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-   -   What size trans cooler do I need? (http://www.hotrodders.com/forum/what-size-trans-cooler-do-i-need-73493.html)

84Z 11-05-2005 06:31 PM

What size trans cooler do I need?
 
Have a 4500 stall converter with a th400 transmission. Has a trans brake and engine is pushing 597 flywheel hp with an additional 300 shot of nitrous at about 6500 rpm. Rear end ratio is 3.73. What size trans cooler / what gvw cooler do I need, thanks.

Brandon

xntrik 11-05-2005 11:34 PM

depends on how hot the trans is getting.... honest.

BIG and use a bypass thermostat is the best idea.

red65mustang 11-06-2005 07:29 AM

if "BIG" is a mounting problem or gona block to much radiator air flow....think about 2 smaller units hosed in series, maybe one on the rad and one down in the gravel pan

ha!....the trans cooler from hell!....us a A/C evaporator....now that is "BIG"!

Crosley 11-06-2005 07:52 AM

Quote:

Originally Posted by 84Z
Have a 4500 stall converter with a th400 transmission. Has a trans brake and engine is pushing 597 flywheel hp with an additional 300 shot of nitrous at about 6500 rpm. Rear end ratio is 3.73. What size trans cooler / what gvw cooler do I need, thanks.

Brandon

I am curious what the car will be used for.

A trans Brake valve body operates the trans at a high main line pressure. This heats the fluid up besides the heat from the high stall speed converter you have.

If the car is street driven much , a larger cooler will be needed. At the drag strip only, a smaller cooler could be used.

84Z 11-06-2005 10:47 AM

it's for a 84 camaro street/strip car, mostly street, any idea about what size gvw would be good, or should i just go for one of the biggest they have like 24,000 gvw? Is overcooling a problem or is it fine? Thanks, and sorry for the noob questions, never dealt with automatics before. Thanks.

xntrik 11-06-2005 04:18 PM

Quote:

Originally Posted by 84Z
it's for a 84 camaro street/strip car, mostly street, any idea about what size gvw would be good, or should i just go for one of the biggest they have like 24,000 gvw? Is overcooling a problem or is it fine? Thanks, and sorry for the noob questions, never dealt with automatics before. Thanks.

Just be sure to use a bypass thermostat... They are only about $ 20 and prevent the trans from getting too cool when operating and make it warm up quicker when it is cold.. you can use the radiator cooler if you want to. I like them for warm ups.

What's the big deal here.. Hasn't anybody ever heard of one before????
Has anybody ever seen a rusty trans dipstick from too cold of oil???

Crosley 11-06-2005 05:03 PM

Quote:

Originally Posted by xntrik
What's the big deal here.. Hasn't anybody ever heard of one before????
Has anybody ever seen a rusty trans dipstick from too cold of oil???



No , I have not.

With the 4500 rpm stall speed converter and a trans brake / full manual shift tranny he says the car has, I doubt the tranny running too cold will be a problem

xntrik 11-06-2005 05:11 PM

cooler thermostats at JEGs....

http://www.jegs.com/webapp/wcs/store...0535&langId=-1

red65mustang 11-07-2005 07:47 AM

you do need to know what is the temp now.... as xntrik asked in the first post to determine cooling needs

best advise I can give with no temp info: phone the tech lines at Hayden, B&M, etc. and ask what size they recommend....they may know from experience

xntrik 11-07-2005 11:02 PM

Quote:

Originally Posted by red65mustang
you do need to know what is the temp now.... as xntrik asked in the first post to determine cooling needs

best advise I can give with no temp info: phone the tech lines at Hayden, B&M, etc. and ask what size they recommend....they may know from experience

If you use a big cooler and the thermostat I suggested, the temperature is irrelavent.

xntrik 11-07-2005 11:47 PM

To answer a PM here:

Yes I have seen a rusty dip stick above the oil level because the oil was staying too cold and the condensation not being evaporated from the ATF. And it was Mobil 1 ATF. Sure the real cool oil is good for parts.... but the water is NOT.

The thermostat splices into both of the lines. When the oil is cold the output oil from the trans is routed directly back into the trans bypassing all cooler function until the thermostat opens the path to the cooler. That makes the transmission warm up faster and maintains a minimum operating temperature just like an engine radiator thermostat does.

Just like an engine coolant radiator, the size of the oil cooler and the airflow across it determines the maximum trans oil temperature.

Contrary to popular belief, the best place to put a transmission cooler is behind the radiator..... between the radiator and the mechanical fan. = Lots of airflow in all conditions and does not increase radiator coolant temperature.

check out site www.readershotrods.com drag cars/georges

red65mustang 11-08-2005 08:13 AM

xntrik, Ha! you got me,

weird....? B&M offers and recommends the same bypass thermostat for their oil coolers.....don't say anything about using it with their tranny coolers

(edited from $20)...$40-60 to know the oil is not "too thick" on a cold day......good plan

(xntrik, $20 if you fab your own ???....just messin')

xntrik 11-08-2005 11:11 PM

The Jegs add link I gave shows specifies them for transmission coolers at $ 40 plus fittings.... $ 60 so what? :welcome:
Hey, they work, used one for years.

Let's all help each other learn. :thumbup:

M&M CUSTOM 11-11-2005 03:20 AM

Until this thread- I have never seen or heard of a transmission suffering from being too cold either, and exactly how were you made aware your transmission fluid WAS indeed not warm enough to evaporate moisture out of itsself? This would be more of a problem in Canada, than Arkansas, and then limited to the cooler months of the winter.

All irrelevance aside the subject here is not enough cooling and what is a figure to go by for enough?

You cannot accurately go by the GVW rating put forth on most of the coolers sold by nearly everyone who sells aftermarket coolers.

A rough generalization is still only a guess, but if you intend on running street with that and want to keep a better eye on it a- transmission temperature gauge with the sensor mounted in the transmission pan would be the BEST starting point. Several threads here on Hotrodders have indicated the pan is THE BEST source of transmission fluid temperature for accuracy. Only after you know how much over the optimum 175(f) degree temperature you are, can you make the most effective purchase of cooler for YOUR particular needs.

red65mustang 11-11-2005 10:32 AM

M&M,

Typical cooler will lower the fluid temp anywhere from 80 to 140 deg in series with the radiator depending on the ambient temp/amount of air flow (vehicle speed)/gpm of fluid.....not hard to be "to cool" on a cold day

Agree a $50 guage is worth the money because ATF viscosity (thickness) is so sensitive to temp changes:
kenetic velocity@ 40*C (112F?)=36
kenetic velocity @ 100*C (212F)=7.5

(and now to prove I'm crazy)
Don't have a oil/tranny temp guage...use a turkey oven thermometer ($5?)...the trick was a hand full of plumbers putty and aluminum foil on the steel trans oil line to get a good "ballpark" reading....175*=beef well done!

xntrik, thanks, the bypass thermostat (on my xmas list) beats hell out of my 2 coolers in parallel in summer, 1 in the winter plumbing mess!


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