Auto Box On BPU

Hi All

I'm gathering the data I need for my BPU upgrade in the next couple of months and I've been told conflicting reports about whether an Auto Box Oil Cooler is needed, I know Auto Supes have one built into the main radiator at the bottom, is this sufficient to cool the box at normal BPU (ie no more than 450) HP. Most people agree the box wont take more than 550 HP anyway but I will be staying at no higher than 450 on this Supe so is it adequately cooled at that? Anyone out there with an Auto BPU that ever had a box overheat? Just want to make sure I cover the bases. Also some people say the radiator cap needs upgrading on BPU or it can blow, is that something anyones ever seen, I cant imagine that ever happening but just wondering?

BPU is generally a max of about 400, but in any case a cooler is one of the first mods I do on a modded auto car

So are you bypassing the existing cooler or running in tandem in some capacity? Are you running the whiff bitz cooler also? I guess I could run a normal rad and that but when I checked the capacity of a brand new rad with cooler built in seems to be on a par with the uprated ones?

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So are you bypassing the existing cooler or running in tandem in some capacity? Are you running the whiff bitz cooler also? I guess I could run a normal rad and that but when I checked the capacity of a brand new rad with cooler built in seems to be on a par with the uprated ones?

retain the stock cooler / heater , it does 2 jobs it helps get the trans fluid to operating temp, and if / when the temps get hi the stock auxiliary fan will kick in and help cool

So whats the suggestions then? Ive been running stock on my bpu. Should they be upgraded?

So are you bypassing the existing cooler or running in tandem in some capacity? Are you running the whiff bitz cooler also? I guess I could run a normal rad and that but when I checked the capacity of a brand new rad with cooler built in seems to be on a par with the uprated ones?

Run in tandem, gearbox to rad to cooler to gearbox

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So whats the suggestions then? Ive been running stock on my bpu. Should they be upgraded?

Like everything its opinions, Id say yes, do it. And it won't do any harm thats for sure

Sorry to jump in here. Building my car up and for now want to stick with the auto box. If I can push 400hp on aftermarket pump and exhaust only with standard engine if I am lucky. I would like to see photos as I seem very blonde at this moment in time of how to run it tandem. I know the Mercs have it running somehow through the radiator. Is it possible for me to just run it through an oil cooler? If so does the auto A340E trans found on an RZ TT model have any lines? I don't think I see any on mine or maybe the previous owner or whoever removed them as they were going manual but didn't take the box out.

Sorry once again for the thread jack.

Same as Mercedes, through the rad. As I said above I put it in the return line from the rad and back to the gearbox

It is not a cooler as such in the bottom of the radiator, it's a heat exchanger, it helps get the box fluid up to optimal working temperature from cold. If you are going to be running more than stock power through the autobox it would be wise to fit an additional cooler, the UK spec Supra has this additional cooler. I would also be tempted if fitting an additional cooler to have it running on a thermostat so it keeps the box fluid within the specific range it's designed to work optimally, therefore prolonging the life of your box.

Thanks for both advice there. Will definitely look into it when I tackle that section of the car.

I have an auto box cooler and an oil cooler Trying to stay on the safe side

I went BPU last summer and got the SRD gearbox cooler. I bypassed the original exchanger at the bottom of the rad (was planning to run tandem but Lee at SRD said they always bypass them) and have noticed no ill effects when cold. Gear changes are super smooth and as quick as when stock. I can recommend the SRD kit

If you run a big auxiliary cooler, or just a none stock, (bypassing or not having a all the in the rad heat exchanger) you should run a thermostat in the cooler line, too cold is as bad as too hot.