transmssion cooler theory question

im looking into getting a tranny cooler for my iroc.
i just had the trans completely built from the ground (case) up and discovered afterwords that there is no transmission cooler built into the radiator.
soooooo.
im getting a transmission cooler.

heres the big question.

given a certain size cooler, one with 6 rows and one with 8, is one nessicarily better?
the items in question are flex-a-lite transmission coolers.
both measure 10" x 20" and have 3/8 tubing.
one has 8 rows and one has 6.

my thinking is that the one with more rows is better because the fluid spreads out more and is more effectively cooled.

the only caveat to this argument is that the more spread out the fluid gets, the higher the pressure drop in the system.


another question i cannot resolve, is where to mount the cooler.
normal practice says to mount the cooler in front of the radiator with little or no space between.

however, in this scenario, the cooler will take up a good portion of the radiators surface area, and might cause the engine to run hot.

my solution is to mount the tranny cooler about 3-5 inches away from the radiator so as to allow air to pass between.

heres the logic:
when at idle, the transmission is doing exactly ZERO work and is not generating much heat. the engine however is MOST prone to overheating at idle. whereas at speed, the tranny is generating heat, and the engine has plenty of air running past the radiator to keep it cool.

if there is space between the radiator and the tranny cooler, then at idle, the fan behind the radiator can suck air into the radiator without the added obstruction of the tranny cooler.

at highway (or higher) speeds, the airflow is great enough that the fan isnt really doing anything anyway, and the heated air from the tranny cooler has some room to mingle with cooler air before it moves on to the radiator.



basically, i am looking for someone who has done this before or who has a clue about what i am talking about to either say "good job, you are right" or "fukcing moron... NEVER DO IT THAT WAY"

thanks guys





p.s.
a little background info
i bought the car from the 2nd owner, who put a 350 into it in place of a 305. the radiator is not stock, the engine is not stock, and puts out about 375-380 hp to the ground

Good questions.

Go with the biggest cooler (most rows) you can, especially since you do not have an in-rad cooler. Smaller coolers only exist to sell at a cheaper price and/or to fit in tight spaces.

Pressure drop due to a longer line does not seem to matter. When I installed an Olds 455 in my '81 Cadillac, I eliminated the air conditioning. However, I left the AC condensor in place (in front of the rad.) I hooked the trans cooler lines up to it, just because it was easier to do than installing a real trans cooler. It has enough tubing to make about 10 transmission coolers, keeps the fluid super cool and has not caused a problem.

The cooler will not block rad airflow enough to make any difference. The factory AC condensor blocks airflow much more than a cooler would, but is just fine in practice. Air does not need to whip through the rad at 60 mph to provide sufficient cooling, Just a few MPH of airflow is enough for a car which is not pulling a trailer.

Most coolers are placed directly on the rad to take advantage of fan airflow and to make installation quick and easy. I have installed coolers both a few inches away from the rad and directly on the rad. IMO so long as the cooler is getting decent airflow, I do not think it matters much, but I prefer mounting away from the rad for max airflow when driving.

what would need to be done with an AC condenser to make it transmission cooler ready?
i have an extra ac condenser from a car with non-working ac...
this might work...

well the space is perfect.
the camaro had its ac removed too, so i have a big wide open space there.
sweet.
im thinking that it will have to be throughly cleaned out though.

ive decided to give it a go.
im going to pour about 2 quarts of fluid through it to clean it out, then fill it and see what happens.
i need a guage as well, but dont know how to wire it in.

Just a flush with fluid should be okay.

Are you looking to wire in a temp gauge? I had good luck installing the temp sender for an electric gauge in the transmission pressure test ports. Fortunately, the threads were the same in the application I had. Just remove the plug and thread in the sender. Do not use any sealer to ensure a good electrical ground.

Do not use any sealer to ensure a good electrical ground.

Something like an aluminium sump plug washer would work too.

my only issue with a temp guage is where to put it.
i dont like the look of guages hanging off all over the place, and i dont have any room in my instrument panel left...

my only issue with a temp guage is where to put it.
i dont like the look of guages hanging off all over the place, and i dont have any room in my instrument panel left...
If you use the AC condensor as a cooler, you will never overheat the transmission, (unless you decide to tow your house up Pike's Peak. )

Therefore, the temp gauge is not really necessary. You could install it in the glove box so you can check it when you are curious. However, IMO you will probably find the gauge stays nice and low all the time, so you do not need to look at it much.

well the ac condenser was about 1/16 of an inch too big (either that or it was the stupid nascar radiator the previous owner put in)

now i am trying to decide between
http://www.hawksthirdgenparts.com/index.asp?PageAction=VIEWPROD&ProdID=2077
and
http://store.summitracing.com/partdetail.asp?autofilter=1&part=FLX%2D4126%2D6&N=700+4294924500+4294839034+4294888847+4294906626+ 4294792802+4294782859+115&autoview=sku


the first one is a radiator with twin electric fans and a shroud.
it would allow me to use the ac condenser, and would help keep the engine nice and cool but is pretty expensive
at least it would be doing it right...

the other option is to use the wrong radiator and "fix" it with a tranny cooler.
the epitome of... well, you know.

I recommend against the AC condenser idea anyway. Its fine and would probably be OK, but I'll explain. Tranny coolers use big lines to promote high flow. The cooler circuit doesn't see high pressures; usually 30-40 psi, but it is part of the supply for the transmission. Restricting it with the small (and undulating) tubes of an AC condenser might not be wise. So for that reason, I use coolers with either 3/8 or 1/2" tubes, and in your case since the two you originally had listed were the same size, the 8-row would theoretically increase the surface area 33%.

It doesn't really matter if its in front of the radiator or off to the side. In a light-ish car like that, even a small tranny cooler is more effective than the heat exchanger in the radiator. As far as overheating the engine, I also wouldn't worry about it. If you had the factory radiator running a tranny heat exchanger, the heat will make it to the engine anyway. Giving your tranny heat to the air in front of the radiator will not effectively transfer as much heat into the coolant as using a factory exchanger.

I say use the 8-row cooler in front of the radiator so its borrowing airflow from the engine fan. Drive it hard, and have fun. Just for the sake of comparison, My car came from the factory with a PS fluid cooler, a heat exchanger in the radiator AND a separate tranny cooler, plus an engine oil cooler, ALL in front of the radiator along with the AC condenser. Never had a failure in 120k.

If you don't want to muck up your dash with wires and gauges, just use a simple dummy light. Find a switch like would be used on a factory coolant dummy light, or an oil temp light. They are designed to ground when they reach a preset temp, so you could just plumb a 12v wire into a little LED on the dash, then out to the sender. My guess is that you'll never ever see that light come on and you'll start doubting if its working.

All of the things you've suggested so far are glorious overkill :)

All of the things you've suggested so far are glorious overkill
well i guess that comes from being an engineer
;-)

my concern of overheating was not due to adding the extra coolers btw.
i am mostly worried about the fact that there is no fan shroud.

also, there is no cooler built into the radiator.
it is a manual transmission cooler put into an automatic.

besides...
whats wrong with overkill?
nothing quite like hunting with a tommy gun as it were.

however, as long as you agree that a simple add on tranny cooler will suffice, then i will go that route.
i still plan on the dual fan setup for the future. ill say its global warming protection.