Proof of the best Y and LT set up!
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Joined: Jan 2005
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From: N Falmouth MA
Proof of the best Y and LT set up!
Ah hA! I found a badass thread on LS1 tech today. It was mostly about the recipie for 500 rwhp. THis guy did a LOT of research and work.
Anyway.. Apparently, when running heads and cam, the exh could almost make or break the combo. It also depends on ho much power you want out of it.. If you want to squeeze every minute bit of power out of it... This advice would help you.
THe Kooks Venturi collector Y LT's and a Merge collector Y. THat is what was advised. It also makes a lot of sense when you read the article.
Read up.. a LOT of good info in here.. I'm not trying to plagiarize his work, I'm just quoting it..
The thread! I'm in awe, boss!
http://www.ls1tech.com/forums/showth...95#post7248595
Anyway.. Apparently, when running heads and cam, the exh could almost make or break the combo. It also depends on ho much power you want out of it.. If you want to squeeze every minute bit of power out of it... This advice would help you.
THe Kooks Venturi collector Y LT's and a Merge collector Y. THat is what was advised. It also makes a lot of sense when you read the article.
Read up.. a LOT of good info in here.. I'm not trying to plagiarize his work, I'm just quoting it..
The thread! I'm in awe, boss!
http://www.ls1tech.com/forums/showth...95#post7248595
Originally Posted by Patrick G
Exhaust selection:
To make big power with a street motor, you need an exhaust that sucks...literally (David Vizard quote). When running a cam with lots of overlap, backpressure is not your friend. But when building a daily driven street car, too free flowing of an exhaust often means too loud. Not in my case.
You want the best headers you can find. For an LS1 F-body, it would be QTPs or Kooks in 1 3/4" size. For a Vette, the LG Pro Long tubes reign supreme. A high velocity merge collector on the header collector is typically worth some nice gains in the mid-range and is known to squeak out a few extra ponies up high as well.
Merging the twin pipes coming off the headers is a critical item for power and sound quality. Vettes have it easy because an x-pipe easily fits and the sound quality is awesome. F-bodies are handicapped because of space constraints. For 500 rwhp, you want to run dual 3" pipes after the headers and you'll want them to merge into a 4" intermediate pipe. Anything smaller will run the risk of flow loss. Most y-pipes on the market slam the 2 pipes together like this:
When the pipes meet at close to a 90 angle, the flow is going to be lower and the sound is going to rasp and drone at 2000-2300 rpm. By using a Flowmaster merge collector or better, your sound quality will improve since the gasses meet side by side as opposed to ramming into each other. Here are a few pics of my exhaust.
Notice the dual 3" pipes merging into a 4" intermediate pipe, then a 4" cutout. After the cutout, the pipe is reduced to a 3" SLP dual dual catback. Compared to open headers with 20" extensions, my motor lost 1 hp with this y-pipe, but gained 10 rwtq in the 2500-4000 rpm range. From a sound standpoint, the rasp/drone is gone with the better y-merge collector. The difference between running with an open cutout and closed exhaust through the tail pipes is 9.5 rwhp. Not bad at all.
To make big power with a street motor, you need an exhaust that sucks...literally (David Vizard quote). When running a cam with lots of overlap, backpressure is not your friend. But when building a daily driven street car, too free flowing of an exhaust often means too loud. Not in my case.
You want the best headers you can find. For an LS1 F-body, it would be QTPs or Kooks in 1 3/4" size. For a Vette, the LG Pro Long tubes reign supreme. A high velocity merge collector on the header collector is typically worth some nice gains in the mid-range and is known to squeak out a few extra ponies up high as well.
Merging the twin pipes coming off the headers is a critical item for power and sound quality. Vettes have it easy because an x-pipe easily fits and the sound quality is awesome. F-bodies are handicapped because of space constraints. For 500 rwhp, you want to run dual 3" pipes after the headers and you'll want them to merge into a 4" intermediate pipe. Anything smaller will run the risk of flow loss. Most y-pipes on the market slam the 2 pipes together like this:
When the pipes meet at close to a 90 angle, the flow is going to be lower and the sound is going to rasp and drone at 2000-2300 rpm. By using a Flowmaster merge collector or better, your sound quality will improve since the gasses meet side by side as opposed to ramming into each other. Here are a few pics of my exhaust.
Notice the dual 3" pipes merging into a 4" intermediate pipe, then a 4" cutout. After the cutout, the pipe is reduced to a 3" SLP dual dual catback. Compared to open headers with 20" extensions, my motor lost 1 hp with this y-pipe, but gained 10 rwtq in the 2500-4000 rpm range. From a sound standpoint, the rasp/drone is gone with the better y-merge collector. The difference between running with an open cutout and closed exhaust through the tail pipes is 9.5 rwhp. Not bad at all.
Thread Starter
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Joined: Jan 2005
Posts: 2,592
From: N Falmouth MA
^ About $1400... $950-$1100 for the kooks headers and about $300 for the Mufflex Y.. That was a custom made Y at Thunder Racing, so I doubt it costs them much to do. Mufflex sells an identical one at TR for about $315.
You don't allways get what you pay for.. My complete exh totals about $2100... it's all junk too.. SLP LT's, SLP Catted Y converted to ORY and was crushed all to hell trying to get it to line up to the cat delete pipes and that damn Borla CB that retails for about $800.. I'm tired of the tone.. once I get the funds for that above exh, my borla will be for sale and I think I'll have to give the SLP LT's away or sell them for scrap metal...
.. I doubt anyone will buy them and I don't want to screw anyone.. I prolly couldn't even give them away.
You don't allways get what you pay for.. My complete exh totals about $2100... it's all junk too.. SLP LT's, SLP Catted Y converted to ORY and was crushed all to hell trying to get it to line up to the cat delete pipes and that damn Borla CB that retails for about $800.. I'm tired of the tone.. once I get the funds for that above exh, my borla will be for sale and I think I'll have to give the SLP LT's away or sell them for scrap metal...
.. I doubt anyone will buy them and I don't want to screw anyone.. I prolly couldn't even give them away.
Last edited by Bayer-Z28; Aug 9, 2007 at 09:29 PM.
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Joined: Aug 2005
Posts: 329
From: Charleston, WV
I read that article when he posted it...good stuff. That's why I'm wanting to just build my own exhaust, but for now, I don't have time. I'm goin' with XS Stainless LTs and Y pipe w/ Magnaflow Catback for now. That way, I can unhook the catback to fab up the true duals I want, or a Y-pipe system and be able to hook the magnaflow back up as needed until it's finished (the car is my daily driver). Lots of good info in that thread for sure.
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Joined: Feb 1999
Posts: 661
From: Montville, NJ, U.S.A.
Thats just the way I had my y pipe built. I run Kooks 1 3/4 to 1 7/8 headers, 3" y to a Mufflex 4" cat back. The 3" pipes are joined together by a Flowmaster dual 3" to single 4" merge collector.
Nick
Nick
Leave it to them alright.. 
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Joined: Jan 2007
Posts: 1,027
From: Lansing, MI via Bowling Green, KY: Dalton, GA: Nashville, TN & Atlanta, GA
What kind of Y-Pipe is in those pics? Is it a custom job, or can you buy one somewhere? I'm planning to do Kooks headers on my '94, and would like to have them Y into whatever catback I end up getting like in the pics above.
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Joined: Feb 1999
Posts: 661
From: Montville, NJ, U.S.A.
Thanks for the compliments. My y pipe was built on the car at Mufflex (they are only an hour away from me), and cost me about $350 to have it done on the car. Mufflex currently does not offer a y pipe for Kooks headers, and I didn’t like the one made by Kooks (because of the crappy merge, as shown in the first pic of this post). The y that Mufflex makes for Hooker long tubes has the good Flowmaster merge collector. You could buy that one and modify it to fit the Kooks.
I like the way they built the y pipe, but I just don’t get why after the merge, they installed a 4-inch cut out, to a 3-inch SLP cat back. They should have used 4-inch pipe throughout the system. I bet the 9.5 rwhp they lost from the cut out open, to it closed, was caused by the turbulence created from the air trying to go out the cutout when its closed. IMO, if you need to use a cutout for power, then you need to put some more thought into designing your exhaust system.
Nick
I like the way they built the y pipe, but I just don’t get why after the merge, they installed a 4-inch cut out, to a 3-inch SLP cat back. They should have used 4-inch pipe throughout the system. I bet the 9.5 rwhp they lost from the cut out open, to it closed, was caused by the turbulence created from the air trying to go out the cutout when its closed. IMO, if you need to use a cutout for power, then you need to put some more thought into designing your exhaust system.
Nick
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Joined: Jan 2007
Posts: 1,027
From: Lansing, MI via Bowling Green, KY: Dalton, GA: Nashville, TN & Atlanta, GA
Are the Mufflex Y Pipe & flowmaster merge collector stainless steel? Any speculation on how difficult it might be to get a Mufflex Y to fit Kooks headers? I was really hoping to avoid going to an exhaust shop whenever I get around to doing this.
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From: NM
would it be easier/cheaper to buy the collector and have the exhaust shop fab up the y pipe?
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Joined: Feb 1999
Posts: 661
From: Montville, NJ, U.S.A.
The y pipe and Flowmaster merge collector are aluminized. I had to have my y pipe fabed up for the Kooks headers because the Hooker y pipe will not bolt right up. You either have to buy the Flowmaster merge collector and have the rest fabed up, or buy the Hooker y y pipe and have it modified to fit.
Nick
Nick
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Joined: Apr 2001
Posts: 1,132
From: Florida
Jet Hot Long Tubes, Mufflex Y pipe, Borla Catback with DMH E-cutout for Borla.
Here's the end result:
http://video.cardomain.com/clip.aspx...CE94B58298D980
Thx,
Claude
Here's the end result:
http://video.cardomain.com/clip.aspx...CE94B58298D980
Thx,
Claude
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