I tried the rear mounted cooler with fan and could not get enough airflow at low speeds. I was not willing to cut up the diffuser to gain the flow needed.

I mounted my 70273 horizontally below the radiator (base model) and until recently was a stand alone cooler. The problem was getting the temps up in the winter and keeping them from going too high in the summer. I currently route the fluid through the B&M unit and then through the OEM radiator cooler. That worked well last winter to keep the temps from being too low. With the 100+ degree days just starting for the next 5 months, I'm hoping there is enough total cooling to stay under 200. If not, I'll double up on coolers and run a 180 inline t-stat.

Below 140 the trans will shift erratically. Consistently above 200 will shorten the life. 175 should be the ideal for me. A 4000 stall makes it more difficult to accomplish.

 

hmmm..I was just checking my temps yesterday and they hovered ~204 in stop and go traffic with ambient ~83°. this is with a stock stall. I gather this would be the norm for stock so how many ppl are running an extra cooler with a stock vehicle.

 

Thanks. I've been looking at the DeWitts, but I think I will hold off a bit in case I decide to go with an ECS kit and, if I decide to go that route, then I'll probably buy the shortened version.
In the meanwhile, I want to do a converter (still trying to decide which one) but I know that will result in increased transmission temps.
What mods do you have done to your car? I'm assuming that you're running a stock converter? Have you had the transmission tuned?
I've always wondered how the A6 would fare on a road course, and it certainly sounds like you've proven that the A6 can survive in that environment.
I'm a believer in this transmissions too, because I've beat the hell out of the one in my truck for the last 5+ years and it's still going strong. The only thing that trans hasn't seen is high temps though - it's never been over 200* , since the truck has a big-*** radiator and and external cooler. I think that with the right tune and temps these transmissions can take a lot, and shift like the PDK in the Porsche to boot.

 

Thanks HOXXOH. I was thinking last night about laying one of the fan cooler modules flat in front off the radiator and pulling air up from the ground through the cooler into the cavity in front of the radiator. Is that how you have yours mounted? That sounds like it could work well, but I would have to see what and how I would need to cut the bodywork under the nose to get enough air through there. I can only imagine that might work like a vacuum cleaner and suck every bit of dust and dirt into the cooler though.
Then I started to think that maybe I'm over-thinking this (as I tend to do) and maybe I should just get a regular flat cooler and mount it in front of the radiator and see how that works.
I agree on 175 being a good temp to aim for.
How does that 4000 feel on the road? What brand is it, BTW?
Thanks again.

 

That's about the same as what I'm seeing at about the same ambient temperatures.
I can also tell you that even with a stock thermostat, you can get the temps down significantly by increasing the fan power. I've used my Intune to turn the fan power up to 99.99% for anything above 190 degrees and have seen about a 10 degree drop in oil and coolant temps. It now sounds kinda like a goddamn Cessna, but it cools much better. I'm sure it's going to fry the fan connector at some stage, but I'll deal with that when it does.

 

Mine is mounted that way, but since it's a base, I didn't need to cut anything. The opening is already there. The base frontal opening is smaller than the GS, so the air dam forces some air up in front of the radiator to compensate for less airflow.
There's not any more dust/dirt than without the cooler. The little bit there is either gets stuck on the cooler or the radiator, take your choice.
The 4000 Yank is a bit much for normal in-town use. The 3600 was more acceptable and the 3200 (yes, I've had all 3) was smoother than stock. At highway speeds (over 40) the converter locks up just like stock. My in-town mileage is now in the 18mpg range, while 70-75mph remains at 28.


The fan connector and fan motor seems to survive at 90%, but die quickly at 100%.

If I could keep my coolant 180-185, the trans 10 less, the oil 20 more, and the IAT no more than 5 above ambiant under all normal driving in any weather, I'd be a real happy guy.

 

Thanks. Was there much of a difference in performance between the 3600 and the 4000? We're these all Yank converters? I have some experience with a couple of H/C C5s with nitrous, one that had a 4000 Yank and the other a 4400 (I think) Vigilante. The one with the Vig hit hard and could knock down 6.4 1/8 ETs and a 1.4x 60' at will with Hoosier slicks.
The one with the Yank seemed tamer although it just didn't have the same power, so it was hard to tell. What I like with the Vig is that you can get it with the multi disc TCC whereas, according to Yanks website, they only offer a single disc?

I agree on the temps. I think ~ 210*F for engine oil, ~ 180* for coolant, and ~ 170 for transmission fluid would probably be about perfect. The one thing that I'm happy with is my IATs which are consistently at or only 1 degree over outside air @ WOT, and no more than 3-4 at cruise. This is with the Halltech MF103 with the beehive.

I'm going to tweak my fan to 90%, which may also make it sound less like I'm taking off in a small prop plane. Thanks for the advice.

 

For what it is worth I have fought the overheating battle and purchased all the parts. The Dewitt's radiator and dual fans do not help much.

Here is what I learned and I have zero cooling issues at all even in stop-n-go traffic.

100% distilled water, 1 gal of coolant, 1 bottle of water wetter.

Had my headers coated at Polydyne and it helped a great deal.

Do not use your radiator for your Trans cooler! Install a B&M fan cooler in the front fender.

On the other fender install a second B&M cooler for you oil!

The last thing that made a world of difference was installing hood vents. This was not very expensive, it looked good, and it works great for removing under hood heat. I used 2014 Mustang GT hood vents and put them in my factory hood.

 

Thanks. This is all good info. It sounds like the problem is underhood heat building up? When you say that the vents (and header coating) made a difference, how much did that help to drop oil and coolant temps?
Ive also used water wetter and distilled water with good results.

 

I just got back a little while ago from testing my car in 93 degree heat. Here's what I observed:
Just cruising around, coolant temps tend to stay about 20 degrees above trans temp I saw ~196* coolant temps and ~174* trans temps. Engine oil was around 205*. Once I started to drive it more aggressively, the temps climbed up - coolant temps went up around ~205* and trans temps came up to ~204*. At this point, engine oil temp went up to ~225*. I then started cruising around again and the coolant temp came down to 197* and guess what, the trans temp stayed right at 199*. I cruised around at about 50mph for about another 20 mins and that's where the trans temp stayed - 199*. Therein lies the problem, once the trans heats up a bit, the trans fluid simply cannot be cooled down below the temp of coolant in the radiator. Worse yet, once you pressure the transmission a bit it looks like it will heat up well beyond the temp of the coolant and the stock in-radiator cooler can't bring the temps back down to where they need to be.
So, if we agree that it's better to keep trans temps well below coolant temps, it's pretty clear that it makes sense to do a stand alone cooler for the transmission.

 

just got back from a 250 mile round trip and my trans temps hovered ~205 while cruising. this was with 84* ambient temps and the ac on the entire trip. I'm running a 160* stat but my fan temps haven't been tweaked yet due to I'm still tuning. I'm thinking of installing the b&m 70255.

 

^^^^ Now add over 200 extra HP to the above scenario and you'll see why it was imperative that I add the trans cooler. The car was almost not drivable because the trans would flare between 3 - 4 - 5 shifts once the fluid temps climbed above 190 or there about. And as you noticed it will NOT drop below coolant temp (which is usually in the 200 range)
It's pretty much a no brainier - on the need for a trans cooler to this car.

 

I installed a trans cooler on the front of the AC condenser and as close to the center of the grill opening as possible and ran it in series with the stock radiator trans cooler. Trans fluid goes to the radiator first to start the cooling process than to the external cooler for further cooling before returning to the trans. In cold weather the radiator will help the trans fluid warming process. Mounting on the condenser will give full air flow with or without the coolant fan running.

I would use a high capacity plate style cooler (they are the best in my book) but not to large. In the vette this time around I did not use the plate style but should have.

The trans temp once it gets hot i.e. "close" to the coolant temp (180/200) racing; it will cool down again below coolant temp (approx. 30 degrees) once you start cruising again. If I put a high stall converter in I would change my small tube type to a larger plate style cooler. Yes I have read that the fan connector will burn up if run above 90% that is why the factory setting does not go higher. I have a 160 degree stat and my car will usually cruise around 178/180 degrees coolant temp on a normal day so the fan does not kick on at cruise most of the time. Since installing this trans cooler I have rarely seen the temps go over 180 even at the track.

Setting coolant temps with intune on C6.

I have read that if you go higher than 25% fan on the very first "temp step" then the fan will run all the time once it kicks on till you turn the car off and also do not jump more than 25% per step; something to do with what is called "inrush". I have mine set= 25% first possible step, 50% second step, 75% third then 90% there out. I think that there is a step or two that will set at 89.99%.

If you look close you will see the trans cooler mounted near the center of the grill opening on the ac condenser.





PS: You can mount the trans cooler where I did if not doing a supercharger set-up and/or move it when you do a sc. I would most likely mount it off to the side as shown in this thread with a supercharger; but I would still run it in series with the factory cooler. More volume is always better. My $0.02

 

This is all good info GSM. It sounds like your setup works well. Now I really have a lot to think about. I spent over an hour last night on Summitracing online trying to figure out which cooler to buy! I think the bigger the better. I see that they have an 11"x13" B&M plate type "supercooler" and Im now thinking that is what I will go with, as I've used that type of cooler before on other cars with good results.
BTW: what kind of hardware did you use to connect the cooler to the radiator? I know GM now uses those snap-in connectors for the TOC, so I'm wondering if there is an adaptor available so I can route the oil from the radiator to the external cooler? Or, did you just cut the hard line and splice the hose into that?
That's a pretty awesome shot, BTW.

 

Your using the "right" cooler in my book. I first bought a B&M "Supercooler" #70274; the actual core size is 11" by 11" but one end is approx. 13" long adding in for the two mounting flanges. This one was to large IMO to mount on the AC condenser, it filled the whole front end . I should of taken some measurements before ordering from Summit so I put the B&M on the shelf for a future use. I than ordered a much cheaper tube style from Summit which I installed. Take your own measurements and maybe buy a little smaller top shelf "Supercooler".

I really try not to over engineer stuff, keep things light and simple. I used braided stainless steel flex hose which will not pop even years down the road from my experience and I cut the OEM return line than "double clamped" 180 degrees apart on the rotation of the clamp screws all the hose ends with fuel injection high pressure screw clamps. I remember making a 180 degree bend in the hard line coming out of the radiator somehow without distorting it to get the flex hose going in the right direction which you don't really need to do. When I made the tubing cut with a tubing cutter no trans fluid came out so I filled the hoses and cooler with trans fluid before making the final connections up near the top of the radiator. Hope I hit everything, if not let me know. I also drilled two holes in the side of the plastic baffle at the right places large enough for the braided hose to pass through. You would have to see it but overall a very neat compact job, most people who look under the hood have to have it pointed out to them.

 

Below is my trans cooler install thread w/pics & Summit SS hose/cooler numbers. Check it out, it's not that long with more in-dept "information".

http://forums.corvetteforum.com/c6-t...r-install.html

 

After reading your post, I'm having trouble with the idea the transmission would cool below coolant temp once the transmission was at temperature. This is an impossible expectation without an external cooler. If you drive the car hard enough to heat the transmission well above the coolant temp, the radiator coolant can and will bring the temp down, though it may not be quick enough for you (it isn't for me either plus I don't like the transmission temps getting to the point where the car goes into limp mode). Here is another thought, with an additional 200hp, figure out the btu's produced by those extra ponies and how much more of a cooling load is placed on the system. This is where a DeWitts or Ron Davis aftermarket radiator makes a lot of sense.

I like the idea of placing the cooler in the front, ahead of the radiator. I too have been thinking about that area and installing both external EOC/TOC's there, side by side.

 

Thanks GSM, that link is helpful. I do need to get under the car and measure the space(s) available and then decide whether to mount the cooler in front of the A/C condenser or do an fan module type setup off to the side.

MikeCsix, I think you hit the nail on the head. There is simply no way that you can expect the factory fluid to fluid heat exchanger in the radiator to do anything other than try to equalise the transmission temps with coolant temps.
In my view, since the consensus seems to be that trans fluid temps need to be lower than the coolant temps, the ideal thing would be to have a stand alone, thermostatically controlled cooling system for the transmission since common sense dictates that the ATF temperature control is just as important as coolant temp control. I can't see how this could be such a difficult thing for the factory to have done, and the simple truth is that this would probably have paid for itself in mitigating transmission related warranty claims.
That way, the transmission fluid would warm up to the temp it needs to be at and basically stay at or around that temperature no matter how hard you drive it.
I just wish that one of the aftermarket companies would make a plug and play fan cooler module kit that fits our cars, with all of the necessary hardware included, rather than an assortment of outdated universal NPT and compression fittings and screw clamps that I see in most of the universal kits.

 

The reason no one makes a P&P for our cars, is that our cars that need it are not all the same. GS, base, with/without oil coolers, FI intercoolers, and CAI, all create different problems to be solved.

As I stated before, if my present setup fails to keep the trans cool in the Phoenix summer, I'll double up and use a 180 t-stat.

 

I haven't tried with the trans cooler running through the rad also, but I can tell you that having it separately works. I suppose if you drive the car in winter, having the rad heating the trans oil quicker might be a benefit. Logic tells me that the engine coolant might run hotter, and keeping a blown high HP engine cool is a whole other issue. I am also not a fan of blocking air flow to the radiator if its not necessary.