hmmm to each his own i guess.
3" ypipe to 4" merge
Here's mine
https://ls1tech.com/forums/generatio...r-4-merge.html
I really don't see a disadvantage with my setup at all. The only thing is the attraction it causes with the cutout open on the street (which I don't do much). I just ran the car last month at the track. It's about 3800-3900lbs and has the exhaust w/ 1 7/8th headers, ls6 intake, 9" w/ 4.11's, lid, and a formato tune. Went 12.5@112 mph w/ a best mph of 113 and 2.0 60' time. Ended up breaking the driveshaft before getting comfortable with launching it, so low low 12's were possible.
Since you ride around with the cutout closed, I don't notice supposed loss of low end tq with the large headers and exhaust. I did what I did to leave room when I mod the car further and won't have to rebuild the exhaust.
https://ls1tech.com/forums/generatio...r-4-merge.html
I really don't see a disadvantage with my setup at all. The only thing is the attraction it causes with the cutout open on the street (which I don't do much). I just ran the car last month at the track. It's about 3800-3900lbs and has the exhaust w/ 1 7/8th headers, ls6 intake, 9" w/ 4.11's, lid, and a formato tune. Went 12.5@112 mph w/ a best mph of 113 and 2.0 60' time. Ended up breaking the driveshaft before getting comfortable with launching it, so low low 12's were possible.
Since you ride around with the cutout closed, I don't notice supposed loss of low end tq with the large headers and exhaust. I did what I did to leave room when I mod the car further and won't have to rebuild the exhaust.
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Joined: Mar 2009
Posts: 2,099
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From: Texas/Afghanistan
Since there isnt a cost problem between the 3.5" and 4" merge, and the ground clearance isnt really a big deal, then why make a big deal over the 3.5? With a 4" merge it gives you the option to upgrade to a full 4" system, or put in a 4" y pipe.
Someone check my math here, but using the ol' "Area of a circle is pie*r^2" I come up with:
4" pipe = 12.56
3.5" pipe = 9.6163
3" pipe = 7.065
2.5" pipe = 4.9063
Dual 3" pipes = 14.13
Dual 2.5" pipes = 9.8125
It looks like the 4" pipe has 23.4% more area than a 3.5" pipe, and 43.8% more area than a single 3" pipe.
It also looks like the 4" pipe is only 11% smaller than dual 3" pipes, but 28% greater than dual 2.5" pipes.
All this just for perspective
Someone check my math here, but using the ol' "Area of a circle is pie*r^2" I come up with:
4" pipe = 12.56
3.5" pipe = 9.6163
3" pipe = 7.065
2.5" pipe = 4.9063
Dual 3" pipes = 14.13
Dual 2.5" pipes = 9.8125
It looks like the 4" pipe has 23.4% more area than a 3.5" pipe, and 43.8% more area than a single 3" pipe.
It also looks like the 4" pipe is only 11% smaller than dual 3" pipes, but 28% greater than dual 2.5" pipes.
All this just for perspective
this pretty much explains it. 3" true duals are the best. followed by a 3"/4" merge. and you would kill that gain by plugging a 3" cat back onto the 4" i-pipe.
https://ls1tech.com/forums/generatio...-y-pipe-3.html
this pretty much explains it. 3" true duals are the best. followed by a 3"/4" merge. and you would kill that gain by plugging a 3" cat back onto the 4" i-pipe.
this pretty much explains it. 3" true duals are the best. followed by a 3"/4" merge. and you would kill that gain by plugging a 3" cat back onto the 4" i-pipe.
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Joined: Mar 2009
Posts: 2,099
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From: Texas/Afghanistan
You do not need 4" exhaust. You wont gain anything from it over a well designed 3". Unless you plan on going over 500rwhp. If you look at the recipe 500rwhp, he only last 10hp with a 3 inch exhaust after y-pipe through a muffler. Compared to 4 inch dump after ypipe. You would never notice 10hp.
IMHO Larger pipe sounds like ****.
And sometimes a 4" pipe will flow worse then a 3" pipe. Heat, volume, air speed, turbulence it is all effected.
IMHO Larger pipe sounds like ****.
And sometimes a 4" pipe will flow worse then a 3" pipe. Heat, volume, air speed, turbulence it is all effected.
http://www.youtube.com/watch?v=uha_J...eature=channel
http://www.youtube.com/watch?v=jwZt9...eature=channel
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Joined: Mar 2009
Posts: 2,099
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From: Texas/Afghanistan
not that i doubt your experience, but a 4" cb > 3" cb. it has to be, just like a 4" merge > 3" merge. it's the same concept.
^and thats where the problem lies, it's your opinion and not based on actual testing or actual hp/tq/cfm #'s.
now i would love to see a dyno comparison between 3" y-pipe with 3" merge and a 3" cb with 2.5" tails vs. a 3" y-pipe with a 4" merge with a true 3" cb vs. a 3" y-pipe with a 4" inch merge with a 4" cb with 3.5" tails.
^and thats where the problem lies, it's your opinion and not based on actual testing or actual hp/tq/cfm #'s.
now i would love to see a dyno comparison between 3" y-pipe with 3" merge and a 3" cb with 2.5" tails vs. a 3" y-pipe with a 4" merge with a true 3" cb vs. a 3" y-pipe with a 4" inch merge with a 4" cb with 3.5" tails.
Example. Trust's old T/A. He made more power(across the board) with a Y pipe (exactly like mine except he had 2.5" tailpipes) and a magnaflow muffler than he did with his 3" true duals and bullets dumped at the axle.
pretty soon here i am goin to be taking my TSP o/r y and doing the flowmaster 3"/4" merge with a 4" i-pipe run as far back as possible into a 3" spintech cat back. i haven't really found too much on the 3" spintech but it looks pretty legit, all 3" piping and has a real deep tone. so hopefully this will kill the rasp, fingers crossed.
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Verdad Gallardo TECH Addict
Joined: Mar 2009
Posts: 2,099
Likes: 3
From: Texas/Afghanistan
Just b/c its 4" doesn't mean it magically makes more power. Its all about what the car needs to exhale. Remember, bigger doesn't always mean better.
Example. Trust's old T/A. He made more power(across the board) with a Y pipe (exactly like mine except he had 2.5" tailpipes) and a magnaflow muffler than he did with his 3" true duals and bullets dumped at the axle.
Example. Trust's old T/A. He made more power(across the board) with a Y pipe (exactly like mine except he had 2.5" tailpipes) and a magnaflow muffler than he did with his 3" true duals and bullets dumped at the axle.
also i came across a guy that had the same cam as i did with more bolt ons than me but had a y-pipe set up and made about 10 hp less than me(when i had my TD's).
also whats the point of having a 4" merge/i-pipe if it's only about a foot long? why not have the 4" cb and stretch the 4" section all the way back over the axle to the muffler? also i do plan on going pretty wild with my set up eventually, probably pretty close to pat g's set up.
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Joined: Mar 2009
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From: Texas/Afghanistan
also whats the point of having a 4" merge/i-pipe if it's only about a foot long? why not have the 4" cb and stretch the 4" section all the way back over the axle to the muffler? also i do plan on going pretty wild with my set up eventually, probably pretty close to pat g's set up.
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Joined: Mar 2009
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From: Texas/Afghanistan
hmm i guess that makes sense. well now it's time to put that search feature to good use and research as much as i can before i actually buy something.
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Joined: Feb 2004
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From: Lexington, KY
I have the new TSP ory. It reduces down to 3 1/2" (I think), then smaller. The factory and aftermarket catbacks are 2 3/4" at this connection, so I assume it is this size. This is going to be a restriction. So what I am going to do is cut the TSP merge before it reduces to the 3 1/2" pipe, weld a 4" pipe on it, run it to a 4" cutout, then reduce it to 3" behind that for the catback. Pretty inexpensive way to do it.
http://www.burnsstainless.com/
They have some badass y pipes. They are the ones that made the y pipes for lg etc.
They have some badass y pipes. They are the ones that made the y pipes for lg etc.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
i have the flowmaster 3 in/4 out merge.its not ran over the axle though.its dumped with a dynatec splitflow muffler.sounds amazing.never had a complaint.it is loud as hell though
