Under hood temps

[landtank]

I thought that I'd start another thread documenting the under hood temps that I have. This is going to have to be very simple and just a jump off point for determining a need for hood ventilation. I have aradio Shack digital thermometer that records both max and min temps and max and min humidity %. So as I stated very low tech data retreival here.

Attached is a pick of how I placed the thermometer in the engine compartment. I was looking for a place high in the bay but not too terribly influenced my direct engine heat. If there is a better place that is as convienent as this let me know and I'll start placing it there.

I drive the truck for about 20 minutes which included some higway time, I then parked the truck in the sun and let it idle for 10 minutes with the thermometer in place before taking the readings.

FYI. I'm running a modified blue clutch with 5K oil in it so at idle the fan engagement is more than a stock unit.

Today's data:

outside readings in the shade: 90%F and 78% humididty

undr hood readings: 144*F and 12% humididty

 

[SUMOTOY]

Rick:
The other side of the motor is my reference.


95degrees high humidity
hood closed
idle, fully heat soaked
A/C on
Aux Fan - on

Passenger Side temps (PSt)
Temp at front of airbox 200f
Temp at rear of firewall 164f
---------------------------------------
Aux Fan off
PSt

Temp at front of airbox 185f
Temp at rear of firewall 165f

Raytek IR temp gun within a couple seconds of hood lift.

Scott Justusson

 

[landtank]

No easy way for me to place the gadget and with the extra air flow on that side it will be lower in temps.

My AC is down so all readings will be with the AC out of the picture.

 

[fzj80kidpen]

It will interesting to compare the drivers side where you have it in the pic with the passenger side (same approx location) directly above the exhaust.

 

[SUMOTOY]

No easy way for me to place the gadget and with the extra air flow on that side it will be lower in temps.

My AC is down so all readings will be with the AC out of the picture.

Try it without A/C. What extra airflow? If it's hotter from more heat exchange, it won't be cooler over there... Remember you have hot exhaust, radiator heat, oil cooler heat, and not much room. I suspect the temps will be higher regardless. Not sure what that thing is you are using, but velcro or big rubber bands can keep it planted.

The easiest way to get air just plain 'out' would be on the Drivers side. My concern with that is that airbox heat. I'd want to get the airflow out the PS with extreme prejudice.

SJ

 

[cruiserdan]

I have measured RH side temps, behind the headlamp, at over 190.

 

[landtank]

What extra airflow?

The air has an easier exit on the exhaust side, the DS has an extra inner wheel flap and all that other crap restricting the air flow.

I'll look again and try a comparison tomorrow. It's supposed to break 105*.

 

[SUMOTOY]

The air has an easier exit on the exhaust side, the DS has an extra inner wheel flap and all that other crap restricting the air flow.

I'll look again and try a comparison tomorrow. It's supposed to break 105*.

It might be an easier exit down low, but up high it's trapped. The DS really has no heat generation or obstruction, so a 144 temp is about what I'd expect, 50 degrees above ambient. The PS approaches 100 degrees + over ambient and has the air intake over there with the exhaust. Dumb design putting the airbox so close to the exhaust. Big time density ratio problem.

My back yard hit 104 today in Chicago. I won't measure temps today, I'm not sure I want to know.

SJ

 

[landtank]

OK here is today's readings

Ambient temp in shade = 93*

DS temp = 154*

PS temp = 151*

I placed the thermometer right next to the wiper motor on the PS and on top of the booster as before on the DS.

 

[SUMOTOY]

OK here is today's readings

Ambient temp in shade = 93*

DS temp = 154*

PS temp = 151*

I placed the thermometer right next to the wiper motor on the PS and on top of the booster as before on the DS.

Idle? A/C on?

Airbox temps possible with that thing? Interesting a 3 degree increase yielded 10degree delta. Those temps indicate to me that vent efficiencies should be pretty darn good. Now we need to figure out if aux fans create more heat, in which case it's a, er, forced convection problem.

Scott J

 

[landtank]

No AC it's broke. Yes at idle same as before.

I would still like to know the acceptable limit of under hood temps. I'm not one to start designing and hacking holes for the sake of an improvement. If these temps aren't an issue then they can stay that way.