accoustic valve mod, what does it do?
The valve itself is there to control induction noise to meet some sort of EU regulation
There are a couple of step by step guides on here showing how to do it - just search for acoustic valve
I replaced mine with a 85mm Cold Air Feed
There are a couple of step by step guides on here showing how to do it - just search for acoustic valve
I replaced mine with a 85mm Cold Air Feed
so what are the results...? any louder?
son of solo said:
Maybe very very slitghly - its just acting as a restriction in your airflow, so a lot of people opt to ditch it
i thought it had two purposes, to lower the engine noise and to increase low down torque by restricting power - not quite sure if the latter is true but i've heard it from a couple of people.
Cue said:
That could be true, but to be honest, if it does give any more low end torque it must be minimal - I have noticed no difference at all since ditching the valve
Can someone explain to me how an inlet restriction can increase low down torque by restricting power? My bull-shit alarm has activated.
Keith
ive only disconected the wire that opens and closes, (obviously leaving it locked open lol) but to me its definately louder, i also get quite a whistle from it when giving it some right boot.
Not sure about any power loss, doesnt seem to have lost anything :?
Not sure about any power loss, doesnt seem to have lost anything :?
I must admit I have noticed no difference what so ever, I did read a theory but it was way over my head - something about pulses and surging of airflow :?
Ben from AngelWorks seems to think its a total waste of time so thats good enough for me lol - he's the man when it comes to air flow etc
Ben from AngelWorks seems to think its a total waste of time so thats good enough for me lol - he's the man when it comes to air flow etc
i took mine out when i put my custom CAF in, didn't notice a difference cos its not standard, it is bloody loud with it in and out :lol:
i'm not that technical with engines, BenR, Donkey or George K would be the best bet, but my very limited understanding of Power & Torque is that power is linked to airflow and calculated by measuring the torque - can't remember the science of the top of my head.
As Dave said it's something to do with surges in airflow - the valve (by restricting the airflow) controls the surges, imrproving torque generation.
I very much doubt that it actually makes any difference to be honest, it's more likely to be noise restriction orientated as I think the valve remains closed at low revs.
Re just disconnecting wire - that may confuse the ECU, which will assume it's constantly open and compensate for it - you may want to check that out.
As Dave said it's something to do with surges in airflow - the valve (by restricting the airflow) controls the surges, imrproving torque generation.
I very much doubt that it actually makes any difference to be honest, it's more likely to be noise restriction orientated as I think the valve remains closed at low revs.
Re just disconnecting wire - that may confuse the ECU, which will assume it's constantly open and compensate for it - you may want to check that out.
Cue
I too have limited understanding but I do know that,
power = torque x engine-speed
That being so, how the heck can one be increased at the expense of the other at the same engine speed? If torque is increased so too is power and visa versa. You don’t need any complicated thinking to figure that out.
I think perhaps the confusion here comes from different states of tune of an engine. A highly tuned engine is optimised to produce more power at high engine speeds and this is often (usually) at the expense of less power (and torque) at low engine speeds compared to a more normally tuned engine.
Keith
I too have limited understanding but I do know that,
power = torque x engine-speed
That being so, how the heck can one be increased at the expense of the other at the same engine speed? If torque is increased so too is power and visa versa. You don’t need any complicated thinking to figure that out.
I think perhaps the confusion here comes from different states of tune of an engine. A highly tuned engine is optimised to produce more power at high engine speeds and this is often (usually) at the expense of less power (and torque) at low engine speeds compared to a more normally tuned engine.
Keith
I wish I'd read this thread sooner.
Power is indeed equal to torque multiplied by engine speed, a nice easy way of working out power from torque is;
Power (bhp) = Torque (ft lbf) x Engine speed (rpm) / 5252.
The 5252 constant is that because of the relationship between the units of torque in foot pounds force and power in brake horsepower.
So from this you can deduce that at 5252rpm the torque in an engine will be equal to the power output (as a number). This is precisely why if you look at any Rolling Road Dynamometer graph that plots power and torque against engine speed, the lines will cross at 5252 rpm.
Torque is the turning force of an engine's output shaft (the brake in brake horsepower refers to the brake band of a dynamometer that is fixed to the crankshaft of an engine), Using the cyclist analogy - think of it as the weight that can be applied to a cyclists pedals in one stroke.
Power is the workdone by this torque over a period of time, so it can be said of an engine that power is equal to torque multiplied by engine speed - think of this as the effort exerted by the cylcists legs in a minute, one cyclist may have very powerful legs (lots of torque) but not able to spin them as fast as another cyclist with less powerful but quicker legs so their power outputs and therefore performance are the same.
This is why diesel engines with shit loads more torque than an equivalently powered petrol engine aren't always as quick in acceleration. They don't have the engine speed range to put the power to the road, it's like a cyclist with big powerful legs that can't ever spin at more than 50rpm, he has to change up every time he gets to 50rpm whereas the less powerfully legged cyclist that can spin up to 90rpm can carry on accelerating in a nice fat powerband. Their power will never equal or surpass their maximum torque as the engine 's rev limiter cuts in before 5252 rpm.
Regarding the acoustic valve mod, as it's only there for reducing resonance in the inlet hoses and airbox to pass EU noise legislation, whip it out and get better airflow. I doubt the difference is significant (it certainly won't reduce torque) but it's a few grams of uselessness that may as well sit on a shelf in the garage than being carted around inside your induction system. Alan Whatshisface from Renaultsport has confirmed it to be nothing more than for acoustic purposes, it's not like it will create an inlet manifold pressure surge by removing it.
Power is indeed equal to torque multiplied by engine speed, a nice easy way of working out power from torque is;
Power (bhp) = Torque (ft lbf) x Engine speed (rpm) / 5252.
The 5252 constant is that because of the relationship between the units of torque in foot pounds force and power in brake horsepower.
So from this you can deduce that at 5252rpm the torque in an engine will be equal to the power output (as a number). This is precisely why if you look at any Rolling Road Dynamometer graph that plots power and torque against engine speed, the lines will cross at 5252 rpm.
Torque is the turning force of an engine's output shaft (the brake in brake horsepower refers to the brake band of a dynamometer that is fixed to the crankshaft of an engine), Using the cyclist analogy - think of it as the weight that can be applied to a cyclists pedals in one stroke.
Power is the workdone by this torque over a period of time, so it can be said of an engine that power is equal to torque multiplied by engine speed - think of this as the effort exerted by the cylcists legs in a minute, one cyclist may have very powerful legs (lots of torque) but not able to spin them as fast as another cyclist with less powerful but quicker legs so their power outputs and therefore performance are the same.
This is why diesel engines with shit loads more torque than an equivalently powered petrol engine aren't always as quick in acceleration. They don't have the engine speed range to put the power to the road, it's like a cyclist with big powerful legs that can't ever spin at more than 50rpm, he has to change up every time he gets to 50rpm whereas the less powerfully legged cyclist that can spin up to 90rpm can carry on accelerating in a nice fat powerband. Their power will never equal or surpass their maximum torque as the engine 's rev limiter cuts in before 5252 rpm.
Regarding the acoustic valve mod, as it's only there for reducing resonance in the inlet hoses and airbox to pass EU noise legislation, whip it out and get better airflow. I doubt the difference is significant (it certainly won't reduce torque) but it's a few grams of uselessness that may as well sit on a shelf in the garage than being carted around inside your induction system. Alan Whatshisface from Renaultsport has confirmed it to be nothing more than for acoustic purposes, it's not like it will create an inlet manifold pressure surge by removing it.
thats what i was thought.
Steve
I think you have your ‘/’ and ‘x’ transposed .
Keith
I think you have your ‘/’ and ‘x’ transposed .
Keith
wow all clever stuff! 8)
kinda woried incase just unpluging my acoustic and leaving it in place could F### things up a bit as you say Cue
although with it out completely out the wire would still be disconnected so would still tell the ecu its permanetely open or am i mixed up ?
kinda woried incase just unpluging my acoustic and leaving it in place could F### things up a bit as you say Cue
although with it out completely out the wire would still be disconnected so would still tell the ecu its permanetely open or am i mixed up
?