Placement of Air Filters
09-25-2009, 09:34 AM
#1
Placement of Air Filters This is to make chevychad happy since I've obviously disturbed him.
As the title says:I know that the turbo housing likes heat for spool up, but on front mounts the filter is attached to the turbo itself taking in heated air from the engine and headders then going thru the intercooler, trying to cool the intake charge back down, isn't this just defeating the purpose? Has anyone made like a cold air intake setup for the turbo? did it make less boost, did it cause lag?
As the title says:I know that the turbo housing likes heat for spool up, but on front mounts the filter is attached to the turbo itself taking in heated air from the engine and headders then going thru the intercooler, trying to cool the intake charge back down, isn't this just defeating the purpose? Has anyone made like a cold air intake setup for the turbo? did it make less boost, did it cause lag?
09-25-2009, 09:43 AM
#2
Placement of the intake filter will not affect lag. A cold air intake is a good idea, but if your intercooler works well enough it will not matter as much where the intake filter is. Put it where there is room. If you can get it away from the body of the turbo great! If you have to attach it directly to the compressor housing don't sweat it.
09-25-2009, 09:48 AM
#3
Placement of the intake filter will not affect lag. A cold air intake is a good idea, but if your intercooler works well enough it will not matter as much where the intake filter is. Put it where there is room. If you can get it away from the body of the turbo great! If you have to attach it directly to the compressor housing don't sweat it.
Thank you sir, that's all I needed to know.....
09-26-2009, 01:33 AM
#4
Try hard to get cool air into the turbo. The IC only strips a percentage of the heat out, and the heat of compression is incremental to the intake air temps, so you will end up with hotter air as you increase the temp of the intake air to the turbo.
Example with hotter air intake:
Engine compartment air = 185° (Often higher in a turbo engine compartment)
Approx. heat of compression added at 10# of boost = 85°
Outlet temp of compressor = 185 + 85 = 270°
Temp drop through IC at 75% efficiency & 70° Ambient Air = (270*.25) + 70 = 137.5°
Example with cooler air intake to turbo:
Air from CAI = 70° (Ambient air temp)
Heat of compresion at 10# of boost = 85°
Outlet temp of compressor = 70 + 85 = 155°
Temp drop through IC at 75% efficiency & 70° Ambient Air = (155*.25) + 70 = 108.75°
Difference between hot air intake and cooler air intake = ~29°
Doesn't seem like a lot, but if you have a hot engine compartment that number will rise, and if you're on the edge of detonation the hot air is going to push you over into engine-breaking territory, or at least give you some knock retard and slow you down.
Then the $100 or so to set up a CAI to your turbo doesn't seem like much at all. An excellent setup is one that uses every edge to maximize power. You see guys all the time that cut corners then wonder why their car isn't as fast as another with similar specs.
Oh yeah, and remember those pictures of the turbo glowing red under heavy load? Think your engine compartment heat (and turbo intake air temp) goes up then, just when you need as much safety margin as possible?
Jim
Example with hotter air intake:
Engine compartment air = 185° (Often higher in a turbo engine compartment)
Approx. heat of compression added at 10# of boost = 85°
Outlet temp of compressor = 185 + 85 = 270°
Temp drop through IC at 75% efficiency & 70° Ambient Air = (270*.25) + 70 = 137.5°
Example with cooler air intake to turbo:
Air from CAI = 70° (Ambient air temp)
Heat of compresion at 10# of boost = 85°
Outlet temp of compressor = 70 + 85 = 155°
Temp drop through IC at 75% efficiency & 70° Ambient Air = (155*.25) + 70 = 108.75°
Difference between hot air intake and cooler air intake = ~29°
Doesn't seem like a lot, but if you have a hot engine compartment that number will rise, and if you're on the edge of detonation the hot air is going to push you over into engine-breaking territory, or at least give you some knock retard and slow you down.
Then the $100 or so to set up a CAI to your turbo doesn't seem like much at all. An excellent setup is one that uses every edge to maximize power. You see guys all the time that cut corners then wonder why their car isn't as fast as another with similar specs.
Oh yeah, and remember those pictures of the turbo glowing red under heavy load? Think your engine compartment heat (and turbo intake air temp) goes up then, just when you need as much safety margin as possible?
Jim