Plenum Advise?
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From: columbia md.
Re: plenum
Originally posted by G3po
With a "constant" air velovity thru the box whihc is 1/2 conductive and one half insulative, the one with 1/2 cooler would impart less heat to the air flow to it. Of course you also must take into account were the main black body source lives(in the plenums case the longblock).
However; "heatsoak" is more than a steady air flow phenomena .
Consider that the airflow is interrupted or slowed dramatically
(ie idle of engine shut off), the box with conductive surface on the top (as opposed to insulative) will generally cool faster , so than when air flow is again present ,(ie when engine is started or accelerated from a standstill conditon the temperature of the box and the energy which it can impart to internal air mass will be lower. This is why you would open your car hood between drag races. With more conductive mass exposed to the top and open air , the faster the cool down and lesser the adverse soaking effect.
Keeping the intake charge cooler is in part an attempt to keep the ECU from seeing a heat induced "ping" which can result in de-timing and hence loss of power just after the intial acceleration.
So for drag raceing and stop and go street driving keeping the top half conductive and exposed reaps more benefit. Under constant highway or road track driveing the top half being non-conductive may reap more benefit. But note where charge temp induced detoation is most likely to occur is in the former circumstances were instantaneous TQ loads from a soak conditon are greater.
With a "constant" air velovity thru the box whihc is 1/2 conductive and one half insulative, the one with 1/2 cooler would impart less heat to the air flow to it. Of course you also must take into account were the main black body source lives(in the plenums case the longblock).
However; "heatsoak" is more than a steady air flow phenomena .
Consider that the airflow is interrupted or slowed dramatically
(ie idle of engine shut off), the box with conductive surface on the top (as opposed to insulative) will generally cool faster , so than when air flow is again present ,(ie when engine is started or accelerated from a standstill conditon the temperature of the box and the energy which it can impart to internal air mass will be lower. This is why you would open your car hood between drag races. With more conductive mass exposed to the top and open air , the faster the cool down and lesser the adverse soaking effect.
Keeping the intake charge cooler is in part an attempt to keep the ECU from seeing a heat induced "ping" which can result in de-timing and hence loss of power just after the intial acceleration.
So for drag raceing and stop and go street driving keeping the top half conductive and exposed reaps more benefit. Under constant highway or road track driveing the top half being non-conductive may reap more benefit. But note where charge temp induced detoation is most likely to occur is in the former circumstances were instantaneous TQ loads from a soak conditon are greater.
plenum
Steady state yes. However; racing was not the only mentioned environment, If you do significant city driving , stop and go and traffic light to traffic light steady state is not the typical environment. It has to do with what the defintion of "heat soak is". Hey to each his own. For now I am useing the crawford and if soemone offers a cast alumimum equivalent of the Kintetxi I may re-consider. If someone performs a thermal FEA under the discussed conditions , I'd love to see them.
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