What Air Temp should we look for from an efficient FMIC if the ambient temperature (outside temp) is around 85-90*F...?

My XS Engineering tube & fin is giving me like 103 *F under 20/21 psi of boost...honestly didn't check the ambient temp but it usually ranges of 85-90*F now.

I logged my intake air temp from my autronic, it has it's own air temp sensor installed in the intake pipe before throttle body.

Thanks in advance for your input

 

Intercooler efficiency is calculated by the ratio between charged air temp and after intercooler temperature. Generally a respectable intercooler should be giving you at least 25-30% efficiency.

Depending on the turbocharger you're running this may or may not be ok. About 5-10 degrees over ambient is usually reasonable under full boost at those boost pressures.

Cheers,

Gary
Gruppe-S

 

Thanks 4 the info Gary...Respec.

 

for a 1-4 gear hammering it's nice to have about +10 degrees at the top of 4th. nice isn't usually what you get tho...

 

There's a billion factors that'll effect the delta temp... I've had inccreases of upto 70 degrees and higher from ambient cruising temps to WOT 2nd ~ 5th.

 

WOW, 70 degrees? Are you sure this is not turbo outlet temperature? You are substantially increasing your risk for detonation any where over 130 degrees charge temp. Turbo outlet temperatures depending on boost pressures you are running can be in excess of 220 degrees, but generally speaking (and this is especially true on an FMIC) if you're in excess of 130 degrees, that's very high. I've been WOT on hill-climbs in the Mojave desert in my Subaru (VF34 / Helix TMIC) and didn't peak more than 130 degrees with 100+ degree ambient temp. This is 210+ degrees turbo outlet temp. Performing similar tests on a prototype front mount in 90 degree ambient, I never exceed 100 degrees. Granted the VF34 is smaller than the 16G-large.

 

Gruppe-s your posting some weird numbers. I would almost call bull**** on the TMIC claim, the only exception is you didn't include enough information to really explain why the temps were so low. Ct9a gsr, is right there are many factors that can affect charge air temp.

First, Intercoolers are usually rated in 70% efficiency ranges, not 25-30%, maybe you were reading an intercooler add claming 25% MORE efficient than stock.

Second, More often than not temperatures coming out of a turbo will be over 300 degrees, 25 pounds on a 100 degree day with a 70% efficient compressor will give you turbo outlet temps over 300 degrees. If your comparing a car running 5 pounds of boost the temps coming out will be much lower, and the inlet air temp for the engine will probably be very close to ambient anyways.

 

Sorry for the confusion. I mean 70-75%, I guess I was thinking in the inverse. The formula to calculate IC efficiency for those that want to know is (ICin - ICout) / (ICin - ambient).

I am most familiar with WRX/STI IC testing as I've done extensive testing on this setup. The detonation threshold for the EJ20 / EJ25 engine is about 130-135 degrees, and Helix IC's as well as most IC's are designed to keep temperatures below this. The 4G63 may have a higher detonation threshold, but honestly charge air temps of anything over 135 degrees is hot. As for 300 degree 16G outlet temperatures, if you're hitting 300 degree outlet temps I would say you are overdriving the turbo. There comes a point where increases in boost pressure will result is actually less air-mass being driven into the engine. At 300 degrees I would say you're past that point. If I have some time today I'll get some better data on the inlet and outlet temperatures of the stock evo FMIC with the 20G that's on my car right now.

Cheers,

Gary
Gruppe-S

 

Here's dyno test numbers for the TMIC temperature with only a fan on it:

 

On a track with ambient temps of 108 I will get to low 140s at 8k in 4th.

 

Thanks for the feedback! Given your circumstances and extrapolating backwards (assuming 30% FMIC efficiency) you'd have a charge air temp of 214 degrees which is pretty much inline with what's expected!

Cheers,

Gary
Gruppe-S

 

Average ambient temps on this run were about 65 degrees before the run and after the run after cooling down. This was done on a road and it was still really cold outside in April.



Granted the ending vehicle speed may be a bit excessive, even at 8000rpm in 4th @ 134mph, air temp was still 117degrees.

 

^ which fmic were you using during this log?

 

Which air-temp sensor are you logging and where is it located? Thanks for the data!

Gary
Gruppe-S

 

Good Info..thanks guys!