My 1994 single turbo RX7 IAT gets hot very easily and at times when I am in the stop n go traffic, and I have seen the IAT reads as high as 80C and luckily I started moving in traffic and IAT started to drop as I moved.

I am always mindful on the temperature, with the water temp it hardly gets over 94 C and I know to take it easy at that level if IAT gets higher than 40C , but I am curious how high IAT have you guys experienced and if any potential damage could happen if it gets so hot? Any feedback is much appreciated ?

 

My single turbo has a front mount Blitz which sits just in front of the radiator and does not block air flow through the nose of the car like old type FMICs did.
My thermostat is a SARD SST12 which opens about 75C.
I have the Apexi PFC cooling fans set to start cooling at 85C for summer without A/C.
I have ducting changes made so direct cool air comes around the passenger side of the IC/radiator to the air filter.

My normal air temps at low speeds do not go over 50C here in Houston.
I also have the cooling mod grounding switch to enable the overheat fan turn on.
Water/Meth injection also keeps the air temps down when needed.

 

what intercooler are you running? In Florida, on stock twins and intercooler, I’m in the 60’s. It has hit around 70 after a pull and will cool down to the 50’s after a bit on the highway

 

I have HKS V Mount set up and koyo radiator fan, as long as the car is moving the IAT is within 35 to 45C on a hot day, it is when I am stuck in traffic the IAT temp goes up quick and I just dont know how high it can get before it is considered danger or when I should be pulling over the car to the road and let it cool down on IAT, some one told me the IAT is irrelevant as long as I don’t boost it which I am already aware off.

 

That someone was correct. So long as the map has the corrections for the iat increase, it can be whatever it wants to be out of any significant load. Nothing will happen.

 

thanks for the feedback 🙏

 

delete

 

as previously posted, elevated IATs are OK as long as the motor is not under load.

it is crucially important to know actual IATs underload/boost. unfortunately, there still remains a majority of the single turbo community unaware of their actual IATs. "what me worry" about my IATs, they are around 27C/80F.

no they aren't.

at 400 rw rotary hp:

if your air filter is in your engine bay it is drawing in 125 F air. if your air filter is anywhere near the back side of your intercooler the temp is a lot more.

your turbo is outputting charge air at 300 F.

an (optimum) air to air IC can remove 65% (max) of the increase T. we don't have optimum ICs because the FD doesn't have adequate space but let's assume we do.

300 - 125 = 175 X .65 = 114 F removed.

175 - 114 = 61 F net of IC add to (ambient) charge air. "ambient" is not the outside air T, it is the T at the air filter.

125 + 61 = 186 F IAT

but your fast IAT sensor says 80.

mine did too. here's my IAT log from my 2003 dyno run at 500 hp. from 2400 to 6800 and no change in the IAT?????????




i switched from a thermistor to a thermocouple the next week. 4 data points per second, accuracy plus or minus 2 F. as soon as i learned my actual IATs i added 100% methanol as AI.

Meth AI drops IAT by approx 60F.

here's a recent run



i switched from a EFR9180 to a Garrett G40-1150 and my suspicions were confirmed by the comparative numbers. new tech beats old tech but i digress.

8032 RPM
21.7 psi
674 rwhp
313.4 F out of the turbo (40 F cooler than the 9180 BTW)
75 F into the motor thanks to 775 cc/min 100% meth and an excellent IC..

the third graph makes my case. notice how the Temp from the turbo (before the IC) rises w boost and RPM.

now notice the IAT. before boost it was about 74 F. instead of following upwards with the turbo charge air, the introduction of methanol (green line) flattens the T rise. the last data point at 100 TPS (8032) shows 75F.

unlike any thermistor which, due to laaaaaag, also shows an unchanged T, this number is the real deal. i run a Turblown UIM and plumbed in a "fast" thermocouple just to compare. the readings in boost turned out to be the same because the thermistor was still fixated on the pre boost temps. if i had wanted to do a real compare i would have turned off my methanol and my actual temps would have been approaching 200 but it was an easy decision not to do that.

how fast are my air thermocouples?

note at the end of the boosted run....on the gas at 4 minutes and 512 thousandths of a second. T 69 F. off the gas at 4 minutes and 561 thousandths. T 93!

24 degrees T change in less than one half of a second.

here's the "air" thermocouple... buy it from The Sensor Connection."




https://thesensorconnection.com/prod...rcharger?v=567

here's a really nice inexpensive amp... one, two or four channels.

https://www.reveltronics.com/en/prod...er-type-k-0-5v


i own two Innovate 4 channel thermocouple amps... neither are accurate so i suggest you don't go there.


BTW, elevated engine coolant temps are not OK whether loaded or not. high coolant temps lead to breached coolant seals.