jessicas xmas pressie
- Thread starter commeracer
- Start date
it is a tad on the heavy going side, but has its place.
the easiest way to understand it is think of a church organ, all the pipes are different lengths, so resonate at different acoustic velocities. pressure waves in a manifold have the same properties.
you can create a supercharge effect by getting the reflected positive wave back to the valve at the right time, it will increase the delivery ratio and ram extra mixture in
Boyles law comes into play as does reynolds and nusselt numbers, its all part of gas thermodynamics. there is certainly more to engine development than meets the eye, its dead easy to get things wrong and not even know. as little as 1mm change in a manifold has an effect on power.
"you were only supposed to blow the bloody SLIDING doors off no.3"
the easiest way to understand it is think of a church organ, all the pipes are different lengths, so resonate at different acoustic velocities. pressure waves in a manifold have the same properties.
you can create a supercharge effect by getting the reflected positive wave back to the valve at the right time, it will increase the delivery ratio and ram extra mixture in
Boyles law comes into play as does reynolds and nusselt numbers, its all part of gas thermodynamics. there is certainly more to engine development than meets the eye, its dead easy to get things wrong and not even know. as little as 1mm change in a manifold has an effect on power.
"you were only supposed to blow the bloody SLIDING doors off no.3"
ooh that sounds good, so is the "frequency" of the wave the RPM?
(does each cylinder start a wave as the inlet valve shuts?) if so I presume the inlet manifold tuning is all geared up for a particular (optimal) rev range. and is the wave bouncing of anything at the other end?...
Do you know of any good books on this stuff?
Hang on.. I'm still sober .... better fix that
Rupert
www.littleyellowcar.co.uk
(does each cylinder start a wave as the inlet valve shuts?) if so I presume the inlet manifold tuning is all geared up for a particular (optimal) rev range. and is the wave bouncing of anything at the other end?...
Do you know of any good books on this stuff?
Hang on.. I'm still sober .... better fix that
Rupert
www.littleyellowcar.co.uk
And by increasing the velocity of the incoming air through the carb venturi the Joules-Thompson effect can have a beneficial effect on the gas charge by cooling it down - therefore increasing the density, and so the amount, of fuel/air mixture that finds its way into the cylinder :I. I think.
'Harvey the RV'
'Harvey the RV'
hey, we,re getting somewhere now
thats it panky, the faster moving air creates a greater pressure drop and lowers the temp, this means greater air density (more oxygen molecules per given volume) and we all know the greater the mass of air the more fuel can be burned. at the moment i am getting ice on the j4 manifold, not much chance of that on sybhil[xx(] (yet)[}].
Rupert, the wave frequency is a factor of port diameter/length/volume cam profile pressure,particle velocity.
as the mixture continues moving after the valve shuts due to inertia/kinetic energy it hits the shut valve and is bounced back as a negative wave, this continues until it looses its amplitude or the valve opens again, hopefully just as a positive wave returns.the wave is reflected as soon as it hits "atmosphere".
the idea is to tune the pulses to compliment things like max torque,peak b.m.e.p,max bhp.
its all a bit acedemic really unless you coroborate it on the dyno.
as with any gain there is generally a loss as well, in computational fluid dynamics you can see it all as a series of peaks and troughs and you just end up shuffling them up and down the rev range. obviously its pointless tuning waves for 10,000rpm on a commer [:0].
getting max flow with max port velocity is the key to success keeping things transonic, as soon as it all goes supersonic VERY odd things start to happen, like nozzles become diffusers and vice-versa [xx(]
can i go to bed now pleeeeeeease
"you were only supposed to blow the bloody SLIDING doors off no.3"
thats it panky, the faster moving air creates a greater pressure drop and lowers the temp, this means greater air density (more oxygen molecules per given volume) and we all know the greater the mass of air the more fuel can be burned. at the moment i am getting ice on the j4 manifold, not much chance of that on sybhil[xx(] (yet)[}
].Rupert, the wave frequency is a factor of port diameter/length/volume cam profile pressure,particle velocity.
as the mixture continues moving after the valve shuts due to inertia/kinetic energy it hits the shut valve and is bounced back as a negative wave, this continues until it looses its amplitude or the valve opens again, hopefully just as a positive wave returns.the wave is reflected as soon as it hits "atmosphere".
the idea is to tune the pulses to compliment things like max torque,peak b.m.e.p,max bhp.
its all a bit acedemic really unless you coroborate it on the dyno.
as with any gain there is generally a loss as well, in computational fluid dynamics you can see it all as a series of peaks and troughs and you just end up shuffling them up and down the rev range. obviously its pointless tuning waves for 10,000rpm on a commer [:0].
getting max flow with max port velocity is the key to success
keeping things transonic, as soon as it all goes supersonic VERY odd things start to happen, like nozzles become diffusers and vice-versa [xx(]can i go to bed now pleeeeeeease
"you were only supposed to blow the bloody SLIDING doors off no.3"
its not quite as simple as that unfortunatly jon, you can easily trash the motor if you dont consider it as a whole system.
and besides superchargers are better
"you were only supposed to blow the bloody SLIDING doors off no.3"
and besides superchargers are better
"you were only supposed to blow the bloody SLIDING doors off no.3"
nah, i am just gonna fudge it
"you were only supposed to blow the bloody SLIDING doors off no.3"
"you were only supposed to blow the bloody SLIDING doors off no.3"
quote:
Originally posted by commeracer
its not quite as simple as that unfortunatly jon, you can easily trash the motor if you dont consider it as a whole system.
and besides superchargers are better
[}][}][}][}]
Originally posted by commeracer
its not quite as simple as that unfortunatly jon, you can easily trash the motor if you dont consider it as a whole system.
and besides superchargers are better
[}
][}][}][}]
Jon
0
quote:
Originally posted by commeracer
its not quite as simple as that unfortunatly jon, you can easily trash the motor if you dont consider it as a whole system.
and besides superchargers are better
"you were only supposed to blow the bloody SLIDING doors off no.3"
It was only a joke i know whats involved in home brew turbo conversion ive been involved with building one[}]
Originally posted by commeracer
its not quite as simple as that unfortunatly jon, you can easily trash the motor if you dont consider it as a whole system.
and besides superchargers are better
"you were only supposed to blow the bloody SLIDING doors off no.3"
It was only a joke i know whats involved in home brew turbo conversion ive been involved with building one
[}]Rupert,
we have an SU setup on "Lillie", would it be simpler for you to know the model we have and also the needle number? She runs well on it.
Cheers
Ruairidh
we have an SU setup on "Lillie", would it be simpler for you to know the model we have and also the needle number? She runs well on it.
Cheers
Ruairidh
that would be great thanks!
I'll drop you an email
cheers
Rupert
www.littleyellowcar.co.uk
I'll drop you an email
cheers
Rupert
www.littleyellowcar.co.uk
here it is all finished
"you were only supposed to blow the bloody SLIDING doors off no.3"
"you were only supposed to blow the bloody SLIDING doors off no.3"
That and a 4 branch and I think you're onto a winner
Can I order mine now
Can I order mine now
if you are serious martin, i will need a exchange manifold.
that goes for anyone else as well, speak now or forever fiddle with your zenith
"you were only supposed to blow the bloody SLIDING doors off no.3"
that goes for anyone else as well, speak now or forever fiddle with your zenith
"you were only supposed to blow the bloody SLIDING doors off no.3"
Yes, I'll e=mail you
I'll sort the cheque out for you today!
Martin, where can I get a 4 branch manifold?
Rupert
www.littleyellowcar.co.uk
Martin, where can I get a 4 branch manifold?
Rupert
www.littleyellowcar.co.uk