pics of my true duals
Personally I don't think the pipe crushed for clearance will be a big issue. The stock pancake Y flows fine. I think think the X is too far back for optimal balancing of exhaust pulses, and I have to wonder about the jog in the drivers side pipe used to bring the pipes together on the passengers side. The exhaust will have to travel through more pipe on the drivers side vs. passengers side. I don't know what effect this would have on flow or balancing of pulses, it just makes me wonder. I'm sure it sounds a lot better than my exhaust though.
The kit LOOKS awesome. But as was said before, exhaust gases don't like making 90* turns. From what I've understood, the closer to the manifolds the X pipe is, the better, it balances the flow sooner. Same goes for the mufflers (if I'm not mistaken).
I actually just complete a true duals project over the weekend, but I'm running off the stock manifolds and catalytic converters. I actually sawzalled the Y pipe and welded/clamped piping from there. That's probably a restriction, but it'll work for now I think. The base of the project was a summit 2.5" true duals X-pipe kit. I had to add a 17" piece of pipe (straight) after the driver side cat, but there was no crimping, etc.
at the end of that generic "kit" sit 2.5" summit bullet style mufflers. It dumps right off the mufflers (somewhat unfinished but will work for now). I'll try to get some pictures this weekend. I think that for flow, it does well...sounds great. But it's not the prettiest out there =\
I actually just complete a true duals project over the weekend, but I'm running off the stock manifolds and catalytic converters. I actually sawzalled the Y pipe and welded/clamped piping from there. That's probably a restriction, but it'll work for now I think. The base of the project was a summit 2.5" true duals X-pipe kit. I had to add a 17" piece of pipe (straight) after the driver side cat, but there was no crimping, etc.
at the end of that generic "kit" sit 2.5" summit bullet style mufflers. It dumps right off the mufflers (somewhat unfinished but will work for now). I'll try to get some pictures this weekend. I think that for flow, it does well...sounds great. But it's not the prettiest out there =\
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From: England
Originally Posted by navyblue2000
The kit LOOKS awesome. But as was said before, exhaust gases don't like making 90* turns. From what I've understood, the closer to the manifolds the X pipe is, the better, it balances the flow sooner. Same goes for the mufflers (if I'm not mistaken).
I actually just complete a true duals project over the weekend, but I'm running off the stock manifolds and catalytic converters. I actually sawzalled the Y pipe and welded/clamped piping from there. That's probably a restriction, but it'll work for now I think. The base of the project was a summit 2.5" true duals X-pipe kit. I had to add a 17" piece of pipe (straight) after the driver side cat, but there was no crimping, etc.
at the end of that generic "kit" sit 2.5" summit bullet style mufflers. It dumps right off the mufflers (somewhat unfinished but will work for now). I'll try to get some pictures this weekend. I think that for flow, it does well...sounds great. But it's not the prettiest out there =\
I actually just complete a true duals project over the weekend, but I'm running off the stock manifolds and catalytic converters. I actually sawzalled the Y pipe and welded/clamped piping from there. That's probably a restriction, but it'll work for now I think. The base of the project was a summit 2.5" true duals X-pipe kit. I had to add a 17" piece of pipe (straight) after the driver side cat, but there was no crimping, etc.
at the end of that generic "kit" sit 2.5" summit bullet style mufflers. It dumps right off the mufflers (somewhat unfinished but will work for now). I'll try to get some pictures this weekend. I think that for flow, it does well...sounds great. But it's not the prettiest out there =\
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Joined: Jun 2005
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From: England
Fyi What the smeg is all this talk about bends not flowing!!!!!!!!!
fluid dynamics are far more complex that just looking at the tubing with the naked and un-trained eye!
Here's a picture of a modern Formula 1 engine. 3.0 litres and nearly 900bhp with rpm ranges upto 19'000rpm.
Take a close look and you'll see some pretty servere bends in the exhaust manifold there. If they really where that restrictive they wouldn't be there, simple as that. Remember F1 teams spend MILLIONS of £/$ in development. As every single HP is important.
fluid dynamics are far more complex that just looking at the tubing with the naked and un-trained eye!
Here's a picture of a modern Formula 1 engine. 3.0 litres and nearly 900bhp with rpm ranges upto 19'000rpm.
Take a close look and you'll see some pretty servere bends in the exhaust manifold there. If they really where that restrictive they wouldn't be there, simple as that. Remember F1 teams spend MILLIONS of £/$ in development. As every single HP is important.
We're not talking about headers here, speaking of untrained eyes. See that big collector there that's close to the engine block. It's close proximity & large size will all but negate those narly bends. It is the close proximity of the collector that makes that set up effective, not the bends. Short pipes w/ few bends equal less flow restriction. Longer pipes/sharp bends equal more restriction. Why do you think cut outs are so effective? His exhaust is unbalanced & more restrictive than it can be. Engine VE = more power &/or less stress.
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From: England
Originally Posted by LS1-450
We're not talking about headers here, speaking of untrained eyes. See that big collector there that's close to the engine block. It's close proximity & large size will all but negate those narly bends. It is the close proximity of the collector that makes that set up effective, not the bends. Short pipes w/ few bends equal less flow restriction. Longer pipes/sharp bends equal more restriction. Why do you think cut outs are so effective? His exhaust is unbalanced & more restrictive than it can be. Engine VE = more power &/or less stress.
Roger Bywater, ex Cheif Engineer of Jaguar Cars would also disagree. And if you take a look at the sticky. Well I'll post it up for you actually.
Here is an exhaust designed by David Vizard, he claims it to be ZERO loss over straightpipe. Seems to have a few bends in it though.
Bends in an exhaust are inevitable. Your picture here is an example of a well routed exhaust. Note the equal length 45 degree bends from the collector to the resonator. They are not sharp 90 degree bends, but smooth 45's (major difference). First bend to the muffler is also greater than 90 degrees (less restrictive). Note how far away these sharper bends are from the headers. This gives the air more space to compress as it forces its way through the sharper bends. If these were directly afterr the header, flow would be more restricted. Note how the most restrictive bends (90 degrees before the muffler) occur directly infront of a large opening (dual tip muffler). This larger area after the sharp bend helps the air flow through the 90 degree bend by decreasing the restriction on the exit side of the bend. Agreed what is shown is an excellent exhaust design & is nothing similar to the exhaust we are commenting on. There are major differences. For one to state simply that bends aren't a problem doesn't address the issue. The shape, location, & area around the bend is important to optimal air flow.
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Verdad Gallardo TECH Addict
Joined: Jun 2005
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From: England
Originally Posted by LS1-450
Bends in an exhaust are inevitable. Your picture here is an example of a well routed exhaust. Note the equal length 45 degree bends from the collector to the resonator. They are not sharp 90 degree bends, but smooth 45's (major difference). First bend to the muffler is also greater than 90 degrees (less restrictive). Note how far away these sharper bends are from the headers. This gives the air more space to compress as it forces its way through the sharper bends. If these were directly afterr the header, flow would be more restricted. Note how the most restrictive bends (90 degrees before the muffler) occur directly infront of a large opening (dual tip muffler). This larger area after the sharp bend helps the air flow through the 90 degree bend by decreasing the restriction on the exit side of the bend. Agreed what is shown is an excellent exhaust design & is nothing similar to the exhaust we are commenting on. There are major differences. For one to state simply that bends aren't a problem doesn't address the issue. The shape, location, & area around the bend is important to optimal air flow.
1. The layout, yes there is always an ideal, but some times you just have to make the best with what you got. The Fbody is not ideal for TD's. So every route will have limitations.
2. I understand what you say about the bends. But again in the sticky it refers to this formula:
2.2cfm for every 1hp
Now the internals of a chambered muffler will cause more terbulance than any 90 degree smooth bend. Yet a chambered muffler can still flow in excess of the engines requirements, thusly having no direct effect on back pressure or engine output.
If the engine is making 500bhp n/a (which probably most Fbody's arn't).
500 x 2.2 = 1100cfm
So you would need a muffler to flow 1100cfm. Or in a dual setup two mufflers (1 per bank) each flowing 550cfm, to not affect backpressure.
A smooth bend in the tubing may reduce the cfm slightly but it will still likely be way above the requirements of the engine.
3. Related to point 1, as I said there are limitations. And as far as the exhaust goes, most V8 engines are limited on the exhaust side due to the uneven firing order. Unless this is corrected then the header design (and thusly the exhaust) will always be further limited.
Originally Posted by 300bhp/ton
try reading the sticky about exhausts (top of this forum), think you may learn something from it.
I've read it once, but since it's a rather lengthly post, why don't you point me to the general area where I need to read, before I bound out of line yet again, and you make more posts making me think I'm more ignorant than what I really am?
I mean...you CAN be helpful when beating someone down
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From: England
Originally Posted by navyblue2000
I've read it once, but since it's a rather lengthly post, why don't you point me to the general area where I need to read, before I bound out of line yet again, and you make more posts making me think I'm more ignorant than what I really am?
I mean...you CAN be helpful when beating someone down
I mean...you CAN be helpful when beating someone down
It's about 2/3rds of the way down. There's an article written by David Vizard, it is very good and informative. I thought it may be of some help if you're designing an exhaust setup.
The X pipe is not there primarily to balance the exhaust, it's function is to scavenge, kinda acts like reverse forced induction. I think the numbers for header scavengine can be responsible for 80% of the air velocity entering the combustion chamber. Which is significant.
The X or H pipe promotes a simlar idea. By coincidence such pipes also cause the exhaust to be quieter.
I'm not to sure about the muffler location either. It would depend on whether chambered or glass ack mufflers are used. The artical talks about sign wave and how the muffler effects it, that is the issue, i.e. the effect rather than just the location.
From the cats back, it's not bad. From the headers to the cats is whats aweful... I would have them put the cats right off of the headers, then reroute the pipe off of them more like a Y going into the two pipes out the back.
You'll eventually tear that pipe off that goes under the tranny mount.
You'll eventually tear that pipe off that goes under the tranny mount.
bump up id like to trade this setup for a catted y pipe and catback if anyones interested email me at dgoodnough@triad.rr.com
Originally Posted by nascarnut3n8
bump up id like to trade this setup for a catted y pipe and catback if anyones interested email me at dgoodnough@triad.rr.com
Originally Posted by 300bhp/ton
The X pipe is not there primarily to balance the exhaust, it's function is to scavenge, kinda acts like reverse forced induction. I think the numbers for header scavengine can be responsible for 80% of the air velocity entering the combustion chamber. Which is significant.
The X or H pipe promotes a simlar idea. By coincidence such pipes also cause the exhaust to be quieter..
The X or H pipe promotes a simlar idea. By coincidence such pipes also cause the exhaust to be quieter..
Someone correct me if im wrong?
Last edited by Jeremiah; Dec 3, 2006 at 09:26 PM.
When it is said that crush bends or pipe routing will restrict hp, that is usually only the case for very extreme setups. For the majority of engines in the 300-400 rwhp range, it ain't gonna make no stinkin difference. 