I got greedy and now have one set of dual exit exhaust then got meself a single exit. What I wanna know is there any real advantage of having a single over the dual exit as it was originally designed with.

 

Only thing I can think of is that single exit is lighter but since your running both exhausts exits down one pipe you have a slight increase in back pressure? Not sure what I'm going on about now so hopefully someone else can tell me otherwise! :mac1: :hyper:

Not an expert, but it probably affects exhaust note rather than performance.

 

Dual more likely to have a rumble, and single more likely to have a sporty, er, sound.

 

Any help?! Probably not! :slap:

Only thing I can think of is that single exit is lighter but since your running both exhausts exits down one pipe you have a slight increase in back pressure? Not sure what I'm going on about now so hopefully someone else can tell me otherwise! :mac1: :hyper:

 

Hi W1NG,

 

I'm not an expert but you are on the right lines talking about back pressure. you need to have the optimum back pressure (bearing in mind any mods) in order to get the most power out of the engine.

 

Mike...

Hi Guys,

 

When I was at college studying cars my lecturers :bow: favourite thing to point out was that "the power of an engine is determined by how much air you can get in and out in a predetermined time".

Therefore you have to presume that 2 is better than one as you have more capacity to get the air out. Hence why performance exhaust are usually a larger bore than standard ones. That said you do need a certain amount of back pressure but for me 2 is the way to go to get more power.

 

Hope this makes sense.

 

Zedhot

Hi Guys,

 

When I was at college studying cars my lecturers :bow: favourite thing to point out was that "the power of an engine is determined by how much air you can get in and out in a predetermined time".

Therefore you have to presume that 2 is better than one as you have more capacity to get the air out. Hence why performance exhaust are usually a larger bore than standard ones. That said you do need a certain amount of back pressure but for me 2 is the way to go to get more power.

 

Hope this makes sense.

 

Zedhot

Presuming 2 is better isnt always the case! But I do get what you mean, thing is the single exit exhaust I have has a bigger bore then the dual exit. I'm guessing that's to compensate for the lack of exhaust on the other end but wouldnt that basically give me a crappy lower end seeing as there isnt as much pressure building up on low revs to get rid of the air due to the fact that there is a larger then usual bore? My guess that is. Which is why I'm still trying to decide if I should put the single or the dual exit on!

 

Maybe I should make a poll instead...! :headvswal

Presuming 2 is better isnt always the case! But I do get what you mean, thing is the single exit exhaust I have has a bigger bore then the dual exit. I'm guessing that's to compensate for the lack of exhaust on the other end but wouldnt that basically give me a crappy lower end seeing as there isnt as much pressure building up on low revs to get rid of the air due to the fact that there is a larger then usual bore? My guess that is. Which is why I'm still trying to decide if I should put the single or the dual exit on!

 

Maybe I should make a poll instead...! :headvswal

iff you want your car to sound low with a bit of bass go for dual,iff you wanna sound like a high pitched ferarri type wail at 7000 rpm :bow: :bow: go single dude you know it makes sense

iff you want your car to sound low with a bit of bass go for dual,iff you wanna sound like a high pitched ferarri type wail at 7000 rpm :bow: :bow: go single dude you know it makes sense

Putting it that way makes it sound tempting! I'll rather it not go boom boom lower down as it's a bloody headache...! As long as it doesnt sound like my friends Blitz Nur spec exhaust!

 

Which comes to this...

 

Dual exit = Apexi Megaphone

Single exit = Something Otto Racing

 

Anyone know if they are actually any good? OR actually had one of the two installed?

if it helped performance in anyway, even a smidgen, dont you think the race teams of the workd would all have single exit in their V's

 

Its all about image a single exit. personaly, ill go with performance anyday of the week.

if it helped performance in anyway, even a smidgen, dont you think the race teams of the workd would all have single exit in their V's

 

Its all about image a single exit. personaly, ill go with performance anyday of the week.

well iff thats the case how come your zed aint black :rofl: :rofl:

single exit,get allunox to make you a single exit with 4"+ pipework throughout then you have heard a proper exhuast :D

Back pressure? On turbos cars? No thanks! Ideally you want to help the two large fans that are trying to push air through your engine not hinder it. 2.5 inch or above for the whole system is the only way to go in my opinion. If you go for a single exit you will loose power due to the one pipe unless you run a 4 inch or similar from the front right back. This will give you ground clearance problems I would imagine. I intend to have dual exits on either side with 3 inch piping from the cats. I should mention that the back boxes I'm going for are 3.25 inch side-by-sides

 

http://etiwebhosting.com/~caroptioncom/product.php?pid=1558&xcSID=e338f99325f101dcf2077f5371eb5509

 

Back boxes make next to no difference really despite what people think.

 

I think that you should also consider that the rear bumper of the stock car is shaped for twins not singles.

Back pressure? On turbos cars? No thanks! Ideally you want to help the two large fans that are trying to push air through your engine not hinder it. 2.5 inch or above for the whole system is the only way to go in my opinion. If you go for a single exit you will loose power due to the one pipe unless you run a 4 inch or similar from the front right back. This will give you ground clearance problems I would imagine. I intend to have dual exits on either side with 3 inch piping from the cats. I should mention that the back boxes I'm going for are 3.25 inch side-by-sides

 

http://etiwebhosting.com/~caroptioncom/product.php?pid=1558&xcSID=e338f99325f101dcf2077f5371eb5509

 

Back boxes make next to no difference really despite what people think.

 

I think that you should also consider that the rear bumper of the stock car is shaped for twins not singles.

and the rear bumper needs changing anyway ;)

 

as said the important factors are forcing more in and forcing more out

I'm just trying to figure out if the lost in weight is really worth going for single exit as it is a fackin hell of alot lighter then a dual exit...! Also just to clear things up a bit I do actually have the pipes from cat back for both systems. I just cant keep both!

Most of what has been said is just opinion!

If you want the best performance then you need to talk to someone who really understands the fluid dynamics involved in engines/exhausts. perhaps someone who makes custom exhausts.

 

Greg is spot on with both of these comments.

 

as said the important factors are forcing more in and forcing more out

 

single exit,get allunox to make you a single exit with 4"+ pipework throughout then you have a proper exhuast :D

Surely Nissan would have had said expert. hence fitting dual exhausts as standard.

Surely Nissan would have had said expert. hence fitting dual exhausts as standard.

 

I'm sure they did have a panel of experts, but the standard exhaust was designed for a standard set of Tubs, standard ECU etc. So if your car is standard you probably can't get much better than the original exhaust.

 

Conversly, if you have fitted a load of mods you will need an exhaust to match.

 

I promise I will never post about exhausts again, it's exhausting...

agreed, but if you mod, then surely a greater diameter twin system would serve you better than a single one.

I have a single exit system made up from old eminox pipework, 3 inch pipes merging at cats, 4 inch to silencer then 2.5 inch straight through the silencer.....isnt too loud unless kicked...then its loud but it sounds fookin awsome.

I didnt care about weight saving, or future mods etc, to me I think it looks better but thats just my taste.

 

Cheers John Crisp

agreed, but if you mod, then surely a greater diameter twin system would serve you better than a single one.

It probably would but I was thinking would putting a single exit exhaust pay off in the fact that I would have gotten rid of some weight. I'm still drawn towards the single exit as there are quite a few companies out there who do them which must mean there is some sort of gains for them to do such a thing!

 

Only problem I have is that the mid section for the damn thing is mild steel! Prob be a good idea to do some anti-rusting...!? :confused:

Saying that Nissan made it twin pipes so must be better is irrelevant as they have many other factors to consider.

 

And why do people "want" or "need" backpressure?????

 

Do you see race cars with great big restrictors to make back pressure?

 

As has been said here, the idea for any engine is to get the fuel/air in, burn it and get it all out as quickly as poss.

 

Without giving any names I know a chap, a mod on another forum, who thought that back pressure actually closed the exhaust valves. Honest.

.................And why do people "want" or "need" backpressure?????

 

Do you see race cars with great big restrictors to make back pressure?...................

 

Exactly Mark!

 

On a turbo car then no back-pressure = more performance. On an n/a a little back pressure is supposed to be better than none at all. Just read that somewhere...... ;)

 

Richard :D

I'm still drawn towards the single exit as there are quite a few companies out there who do them which must mean there is some sort of gains for them to do such a thing!

 

How much weight would it actually save though? What other weight saving have you done? Would be amazed if you actually saved that much to be worth it. but, if you like the single exit theres no question to answer.

 

Dai ;)

I think a lot of the above posts are opinions and you really need to see an expert who knows how the exhaust is going to affect your engine.

 

One thing you should be careful of is that a single big exhaust can shift much more air than two half sized ones. This is because of poiseuille's law which describes how much resistance the exhaust will give to the air trying to escape from your engine.

 

Rule one is that resistance is DIRECTLY proportional to the length of the exhaust - so an exhaust that is 4 feet long will provide twice the resistance to escaping air compared to an exhaust that is 2 feet long.

 

 

Rule two concerns the radius of the actual pipe itself. In basic terms, resistance is INVERSELY proportional to the radius of the pipe to the power of 4 (1/r^4). So if you have an exit pipe 4 inches in radius the resistance will be (approx) one divided by 256 (ie 4x4x4x4).

 

1/256 = 0.004 and the smaller the resistance the better as that means you can shift more air. Now if you have an exhaust with a two inch radius resistance is one divided by 16 (ie 2x2x2x2). ie 0.0625 still a small number but one that is way way way bigger than the 4 inch pipe. This is why one big pipe can shift way way way more exhaust than TWO half sized pipes.

 

Sorry if ive lost you but its the simplest way i could think to describe it. Helpful link here:

http://hyperphysics.phy-astr.gsu.edu/hbase/ppois.html

 

You obviously do need some backpressure for the engine to work otherwise why bother with an exhaust at all? the correct setup will need a z mechanic with an intimate knowledge of the turbo engine and a good grasp of physics.

Sir Mixalot said "You obviously do need some backpressure for the engine to work otherwise why bother with an exhaust at all? the correct setup will need a z mechanic with an intimate knowledge of the turbo engine and a good grasp of physics"

 

 

You need an exhaust to a) make the car quiet enough to be legal. b) to make the fumes exit from not underneath the car and c) because there is an ideal "tuned" length for all engines (which varies from one to another). Back pressure? Ha ha

You could be right but ive seen a lot of people who just whack the biggest exhaust on they can buy aftermarket and totally ruin the driving characteristics of their car with poor pickup at normal revs. PHNW are of the opinion that the right amount of backpressure is crucial for the correct running if the z engine. Just my humble opinion bud.

either way 2 twin exhausts look a load better than one big bore "max power" corsa style exhaust....

 

Keep the car looking how it should... damn sexy!!