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Doc Olds -> RE: H3 Hummer Performance Intakes Systems (3/18/2008 7:59:21 PM)
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quote:
ORIGINAL: ChevyHighPerformance
oooh that metal intake might get hotter than plastic!
The steel tube has to conduct more heat than a plastic tube - its just physics. The real question is how much heat gets conducted to the air with a metal tube. While you are moving, there is probably not too much heating of the air through the tube - perhaps 5 F??? more than a plastic tube.
My issue was the heat coming up from the exhaust manifold while you are parked. The steel has a higher thermal conductivity, specific heat, and mass than a plastic tube. The metal tube has to heatsoak more than a plastic tube and the heat in the metal tube mostly has to go into the incoming air. Take the H3 out after sitting for a while and the incoming air will be heated more than normal until thermal stabilization is reached.
I'm not saying your product is bad. I'm pointing a potential for heatsoaking.
Again this is a purist opinion from someone who has designed at least 5 intakes for the H3 and was sent intake products from manufacturers for free to test and report back to them. If you look at the H3's programming, the I5 is very sensitive to engine coolant temperature and inlet air temperature. Did I mention I can dyno the H3?
I note your observations, and thank you for your interest. I have not, nor will I, lose a moment of sleep over heatsoaking issues with AirDocIntake systems.
The steel tube has to conduct more heat than a plastic tube - its just physics. Says who??? You mentioned: has to "conduct" heat more than plastic. You hit your own nail on the head. Heat is transferred by many means, conductive heat transfer is not one of them here.
There is probably not too much heating of the air through the tube - perhaps 5 F??? more than a plastic tube. Great theory, but no data? Have you measured or calculated the velocity of the intake charge at all rpms given the combustion of the 3.5L and 3.7L............if you have, then you know how long that air is in the
13 7/8" long metal tube at 2000 rpm and above. Let me use the technical term ....not very friggin long! [:D] I have done a wee bit of testing (I did not fall off the turnip cart yesterday) and when comparing the MAF input reading from the H3 to the throttle body end of the AirDoc pipe (I made a sensor from a second bosch MAF), I could not reliably measure any heat increase beyond margin of error (3/10ths of one degree) at any rpm over 2000, but let us assume it is one or two degrees? I'm thinking there is a lot of theory going out the window???
Anybody doing bracket racing, 1/8 mile powder puff racing, F.A.S.T. drag series, any qualifying time runs, any racing with their Hummer? No, hummmm........heatsoaking seems to be irrelevant.
If it were, wonder what that big old honking stock black plastic throttle body resonator box sitting right up top over the head and rocker cover that is bolted by brackets in contact with the engine soaks up???? Compared to a 3.5" metal pipe flowing air from outside the engine compartment directly to the throttle body isolated from any contact with the engine by 4 ply silicone couplers?
Let me make it abundantly clear. The reason GM, and most intake kit makers use rubber and/or plastic is because it is CHEAP. Plain and simple.
AirDocIntakes uses steel because it is far superior in strength, durability, function, and it looks cool too!
Oh, I almost forgot, I made a few intakes for the 06/07 H3 (11 different types if I count my test pipe with 2nd MAF) not counting Colorado/Canyon intakes and the 2008 H3 I5 in testing, and I have found the vibration culprit (did not have to use an old piece of Comaro coupler
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