assume?

01-31-2005, 03:09 PM

If your getting the hole catback system don't worry it bolts right up.

Kdawg207 · 01-31-2005, 03:09 PM

...sorta what i already said no?

Ant · 01-31-2005, 03:27 PM

mike2002 · 03-02-2005, 08:42 PM

Quote:

Originally Posted by Ant

2.25

im replacing the exhaust on a 2001 alero GLS, 3400. and the stock exhaust is 1 7/8"....i just looked at it 20 minutes ago while changing the oil

did gagt's get 2.25's, and ga se's / alero's get 1.875.

im getting pressure bent, custom, either 2.25 or 2.5

atc3434 · 03-03-2005, 11:43 AM

Quote:

Originally Posted by mike2002

im replacing the exhaust on a 2001 alero GLS, 3400. and the stock exhaust is 1 7/8"....i just looked at it 20 minutes ago while changing the oil

did gagt's get 2.25's, and ga se's / alero's get 1.875.

im getting pressure bent, custom, either 2.25 or 2.5

1 & 7/8th's is the suck! I didn't know Aleros were so restricted. You're sure thats the size it is? Not doubting, as I've never looked under an Alero, but I would have figured it would be the same as the GA... GM doesn't usually cramp exhausts too bad.

mike2002 · 03-03-2005, 05:52 PM

100% sure it is. first i noticed it was so small, i can EASILY close my hand around it, i cant rap my hand around a 2 1/4" id pipe. so i measured the circumfrance and figured it all out to be 1.85 (1.875 is 1 7/8, my measurements where a little off)

so your saying yours was for sure 2.25 stock? im 99% sure the alero's and grandam use the exact same exhaust. i know the GT's different, maybe thats the confusion, GT's get 2.25, everyone else gets 1.875? i dont know, but a 2001 3400 alero has 1.875".

im having my exhaust put on tomorrow, most likely 2.25 pressure bent, ill see if they have 2.375" because that would fit around the muffler

i just think 2.5 is to big....ive got a pushrod v6 with 170hp, that will never see above 200 crank HP, intake, exhaust, dhp is all my car will ever see

2.5 is what they recommend for a near stock or very slightly modified GTP, and im 100hp short of a near stock GTP.

atc3434 · 03-03-2005, 06:11 PM

Well, I think 3" would be too big, but 2.5" isn't going to hurt the 3400, it's still small enough to develop good scavenging at lower rpms, and it will flow better on the topend than a smaller exhaust. And yea, I'm positive my stock exhaust was 2.25", I had done just a muffler for a while, it was 2.25 when I measured it. If guys have found gains w/ a better muffler and 2.5", I'd say thats the way to go. Mine ran better w/ the SLP.

mike2002 · 03-03-2005, 06:24 PM

that sucks that they did that to us alero owners...., because i see you have a SE, they have the same ratings as our alero's for power...oh well, ill just see bigger gains

i think ill see if they can fit a 2.5" pressure bent pipe up there, when they were looking at it before, they said it would be tough...my muffler is a 2.25" ID, but i dont think it will be a bottle neck, its a strait through magnaflow. the biggest bottle necks would probalby be the bends, since a 2.5 probably gets to around 2.125 at the bends

could be a year thing too....99's did have some differences over the later years

03-03-2005, 10:04 PM

Quote:

Originally Posted by mike2002

that sucks that they did that to us alero owners...., because i see you have a SE, they have the same ratings as our alero's for power...oh well, ill just see bigger gains

i think ill see if they can fit a 2.5" pressure bent pipe up there, when they were looking at it before, they said it would be tough...my muffler is a 2.25" ID, but i dont think it will be a bottle neck, its a strait through magnaflow. the biggest bottle necks would probalby be the bends, since a 2.5 probably gets to around 2.125 at the bends

could be a year thing too....99's did have some differences over the later years

Why not mandrel-bent pipes?

mike2002 · 03-03-2005, 10:26 PM

i dont think a regular exhaust shop can do those... i was under the impression that its a very very expensive machine that most places dont have

ill see if they have 2 3/8" LOL, thats a good compermise!

AznGA · 03-03-2005, 10:53 PM

Ya, SLP used to sell just the pipings (2.5" mandrel bent) but they do not sell those anymore. Local shops can charge you a lot for mandrel bent pipes.

GrahamKracka · 03-03-2005, 11:10 PM

the gt stock exhaust is 2.25...and yes the borla would bolt right up

sprague67 · 03-04-2005, 12:28 AM

I also did not know that Alero's were that small, damn.

01-31-2005, 12:51 PM	#1
timSSmokedGT1 GAGT - Newbie Join Date: Jan 2005 Location: Youngstown, Ohio Age: 33 Posts: 1 Vehicle: 2004 Grand Am GT	what is the size of the stock exhaust pipe i am looking @ getting a borla exhaust system for my car but i wondered what inlet and outlet i would need ?

01-31-2005, 03:27 PM	#5
Ant LS2 - Member AKA: Anthony Join Date: May 2003 Location: DC metro area Age: 31 Posts: 2,251 Vehicle: S5/GTO	2.25 __________________ USAF -06 IBM GTO/M6 - 477 WHP Best e/t before H/C - 12.71 @ 111.77 -18 Audi S5 Prestige Navarra Blue/A8 - DTUK Tuned 12.14 @ 111.19

03-03-2005, 06:11 PM	#9
atc3434 Grand Am Again AKA: Andrew Join Date: Apr 2003 Location: Auburn, NY Age: 35 Posts: 1,999 Vehicle: 1999 Grand Am SE	Well, I think 3" would be too big, but 2.5" isn't going to hurt the 3400, it's still small enough to develop good scavenging at lower rpms, and it will flow better on the topend than a smaller exhaust. And yea, I'm positive my stock exhaust was 2.25", I had done just a muffler for a while, it was 2.25 when I measured it. If guys have found gains w/ a better muffler and 2.5", I'd say thats the way to go. Mine ran better w/ the SLP. __________________ 1999 Grand Am SE2 - Blue, TOG Headers, SLP Exhaust, DHP - SOLD 1996 Vert' Z-28 - M6, magnaflow muffler-back, K&N FIPK, Hurst Short-throw - 13.6 @ 103mph. 2006 Dodge Charger R/T Daytona - Go Mango Orange #2832 of 4000. Tune/exhaust. 14.009@97mph. 2002 Saab 9 5 Aero Wagon - 3" turboback/tune. 17psi of sleeper fun just waiting to surprise you.

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01-31-2005, 03:09 PM	#3
CoopGT Guest Posts: n/a	If your getting the hole catback system don't worry it bolts right up.

03-03-2005, 05:52 PM	#8
mike2002 GAGT - Member Join Date: Oct 2004 Location: rosemount Age: 34 Posts: 158 Vehicle: 2001 alero gls	100% sure it is. first i noticed it was so small, i can EASILY close my hand around it, i cant rap my hand around a 2 1/4" id pipe. so i measured the circumfrance and figured it all out to be 1.85 (1.875 is 1 7/8, my measurements where a little off) so your saying yours was for sure 2.25 stock? im 99% sure the alero's and grandam use the exact same exhaust. i know the GT's different, maybe thats the confusion, GT's get 2.25, everyone else gets 1.875? i dont know, but a 2001 3400 alero has 1.875". im having my exhaust put on tomorrow, most likely 2.25 pressure bent, ill see if they have 2.375" because that would fit around the muffler i just think 2.5 is to big....ive got a pushrod v6 with 170hp, that will never see above 200 crank HP, intake, exhaust, dhp is all my car will ever see 2.5 is what they recommend for a near stock or very slightly modified GTP, and im 100hp short of a near stock GTP.

03-03-2005, 06:24 PM	#10
mike2002 GAGT - Member Join Date: Oct 2004 Location: rosemount Age: 34 Posts: 158 Vehicle: 2001 alero gls	that sucks that they did that to us alero owners...., because i see you have a SE, they have the same ratings as our alero's for power...oh well, ill just see bigger gains i think ill see if they can fit a 2.5" pressure bent pipe up there, when they were looking at it before, they said it would be tough...my muffler is a 2.25" ID, but i dont think it will be a bottle neck, its a strait through magnaflow. the biggest bottle necks would probalby be the bends, since a 2.5 probably gets to around 2.125 at the bends could be a year thing too....99's did have some differences over the later years

03-03-2005, 10:26 PM	#12
mike2002 GAGT - Member Join Date: Oct 2004 Location: rosemount Age: 34 Posts: 158 Vehicle: 2001 alero gls	i dont think a regular exhaust shop can do those... i was under the impression that its a very very expensive machine that most places dont have ill see if they have 2 3/8" LOL, thats a good compermise!

03-03-2005, 10:53 PM	#13
AznGA GAGT - Junkie AKA: YJ Join Date: Nov 2002 Location: Midwest Posts: 4,440 Vehicle: GAGT	Ya, SLP used to sell just the pipings (2.5" mandrel bent) but they do not sell those anymore. Local shops can charge you a lot for mandrel bent pipes.

03-03-2005, 11:10 PM	#14
GrahamKracka WannaBe Fat Kid AKA: Richard Join Date: Aug 2004 Location: San Antonio, Texas Age: 33 Posts: 1,517 Vehicle: 2005 Nissan Titan	the gt stock exhaust is 2.25...and yes the borla would bolt right up

03-04-2005, 12:28 AM	#15
sprague67 2000 GT1 AKA: Todd Join Date: Nov 2004 Location: Cedar Falls, Iowa Age: 34 Posts: 243 Vehicle: 2000 GT1 Coupe	I also did not know that Alero's were that small, damn.