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Loki047 01-23-2008 05:01 PM

All that matters is that the heat transfer coefficient for silicon is less than that of a metal.

You get greater heat transfer from the metal pipes

jayc72 01-23-2008 05:06 PM

I'm not disputing that. But how much difference? And does that difference actually have any real impact on the IAT? And if so how much? Ultimately does that have any impact on performance?

I guess it comes down to want the ideal or good enough.

Joe Perez 01-23-2008 05:20 PM


Originally Posted by jayc72 (Post 203681)
He states this as a fact. Strongly tells people not to use an insulated pipe, but shows no actual data that would prove this.

One cubic inch of Kellogs' puffed wheat cereal has less mass than the moon.

I have asserted that this is a fact. Am I required to make a trip down to NASA's HQ in Houston, TX to photocopy all of their relevant documentation about the composition of the moon, and then provide lab results which demonstrate the physical properties of puffed wheat cereal? Of course not. This statement is what Hartley Rogers would call "Intuitively Obvious."

Likewise, it is fairly obvious that when hot air is contained within a pipe, the pipe is surrounded by air which is less hot than the air inside the pipe, and it is desireable for the air inside the pipe to become cooler, then making the pipe out of a thermally conductive material is better than making it out of an insulating material.

AbeFM 01-23-2008 05:26 PM

FYI FM sells two intercoolers, one is compatible with Ac, one is not.

And I totally didn't know this when I got mine!

Since I have no AC, I really want the bigger one. In short, if someone is thinking of getting this kit (which I have, and I really like it, and have pics of how to install it, etc) let me know, I might want to sell my essentially brand new intercooler to you for damn close to what it's worth new, and get myself a bigger, non-AC friendly one.

I'm sure there is some cooling from the pipes (I wonder how much of it isn't heat-soaking into the metal walls) but the IC does the majority of the cooling. An awesome IC beats metal pipes and a crappy IC. The rubber ones have a couple advantages: Light weight, easy fitment, less vibration transfer, less joints to break.

Pics of my install (fm will tell you you need a $250 "intake kit" which I functionally replaced with a $2 bathroom sink u-pipe).
(oh, nevermind, I never posted those. Guess I'll dig for them if folks are interested)

Loki047 01-23-2008 05:42 PM


Originally Posted by jayc72 (Post 203739)
I'm not disputing that. But how much difference? And does that difference actually have any real impact on the IAT? And if so how much? Ultimately does that have any impact on performance?

I guess it comes down to want the ideal or good enough.

Look up their heat transfer coeffcients. And get an idea.

TO put it in perspective. If you take the inverse of the heat transfer coefficient you get its R value. The R value should give you and idea of its comparable insulators

AbeFM 01-23-2008 06:08 PM

Yes, but have you stopped to think about the surface area at all here? The air is going through a 2.5" tube. That's 4.9 square inches and only 7.85 inches circumference.

Now, an intercooler has ~15 channels, about 1/2x3" passages. That's a 22.5" of cross section and 105 inches of circumference.

That means the air travels through the intercooler at 22.5/4.9 ~ 5 times as slowly through the intercooler, so it has a LOT more time to exchange heat with the outside world.

Now, the area that it's in contact with is 105/7.85 ~ 13 times as great. This dedicated aluminum cooler is touching a lot of air, for a long time.

You can touch the tips of a fork that just came out of a pot of hot water for an instant, and be ok. But go ahead and lay your hand flat on a hot pan for 10 seconds, and see how it goes. (Actually, don't do that. You'll burn yourself badly and require medical attention).

In short, for a given length of travel (IC or IC pipe) you get over 61 times the cooling.

So, get an intercooler 1" wider, and you've totally negated five feet of aluminum tubing. It's good to get it, and the point is valid, going out of your way to insulate tubes is DUMB. Get a nice intercooler (like, buy mine!) and be happy. Shorter tubes with less bends will show better gains since you don't have to heat the air as much to get it through them.

jayc72 01-23-2008 06:14 PM

You guys are right. It makes a difference, I never argued that really. My issue is that Corky is saying to NEVER EVER use an insulated pipe on the hotside. With out actual testing of both how can he possible make this claim? Other than to take an authoritative stance to discredit another vendor. OEM have been using non-metal pipes for ears on boosted cars, why didn't he speak out about this before? It was only after his competitor entered the market with that product that he writes his article.

If that article was written by Tom at FFS how well would it be received.

I'm done.

Braineack 01-23-2008 06:19 PM

Yeah it was a direct slap int he face to FM in response to some of their remarks. I agree, an insulated pipe should have been tested, but I assume a silicone charge pipe will shed 0 heat. The argument is valid....i posted it for face value, just food for thought.

if the article was written by tom it would be full of ups and downs and id rather walk the dog than read it.

Stephanie Turner 01-23-2008 08:04 PM


Originally Posted by jayc72 (Post 203664)
I'd take what Corky wrote above with a BIG grain of salt. I think what he's testing is flawed, and honestly not terribly relevant in real life. He never tests both types of pipes under the same conditions. He tests the difference between the outlet of the turbo and the inlet of the I/C. Distance traveled could have as much to do with heat shed and the type of material the pipe is made from. But we wouldn't know that because he only shows data to prove his point.The bit of data that we REALLY care about is post i/c temps. I would really like to see the difference between his metal tube and something that insulates. I'm willing to bet that the big assed i/c most are using will eat up the potential couple of degree difference. .

If what he is testing is flawed, then I suggest you think twice about stepping foot in a helicopter and airplane. It is the same mechanics, physics, and thermal properties taught to all mechanical engineers. And he happens to have a wee bit more experience at it than most folks..

As for testing both sets of tubes: FM makes the opposite claim that we do. However, is anyone else crying foul and challenging their testing procedures? Do they have actual data and numbers to back it up? You should have the same standards for everyone.

If we had a set of tubes, I would be happy to test them. I think the fact that the metal tubes shed heat prior to the IC is proof enough that they are better. Insulated tubes cannot shed heat. Period. Distance traveled does not matter in this comparison since both sets of tubes are flowing in the same direction, place and manner.


Corky isn't god, just another vendor. And like FM, Trackdog, Goodwin ... etc, he has an adgena. To sell product. I'm not saying that he's wrong, but I don't see the above as anything more than a criticism of FM's product.
God like, no. But like I said, he knows a whole lot more about it than you or I. Sure it is a criticism of any insulated IC tube. If FM happens to sell the stuff.... FM will poke holes at our stuff when they get the chance, that is the nature of the game.
Stephanie

jayc72 01-23-2008 08:57 PM


I think the fact that the metal tubes shed heat prior to the IC is proof enough that they are better.
But how much better? Enough to warrant this? :

Summary: Regardless of where the turbo is located,
NEVER, NEVER (NEVER SQUARED??) INSULATE THE COMPRESSOR OUTLET TUBE.
I need a dead horse smiley :)

Jay :hustler:

AbeFM 01-23-2008 09:51 PM


Originally Posted by jayc72 (Post 203874)
But how much better? Enough to warrant this? :


Originally Posted by Stephanie Turner (Post 203826)
Insulated tubes cannot shed heat. Period. Distance traveled does not matter in this comparison since both sets of tubes are flowing in the same direction, place and manner.


I think that's the point, Jay - if the tube drops 20*, and the intercooler 40, or the tube drops 1, and the intercooler 57... You haven't lost a lot.

The distance traveled is only to say that you would need an obscene amount of metal tubing to make up the difference of a marginally bigger intercooler. Sure, you could have, well, an 24" intercooler on the end of a rubber hose, or an 18" intercooler on the end of 30 foot IC pipe, and get the same effect. Assuming there was airflow over this, and the weight of such a device wouldn't make the car front heavy and all sort of other silly conciderations (the biggest one being the compressor needing to generate 5-10 psi more to overcome the loses in such a system....

All that said though, there's no reason to give up the free benefits from a well conducting metal tube. Perhaps you could run radiator water through it, since compressor outlet temps are high. Got me.

cjernigan 01-23-2008 10:05 PM


Originally Posted by jayc72 (Post 203874)
But how much better? Enough to warrant this? :


I need a dead horse smiley :)

Jay :hustler:

http://forums.beyondunreal.com/image.../deadhorse.gif


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