Exhaust Geeks required
Discussion
Great replies, gotta love PH!
If it helps I'm actually looking to decat the car, my Saxo responded very well to the decat and I've read on ClioSport that the Clios do just the same (as I imagine any car would)
As my car already has an exhaust on it I didn't want the car to be too loud, which is why I am considering silenced decat pipes such as the Janspeed one below:
but I would rather have the best performance from the change in exhaust, and was worried the silencer might create back pressure and thus not give as big a performance increase as the straght through pipe below;
If it helps I'm actually looking to decat the car, my Saxo responded very well to the decat and I've read on ClioSport that the Clios do just the same (as I imagine any car would)
As my car already has an exhaust on it I didn't want the car to be too loud, which is why I am considering silenced decat pipes such as the Janspeed one below:
but I would rather have the best performance from the change in exhaust, and was worried the silencer might create back pressure and thus not give as big a performance increase as the straght through pipe below;
kambites said:
An interesting question. Would a typical modern petrol engine running with no exhaust (assuming you can somehow get the mixture the same with no lambda sensor) produce more or less power than one with an exhaust if no other modifications were made?
assuming by "no exhaust" you mean nothing downstream of the exhaust manifold, then the answer is "more power" (but if you also loose the exh man then the answer is "less power")DannyVTS said:
Great and thus not give as big a performance increase as the straight through pipe
Considering that the maximum difference on an otherwise std engine will be in the order of 1-3bhp, i doubt you'd notice (or be able to measure) the difference!!(most people stick on fart cans, and all the extra noise makes then think it's much faster, when in reality the difference is not measurable) If you actually want to go faster, either 1) just buy a quicker car, or 2) get into some proper N/A tuning (for which you wil of course have to pay mucho ££)
Max_Torque said:
Considering that the maximum difference on an otherwise std engine will be in the order of 1-3bhp, i doubt you'd notice (or be able to measure) the difference!!
(most people stick on fart cans, and all the extra noise makes then think it's much faster, when in reality the difference is not measurable) If you actually want to go faster, either 1) just buy a quicker car, or 2) get into some proper N/A tuning (for which you wil of course have to pay mucho ££)
The pop and bang and the smell of petrol in the morning are going to be nice too (most people stick on fart cans, and all the extra noise makes then think it's much faster, when in reality the difference is not measurable) If you actually want to go faster, either 1) just buy a quicker car, or 2) get into some proper N/A tuning (for which you wil of course have to pay mucho ££)
So silenced, or straight through?
Dan
Max_Torque said:
kambites said:
An interesting question. Would a typical modern petrol engine running with no exhaust (assuming you can somehow get the mixture the same with no lambda sensor) produce more or less power than one with an exhaust if no other modifications were made?
assuming by "no exhaust" you mean nothing downstream of the exhaust manifold, then the answer is "more power" (but if you also loose the exh man then the answer is "less power")So is there no way that removing the exhaust after all junctions are completed (ie after the manifold) could reduce power assuming that you feed the engine the same mixture and use the same timings?
DannyVTS said:
Great replies, gotta love PH!
If it helps I'm actually looking to decat the car, my Saxo responded very well to the decat and I've read on ClioSport that the Clios do just the same (as I imagine any car would)
As my car already has an exhaust on it I didn't want the car to be too loud, which is why I am considering silenced decat pipes such as the Janspeed one below:
but I would rather have the best performance from the change in exhaust, and was worried the silencer might create back pressure and thus not give as big a performance increase as the straght through pipe below;
The sign of a poorly designed exhaust....If it helps I'm actually looking to decat the car, my Saxo responded very well to the decat and I've read on ClioSport that the Clios do just the same (as I imagine any car would)
As my car already has an exhaust on it I didn't want the car to be too loud, which is why I am considering silenced decat pipes such as the Janspeed one below:
but I would rather have the best performance from the change in exhaust, and was worried the silencer might create back pressure and thus not give as big a performance increase as the straght through pipe below;
As for the decat pipe, a straight pipe is better as it preserves flow velocity.
The way I have approached exhausts is :
They are not like a 2 stroke - there is no big power gain (no matter what people
might claim)
It's easier too loose power and gain noise .. often by having too big a pipe
diameter (not just the tail pipe).. if you loose mid range then the car will be slower as that is where a road car will spend most of its time.
Decat pipes - well always a good thing but it can make the MOT difficult.
They are not like a 2 stroke - there is no big power gain (no matter what people
might claim)
It's easier too loose power and gain noise .. often by having too big a pipe
diameter (not just the tail pipe).. if you loose mid range then the car will be slower as that is where a road car will spend most of its time.
Decat pipes - well always a good thing but it can make the MOT difficult.
DannyVTS said:
So silenced, or straight through?
Dan
. It came with it and when and if the time comes it will be replaced with a OEM stealth pipe. How would you like a load of boy racers driving past your house with noisy pipes on? Flippin' antisocial is what it is.
Just go to a motor factor or main dealer and get the correct part for your Clio.
Willy Nilly said:
I have a slightly noisy pipe on my bike . It came with it and when and if the time comes it will be replaced with a OEM stealth pipe.
How would you like a load of boy racers driving past your house with noisy pipes on? Flippin' antisocial is what it is.
Just go to a motor factor or main dealer and get the correct part for your Clio.
LOL. It came with it and when and if the time comes it will be replaced with a OEM stealth pipe. How would you like a load of boy racers driving past your house with noisy pipes on? Flippin' antisocial is what it is.
Just go to a motor factor or main dealer and get the correct part for your Clio.
rev-erend said:
The way I have approached exhausts is :
They are not like a 2 stroke - there is no big power gain (no matter what people
might claim)
It's easier too loose power and gain noise .. often by having too big a pipe
diameter (not just the tail pipe).. if you loose mid range then the car will be slower as that is where a road car will spend most of its time.
Decat pipes - well always a good thing but it can make the MOT difficult.
Ah, I think I'm going to buy a used one off the forum, if I don't like it I can always sell it again after for about the same money.They are not like a 2 stroke - there is no big power gain (no matter what people
might claim)
It's easier too loose power and gain noise .. often by having too big a pipe
diameter (not just the tail pipe).. if you loose mid range then the car will be slower as that is where a road car will spend most of its time.
Decat pipes - well always a good thing but it can make the MOT difficult.
Plus I'd gain some knowledge on the subject and get to know the Clio better...
Cheers
Dan
On a bog standard engine, any power gains will be minimal, and running an oversized system will almost certainly result in a loss of power / torque through the midrange.
All you'll do is move the torque and power peaks further up the rev range, which on a road car is usually undesirable anyway (in the case of small 4 cyl. engines).
For best results, you need to consider the entire process.
i.e. start with a decent head / cam that will give good flow, along with an enlarged (and preferably multi port) intake system.
Then worry about the exhaust.
Most cars will give significantly greater power gains by tweaking the induction system, even when retaining the standard exhaust.
All you'll do is move the torque and power peaks further up the rev range, which on a road car is usually undesirable anyway (in the case of small 4 cyl. engines).
For best results, you need to consider the entire process.
i.e. start with a decent head / cam that will give good flow, along with an enlarged (and preferably multi port) intake system.
Then worry about the exhaust.
Most cars will give significantly greater power gains by tweaking the induction system, even when retaining the standard exhaust.
Another thing to consider is the way the down pipes from the separate cylinders are joined at the collector boxe(es)before they meet the silencer.
Taking an ordinary 4 cylinder engine configerations such as 4 into 1, 4-2-1 or 4-2 can all have a different effect on the BHP/Torque curve.
Then you have things like Yamahas' EXUP valve in the collector box which can help to "prop up" a weak mid-range on a 4-1 exhaust tuned for top end. Or link pipes between down pipes which are sometimes found on engines with an odd numbers of cylinders such as 3 or 5.
Taking an ordinary 4 cylinder engine configerations such as 4 into 1, 4-2-1 or 4-2 can all have a different effect on the BHP/Torque curve.
Then you have things like Yamahas' EXUP valve in the collector box which can help to "prop up" a weak mid-range on a 4-1 exhaust tuned for top end. Or link pipes between down pipes which are sometimes found on engines with an odd numbers of cylinders such as 3 or 5.
kambites said:
Max_Torque said:
kambites said:
An interesting question. Would a typical modern petrol engine running with no exhaust (assuming you can somehow get the mixture the same with no lambda sensor) produce more or less power than one with an exhaust if no other modifications were made?
assuming by "no exhaust" you mean nothing downstream of the exhaust manifold, then the answer is "more power" (but if you also loose the exh man then the answer is "less power")So is there no way that removing the exhaust after all junctions are completed (ie after the manifold) could reduce power assuming that you feed the engine the same mixture and use the same timings?
The only way you can "Loose" power, is if your exhaust system was actually creating a lower "dynamic" pressure at the exh manifold junction. However this only really happens when you suddenly shut the throttle, and the mass of exhaust gas traveling at high velocity down the exhaust actually pulls a partial vaccuum in the exhaust. (but, making more power on a shut throttle is pretty counter productive......... ;-) (and hence why the F1 boys don't both with any exhaust "system" as such)
For ultimate peak power, you can even forgo an exhaust manifold with "scavangeing", relying on simple single tuned length exhaust runner per cylinder (a-la drag race engine), but you will seriously restrict the spread of power (not an issue in a "single speed" drag racer which uses the clutch pack to moderate road speed to a failry constant engine speed (and hence power))
TonyRPH said:
On a bog standard engine, any power gains will be minimal,
Correct !TonyRPH said:
and running an oversized system will almost certainly result in a loss of power / torque through the midrange.
Incorrect ! (assuming by "system" you mean post exhaust manifold /runner merge point)Max_Torque said:
TonyRPH said:
and running an oversized system will almost certainly result in a loss of power / torque through the midrange.
Incorrect ! (assuming by "system" you mean post exhaust manifold /runner merge point)Back in the 80's, I ran a Toyota 1.6 with the "2T" engine.
The exhaust manifold was 4-2-1. In my (then) infinite wisdom, I separated the exhaust at the 2-1 junction, and ran twin pipes via 2 'cherry bomb' silencers to the rear.
There was a decent (note: not massive) improvement between 5 - 6k revs, but below that the loss of low end torque was considerable.
The car required a noticeably larger throttle input (in low gears at lowish speeds) to achieve the same momentum as previously with the standard exhaust.
I found the best solution was a shorter system, 2" diameter with 2 decent freeflow silencers (side exit just before the rear wheel).
Not too noisy, decent improvement at the top end (although less than with the first system), and no loss of low down torque.
rev-erend said:
Having had a Clio 182 - you might as well start by looking at what is available.
I found that you had :
Renault (lot of money for a steel cat back system)
Quick fit and all others just did not supply
K-Tec - great source for exhausts and other stuff
but you have to ask if you want the added noise..
the one I went for was a bit louder than standard
but some are McDonalds car part loud.
This, the OEM ones are mild steel and about £1500 from a dealer. I went to K-Tec and got a stainless system with 25yr warranty for about £330 fitted. It is slightly louder but not offensive.I found that you had :
Renault (lot of money for a steel cat back system)
Quick fit and all others just did not supply
K-Tec - great source for exhausts and other stuff
but you have to ask if you want the added noise..
the one I went for was a bit louder than standard
but some are McDonalds car part loud.
Tycho said:
rev-erend said:
Having had a Clio 182 - you might as well start by looking at what is available.
I found that you had :
Renault (lot of money for a steel cat back system)
Quick fit and all others just did not supply
K-Tec - great source for exhausts and other stuff
but you have to ask if you want the added noise..
the one I went for was a bit louder than standard
but some are McDonalds car part loud.
This, the OEM ones are mild steel and about £1500 from a dealer. I went to K-Tec and got a stainless system with 25yr warranty for about £330 fitted. It is slightly louder but not offensive.I found that you had :
Renault (lot of money for a steel cat back system)
Quick fit and all others just did not supply
K-Tec - great source for exhausts and other stuff
but you have to ask if you want the added noise..
the one I went for was a bit louder than standard
but some are McDonalds car part loud.
TonyRPH said:
Max_Torque said:
TonyRPH said:
and running an oversized system will almost certainly result in a loss of power / torque through the midrange.
Incorrect ! (assuming by "system" you mean post exhaust manifold /runner merge point)Back in the 80's, I ran a Toyota 1.6 with the "2T" engine.
The exhaust manifold was 4-2-1. In my (then) infinite wisdom, I separated the exhaust at the 2-1 junction, and ran twin pipes via 2 'cherry bomb' silencers to the rear.
There was a decent (note: not massive) improvement between 5 - 6k revs, but below that the loss of low end torque was considerable.
The car required a noticeably larger throttle input (in low gears at lowish speeds) to achieve the same momentum as previously with the standard exhaust.
I found the best solution was a shorter system, 2" diameter with 2 decent freeflow silencers (side exit just before the rear wheel).
Not too noisy, decent improvement at the top end (although less than with the first system), and no loss of low down torque.
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