Help Me Build My Exhaust! - JeepForum.com

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post #1 of 45 Old 04-22-2012, 07:04 AM Thread Starter
torchd
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2003 WJ 
 
Join Date: Jan 2010
Location: Chicago
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Help Me Build My Exhaust!

Before I get started on my exhaust, I still need to put in my 99+ intake and my "703" injectors that are all sitting at home.

But, while I'm doing the intake I will be a doing a header while I'm there. I was talking to a guy that lives like 10 mins from me in IL, he has a buld thread here about his turbo. For a header he is using a header from a TJ. I was thinking that a header from a WJ would work to, no? I want that specific header bc I want to build a Y pipe.

Obviously my Y pipe is going to be custom. My goal is to make the whole exhaust 2.5" from the the Y pipe all the way out back.

Since I am bulding a custom Y pipe, I have 2 questions: Should I go with a merge that is 2.5" inlet and the outlet is 3", or should I do 2.5" inlet and outlet? Same thing goes for my hi flow cat. Do I want 2.5" in/out or 3" in/out?

Now onto a catback. I do not want crapmaster, it is exaclty that.. CRAP.. LOL.. What is a good 2.5" catback? I could even jsut buy a 2.5" or 3" muffler and make my own cat back. I heard a sound clip from Squazzs Jeep, he has a Thrush Weld muffler, sounded really good. This is my DD, if I want loud that is when I pull my 2002 Trans Am with H/C/I out of the garage

So basically should my piping for my exhasut be a combo of 2.5" and 3", straight 2.5" (but nothing will mate together unless I expand the pipe a little) or straight 3" which is prolly overkill.

All I want to do is gain a little power out of my Jeep. This thing is soooooo damn slow. Hency why I am doing the 99+ intake and injectors with a good header and free flowing exhaust.

Some input would be greatly appreciated!!!

Thanks


1998 Jeep Grand Cherokee Laredo
2" BB Pucks | SkyJacker Hydro Shocks | Rubicon Wheels | Cooper 245/75/16 Tires

2002 Trans Am
Cam, Full Exhaust, Stock Heads, Stock LS6 Intake and Stock 10 bolt with 3.42s
420 RWHP and 382 RWHTQ
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post #2 of 45 Old 04-22-2012, 10:26 AM
AlphaLorde
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I built a nasty 4.0 on my first zj.

The header I used went into a single pipe at the end.

If you are talking about using a y-pipe on the 4.0, is this the style of header you are talking about?
Different Style of 4.0 Header

That is new to me, looks like it could really help torque.

Now if it were me, I would use a y-pipe with the same size inlet as the outlets on the header. IIRC it's about 2" or just under. I would have a 2.5" outlet on the merge pipe, running 2.5" piping w/ 2.5" inlets/outlets for the muffler and cat.

I ran a cheap ebay header and cat w/ a dynomax muffler. I added a big tip(3.5-4") on the end, it gave it a nice low growl.

3" is way to big for a 4.0.

1998 ZJ Laredo 5.2L 139k 231 w/SYE artec trussed 8.8 4.25"F/5"R lift
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post #3 of 45 Old 04-22-2012, 10:29 AM
paulyboy
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they are slower but I was told 2.5 " is optimal for that motor by a mechanic. He said the 3 inch is overkill. I would want to believe him because my gto exhaust is only 3" and good up to 700 hp before having to go bigger. I made my exhaust short and out the side because the p.o before me put a regular Cherokee tailpipe and I was having clearance issues. I went with a chepo thrush turbo muff and she sounds like a tractor......lol


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post #4 of 45 Old 04-22-2012, 10:31 AM
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post #5 of 45 Old 04-22-2012, 11:53 AM Thread Starter
torchd
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This is the header that I am looking at

http://www.ebay.com/itm/140722028194...84.m1432.l2649

I agree that 3" is way too big and is overkill. 2.5" would be perfect. My Trans Am is 3" from the LTs to the c/b and everything in between

This is my plan: Custom Y with a nice flowmaster merge into a magnaflow hi flow metallic high spun cat into (insert c/b here)

Again I jsut want a nice tone and to gain som RWHP/RWTQ

1998 Jeep Grand Cherokee Laredo
2" BB Pucks | SkyJacker Hydro Shocks | Rubicon Wheels | Cooper 245/75/16 Tires

2002 Trans Am
Cam, Full Exhaust, Stock Heads, Stock LS6 Intake and Stock 10 bolt with 3.42s
420 RWHP and 382 RWHTQ
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post #6 of 45 Old 04-22-2012, 11:58 AM
paulyboy
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dam thats pricy why go to the newer design? Im actually ordering a header this week to fix my cracked one and am looking at this one on e bay. Seems to copy the rugged ridge one they sell. And its only like 125.00

http://www.ebay.com/itm/310394037118...84.m1423.l2649
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post #7 of 45 Old 04-22-2012, 12:14 PM Thread Starter
torchd
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Quote:
Originally Posted by AlphaLorde View Post
I built a nasty 4.0 on my first zj.

The header I used went into a single pipe at the end.

If you are talking about using a y-pipe on the 4.0, is this the style of header you are talking about?
Different Style of 4.0 Header

That is new to me, looks like it could really help torque.

Now if it were me, I would use a y-pipe with the same size inlet as the outlets on the header. IIRC it's about 2" or just under. I would have a 2.5" outlet on the merge pipe, running 2.5" piping w/ 2.5" inlets/outlets for the muffler and cat.

I ran a cheap ebay header and cat w/ a dynomax muffler. I added a big tip(3.5-4") on the end, it gave it a nice low growl.

3" is way to big for a 4.0.
What was your exhaust set up?

1998 Jeep Grand Cherokee Laredo
2" BB Pucks | SkyJacker Hydro Shocks | Rubicon Wheels | Cooper 245/75/16 Tires

2002 Trans Am
Cam, Full Exhaust, Stock Heads, Stock LS6 Intake and Stock 10 bolt with 3.42s
420 RWHP and 382 RWHTQ
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post #8 of 45 Old 04-22-2012, 12:17 PM Thread Starter
torchd
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Quote:
Originally Posted by paulyboy View Post
dam thats pricy why go to the newer design? Im actually ordering a header this week to fix my cracked one and am looking at this one on e bay. Seems to copy the rugged ridge one they sell. And its only like 125.00

http://www.ebay.com/itm/310394037118...84.m1423.l2649
With a single collector you cannot run a Y pipe. The new design has to 2 collectors so that I can yun a Y pipe set up.

I couldn't use a Y pipe with the header in your link

1998 Jeep Grand Cherokee Laredo
2" BB Pucks | SkyJacker Hydro Shocks | Rubicon Wheels | Cooper 245/75/16 Tires

2002 Trans Am
Cam, Full Exhaust, Stock Heads, Stock LS6 Intake and Stock 10 bolt with 3.42s
420 RWHP and 382 RWHTQ
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post #9 of 45 Old 04-22-2012, 12:36 PM
paulyboy
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i know but why go two back to one when all you need is 2.5 all the way?
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post #10 of 45 Old 04-22-2012, 12:39 PM
paulyboy
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for instance i had an import at one time and bought the 4 into 1 racing headers. They were great but when they rusted out I replaced them with a 4 into 2 into 1 design and noticed the lack of power right away.
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post #11 of 45 Old 04-22-2012, 01:21 PM Thread Starter
torchd
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Quote:
Originally Posted by paulyboy View Post
i know but why go two back to one when all you need is 2.5 all the way?
Quote:
Originally Posted by paulyboy View Post
for instance i had an import at one time and bought the 4 into 1 racing headers. They were great but when they rusted out I replaced them with a 4 into 2 into 1 design and noticed the lack of power right away.
With 2 merge collectors, 2.5" exhaust piping and good merge collector on the Y pipe, there shouldn't be any reason to see a gain in RWHP/RWTQ. Plus a Y pipe has 2 pipes that are 2.5" vs. a single pipe at 2.5". You will see an increase in exhaust scavenging thus creating more power. At least in theory

1998 Jeep Grand Cherokee Laredo
2" BB Pucks | SkyJacker Hydro Shocks | Rubicon Wheels | Cooper 245/75/16 Tires

2002 Trans Am
Cam, Full Exhaust, Stock Heads, Stock LS6 Intake and Stock 10 bolt with 3.42s
420 RWHP and 382 RWHTQ
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post #12 of 45 Old 04-22-2012, 07:19 PM
paulyboy
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yeah but after the y your still going into a 2.5 inch single pipe. I fyou were to bring two pipes right to the muffler then I would say yeah that should work But for all that money on a theory isn't worth it for me personaly. Just asking but do you have supported dyno hp with this setup? You got me curious now lol. I would want believe that the banks revolver header being 6 into 1 would yield better hp tq.
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post #13 of 45 Old 04-22-2012, 07:48 PM Thread Starter
torchd
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Quote:
Originally Posted by paulyboy View Post
yeah but after the y your still going into a 2.5 inch single pipe. I fyou were to bring two pipes right to the muffler then I would say yeah that should work But for all that money on a theory isn't worth it for me personaly. Just asking but do you have supported dyno hp with this setup? You got me curious now lol. I would want believe that the banks revolver header being 6 into 1 would yield better hp tq.
True, but with the (2) 2.5" pipes going into a merge, you're going to have more velocity and better scavenging affect vs. 1 single 2.5" pipe.

Well my theory is coming from my Trans Am. I make with this set up 420 RWHP and 385 RWTQ.

My exhaust is as follows:

QTP 1 3/4" x 3" LTs + Custom Kooks 3" O/R Y Pipe + 3" x 3.5" Flowmaster Merge + 3" x 3" x 25" Powerstick Bullet Muffler + DMH 3" E-CutOut + GMMG Catback












1998 Jeep Grand Cherokee Laredo
2" BB Pucks | SkyJacker Hydro Shocks | Rubicon Wheels | Cooper 245/75/16 Tires

2002 Trans Am
Cam, Full Exhaust, Stock Heads, Stock LS6 Intake and Stock 10 bolt with 3.42s
420 RWHP and 382 RWHTQ
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post #14 of 45 Old 04-22-2012, 07:56 PM
paulyboy
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that's pretty much same way my gto exhaust is set up also with slp headers and corsa exhaust


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post #15 of 45 Old 04-22-2012, 07:58 PM
paulyboy
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dam now im unsure about getting that header now......Like u i want to make as much useful hp with this thing as possible without breaking the bank.

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