my scientific tranny temp study

[Landshark]

ok, so i removed my belly pan today and replaced the insulation (aluminum-backed foam tape) around my temp sender. tranny cooler is TCI brand. the temp sender is incorporated into a Permacool external filter, which is mounted to the panel below the battery. the gauge used is a Nordskog digital. outside temps used were taken from the outside temp display on the climate control head. air conditioning on both days. i was keeping notes on the tranny temps driving to work yesterday and today (3:30PM, heavy stop-n-go traffic, several hills). here's the results:

YESTERDAY - undertray on, no insultion on temp sender
outside temp: 83degF
max tranny temp: 212degF average cruising temp: 195-ish

TODAY - undertray removed, insulated temp sender
outside temp: 82degF
max tranny temp: 189degF average cruising temp: 175-ish

TONIGHT - " " (return home - same route, less traffic, no AC)
outside temp: 64degF
max tranny temp: 177degF average cruising temp: 170-ish

the temp gets scrubbed off much quicker without the undertray as well. cools down noticeably quicker on a flat or downhill stretch of road. now i'm off to conduct a study on the reaction of beer and nachos in my stomach.


Alan (Mr. Science)

[mbtoloczko]

I've seen similar temp drops with the belly pan removed. It seems like its a good idea to remove it in the summer months. I wonder how it allows more effective cooling.

[deruvian]

I'd remove the belly pan, but I'm sort of paranoid about something flying up and denting or breaking my oil pan, or causing a coolant line to pop off. I do live in an area where driving in gravel is somewhat of a common occurence.

[nubs]

Originally posted by deruvian
I'd remove the belly pan, but I'm sort of paranoid about something flying up and denting or breaking my oil pan, or causing a coolant line to pop off. I do live in an area where driving in gravel is somewhat of a common occurrence.

There are not many cars on the road, past or present, that have any type of under engine protection like our cars. I am sure you will not have any of the above mentioned problems.
Unless you are planning to do some serious off roading.:)
I keep mine off all summer and have not had any problems.

[oab_au]

Alan how about doing another test, to compare the temps that occure using Drive for one, and another run using 3rd, to see if there is a difference in temps.

Same conditions. just 4th vers 3rd.

Harvey.;)

[Snickers]

When you say belly pan do you mean the partial shroud that starts under the radiator? Are you friggin' kiddin' me? This simple 'mod' can lower the tranny temp by 20 degrees? If so, this should be the #1 mod of all time. Are there any drawbacks?

[Chiketkd]

I also would like to know where the belly pan is exactly...

[immortal_suby]

The belly pan is the big plastic thing under the front of the car.

[Green1995SVX]

I removed my belly pan back when I had the auto, and it lowered tranny temps by about 20 degrees. It did, though, significantly increase the amount of road 'dust' that got into the engine bay. I found myself having to dust the engine bay and re-apply protectant to all of the black stuff once a week to keep it looking nice under there.

Mike

[SVXer95]

My belly pan "fell off" about 6 months ago. I use quotes because it was really taken off by breaking the bolts by a dealership, but I didn't notice for a little while. When I asked them about it they said it must have fell off.

Anyway, back to the topic at hand, I have driven the car like this for some time. It has even been in snows over 1 foot with no problem. I don't plan on replacing it anytime soon.

[ensteele]

Alan (Mr. Science)

I was wondering what the effect would be in insulating the temp sender. If that is giving you a different reading than if it was not put on. That is something to consider. If it was on at the start of the experiment, it would show what happened when everything is the same. :) Maybe take the tape off (insulation) and see what happens. Does it increase the temp reading, or stay the same. :)

[Landshark]

Originally posted by oab_au
Alan how about doing another test, to compare the temps that occure using Drive for one, and another run using 3rd, to see if there is a difference in temps.

Same conditions. just 4th vers 3rd.

Harvey.;)

that's a good idea, Harvey - i was thinking about doing that, too. i forgot to mention i also have the smallcar shiftkit installed, and its at the default setting. probably not a big effect on temps, but a little i'm sure.

[Landshark]

Originally posted by ensteele
Alan (Mr. Science)

I was wondering what the effect would be in insulating the temp sender. If that is giving you a different reading than if it was not put on. That is something to consider. If it was on at the start of the experiment, it would show what happened when everything is the same. :) Maybe take the tape off (insulation) and see what happens. Does it increase the temp reading, or stay the same. :)

i wish i had time to test all these different factors - i'll try to do it if i get a chance. the bellypan definitely affects cooldown time when the fluid does get hot. with the bellypan on, it never seems to drop - only increase. it will cool off quicker with no bellypan.

the bottom line is, no bellypan (and an insulated sender, if you have a gauge) will result in lower temps and more accurate readings on your gauge. :)

[ensteele]

Why would the insulated sender give you lower temps? Or would it just give you a reading that is more true than without?

[Landshark]

Originally posted by ensteele
Why would the insulated sender give you lower temps? Or would it just give you a reading that is more true than without?

it wouldn't actually lower the temp, but it would give you a more accurate reading without all the ambient heat from the engine affecting it. our boxers kick out the heat! :)

[ensteele]

That was my thought too, so if you removed the tape, then see what the temps are, maybe there is more to the insulated tape than is thought. :)

[svx_commuter]

Originally posted by mbtoloczko
I've seen similar temp drops with the belly pan removed. It seems like its a good idea to remove it in the summer months. I wonder how it allows more effective cooling.

I think I know why. :) It controls the air flow area around the engine. Take a look at the space between the top of the pan and the bottom of the engine. There is not that much space there. Take a look at the space between the valve covers and the frame. Not much space there either.

There is another reason too, all the heat from the radiator gets channeled over the engine and then get to leave the engine compartment. This air gets hot from the engine and blows back onto the tranny. I think the tranny warms up some from teh hot engine air.

Take off the "under cover" and what happens? The air through the radiator goes up, the tranny cooler gets more cool air and less hot air makes it to the tranny.

As Mike said dust is a problem. How about water? Riding in the rain and through puddles must run some tire splash into the engine bottom also.

How about trying an air dam at the back of the under cover? This should create a pressure drop that will pull more air through the coolers up front.