What about some type of insulation that could be wrapped on the outside of the metal pipe? If your that worried about it, do they make some high temp foil covered insulation?

 

I thought I was doing well with mileage and trying to stick to highway-only driving, but my last half-tank I ended up mostly driving stop and go so I didn't really get anything better. I got around 18 MPG. It's unrealistic for me to think I'm going to be doing any full-time highway driving anytime soon, so I can say it seems like the mileage increased, but I do usually get around 200 miles by the time it hits half-way. This time I got to about 230 and then hit the stop-and-go stuff. So based on that, yes I would say my mileage is increasing. It's obvious.

 

You could wrap it in heat tape if you want, but it is not needed. The pipe DOES NOT GET HOT!!!!It is an intake, not an exhaust pipe. You cab grab that pipe the second you shut off the 3 and pop open the hood, warm is what you will find, just like the air filter box, silicone couplers, brake fluid reservior, battery box..... I think you get the point.

There will always be somebody, like they did in this thread, that says they think a metal intake pipe will gethotter than a plastic. Plastic, metal,rubber.........
whatever, all gets heated by the same source to nearly the same temperature. Great observation, just nota fact as it relates toan intake for a passenger vehicle
like the H3.Now, if the pipe were bolted to the engine by a metal bracket in some way, then it would be constantly heated by that metal to metal contact and
it could possibly be an issue?

So no worrieshere.

 

Just in case, can you come up with a reservior and a cooling manifold to wrap around the tube for those balmy 75 degree days, thenwe can stop and get a bag of ice at every corner to make it to the next light?

 

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.

GM's performance intake uses a metal tube, K&N uses a metal shield and doesn't seal off engine compartment air off, the Airaid intake uses a metal extender on the stock air box base and doesn't seal off, AEM uses a metal pipe and a metal shield and doesn't seal off, etc. Heat is an issue with practically every intake except perhaps the Volant which I didn't test.

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?

Here are a couple other suggestions:

1) The I5 wiggles a lot, you need to make sure that you have good flexibilty in your setup to decouple the vibrating motor and the fixed air box. The flexibility will limit the torque on the air box and cut down on some conducted noise.

2) The colorado has another port in the intake for the FPR. Perhaps you can add another hose barb to the tube and a rubber cap to make one intake compatible with the H3 and the colorado/canyon.

 

CHP, how about providing us with some IAT data. Stockand any of the aftermarket kits you have tested.
It would be interesting to see the difference between stock and aftermarket kits.

Doc, I threw that out for anyone worried about the temps. I know it is usually used on exhaust parts, but
would help insulate the intake tube. Probably overkill like you stated.

 

Yeah...................in your own thread.

 

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: hasto "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! I have done a wee bit of testing (I did not fall off the turnip cart yesterday) and whencomparing the MAF input reading from the H3 to the throttle body end of the AirDoc pipe (I made a sensor from asecond bosch MAF), I could not reliablymeasure 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 thereisa 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 stockblack 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 memake 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 I5in testing, and I have found the vibration culprit (did not have to use an old piece of Comaro coupler

 

Actually the FPR port is only on 04 and 05 model years. They went to a different system that eliminates the fuel return lines in 06 to qualify for LEV for evaporative emissions, which was carried over to the 3.7 in 07.

I'm not trying to hijack this thread, but I just googled "plastic heat soak" and found the following:[*]Whether or not an inlet system is made from aluminum, steel or plastic, the thermal conductivity of the duct material has little effect on engine power[*]The rate at which air travels through the inlet path under open throttle, when one is asking the engine for maximum power, negates the effect of material heat soak, regardless of the material[*]For example, the inlet air speed of a 5.7L engine with a four-inch duct at full throttle is 34 feet-per-second, based on a volumetric efficiency of 70% and an engine speed of 3,000 rpm. Most inlet systems for every intake manufacturer for this engine are 30 inches or less. This means that the air in the duct of a 30-inch inlet length on this engine at the given rpm is 1/10th of a second—hardly enough time to transfer an appreciable amount of heat into the air stream on any system.

 

So we can now put this heat sink issue to rest.