View Poll Results: What type of aftermarket exhuast
One with tip coming from both sides of the car
56
73.68%
Or one with a single pipe
20
26.32%
Voters: 76. You may not vote on this poll
Exhaust Dual or Single
10-15-04, 01:29 AM
#52
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Originally Posted by Makenzie71
Can you sit there and tell me that, all else being equal, a smooth and fluid bend to a single outlet will not flow as well as or better than a dual out with a rather abrupt "Y" joint.
The other point I've repeated again and again is that pipe sizes are more important just the configuration. If you truly believe that "single flows better" no matter what, then you must believe that a single 2" pipe flows better than a 3" pipe that splits into two 3" pipes. But that is obviously not the case. A system that consists of a 3" pipe splitting into two 2.5" pipes will flow as well a single 3" system, but not nearly as well as a single 3.5" system.
Originally Posted by 87base RX-7
Though a catback dual on a stock car will rob u of power and add redundant weight. I prefer a larger single (3in or so)...
Originally Posted by Dom_C
think of it this way, for those simple minded people out there. if you cut the pipe off before the Y would it flow better then with the Y in there? (regardless of mufflers)
Originally Posted by 87base RX-7
but if there both about basically equal and its just preferance like ur saying then wouldnt thesingle be less weight so therefore more advantages?
Originally Posted by Makenzie71
...going from a single 2.5" section to two 2" sections requires a "Y". This "Y" section is going to cause turbulance and IS going to cause a build of pressure which will result in flow being interupter prior to the two 2" sections.
Originally Posted by rotarygod
If the merge collector is a crappy design then I would agree with you but all of them don't suffer from this. Just because the flow splits is alone not justification of heavy turbulence and backpressure. It has to be a really bad design for this to be an issue.
Originally Posted by Makenzie71
This is also like the fourth time I've seen "duals flow better because there's more room." That's ridiculous. If having more room was so much better, why don't we run 3" tubing or larger on our N/A's?
I still don't think a "Y" could be made adequate enough to (all else being equal) perform as well as a straight pipe...
10-15-04, 02:07 AM
#54
...94% correct.
Amongst a bunch of other stuff you said I don't agree with...
You did, actually. Repeatedly.
Originally Posted by NZConvertible
Nobody ever said it could. See above about the horse...
10-15-04, 02:12 AM
#55
...94% correct.
...screw it...
This is all opinion. I think a 30* "Y" is pretty abrupt. You don't? Fine. It's opinion.
See above statement, and you never answered my question.
I'm sorry, tuning has to work around set perameters. You can not set a particular tune then change things around at whim.
See previous post.
Originally Posted by NZConvertible
For starters, the Y in an FC's dual exhaust is far from abrupt, with the pipes diverging at an angle less than 30deg. And if you really did read what I posted, you'd know that I never said the Y doesn't cause any restriction. In fact I mentioned the restriction it causes numerous times. I also said that a well-built Y is less restrictive than most people tend to think. I know this because I use technical manuals at work that show how to calculate the losses in duct and pipe systems. I also went to great lengths to explain that the extra restriction from the Y is balanced out by the fact that if the pipes are sized correctly, the restriction caused by two pipes will be much less than the restriction caused by one. Some people have this totally unfounded idea that the Y is such a huge restriction that it doesn't matter what you put after it, which is a load of BS.
Please stop flogging this dead horse. You're blowing it way out of proportion.
I guess you haven't seen a lot of high-power NA rotaries. You can easily run a 3" exhaust if the collected part of the system is tuned properly. Once you're past the tuning point, you can go as big as you want. The reason people don't is because most collected rotary exhausts are not properly tuned.
Nobody ever said it could. See above about the horse...
10-15-04, 02:33 AM
#56
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nz wins!!!!
however its news to me that 3" exhaust would be beneficial on an n/a. they need some restriction (smaller diameter tube) to develope decent torque rigth? or are these setups just going for top end?
however its news to me that 3" exhaust would be beneficial on an n/a. they need some restriction (smaller diameter tube) to develope decent torque rigth? or are these setups just going for top end?
10-15-04, 02:56 AM
#57
...94% correct.
Originally Posted by andrew lohaus
nz wins!!!!
however its news to me that 3" exhaust would be beneficial on an n/a. they need some restriction (smaller diameter tube) to develope decent torque rigth? or are these setups just going for top end?
however its news to me that 3" exhaust would be beneficial on an n/a. they need some restriction (smaller diameter tube) to develope decent torque rigth? or are these setups just going for top end?
But the exhaust is only one thing in what can be a REALLY big picture.
10-15-04, 03:07 AM
#58
...94% correct.
I'll put it like this, though...if you're putting down the kind of power to utilize a 3" exhaust on a NA 13b, you probably don't need any advice from any of us...
10-15-04, 04:49 AM
#59
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Originally Posted by Makenzie71
You did, actually. Repeatedly.
Prove it. Show me where I said (or even implied) that "a Y could be made adequate enough to perform as well as a straight pipe" (your words). Show me or admit you're wrong. If you want I'll find all the times I said it couldn't. A couple are even in this thread.
This is all opinion. I think a 30* "Y" is pretty abrupt. You don't? Fine. It's opinion.
What's funny is that you think a Y with an included angle of 30deg is abrupt, yet you say the bend in a single system is "smooth and fluid", despite the fact they're about the same shape. Look at this pic of the Y in the RB system. Looks pretty smooth to me. How is the change in pipe angle at the Y different to the bend in a single system?
I'm sorry, tuning has to work around set perameters. You can not set a particular tune then change things around at whim.
10-15-04, 05:01 AM
#60
...94% correct.
Originally Posted by NZConvertible
Prove it. Show me where I said (or even implied) that "a Y could be made adequate enough to perform as well as a straight pipe" (your words). Show me or admit you're wrong. If you want I'll find all the times I said it couldn't. A couple are even in this thread.
My "opinion" is based on my training in mechanical engineering and my experience as an HVAC design engineer.
What's your based on?
What's funny is that you think a Y with an included angle of 30deg is abrupt, yet you say the bend in a single system is "smooth and fluid", despite the fact they're about the same shape. Look at this pic of the Y in the RB system. Looks pretty smooth to me. How is the change in pipe angle at the Y different to the bend in a single system?
WTF are you talking about?
Once you're past the tuning point, you can go as big as you want.
Last edited by Makenzie71; 10-15-04 at 05:03 AM.
10-15-04, 06:12 AM
#61
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Originally Posted by Makenzie71
ONly once in this thread did you imply that it couldn't. You've said countless times that (all else being equal) a "Y" pipe "could" flow as well as a single.
You said a "Y" pipe doesn't have to be abrupt. I'm sorry but sticking a splitter right in the path of movement is "abrupt" in my opinion.
What does that have to do with your experience as an HVAC design engineer?
You can not set a vehicle to run a particular way with a particular setup and then go altering things and expect it to still all run in prime condition without re-tuning...
Last edited by NZConvertible; 10-15-04 at 06:19 AM.
10-15-04, 10:04 AM
#62
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People peolple let's go a little easy huh!
I think it's time to put this to rest once and 4 all.........someone write MYTH BUSTERS on the discovery channel and let them take care of this he he.
Would be VERY interesting to watch! I'm sure all of us would be glued to the tube if it ever did happen to make it to the show. ha ha
But.....my personal pref.....I like the look of a SINGLE with a nice slight angle of the muff and other whole patched up.
I think it's time to put this to rest once and 4 all.........someone write MYTH BUSTERS on the discovery channel and let them take care of this he he.
Would be VERY interesting to watch! I'm sure all of us would be glued to the tube if it ever did happen to make it to the show. ha ha
But.....my personal pref.....I like the look of a SINGLE with a nice slight angle of the muff and other whole patched up.
10-15-04, 12:55 PM
#63
...94% correct.
Originally Posted by NZConvertible
I asked you to show me where I said that, so put up or shut up. I have never said a Y flows as well as a piece of straight pipe. I've said a dual muffler exhaust system can flow as well as a single system if sized correctly. Totally different. Stop making **** up in a lame attempt to salvage your argument.
Well the engineering data used to calculate pressure drops in pipe and duct systems says your opinion isn't worth much.
Knowledge of fluid flows (air in ducts, water in pipes, etc) is a fundamental part of HVAC design. Pretty obvious really...
Who mentioned altering anything? Not me. More made-up ****...
Once you're past the tuning point, you can go as big as you want.
Have a nice day
10-15-04, 06:58 PM
#69
...94% correct.
Sorry...I read that wrong. You said "if sized propperly"...which I can agree with in some ways and disagree with in some ways. Several times, though, you've said that if everything else remains equal (ie, tubing can displace same volume, mufflers same volume, etc) a dual catback would flow as well as a single...or that's the way I understood it.
...I may have misunderstood you. Which is why I asked, repeatedly, if that's what you meant.
...I may have misunderstood you. Which is why I asked, repeatedly, if that's what you meant.
10-15-04, 07:09 PM
#70
Single exhaust:
less weight
no obstructions in exhaust flow/straighter exhaust flow path
leaves empty gap in stock rear bumper
looks ricey
Duel exhaust:
more pipe volume for less exhaust flow restriction
better front-rear weight distribution
looks more intimidating
its what the original RX-7 engineers designed for
Im going with duel exhaust
less weight
no obstructions in exhaust flow/straighter exhaust flow path
leaves empty gap in stock rear bumper
looks ricey
Duel exhaust:
more pipe volume for less exhaust flow restriction
better front-rear weight distribution
looks more intimidating
its what the original RX-7 engineers designed for
Im going with duel exhaust
10-15-04, 07:36 PM
#72
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this is just my .02, but I am currently going to school for nuclear power for the navy. All we do in a reactor plant is move water, steam, and heat to make power (don't worry I'm getting to my point). we have to take a class called heat transfer and fluid flow. Exhaust is a fluid, so all the same priciples and properties apply. what you put into the pipe is obviously goin to come out. With a single pipe, you have less bends, but Mazda made the car with 2 mufflers for a reason. That reason is that if you have a 2 exits instead of one, you can dispel more gas at a faster rate then trying to cram it all in one pipe. I would preferrably go with duals, but I don't make enough to make my own system. no matter if you run N/A or turbo, your car will benefit from a free flowing exhaust. N/A's just need a little backpressure. my point is that duals are better, because you have more room at the y pipe to move more gas, which makes more power.
but that's just my take on it.
but that's just my take on it.
10-15-04, 07:40 PM
#73
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Originally Posted by 88convert
this is just my .02, but I am currently going to school for nuclear power for the navy. All we do in a reactor plant is move water, steam, and heat to make power (don't worry I'm getting to my point). we have to take a class called heat transfer and fluid flow. Exhaust is a fluid, so all the same priciples and properties apply. what you put into the pipe is obviously goin to come out. With a single pipe, you have less bends, but Mazda made the car with 2 mufflers for a reason. That reason is that if you have a 2 exits instead of one, you can dispel more gas at a faster rate then trying to cram it all in one pipe. I would preferrably go with duals, but I don't make enough to make my own system. no matter if you run N/A or turbo, your car will benefit from a free flowing exhaust. N/A's just need a little backpressure. my point is that duals are better, because you have more room at the y pipe to move more gas, which makes more power.
but that's just my take on it.
but that's just my take on it.
1) an exhaust system is only as good as it's wakes point.
2) a single pipe could flow just as much as a dual becaust teh piping is usually bigger, after the Y duals usually decrease in pipe diameter
10-15-04, 07:43 PM
#74
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Originally Posted by Makenzie71
Several times, though, you've said that if everything else remains equal (ie, tubing can displace same volume, mufflers same volume, etc) a dual catback would flow as well as a single...
It should be pretty obvious that to directly compare single and dual muffler systems, the mufflers have to be of the same basic design. If you replace a dual system that uses restrictive triple-flow mufflers with a system that uses single a straight-through muffler, or course it'll flow better.