Calculating approximate pre intercooler temps.

[RedMist]

I've a fellow offroad racer that has a very new 4g63 that he's plugging into the rear of a small, light offroader. The only problem is, he's gone budget and not installed an intercooler of any sort. As I'm not turbo oriented I wondered how to calculate his effective intake temp given he plans to run this engine to 18psi.

[Lloyd]

Would depend a lot on the turbo used and various other bits and pieces, if its a standard turbo on it then I'm sure someone can have a reasonable guess. Chuck a temp sensor in there anyway, be interesting to find out what sort of temps its actually running

[RedMist]

It is a stock turbo off a 2002 (odd) 4g63. I realize its still going to be hard to estimate. However I think his intake temps are going to rocket to the point that the IAT will trigger the ECU to knock it into some form of limp home mode... if the Mitsi ECU does so.... yes he is running a stock ECU.

[~SlideWays~]

It is a stock turbo off a 2002 (odd) 4g63. I realize its still going to be hard to estimate. However I think his intake temps are going to rocket to the point that the IAT will trigger the ECU to knock it into some form of limp home mode... if the Mitsi ECU does so.... yes he is running a stock ECU.

I temporarily had my 4agze running no intercooler. It was shocking, performance was none existant.

I can't comprehend why he wouldn't want to run one? They are cheaaaap these days.

[Stealer Of Souls]

I can't comprehend why he wouldn't want to run one? They are cheaaaap these days.

Space issues??


I guess to start estimating temperatures you'd first need the compressor chart. That'll tell you the compressor efficiency at whatever flow rate is most appropriate.
From there I suppose you have to make some assumptions. For 1.3bar boost (in a relatively perfect world) I guess would increase the intake temperatures by 2.3 times divided by the efficiency (100% = 1.0)...
So for 25 degrees the outlet from the compressor I would be guessing at least 70 deg at peak efficiency... So average temps would be 70-100... (heat leeching from turbine, additional frictional gains, compressor will actually be trying to create additional boost preesure to overcome pressure drops etc)

There are probably a million and one other mitigating factors involved. But this probably a reasonable starting point.

[Mr Revhead]

id say probing it would be the only way to get even close.

[Quint]

He'd get major detonation anyway, and the knock sensors(equivilent) would retard the shit out of the timing to prevent it.

[fivebob]

Typically you'd expect a turbo outlet temp around 100-130°C, or even higher, depending on ambient temp and compressor efficiency.

Try http://www.stealth316.com/2-turbotemp.htm for a calculator, but you'll need to convert to Celcius, bloody yanks still use that odd Fahrenheit system

[RedMist]

Great site fivebob, many thanks.
It'll certainly be relevant for my playing with the 3sgte.

[vvega]

ive seen 150+ dgrees on a 20v turbo.........wta had no water in it :S

v

[matt dunn]

I temporarily had my 4agze running no intercooler. It was shocking, performance was none existant.

A S/C will create way more heat than a turbo nomally,

and dont Mitsi ECU's sense the air temp in the AFM and just factor in the fact that it expects an intercooler to be there,
as they run no map, airflow, or air temp sensors after the turbo normally.

Matt