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
10-14-04, 04:43 PM
#26
Mmm...unburned exhaust
Join Date: Sep 2004
Location: SeaTac, WA
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Wow, just read the comments from some people saying that a single would flow better than a duel setup. Hmmm, that's why all the muscle cars that pump tremendous amounts of horse power run duel pipes with an "H" pipe or a "Y" pipe added (some said this incresed 'turbulance'). The H or Y addition actually help exhaust scavenging. Duels have more space to distribute the gases, that's one of the reasons why they are quieter than single exhaust setups.
There are great exhaust writeups out there for other cars than ours since cars that pump in air and spit out exhaust have been around for so long. I suggest everyone take a gander. Engines are just a big giant airpump, pretty cool when you think about it. I love good information
Edit: I should add that scavenging is very beneficial in the lower rpms (mainly piston engine design). When people talk about engines breathing, they really do! The engine will suck back some exhast into the chamber due to overlapping valve timings (pistion engine of course)
There are great exhaust writeups out there for other cars than ours since cars that pump in air and spit out exhaust have been around for so long. I suggest everyone take a gander. Engines are just a big giant airpump, pretty cool when you think about it. I love good information
Edit: I should add that scavenging is very beneficial in the lower rpms (mainly piston engine design). When people talk about engines breathing, they really do! The engine will suck back some exhast into the chamber due to overlapping valve timings (pistion engine of course)
Last edited by twoedge; 10-14-04 at 04:50 PM.
10-14-04, 05:32 PM
#27
Senior Member
Join Date: Mar 2004
Location: USA, PA, Harrisburg area.
Posts: 309
Likes: 0
Received 2 Likes
on
2 Posts
less weight= single "true" dual=power in my opinion. 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) and patching the other opening up but some true dual setups are badass and since there are only two exaust exits its pretty easy to make ur own dual from the headers back cuz u dont have to worry about the exaust flow joining at the headers.
10-14-04, 05:46 PM
#29
Rotary Enthusiast
Join Date: Feb 2004
Location: Freeport, Maine
Posts: 1,225
Likes: 0
Received 0 Likes
on
0 Posts
i prefer single also. 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) Yes, also in my opinion in the asthetics department i personaly love the side pipe! side pipes are bad ***. at the moment i have a single side pipe on the passengers side of the car. Pretty soon once my header gets here i will have tomake the decision of either keeping the side pipe and improving it or going back to the Y pipe. i don't want to go to the Y pipe for performence reasons but i'm afraid of how loud it's gonna be with the RB header and a single side pipe. . might be too much. But in my opinion Side pipes are badass. either duel or single they are by far the coolest of all and they are shorter witch is less weight and possible flows better. Just my two cents
Dom
Dom
10-14-04, 05:46 PM
#30
Here's something to think about for anyone thinking that a single flows better. If you have a 2.5" pipe that splits to 2-2" pipes, you have increasd the available flow area. The single main pipe has an area of 4.91" while the total area of the dual 2" pipes adds up to 6.28". After the split, the duals flow more. Splitting the pipes and adding one bend will not offest the available flow area and give the advanage to the other system. Dual mufflers also have twice the muffling ability. Since there is greater total area in the dual pipes, the exhaust gasses are moving slower. A slower moving gas is less restricted by a muffler than a faster moving gas. It also has more time inside the muffler to get sound absorption.
In the end whether or not a certain system has the ability to flow more is really irrelevant if both of them have the ability to outflow the engine requirements. There is more than one way to do it and in the end neither has an advantage over the other. Looks are purely subjective but no one can argue that one system definitively performs better than her other.
In the end whether or not a certain system has the ability to flow more is really irrelevant if both of them have the ability to outflow the engine requirements. There is more than one way to do it and in the end neither has an advantage over the other. Looks are purely subjective but no one can argue that one system definitively performs better than her other.
10-14-04, 05:52 PM
#31
Senior Member
Join Date: Mar 2004
Location: USA, PA, Harrisburg area.
Posts: 309
Likes: 0
Received 2 Likes
on
2 Posts
but if there both about basically equal and its just preferance like ur saying then wouldnt thesingle be less weight so therefore more advantages? (increased diameter more air per pound of weight then dual)
10-14-04, 05:54 PM
#32
...94% correct.
Originally Posted by rotarygod
Here's something to think about for anyone thinking that a single flows better. If you have a 2.5" pipe that splits to 2-2" pipes, you have increasd the available flow area. The single main pipe has an area of 4.91" while the total area of the dual 2" pipes adds up to 6.28". After the split, the duals flow more. Splitting the pipes and adding one bend will not offest the available flow area and give the advanage to the other system. Dual mufflers also have twice the muffling ability. Since there is greater total area in the dual pipes, the exhaust gasses are moving slower. A slower moving gas is less restricted by a muffler than a faster moving gas. It also has more time inside the muffler to get sound absorption.
In the end whether or not a certain system has the ability to flow more is really irrelevant if both of them have the ability to outflow the engine requirements. There is more than one way to do it and in the end neither has an advantage over the other. Looks are purely subjective...
In the end whether or not a certain system has the ability to flow more is really irrelevant if both of them have the ability to outflow the engine requirements. There is more than one way to do it and in the end neither has an advantage over the other. Looks are purely subjective...
...but no one can argue that one system definitively performs better than her other.
10-14-04, 06:00 PM
#33
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? (increased diameter more air per pound of weight then dual)
Last edited by rotarygod; 10-14-04 at 06:04 PM.
10-14-04, 06:01 PM
#34
...94% correct.
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? (increased diameter more air per pound of weight then dual)
Just to try and spill out something long and arguementative...
Yes, two pieces of tubing witha 2" diameter are going to be capable of flowing more than a single 2.5" piece of tubing. Hoever, 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.
And to the reference to V8's using "H" and "X" pipes...V8 and V6 drag cars and track cars do not collect both banks.
10-14-04, 06:07 PM
#36
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.
10-14-04, 06:50 PM
#40
I vote for dual exhaust all the way. They look a lot better than a single, and the weight of the extra muffler/piping helps with the car's weight distribution.
And I may be wrong, but I always thought that dual exhausts flow better than a single of the same piping size, because there is more room for the exhaust to escape.
And I may be wrong, but I always thought that dual exhausts flow better than a single of the same piping size, because there is more room for the exhaust to escape.
10-14-04, 06:56 PM
#41
...94% correct.
Originally Posted by gxl90rx7
I vote for dual exhaust all the way. They look a lot better than a single, and the weight of the extra muffler/piping helps with the car's weight distribution.
And I may be wrong, but I always thought that dual exhausts flow better than a single of the same piping size, because there is more room for the exhaust to escape.
And I may be wrong, but I always thought that dual exhausts flow better than a single of the same piping size, because there is more room for the exhaust to escape.
A few pounds to one side won't help distribution....think about it, the rolling chassis, plus motor and tranny, is almost perfectly ballanced. Then add the battery and driver...how much weight do you need on the driver's side? Not that the weight is significant enough to be considered anyways...
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? Hell...lets just vent the ports to open atmosphere...that'll give LOTS of room for the exhaust to escape...
10-14-04, 07:05 PM
#42
Lets rock.
Join Date: Apr 2004
Location: SLC, Utah
Posts: 1,355
Likes: 0
Received 0 Likes
on
0 Posts
Ok I've got a little project for you guys. Take a wide mcdonalds straw and tape two smaller straws with the bendy part and tape them so they make a Y shape. Use your imagination and make it look like the exhaust on a RX-7. Bending the straws like it is on RX-7 mufflers. Blow through it. Now take a regular MCdonalds straw and blow through that straw itself. Just the straw. Notice a difference? If any feels this is in some way irrelevant please explain.
10-14-04, 07:17 PM
#43
...94% correct.
Originally Posted by flamin-roids
Ok I've got a little project for you guys. Take a wide mcdonalds straw and tape two smaller straws with the bendy part and tape them so they make a Y shape. Use your imagination and make it look like the exhaust on a RX-7. Bending the straws like it is on RX-7 mufflers. Blow through it. Now take a regular MCdonalds straw and blow through that straw itself. Just the straw. Notice a difference? If any feels this is in some way irrelevant please explain.
Way too many variables with the human body. Better lest would be to suspend the straw apparatus upside-down at a 90* angle and secured to a board or something. Then, usung a sealed funnel, pour a measured amount of fluid through them and calculate the difference in time it takes the fluid to travel through the straws.
Both tests are irrellevent, though, because I doubt it's possible to simulate real-world variences in tubing size and structure.
10-14-04, 07:47 PM
#44
Lets rock.
Join Date: Apr 2004
Location: SLC, Utah
Posts: 1,355
Likes: 0
Received 0 Likes
on
0 Posts
Uh way to technical. The point was to see which one was easier to blow through. I wasn't gauging it on how much air was displaced. If you tried it you would notice a difference in the difficulty of blowing air through each one.
10-14-04, 07:56 PM
#45
The accordian shape of the straw in the bends wouldn't help anything.
We don't run 3" tubing on our cars because we need some flow velocity. However, the Y-pipe is far enough back that we keep this effect as long as we have a smaller pipe up to this point. Whether the exhaust area gets larger or not after this point is irrelevant. A 3" pipe at the engine wouldn't be good. A 2.5" pipe all the way to the Y-pipe is fine. It doesn't matter if it stays this size from there out or gets larger. Saying a smaller total area single pipe flows better than larger area dual pipes because there is one less turn in 1 pipe is what's ridiculous. A 90 degree bend on a 2" radius would be bad. A gentle turn won't hurt. There is ZERO performance gain to be had from going to a properly designed single vs a properly designed dual. If you think otherwise, I challenge you to PROVE IT. You can't!
We don't run 3" tubing on our cars because we need some flow velocity. However, the Y-pipe is far enough back that we keep this effect as long as we have a smaller pipe up to this point. Whether the exhaust area gets larger or not after this point is irrelevant. A 3" pipe at the engine wouldn't be good. A 2.5" pipe all the way to the Y-pipe is fine. It doesn't matter if it stays this size from there out or gets larger. Saying a smaller total area single pipe flows better than larger area dual pipes because there is one less turn in 1 pipe is what's ridiculous. A 90 degree bend on a 2" radius would be bad. A gentle turn won't hurt. There is ZERO performance gain to be had from going to a properly designed single vs a properly designed dual. If you think otherwise, I challenge you to PROVE IT. You can't!
10-14-04, 08:04 PM
#46
...94% correct.
I still don't think a "Y" could be made adequate enough to (all else being equal) perform as well as a straight pipe...
You'll never see me argue with how well 2 2" pipes will flow in comparison to a singe 2.5" or 3"...you WILL see me argue over how efficient the transition is.
...I don't even like to make collected headers...:/
You'll never see me argue with how well 2 2" pipes will flow in comparison to a singe 2.5" or 3"...you WILL see me argue over how efficient the transition is.
...I don't even like to make collected headers...:/
10-14-04, 08:26 PM
#48
Rotary Enthusiast
Join Date: Feb 2004
Location: Freeport, Maine
Posts: 1,225
Likes: 0
Received 0 Likes
on
0 Posts
I'm tellin you, go with side pipes. duel or single they are sweet. anyone think about what i said? if you were to cut the exhaust before the Y it would flow much better than if you were to have the Y . You all must see this. Therefor i say in an all out performance veiw point, go with true duels. if you ahve a collected header then go with single. (side piped of coarse) haha just some food for the thinking process. . ----< or -----
