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Old 01-30-2011, 10:39 PM   #1
spokeshave
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Default EBay TMIC tests

OK, I know that three are a bunch of threads on EBay TMICs already, but none of the ones I read contained any objective data on their performance - or lack thereof. So, I thought I would buy one and test it. I chose the Godspeed TMIC, mostly because it was inexpensive - about $200. It is also very big - about as big as a TMIC can be while still fitting in the available space. The core is about 4" deep, 8" tall and 20" wide. It came with a cast aluminum y-pipe and all necessary tubes and fittings.



I wanted to compare this IC to the STi TMIC, since that is a very popular upgrade. I did the testing on my 2006 WRX wagon.

The first thing I wanted to test was flow. I set up a very rudimentary flow test using my shop vac discharge, some PVC pipe and a gauge that reads in inches of water. The shop vac flows about 300 cfm according to its literature. I took pressure measurements at the inlet and outlet, and the difference is the pressure drop across the IC.



Inlet:



Outlet:



As you can see, the pressure drop is about 3 inches of water at 300 cfm. That equated to about 1/10 of a psi. Clearly this IC flows well. Unfortunately I don't have any pics of the STi IC tests - I did that today and simply forgot to take pics. Anyway, the STi IC had a pressure drop of 6 inches of water, which is a little more than 2/10 of a psi. Obviously the Godspeed IC has less pressure drop, and this is to be expected since it is a bar-and-plate design versus the STi tube-and-fin design.

So the next test was efficiency. In order to test efficiency, I need to know turbo outlet temp, intercooler outlet temp and ambient temp. I decided to insert these Delco temp sensors into the intercoolers.



I selected these because they are inexpensive, fit into a 3/8" NPT hole and they are provided with a complete response curve. I connected the sensors to an Innovate SSI-4 module that allows me to log any sensors that have a 0 - 5 Volt output.

The first sensor was placed in the outlet tank near the outlet port. The other one was placed in the inlet tank near the y-pipe inlet. The tank castings on the Godspeed IC are nearly 1/4" think, and I had no trouble tapping the holes:





I did the same with the STi IC (again, sorry no pics). This was a bit touchier, since the tank walls are more like 3/16" thick, but I had two full threads, so I am confident that it will easily hold the pressure.



Continued...
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Old 01-30-2011, 10:41 PM   #2
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Continued...

Of course, to be a good test, I needed a splitter that worked well with both ICs. I fabbed this:





By simply changing the rubber seal, I was able to make it fit both ICs very well.

The Godspeed IC installed (with the tanks painted):



I did several pulls with each IC. I tried to do it underas similar conditions as possible, but the ambient temps for the Godspeed IC were about 5 degrees F warmer. Here are charts containing the turbo outlet temps, IC outlet temps and efficiencies for both (fixed to make the scales the same):

EBay TMIC:



STi TMIC:



The Ebay IC log contained more data, but the most important part is the efficiency curve. Note that for the STi IC, the efficiency never dropped below about 83%, whereas the Godspeed IC went as low as 56%. That's a huge difference. It's the difference between a manifold inlet temp of 30 degrees C (86F) for the STi IC versus nearly 50 degrees C (122F). The 56% efficiency is completely unacceptable, whereas the STi IC efficiency is surprisingly very good.

So, what's the conclusion? Well, the EBay TMIC is big and heavy, and it flows very well, but it doesn't cool worth a damn. The low pressure drop is it's only advantage, but even the restrictive tube-and-fin STi IC only lost less than a quarter of a psi. If the pressure losses during my testing conditions are mathematically extrapolated to to redline WOT conditions, the STi IC still only loses less than 1 psi, which is trivial given the far superior cooling capability of the SIi IC. So, in conclusion, the Ebay TMIC does not work well at all and would be a very bad choice as an upgrade. I suspected that it would perform pooly, but was completely taken by surprise by how poorly it actually performed. I was also suprised at how well the STi intercooler performed.

Disclaimer: These were not comprehensive scientific tests. My intention was to determine the relative performance differences of the two intercoolers, not to determine precise performance curves for each test. The pressure drop and efficiency characteristics are representative of testing conditions only, although the pressure drop characteristics can be relaibly inferred for other conditions using the well-established relationship of aerodynamic drap to the square of the velocity of the air. The efficiency curves are not intrinsic. They are a snapshot of the efficiencies of the two intercoolers under similar testing conditions. If the ambient temperatures were lower, both efficiencies would be higher and vice-versa. However, the dramatic difference in efficiencies would remain.

Last edited by spokeshave; 02-01-2011 at 09:24 AM. Reason: re-scale charts and clarify conclusion
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Old 01-30-2011, 10:57 PM   #3
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Nice work.
I remember hearing about tests and people saying the eBay units tested worse than the STi unit, however I never actually saw those tests. Nice to see the work you put into this, I'm sure it will be greatly appreciated by people looking at these for an upgrade.
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Old 01-30-2011, 11:06 PM   #4
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I vote you for n00b of the month! Great job! One point though....can you change the charts to have the same scaling as that's more Christian for comparison.
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Old 01-31-2011, 12:16 AM   #5
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Great test!
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Old 01-31-2011, 12:25 AM   #6
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This thread actually made me stand @ my computer...and applaud. I was shopping for TMICs on eBay. Think I'll pass.

Well designed & executed experiment. Not that it's important, but I wonder how much of the delta P across the STi TMIC was due to cooling and how much was due to frictional losses?
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Old 01-31-2011, 12:29 AM   #7
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Quote:
Originally Posted by T-dub View Post
Well designed & executed experiment. Not that it's important, but I wonder how much of the delta P across the STi TMIC was due to cooling and how much was due to frictional losses?
A change in temperature won't cause a pressure drop from inlet to outlet. The air density will change, but that would just affect the volumetric flow rate, not the pressure. All of the pressure drop would be due to restrictions in the TMIC.

Besides, when he did the pressure drop test it was on a bench with air at atmospheric temp and no air passing over the TMIC fins, so the TMIC wasn't doing any cooling anyway.
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Old 01-31-2011, 12:31 AM   #8
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Excellent work! The real question is, how do they both compare against a name brand TMIC? The reason why I ask is because if you look at most of the big-name TMICs, they have the same number of bars and plates, and the same number of fins. Exact same size as well, although some are 4.5" thick instead of 4". Here is a high-res photo of a Spearco, count them up and you will find the same number of fins:

http://i496.photobucket.com/albums/rr323/Tussen_pics/IMG_3829.jpg
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Old 01-31-2011, 12:32 AM   #9
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...and people always smirked and laughed at me for using a v7 jdm sti tmic with the proper splitter and skirt



but what do I know.....
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Old 01-31-2011, 12:37 AM   #10
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Quote:
Originally Posted by accelerator View Post
Excellent work! The real question is, how do they both compare against a name brand TMIC? The reason why I ask is because if you look at most of the big-name TMICs, they have the same number of bars and plates, and the same number of fins. Exact same size as well, although some are 4.5" thick instead of 4". Here is a high-res photo of a Spearco, count them up and you will find the same number of fins:

http://i496.photobucket.com/albums/r...s/IMG_3829.jpg
What about inside the core? There are fins to transfer the heat from the hot air to the TMIC, then more fins to transfer heat from the TMIC to the cool air blowing over it. That picture just shows the fins to transfer heat to the outside air, which might be the same as the brand name TMICs, however it's always been the fin density inside the core (transferring heat from the hot air to the TMIC) that sucks on the cheap units. It's usually something like 1/2 the fin density of decent cores, there have been pictures posted in the past that showed how bad it was.

Here's a thread with pictures:
http://forums.nasioc.com/forums/show...t=turboxs+tmic

Last edited by the suicidal eggroll; 01-31-2011 at 12:43 AM.
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Old 01-31-2011, 12:45 AM   #11
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AMAZING. So glad I read this!
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Old 01-31-2011, 12:53 AM   #12
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Quote:
Originally Posted by the suicidal eggroll View Post
What about inside the core? There are fins to transfer the heat from the hot air to the TMIC, then more fins to transfer heat from the TMIC to the cool air blowing over it. That picture just shows the fins to transfer heat to the outside air, which might be the same as the brand name TMICs, however it's always been the fin density inside the core (transferring heat from the hot air to the TMIC) that sucks on the cheap units. It's usually something like 1/2 the fin density of decent cores, there have been pictures posted in the past that showed how bad it was.

Here's a thread with pictures:
http://forums.nasioc.com/forums/show...t=turboxs+tmic
Yeah the internal fin density certainly plays a role. Here are some pics of the Process West TMIC, the internal fins look pretty similar to the ebay TMIC in your link above.

http://www.iwsti.com/forums/2758449-post14.html
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Old 01-31-2011, 01:13 AM   #13
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Great confirmation for the sti tmic...

Last edited by theotherguy; 01-31-2011 at 01:25 AM.
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Old 01-31-2011, 01:21 AM   #14
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Quote:
Originally Posted by spokeshave View Post
<snip>

So, what's the conclusion? Well, the EBay TMIC is big and heavy, and it flows very well, but it doesn't cool worth a damn. The low pressure drop is it's only advantage, but even the restrictive tube-and-fin STi IC only lost less than a quarter of a psi. I can't reproduce WOT flow conditions (about twice what I was testing at), but can't imagine that it would be much more than 1 psi of loss for the STi IC. So, in conclusion, as everyone suspected, the Ebay TMIC does not work well at all and would be a very bad choice as an upgrade.
Nice work!

But you might want to mention which version of STI intercooler you used in your test.
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Old 01-31-2011, 01:42 AM   #15
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Awesome....I was just about to buy one of those TMIC's...I hope it doesn't raise the prices of the STI top mounts....bought the hard pipe kit instead.
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Old 01-31-2011, 02:25 AM   #16
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Quote:
Originally Posted by the suicidal eggroll

A change in temperature won't cause a pressure drop from inlet to outlet. The air density will change, but that would just affect the volumetric flow rate, not the pressure. All of the pressure drop would be due to restrictions in the TMIC.

Besides, when he did the pressure drop test it was on a bench with air at atmospheric temp and no air passing over the TMIC fins, so the TMIC wasn't doing any cooling anyway.
Density & viscosity are nonlinear functions of pressure @ tempurature. Take a big tank of air & heat it. Will the pressure go up? Cool it off. Will it go back down? The volume didn't change, so what caused the pressure change? Drop in pressure = increase velocity AND drop in temp. You can't have one without the other.

Good point about the IC not actually cooling, but if there is friction then there is heat & consequently temp affects. Pretty much negligible though.
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Old 01-31-2011, 06:35 AM   #17
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Quote:
Originally Posted by accelerator View Post
Excellent work! The real question is, how do they both compare against a name brand TMIC? The reason why I ask is because if you look at most of the big-name TMICs, they have the same number of bars and plates, and the same number of fins. Exact same size as well, although some are 4.5" thick instead of 4". Here is a high-res photo of a Spearco, count them up and you will find the same number of fins:
I was really surprised how much the EBay core looked like the cores from the big name brands. As you pointed out, it has the same number of bars and the same fin density inside and out, yet it performed soooo badly. That would be the next phase of the experiment, but I am reluctant to spend the $500 to $900. If someone has an old Spearco or other name brand top mount laying around and they don't mind if I drill holes in it, send it on to me and I'll test it.

Last edited by spokeshave; 01-31-2011 at 09:57 AM.
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Old 01-31-2011, 06:39 AM   #18
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Quote:
Originally Posted by seattle944t View Post
Nice work!

But you might want to mention which version of STI intercooler you used in your test.
I'm not sure which version it is. I believe it came off an 04 STi. I bought it used a few days ago. Here is the pic from the listing:

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Old 01-31-2011, 07:58 AM   #19
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Great stuff on taking the time to do some comparison tests and plot your results

However, please do not take this the wrong way, but your efficiency plots needs more data to be useful. At a minimum, it should have included ambient temp, vehicle and engine speed and a time constant as well.

While the data you collected is useful, it only paints a small part of the picture and is IMHO to minimalist to draw an accurate conclusion.

I just don't see how it is possible to plot "efficiency" without also taking into consideration the ambient temperature of the air that was actually passing through the IC, the speed the vehicle was traveling to ensure the actual amount of air passing through the IC was at least similar during testing, and how long each test was performed and when exactly during that time the small amount of data used to create the plots was selected.

If you can repeat the tests, do the following:
  1. Use a dyno with a slow ramp rate or the same long stretch of road with a slow gradiant
  2. Ensure the dyno cell is the same ambient temp before each test run and the fan is not moved during runs - or the road tests are performed at the same ambient temps and under the same weather conditions
  3. Ensure the engine is at operating temp before each test run - your goal is to ensure underbonnet temps are as similar as possible for each test run
  4. You will need to log 2+ WOT 4th gear pulls from 2000rpm to redline for each IC setup
  5. log the following for each test run:
    • engine rpm
    • vehicle speed
    • manifold pressure
    • ambient temp
    • intercooler in air temp
    • intercooler out air temp
    • intercooler surface temp (can be used to show heatsoak of intercooler)
    • time
  6. create your "efficiency" plots based on IC in temp and IC out temp with temp and efficiency as the Y axis and rpm or time as the X axis
  7. post all the logged data with any plost created

The above will provide the kind of data needed to make a more accurate conclusion of which is actually better.

Leslie

Last edited by wrxsti.l; 01-31-2011 at 08:25 AM.
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Old 01-31-2011, 09:12 AM   #20
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Nice work!
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Old 01-31-2011, 09:29 AM   #21
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Of course I accounted for ambient air temp. I didn't plot ambient temp for two reasons - first, it remained relatively constant for the duration of the log, and I don't have a ready method to log ambient temp without adding another sensor. I thought about using IAT from the ECU, but that's not necessarily the same as the temp of the air moving through the IC.

I suppose I could have logged more information, but honestly I haven't figured out how to incorporate ECU data into Logworks yet. Nonetheless, the only important data when looking at IC efficiency are the ones that I logged. If anyone is interested, I am runnning the stock TD04 turbo with a stage 2 tune running a peak of 17 psi of boost. Both charts contain a 3rd gear pull to redline.

I likely won't be doing any more tests on the EBay IC simply because I don't have enough confidence in it to even put it back on my car. It is that bad. I also didn't intend this test to be a thorough treatment of intercooler efficiency. I only intended to compare the relative efficiencies of the two intercoolers. The logs were done under very similar conditions, and the STi IC was clearly and unambiguously much, much better. I question your statement that this is not enough information to determine which IC is actually better. I think the results are quite definitive.

I may to some more tests with the STi IC. I am particularly interested in heat soak. There is a lot of talk about it, but again, no hard data. I'll probably have to wait for a bit warmer weather though.
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Old 01-31-2011, 09:32 AM   #22
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Quote:
Originally Posted by Unabomber View Post
....can you change the charts to have the same scaling as that's more Christian for comparison.
Yeah, I got in a little bit of a hurry last night. 0500 comes pretty early and I needed to get to bed. I'll fix the scales when I get home this evening.
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Old 01-31-2011, 09:40 AM   #23
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Excellent test! Will be keeping my STi tmic
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Old 01-31-2011, 10:42 AM   #24
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Great testing!

If you could test a 08+ sti TMIC that would be great. Ive always wondered "how much better the 08+ works"...

Thanks, keep it up!!!
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Old 01-31-2011, 12:46 PM   #25
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Someone send him a spearco! Awesome test Im glad I stayed stock tmic for my tune
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