Engine Compartment Temperature Probe

[1968SWTs]

I know someone has measured an engine compartment in 110F heat under load and under idle at rest over time. Contrary to common perception, an air cooled compartment should be much cooler than a water cooled compartment.
I am guessing inside the shroud might be 130F and on top of the sheet metal will be mostly close to ambient, unlike your standard water cooled car where the
air behind the radiator might be 140 and the center of the hood might reach 170

Some random standards for components that seem to exist:
Coil-on-plug -20 to +140C
Ignition driver for -40 to +120C
ECU -25 to +85C
Regulators -40C to +140C
Starter Cable Near Manifold 205 C ( 400F)
Dash Panel 140 C ( 285F)
on Engine (Typical) 150C ( 300F)
Choke Housing 205C ( 400F)
Exhaust Manifold 650C (1200F)

I am looking for something similar to this data:

[1968SWTs]

positions 1 and 2 could be very "cool"

[sjf911]

I just placed 4 additional thermistors in my engine bay this winter and one ambient inside the front bumper but will not have any data for a while. I have one measuring engine bay air temp in front of the fan, one in the intercooler core at the distal end, and then one on the fuel rail and one on a fuel injector. That is in addition to preIC IAT, post IC IAT, and cylinder head temp. If there is any interest, I can certainly post the data throughout the year. These are also easily relocated if there are any specific requests.

[RWebb]

sjf011 - I'm interested; hope you will do idle, at speed, etc.

- themistors?? very old school...


1968SWTs - I'm curious where the diagram is from (not the R&T base, but the colored parts)

[1968SWTs]

Originally Posted by RWebb

sjf011 - I'm interested; hope you will do idle, at speed, etc.

- themistors?? very old school...


1968SWTs - I'm curious where the diagram is from (not the R&T base, but the colored parts)

the colored parts are just me the talking monkey with a paint brush - just a wild guess

[1968SWTs]

I would love to have data for these two points!

thanks

[1968SWTs]

I used one of these in the past

Gun Style Infrared Thermometer | Instawares Restaurant Supply

[1968SWTs]

[OldSpool87]

Originally Posted by sjf911

I just placed 4 additional thermistors in my engine bay this winter and one ambient inside the front bumper but will not have any data for a while. I have one measuring engine bay air temp in front of the fan, one in the intercooler core at the distal end, and then one on the fuel rail and one on a fuel injector. That is in addition to preIC IAT, post IC IAT, and cylinder head temp. If there is any interest, I can certainly post the data throughout the year. These are also easily relocated if there are any specific requests.

Thread resurrection....are you able to share temp findings?

Thanks

[chrismorse]

Slight hijack, but similar interest.

Can you recommend an air pressure sensor??? I am curious about the hoped for increase in air pressure in the engine compartment, at various speeds, with the stock engine lid and a duck tail.

I have read a few posts indicating reduced engine temps with the Duck. It would be nice to quantify this at various speeds.

IIRC, i've read that a duck will reduce drag, lift and move the aerodynamic center of pressure rearward on the car.

[911pcars]

As another data point, once upon a time, I inserted the end of a thermocouple wire from my Fluke DMM inside the intake airbox. The temperature at speed was basically ambient - same with the engine compartment temp. Thus, the ubiquitous default "cold air intake" in our cars is active when the air temperature is whatever it is.

OTOH, excessive heat soak after engine shutdown can be controlled by a temperature sensitive relay that controls a fan motor attached to the grill.

Sherwood

[RWebb]

Originally Posted by chrismorse

Slight hijack, but similar interest.

Can you recommend an air pressure sensor??? I am curious about the hoped for increase in air pressure in the engine compartment, at various speeds, with the stock engine lid and a duck tail.

I have read a few posts indicating reduced engine temps with the Duck. It would be nice to quantify this at various speeds.

IIRC, i've read that a duck will reduce drag, lift and move the aerodynamic center of pressure rearward on the car.

https://www.sensorsone.com/high-speed-pressure-sensors/

[spuggy]

Originally Posted by 911pcars

As another data point, once upon a time, I inserted the end of a thermocouple wire from my Fluke DMM inside the intake airbox. The temperature at speed was basically ambient - same with the engine compartment temp. Thus, the ubiquitous default "cold air intake" in our cars is active when the air temperature is whatever it is.

OTOH, excessive heat soak after engine shutdown can be controlled by a temperature sensitive relay that controls a fan motor attached to the grill.

Sherwood

I have an IAT fitted in the intercooler outlet just before the throttle body, the readings are data logged.

At any speed/boost conditions, IAT doesn't exceed ambient by more than 5F or so. If I stop with the motor hot for a few minutes (say 10), intercooler heat-soaks 20-30 degrees C. Just driving along city streets for 3 minutes - heat soak gone.

Any freeway speed or moving == IAT reads ambient. As long as the wastegate isn't open. The MOTEC mounted in the engine bay monitors its own temperature; that's also ambient, or close to it (the vibration mounting stops it getting rid of heat, but it starts off agreeing exactly with the IAT and gets warmer).

Sit idling for 15 minutes, the MOTEC temperature alarm (200C) trips for the CHT reading. And the engine bay feels like putting your head in an oven if you check the oil level.

[911pcars]

Originally Posted by chrismorse

Slight hijack, but similar interest.

Can you recommend an air pressure sensor??? I am curious about the hoped for increase in air pressure in the engine compartment, at various speeds, with the stock engine lid and a duck tail.

I have read a few posts indicating reduced engine temps with the Duck. It would be nice to quantify this at various speeds.

IIRC, i've read that a duck will reduce drag, lift and move the aerodynamic center of pressure rearward on the car.

From some reason, the term, "pitot manometer" popped into the gray matter, whatever is left. I recall seeing a film of early aero engineers measuring body work airflow on a race car with a manometer mounted on the instrument panel and several flex tubes stretching over to all points. So I went to Google. Have fun:

https://www.google.com/search?q=early+vehicle+aerodynamics%2C+pitot+manom eter&tbm=isch&ved=2ahUKEwinp43-r4bvAhUJGzQIHWSPBB0Q2-cCegQIABAA&oq=early+vehicle+aerodynamics%2C+pitot+manometer&gs_lcp=CgNpbWcQA1C6PFi-amCFcmgAcAB4AIABW4gBrQySAQIyMpgBAKABAaoBC2d3cy13aX otaW1nwAEB&sclient=img&ei=nEs4YKfpOIm20PEP5J6S6AE&bih=1125&biw=1633

This is a rig that's a little more contemporary.

[chrismorse]

Thanks Rweb and 911pcars. Quite a range of instruments. I'll do a little more looking around. I used two 4 cyl motorcycle manometers taped to a board to sync 4 2 bbl Webbers after a rebuild - worked fairly well.
chris

[Tom Elder]

I would be interested to know what temperature the engine mounting crossbar gets to if anybody knows.
Thanks