Truck intake restrictive to volume or velocity?
Nov 22, 2005 | 04:31 PM
#21
Originally Posted by treyZ28
your engine is a constant volume pump. it is going to suck 5.3 liters of air whether it be through a staw or LS7 top end. The mass will varry.
Anyway, here is the important thing about intakes. What powerband they are tuned for. That has to do mainly with thier runner lengths. think of it more as a cam than a catback.
its why F1 cars have intake runners that are always changing length.
they grown and shrink a good amount. very cool stuff.
Anyway, here is the important thing about intakes. What powerband they are tuned for. That has to do mainly with thier runner lengths. think of it more as a cam than a catback.
its why F1 cars have intake runners that are always changing length.
they grown and shrink a good amount. very cool stuff.
Nov 22, 2005 | 07:39 PM
#23
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prob wont make much difference. boost likes cross section.
again, depends on your powerband. although the speed of sound is effected by the density of the medium, i dont think you're going hardcore enough to even warrant calculating it. If you were, you'd be asking Hogan to make you an intake
again, depends on your powerband. although the speed of sound is effected by the density of the medium, i dont think you're going hardcore enough to even warrant calculating it. If you were, you'd be asking Hogan to make you an intake
Nov 22, 2005 | 07:48 PM
#24
ok... here is a table I pulled off "smokemup.com"
Part #______Engine_________Plenum Volume___Runner Volume__Runner Length
12556333___1997-2000 LS1___5.06 L__________0.536 L_______262 mm
12561182___2001-2002 LS1/6_5.19 L__________0.541 L_______262 mm
12573572___2002+ LS1/6_____5.19 L__________0.541 L_______262 mm
??_________LQ4_____________4.0L___________0.541 L_______263 mm
__________________________________________________ ________________________
Ok...air has to fill the plenum before it goes into the cylinders...the velocity of the air through the intake system is limited by friction, that means the larger plenums are going to be more efficient up top...thats why the 5.3 is better at high RPM than the 6.0 as they share the same intake...there is alot of math involved, but the idea is the plenum volume must be matched to the runner length and volume...larger plenum volume allows for sufficient air at higher rpm, runner length determines the RPM range at which the intake has its peak effectiveness(remember the sound wave from earlier), the runner volume, is to determine the velocity of the air entering the cylinders more velocity = more torque it should be match to the runner lengths and plenum volume...I havent looked up the calculations on the web, but I am sure they are out there...but I would chose your intake by how many RPM you intend to spin, and where you want your truck to make peak power.
Part #______Engine_________Plenum Volume___Runner Volume__Runner Length
12556333___1997-2000 LS1___5.06 L__________0.536 L_______262 mm
12561182___2001-2002 LS1/6_5.19 L__________0.541 L_______262 mm
12573572___2002+ LS1/6_____5.19 L__________0.541 L_______262 mm
??_________LQ4_____________4.0L___________0.541 L_______263 mm
__________________________________________________ ________________________
Ok...air has to fill the plenum before it goes into the cylinders...the velocity of the air through the intake system is limited by friction, that means the larger plenums are going to be more efficient up top...thats why the 5.3 is better at high RPM than the 6.0 as they share the same intake...there is alot of math involved, but the idea is the plenum volume must be matched to the runner length and volume...larger plenum volume allows for sufficient air at higher rpm, runner length determines the RPM range at which the intake has its peak effectiveness(remember the sound wave from earlier), the runner volume, is to determine the velocity of the air entering the cylinders more velocity = more torque it should be match to the runner lengths and plenum volume...I havent looked up the calculations on the web, but I am sure they are out there...but I would chose your intake by how many RPM you intend to spin, and where you want your truck to make peak power.
Nov 22, 2005 | 08:00 PM
#25
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I was always under the assumption that the intake plenum should hold 1/2 the displacement.
but thats not true. racecars i've work with (like 427s and other smaller sizes) had small intakes... id say the 427 had maybe 2 or 2.5 liters (on a 7.0 engine with huuuge runners)
but thats not true. racecars i've work with (like 427s and other smaller sizes) had small intakes... id say the 427 had maybe 2 or 2.5 liters (on a 7.0 engine with huuuge runners)
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