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intercooler pipe routing (mythbusters style)


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It has been talked about before. I would like to find out some hard evidence on the way to route intercooler piping in the S30. The three designs I am interested in this topic are as follows in the pics.

First up is the way I currently have my IC pipes setup.

1 DSC00152.JPG

 

Second up is the way Austin used to have his IC pipes with the cold and hot sides swapped.

2 DSCN6159.sized.jpg

 

The third is using the IC inlet and outlet on the same side as austin does in his new setup.

3 verticle_IC_012.sized.jpg

 

Austin, or anyone else. Do you have the intake temps to go along with each of these setups? Hard data to tell which way is the most effecient and has the lower intake temps. I am looking for real facts here and personal exp. I currently am running the stock ECU so I dont have a way to monitor intake temps. pretty soon I will be running MsNs. Does anyone out there have about the same IC setup as do I and a ECU that monitors intake temps? Is all of this Moot, since the turbo sits under the intake manifold anyways and just soaks it in that dreaded "HEAT"

Thanks for stopping by and let the mythbusting begin.

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I don't have any hard data but just from observation, the same side inlet / outlet will be the most efficient due to the shorter pipping distance. The difference between the other two I think would be negligable since like you said, the turbo sits under the intake manifold. You could always wrap the pipe and the turbo to negate the heat transfer.

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My thoughts would be along the lines of #2 over #1, as the cool side is shorter; and #3 over #2 as overall length is shorter.

 

The differences you will see will be different based on the intercooler used in each case, as well. But you DO have a way to easure intake temps: Go to Omega.com and get some thermocouples...stick them in the piping and monitor with a recording multimeter. My Fluke 87 has "Min-Max" so charting max rises and drops is fairly easy. If you get a rotary switch and a readout, you can flip as you drive.

 

It's how the OEM's did it before all the fancy digital logging instrumentation came along. Heck, even reading millivolts directly off the thermocouple and then doing the conversion will work....

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I have a cheap FMC I/C from EBay ($170 shipped) 12X20X3" which keeps within 10F of ambient and drops 0.7 psi at 15 psi boost. Pressure drop starts at 4.5 psi until intake vol pumps up to steady state which takes less than a sec. I measure press drop between compr scroll and intake using Innovate LMA-3 data log.

 

My motor is L28 N42 and routing is thru 90 from turbo thru rad support to I/C then return across back of rad into 65mm TB, all 2.5". Return is wrapped with alum foil backed adhesive polyurethane R3 2" wide pipe insul, which dropped temp 30F. There are total of 5 90's.

 

I can post pix and data log if interested.

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One thing to consider is getting cooler/fresh air to the filter, on the turbo inlet side. Reducing those inlet temps before the air is compressed will help keep the air more cool and therefore dense after the turbo.

Also, agreeing with Tony, #2 would be better than #1 because you are not "potentially" reheating the air in the engine compartment after it has passed through the intercooler.

And from reading Corky Bell's Boost book, #3 intercooler is better then the #1/#2 intercooler because: the path the air has to travel through the IC core is shorter which helps reduce pressure drop across the intercooler, but the IC has a similar crossflow area, so your cooling efficiency is about the same. Also less piping is less volume to pressurize, another reason I will never make my piping larger than 2.5inches diameter.

What does Austin do with his filter/air intake? Just a cone filter on the turbo or is there some piping there too?

 

I would like to see pics of your setup too, dapiper! Datalog would be great too, does that include temps? or just pressures?

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One thing to consider is getting cooler/fresh air to the filter, on the turbo inlet side. Reducing those inlet temps before the air is compressed will help keep the air more cool and therefore dense after the turbo.

Also, agreeing with Tony, #2 would be better than #1 because you are not "potentially" reheating the air in the engine compartment after it has passed through the intercooler.

And from reading Corky Bell's Boost book, #3 intercooler is better then the #1/#2 intercooler because: the path the air has to travel through the IC core is shorter which helps reduce pressure drop across the intercooler, but the IC has a similar crossflow area, so your cooling efficiency is about the same. Also less piping is less volume to pressurize, another reason I will never make my piping larger than 2.5inches diameter.

What does Austin do with his filter/air intake? Just a cone filter on the turbo or is there some piping there too?

 

 

The first pic there is of my Z. I made a cold air intake and have it there. What I am trying to find out though is hard data if the air gets "reheated" and at noticeable rate the way I currently have it. This thread is interesting so far guys. keep em coming..

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My thoughts would be along the lines of #2 over #1, as the cool side is shorter; and #3 over #2 as overall length is shorter.

....

That was my thinking when I did mine back in.....err, let's just say a long time ago :D Never measured the temp difference but since the air off the rad/fan is expected to be maybe 180*+, it would definitely be warmer than the outlet of the I/C. Rule of thumb says you gain about 1% power for every 10* you reduce the IAT. However, as you increase boost you also increase the temp of the charge going into the I/C, so the temp differential becomes less depending on the efficiency of the I/C.

 

While #3 is the best, you have to route the 2 I/C pipes and as big as possible a pipe for the filter through that one side.

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Guest 280ZForce

I like #3 ideally, you can cut out the core support and could fit two 3" pipes if you wanted. I run a 3" charge pipe and a 2.5" hot pipe through the core support. Then a 4" intake pipe that goes under the car and around the front.

 

IMG_3420a.jpg

IMG_3499a.jpg

IMG_3491a.jpg

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I started a thread a long time ago with a link to a company that manufactures intercoolers in Oz.

 

The same side inlet/outlet intercooler is better the shorter it is - the first 25% of the core after the inlet gets 80% of the flow.

 

For maximum efficiency, an inlet and outlet diagonally opposed is better.

 

Small turbos with high boost need longer core dimensions with less height than bigger turbos with either less boost or the same amount, which should use shorter core length and more height. Using height for measurement perpendicular to the direction of air flow and length as the length of the core the air is traveling through.

 

I would expect that for drag racing, the most efficient intercooler would be wanted (for all-out drag racing and air/water setup running through dry ice), but for street use, minimizing volume, hence the same side inlet intercooler would be more responsive. Combination of less volume and less bends in the tubing.

 

Everything is a compromise.

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The same side inlet/outlet intercooler is better the shorter it is - the first 25% of the core after the inlet gets 80% of the flow.

 

For maximum efficiency, an inlet and outlet diagonally opposed is better.

 

I would disagree only because I have seen crossflow 'two pass' intercoolers where both inlet and outlet are on the same side. They can be configured any number of ways...say for a 12" high I/C, the bottom 6" flows left to right, and the top 6" flows right to left---with an open plenum on the end to allow the reversal.

 

If you have a conventional tank setup, yeah, I could agree that diagonally opposed is better.... Then again changing the tanks isn't that big a deal either!

 

Why Comprimise?

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I obviously would go with Choice 3 :).

 

Its fairly easy to do and makes for a very clean setup, short pipes out of the engine bay. I dont have any facts regaurding air temps to back up my butt dyno but I did notice shorter spool and response times. I did more then just make the pipes shorter, the intercooler is now properly sized and is HALF the size of my original one. I think most intercoolers are way oversized and with the proper ducting on a small unit you will be happier.

 

I am also running around 26psi without any signs of detonation.... meth might just having something to do with it though :) .

 

I need to post of new pictures like I've have been saying I will... Ill finally take some this weekend. I easily ran a 3" pipe through the radiator support without hacking it up to much. So I have a nice big air filter up high and out front.

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