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Discussion Starter #1
If it's been covered, somebody please direct me to the thread. If not, have knowledgeable people addressed the issue of whether a fan aimed at the front of the car can ever provide enough air to properly cool a TMIC? In Automobile mags dyno testing of the GTi and MS3, the GTi showed a 10% "loss" from it's claimed crank output. The MS3 showed 18%. Same day, same dyno. This really has me wondering b/c I don't think Mazda is gonna overrate the MS3 after the RX-8 debacle and the implementation of the new, stricter SAE standards. I know it's only one dyno, but such a big difference in "loss" needs explaining.

When the car is on the road air is blasting through the ducts right into the TMIC. During a dyno, the air is blowing over the TMIC but not through it. Could this be the reason that MS6/3's often register a high % of "loss" from the claimed crank hp? Granted the 6 also has some additional drivetrain loss, but maybe it's not as much as it is thought to be. If so, could a data logger and other instrumentation show what the charge temp is and whether the ECU is retarding timing?

Lastly, short of putting ice on the IC, are there any special measures that the people dynoing Subies typically take to make sure their TMIC's are getting enough cooling air?
 

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Lastly, short of putting ice on the IC, are there any special measures that the people dynoing Subies typically take to make sure their TMIC's are getting enough cooling air?
[/b]

When I dyno tuned my STi, Mike at Gruppe-S mounts a fan directly on top of the TMIC.

The goal when dyno tuning is to create a real world scenario, so unless you're going to have smurfs in heat resistant suits putting ice on your TMIC, I think we'd all like to know about the origin of the smurfs rather than the gains you get from icing the TMIC in a real world environment.

:D
 

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Discussion Starter #3
When I dyno tuned my STi, Mike at Gruppe-S mounts a fan directly on top of the TMIC.

The goal when dyno tuning is to create a real world scenario, so unless you're going to have smurfs in heat resistant suits putting ice on your TMIC, I think we'd all like to know about the origin of the smurfs rather than the gains you get from icing the TMIC in a real world environment.

:D
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Agreed, the ice is an interesting experiment, but obviously cools off the IC way more than it would ever be in reality. Thanks for the info. Do you or Gruppe-S have a sense of how much lower the car would dyno without the fan?
 

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that's not 100% true but it's not wrong either. It depends on where you live and the season, the northeast in the winter is soo cold, ice on the IC isn't that far fetched for a winter tune here. You need to have at least 2 tunes here, a summer tune and a winter tune. For my summer tune i usually pull timing slightly and in the winter you have alittle more room for boost/timing because the ambient and IAT are usually much lower. This has been the case on at least 4 other cars. Once a tuning solution is available for this car you can bet i'll do the same thing.
 

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Discussion Starter #5
that's not 100% true but it's not wrong either. It depends on where you live and the season, the northeast in the winter is soo cold, ice on the IC isn't that far fetched for a winter tune here. You need to have at least 2 tunes here, a summer tune and a winter tune. For my summer tune i usually pull timing slightly and in the winter you have alittle more room for boost/timing because the ambient and IAT are usually much lower. This has been the case on at least 4 other cars. Once a tuning solution is available for this car you can bet i'll do the same thing.
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Point taken, hard to remember what ice on a car is like it has been so long for me. Moscow, 1998, to be exact.
 

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Discussion Starter #6
Bump to see if there really is no interest in the effect of cooling fan placement on TMIC dynos vs. FMIC. Is it a given to most that the air redirected by the hood is sufficient? Or do people believe it just wouldn't make much difference to either the resulting peak figures or power curve?
 
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