Exhaust guru's, does this make sense and sound like a good idea for a y-pipe?
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From: Bayville NJ and Newark at NJIT.
Exhaust guru's, does this make sense and sound like a good idea for a y-pipe?
In case you didn't know, 2.8's are getting custom headers made by a guy on the V6 forum, he'll also be making us custom y-pipes. What he's saying to do do, is from the 2.5in collectors on the drivers side, reduce it to 2.25 and run that till it mates with the passengers side and tie it together, he wants to leave the passengers side from collector to y-collector 2.5 in. Here is an exerp from a post there.
quote:
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Originally posted by Xenodrgn:
Camaro_hunter_D:
Primarys: 1.5 in
Collectors: 2.5 in OD
When you say "crossover pipe" you mean the y-pipe? Just making sure our vocab works out...
Why not do a 2.5 inch ID y-pipe, have it collect into a 3in pipe and then run a full 3 inch exhaust... I think thats what I'm going to do... why use reducers and such and use different sized pipes? Why not progressivly get bigger to accomodate the ever increasing exhaust volume... I could see using a 2.5 in full exhaust instead of 3in, but I'm not getting the whole reducer thing...
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3 inch for the non forced induction is too big. 2 1/2 is the biggest you should really go, keep a little back pressure so you do not lose torque. The reason of running the smaller tube into the large is to create a semi vacuum on the drivers side to help evacuate the exhaust a little quicker since it has to travel longer to the main system. and yes the crossover = Y Pipe. Hope that makes sense.
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1985 Camaro SC - 2.8L, auto.
C'mon, spin 'em for papa...
http://www.xenodrgn.f2s.com/Frontright.jpg
quote:
--------------------------------------------------------------------------------
Originally posted by Xenodrgn:
Camaro_hunter_D:
Primarys: 1.5 in
Collectors: 2.5 in OD
When you say "crossover pipe" you mean the y-pipe? Just making sure our vocab works out...
Why not do a 2.5 inch ID y-pipe, have it collect into a 3in pipe and then run a full 3 inch exhaust... I think thats what I'm going to do... why use reducers and such and use different sized pipes? Why not progressivly get bigger to accomodate the ever increasing exhaust volume... I could see using a 2.5 in full exhaust instead of 3in, but I'm not getting the whole reducer thing...
--------------------------------------------------------------------------------
3 inch for the non forced induction is too big. 2 1/2 is the biggest you should really go, keep a little back pressure so you do not lose torque. The reason of running the smaller tube into the large is to create a semi vacuum on the drivers side to help evacuate the exhaust a little quicker since it has to travel longer to the main system. and yes the crossover = Y Pipe. Hope that makes sense.
------------------
1985 Camaro SC - 2.8L, auto.
C'mon, spin 'em for papa...
http://www.xenodrgn.f2s.com/Frontright.jpg
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Joined: Jul 1999
Posts: 4,310
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I'd say have dual 2" or 2.25" to single 2.5" catback or try to see about 2.75" replacement catbacks from dynomax for 350 TPIs
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-Tas
'89 Formula WS-6
305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
[This message has been edited by Tas (edited November 17, 2001).]
------------------
-Tas
'89 Formula WS-6
305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
[This message has been edited by Tas (edited November 17, 2001).]
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From: California
I think 2.75" would be too large. Think about how much flow is really necessary. Lets compare a v8 to the v6. A 5.7 v8 typically has 1 3/4" primaries to a 3" collector with 3" all the way back. 5.7/2.8=2. So shouldn't the v8 have about twice as much exhaust flow? That would mean the v6 would need 7/8" primaries to a 1.5" collector.
Now, creating this direct relationship may be a little ignorant of me, but wouldn't it still show how much too large some of that piping would be? The goal of the perfect exhaust is to maintain velocity as the air cools and eliminate as much backpressure as possible. Large piping eliminates backpressure, but hurts the velocity of the exhaust flow, effectively hurting performance.
I say that he makes at least three sets of headers and catbacks and tests each one before producing anything.
By the way, if anyone who really knows what they are talking about in terms of exhaust sizing could post with some mathematical support, that would be very interesting =)
[This message has been edited by rezinn (edited November 18, 2001).]
Now, creating this direct relationship may be a little ignorant of me, but wouldn't it still show how much too large some of that piping would be? The goal of the perfect exhaust is to maintain velocity as the air cools and eliminate as much backpressure as possible. Large piping eliminates backpressure, but hurts the velocity of the exhaust flow, effectively hurting performance.
I say that he makes at least three sets of headers and catbacks and tests each one before producing anything.
By the way, if anyone who really knows what they are talking about in terms of exhaust sizing could post with some mathematical support, that would be very interesting =)
[This message has been edited by rezinn (edited November 18, 2001).]
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Joined: Jul 1999
Posts: 4,310
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<font face="Verdana, Arial" size="2">Originally posted by rezinn:
I think 2.75" would be too large. Think about how much flow is really necessary. Lets compare a v8 to the v6. A 5.7 v8 typically has 1 3/4" primaries to a 3" collector with 3" all the way back. 5.7/2.8=2. So shouldn't the v8 have about twice as much exhaust flow? That would mean the v6 would need 7/8" primaries to a 1.5" collector.
Now, creating this direct relationship may be a little ignorant of me, but wouldn't it still show how much too large some of that piping would be? The goal of the perfect exhaust is to maintain velocity as the air cools and eliminate as much backpressure as possible. Large piping eliminates backpressure, but hurts the velocity of the exhaust flow, effectively hurting performance.
I say that he makes at least three sets of headers and catbacks and tests each one before producing anything.
By the way, if anyone who really knows what they are talking about in terms of exhaust sizing could post with some mathematical support, that would be very interesting =)
[This message has been edited by rezinn (edited November 18, 2001).]</font>
I think 2.75" would be too large. Think about how much flow is really necessary. Lets compare a v8 to the v6. A 5.7 v8 typically has 1 3/4" primaries to a 3" collector with 3" all the way back. 5.7/2.8=2. So shouldn't the v8 have about twice as much exhaust flow? That would mean the v6 would need 7/8" primaries to a 1.5" collector.
Now, creating this direct relationship may be a little ignorant of me, but wouldn't it still show how much too large some of that piping would be? The goal of the perfect exhaust is to maintain velocity as the air cools and eliminate as much backpressure as possible. Large piping eliminates backpressure, but hurts the velocity of the exhaust flow, effectively hurting performance.
I say that he makes at least three sets of headers and catbacks and tests each one before producing anything.
By the way, if anyone who really knows what they are talking about in terms of exhaust sizing could post with some mathematical support, that would be very interesting =)
[This message has been edited by rezinn (edited November 18, 2001).]</font>
------------------
-Tas
'89 Formula WS-6
305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
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<font face="Verdana, Arial" size="2">Originally posted by rezinn:
I think 2.75" would be too large. Think about how much flow is really necessary. Lets compare a v8 to the v6. A 5.7 v8 typically has 1 3/4" primaries to a 3" collector with 3" all the way back. 5.7/2.8=2. So shouldn't the v8 have about twice as much exhaust flow? That would mean the v6 would need 7/8" primaries to a 1.5" collector.
</font>
I think 2.75" would be too large. Think about how much flow is really necessary. Lets compare a v8 to the v6. A 5.7 v8 typically has 1 3/4" primaries to a 3" collector with 3" all the way back. 5.7/2.8=2. So shouldn't the v8 have about twice as much exhaust flow? That would mean the v6 would need 7/8" primaries to a 1.5" collector.
</font>
Assuming that exhaust sizes scale nicely (but I somehow doubt they do), the V6 primaries would be around 1 7/16".
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From: Bayville NJ and Newark at NJIT.
Hedman created headers for 2.8's a long time ago, they have since stopped production... he is creating copies of these headers...
I'm not conserned about primary length or size, we've already got that figured out to be perfect...
I'm conserned about the y-pipe... and the reducing that that I've talked about... what do you have to say about it?????
I'm not conserned about primary length or size, we've already got that figured out to be perfect...
I'm conserned about the y-pipe... and the reducing that that I've talked about... what do you have to say about it?????
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