Exhaust
- Thread starter duratrac
- Start date
T9 man
TC ModFather
Greetings and Welcome to our TorqueCars Forum my Friend! 
I am unable to help you with your question directly, but you are definitely in the right place for the answers! Somebody will be along in a little while who will be able to assist you with some answers or suggestions to your query!
Good luck!
I am unable to help you with your question directly, but you are definitely in the right place for the answers! Somebody will be along in a little while who will be able to assist you with some answers or suggestions to your query!
Good luck!
Hello and Welcome to TorqueCars.:bigsmile:
Hope you enjoy your time with us.
Hope you enjoy your time with us.
Thanks Guys ,, When talking with the muffler shops ,, all they want to do is sell u stuff, Your site looked like eh good place to ask, as you all have some really nice cars , and I bet they run really good to and u all know more about this then they do. Thanks again
The way I understand it is that the fast flow of exhaust gases helps with evacuation as a suction is created behind the moving gases in the next cylinder along, if you go to a twin exhaust this effect will be reduced somewhat. (Although in reality it will make a minimal difference.)
I would stick with a Y piece and go with a slightly larger bore size and then split it at the end again if you really wanted twin tail pipes.
I would stick with a Y piece and go with a slightly larger bore size and then split it at the end again if you really wanted twin tail pipes.
lexus8
Tuner
Hi and welcome , my 91 Hilux Surf is powered with a Lexus V8 , it has a 2 and a half inch pipe in a Y shape into a single pipe wouldnt have it any other way
Charliep
Torque Junkie
On a V6, V8, V10 and V12 you can run separate pipes without a problem. However, the pipe sizes have to be corrected. And that's whereit gets a bit tricky and expensive if you don't want tolose low end torque.
I rather would go for a Y-piece. Place the Y-Piece as far back as possible and make sure that the pipe reduce in size after the split.
I rather would go for a Y-piece. Place the Y-Piece as far back as possible and make sure that the pipe reduce in size after the split.
lexus8
Tuner
can i ask why you say reduce size after split mine is the same size through out , and it holds its own on the street
Charliep
Torque Junkie
To keep gas speed up. It does help more than people think.
Even if you do not have a Y-piece, every exhaust should reduce along the collector pipe. Best would be a tapered pipe. Unfortunately this is virtually impossible at acceptable cost.
Next best option is a reduction, which is a soft step (no sharp edges).
Fitting a smaller exhaust than the OEM standard one will certainly not help at all.
There are obviously optimums here but a really large exhaust bore slows up gasses so conversely a narrower on will cause the gases to flow faster than it would in a large bore exhaust.
Using your analogy of the hosepipe for a high power jet that travels faster and further you use a setting with a small hole in it, a large hole and the water will just dribble out with no velocity at all.
SLEEPER
Pro Tuner
- Points
- 592
I think we agree waynne ?
I used the hosepipe because it is easier to explain/understand
Specifically whatever size pipe you have if you enlarge it you may get more water out you may not it depends .
If the pressure was restrictive before you probably will. If not you probably wont
The water may appear to be coming out slower with a bigger bore but it isnt.
Restricting the size may make the jet longer but the volume doesnt go up so in my eyes the speed does not either ( speed = how long in time a set volume of gas /water takes to travel a set distance)
The pressure can and certainly does change which maybe was what was meant .
High power exhaust system are very complicated. Back pressue and gas speed both count
Lastly different engines demand different calculations epecially when a turbo is involved.
So much so that they are worked out on a computer for best results and are way beyond most people ( inc moi )
One thing I do know though - racing exhaust are larger than non racing ones
I used the hosepipe because it is easier to explain/understand
Specifically whatever size pipe you have if you enlarge it you may get more water out you may not it depends .
If the pressure was restrictive before you probably will. If not you probably wont
The water may appear to be coming out slower with a bigger bore but it isnt.
Restricting the size may make the jet longer but the volume doesnt go up so in my eyes the speed does not either ( speed = how long in time a set volume of gas /water takes to travel a set distance)
The pressure can and certainly does change which maybe was what was meant .
High power exhaust system are very complicated. Back pressue and gas speed both count
Lastly different engines demand different calculations epecially when a turbo is involved.
So much so that they are worked out on a computer for best results and are way beyond most people ( inc moi
)One thing I do know though - racing exhaust are larger than non racing ones
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Charliep
Torque Junkie
High power exhaust system are very complicated. Back pressue and gas speed both count
Lastly different engines demand different calculations epecially when a turbo is involved.
So much so that they are worked out on a computer for best results and are way beyond most people ( inc moi
One thing I do know though - racing exhaust are larger than non racing ones
The Thiele-Small parameters are applicable in turbo as well as in N/a applications.
The reason why race exhaust are bigger is because the aim is to set the peak power point as high as possible. Race cars usually operate in a very narrow band, which makes it necessary for professional racing to adapt more than the exhaust to make the best out of individual tracks.
Rally cars usually have a smaller bore, which is calculated to a lower peak power point and a spread in torque.
your hose pipe analogy does not work,because we are talking exhaust not watering your garden.
Pulse tuning results in exhaust dimension that might not look logical to the onlooker but is correct.
The reason why a reduction is advised is because gases contract on the way out. The temperature drop is several hundred degrees. Therefore it is advised to reduce along the collector pipe.
hen splitting the collector pipe in 2 the gas speed is suddenly reduced, which costs power and has got a negative effect along the system in reverse. My partners and me are spending thousands of hours on the rolling road and track to get these things right. If it were this easy as you claim then we would have a much easier life.
SLEEPER
Pro Tuner
- Points
- 592
In fact I said the exact opposite and that it was very complicated.
I will keep this polite as I very much am interested in any new information - the hose analagy was just about narrowing a pipe/speed . True gases are not liquids soi will happily make my comment irrellevant for this specific point
However I am still persuaded otherwise as nobody in any performance car sphere that i know ( leaves out rallying) uses narrowing exhausts.
Constant bore size is the considered the optimum almost everywhere
Your claims to be this and that may well be true but if narrowing an exhaust is so wonderful why dont the rest of the tuning companies do this .(apart again from rallying)
And some these tuners have larger R & D budgets than you possily can unless of course you own honda etc.
last thing are you saying that exhaust tuning on turbo engines follows the same principles as on na ones ?
I will keep this polite as I very much am interested in any new information - the hose analagy was just about narrowing a pipe/speed . True gases are not liquids soi will happily make my comment irrellevant for this specific point
However I am still persuaded otherwise as nobody in any performance car sphere that i know ( leaves out rallying) uses narrowing exhausts.
Constant bore size is the considered the optimum almost everywhere
Your claims to be this and that may well be true but if narrowing an exhaust is so wonderful why dont the rest of the tuning companies do this .(apart again from rallying)
And some these tuners have larger R & D budgets than you possily can unless of course you own honda etc.
last thing are you saying that exhaust tuning on turbo engines follows the same principles as on na ones ?
Charliep
Torque Junkie
Supersprint exhausts are designed this way as being the biggest perofrmance exhaust manufacturer.
Dave Vizard, the Mini guru of all times would disagree with you.
I am a technical consultant to the automotive industrty other than having my own business and know that they do what I stated.
We develop exhaust systems ourselves and come time and time again to the same conclusion.
Most of the performance tuning specialists I know (and I know many personally) do it too.
There is also a lot of info about it on the net by credible institutions.
Force induced and n/a exhaust have several things in common. One thing they differ is that n/a engines rely on the scavenging helped by the exhaust design, which force induced engines do not need as the boost takes care of it resulting in a different lobe separation of the cam arrangement.
Dave Vizard, the Mini guru of all times would disagree with you.
I am a technical consultant to the automotive industrty other than having my own business and know that they do what I stated.
We develop exhaust systems ourselves and come time and time again to the same conclusion.
Most of the performance tuning specialists I know (and I know many personally) do it too.
There is also a lot of info about it on the net by credible institutions.
Force induced and n/a exhaust have several things in common. One thing they differ is that n/a engines rely on the scavenging helped by the exhaust design, which force induced engines do not need as the boost takes care of it resulting in a different lobe separation of the cam arrangement.
T9 man
TC ModFather
Sorry I don't quite understand, can you explain in laymans terms CP as to what the different lobe separation of the cam arrangement - means please? :embarrest: Thanks.Charliep
Torque Junkie
Sorry.
When talking about lobe separation it refers to the angle between the exhaust lobe and the inlet lobe describing the overlap of valve opening between both the exhaust and inlet valve, which occurs at the end of the exhaust stroke leading into the intake stroke.
boostnturbos
Torque Junkie
what is scavaging for?
