Intake temperatures from the Air Intake Temperature (AIT) sensor in the stock position on the underside of the UIM are known to be highly misleading because they are substantially influenced by heat soak of the UIM.

Read more about it here:

https://www.rx7club.com/forum/showth...ghlight=sensor

 

Yeah, after reading all of this, I think I'll just stick at 10psi until I can afford the FMIC, single turbo, and other stuff.

 

Your right, if your air temp sensor is reading temps that high you dont need to be running high boost. If temps are over about 50C I wouldnt want to run high boost unless your tuned for high boost in that temp range. Even if the sensor is just suffering from heat soak you still shouldnt. As a matter of fact heat soak of the sensor is far more dangerous than if the actual air temps are that hot. The reason is if the actuall air going into the engine is 50C but your temp sensor is heat soaked my the uim and its showing 70C your going to run lean. Your ecu is going to think its 70C air temp and pull fuel when in reality your air temps are 50C, hence it creates a lean condition.

STEPHEN

 

STEPHEN,

I'm not entirely sure you are correct about this. I agree that the ECU reads air intake temperature and adjusts A/F. I also agree that the higher the air intake temperature, the lower the air density, and therefore less fuel is need.

What I question is that I believe the ECU is programmed to take an "ultra safe" approach when it reads high air intake temperatures. So, when the ECU reads high air intake temperatures it actually increases fuel above what it should be so that the extra fuel will help cool down the combustion zone temperature to protect against detonation.

Is there anypone out there who knows for sure and can set the record straight?

 

The PFC reduces fuel when the intake temps get above 50C. It increases fuel when the intake temps are below 50C. However, the percentage of fuel removed or added at real world intake temps is relatively small. If you look at the data-logit screen, the most fuel the PFC takes out is about 1-1.5% at 80C+ intake temps. The most it adds is around 3% (below zero intake temps). If you are on the ragged edge, this might put you over it in some circumstances...

I don't know how the stock ecu handles it, but I would guess the PFC is closely modeled after the stock ecu for most things.

 

According to Racing Beat http://www.racingbeat.com/FRmazda3.htm , their stock intercooler clamps will hold boost up to 20 psi http://www.racingbeat.com/resultset....rtNumber=18300

I've hit 15 psi and it still holds together.

As I've said, I've been running this way for years without any problems. I am not saying that this is the ideal setup and a larger intercooler would surely help. But for my occasional on-boost bursts it works just fine. Seems that I always have other issues with the FD which require the $$ which would otherwise go to the intercooler and new intake. Since I don't track the car, spending $1500+ for the intercooler and intake is not a high priority...

 

I have PFC, DP, MP, CP, and my boost hits about 12 psi on the stock intercooler. I know this now because I have just recently gotten a boost gauge. Is this normal for it to be boosting to around 12 psi? The map is set for my mods, which are intake, fuelpump, and the ones above.

 

Its not the IC clamps you should be worried about. Its how hot the 15psi worth of compressed air is going into your engine and how much harder the turbos have to work at 15psi and a small *** IC.

 

i hit 1.1 kg/cm^2 a few times which is around 15 or so psi. . . i think ive gotten higher than that to tell you the truth. hahahaha.

paul