Well, you may not have been far off on that front, Doug. A compressor running efficiently may be running at 200 - 400F. Once a compressor falls off its map, this number increases a massive amount. I haven't done any testing myself, but I recall reading a turbo book that made 800F statements.

Rod

 

wow. well I guess thats still pretty warm, and you don't want to bolt up a metal air intake pipe to it. after all we're talking about pushing limits -- otherwise we wouldn't need the after market intake system in the first place.

 

I would like a tourqe tube for my ram air III. Less curves to the trubo could make a real differance.

 

im running the mac air induction, i did notice an increase in power and turbo whistle

 

checked the air intake pipe after a 30 minute HARD DRIVE home and its not as hot as everyone thinks it would be, im sure there are other pipes that run cooler but this one isnt as bad as you would think. all the rice rockets have metal pipes for intakes, they are lowered and run 3 times as many rpm's and you dont hear them pitchin a fit over a metal air intake........ just my .02

 

A month or so ago, someone on TDR posted a link in the 3rd Gen area to an article on this very subject as it relates to diesels, however, I was unable to find it again (not a member - can't use SEARCH). The end result was a metal intake pipe had no affect on the incoming air temperature. I did run across this on Isuzu’s performance web site:

"Some will claim that heat from the engine compartment will be transferred through the pipe of the intake system and into the air passing through the pipe, but this is not true. Testing by Sport Compact Car showed negligible change in intake temperature between where it enters the filter and when it passes through the throttlebody. Their conclusion was that the air is passing through the pipe at a high enough speed that it does not have time to pick up any heat from the pipe itself. Further evidence of this is the fact that the Ice Man brand intake system, made of heat insulating PVC plastic, tested at 9 HP while the AEM brand intake system, made of heat conducting aluminum, tested at 12.9 HP. The conclusion is clear that the design of the intake system is more important than what type of pipe is used to make the intake system."

Just thought it was interesting.

 

very interesting. I would have thought that bolting the intake pipe to a hot turbocharger would conduct heat into the pipe via convection and then to the incoming air from the pipe. While the air velocity argument does have some mertit, I keep thinking that at the end of the metal tube is a very hot turbocharger which, when pushed to the limits as we are discussing (or else IAT would not be of interest) would result in a loss of EGT margin. I just seems like, given the choice and if the interest is in reducing IAT to the last degree possible, that a metal intake pipe would be down the list. Especially for today's CTD where the turbocharger is small, there is a fueling box, and the owner is trying to do everything possible to reduce EGTs but still keep the stock turbo. meanwhile the stock turbo is frequently pushed outside of its optimum map and generates high temperature compressed air. It seems like this situation is one where every degree would count, the metal intake tube would be questionalble if not simply a bad idea.

I wish we had some real measurements that would apply to our trucks. a stock gasser compact sports car doesn't seem to compare very well to a CTD pushed to the EGT limits and for which an after market intake systems is employed to eek out every possible advantage.

 

Doug,

I have a question. You seem very concerned over "that little metal intake pipe" increasing the temp. of the intake air.

What about the intake manifold pipe on the other side of the engine? It is metal also and able to pick up heat from the engine that it is bolted to and well as the hot air in the engine compartment.

 

thats a good point. I guess what I'm questioning is the choice to go with metal on the cold air intake side when there are other choices. There may be advantages that I don't know of, but I can see only a disadvantage to the most important goal of an after market intake system. I dont' yet understand the motivating factor behind metal versus a large diameter plastic inlet. All the after market intake systems I've reviewed have on goal in common, and that is to reduce EGT. it just surprised me to see that the metal pipe would be consistent with that goal.

the post-intercooler intake houses the grid heaters so there's really no choice there to go with plastic. And even if this side of the engine was just as warm as a turbocharger operating outside of its efficiency map, the argument can be made that no other choice was possible. And the question remains why one would bolt up a metal pipe to a hot turbo if you had the choice to use plastic instead and the goal was to acheive every possible degree reduction in IAT.