Hello and welcome! :beer:

The stock automatic transmissions in a MK3 turbo are indeed pretty well made, and will usually support 350-400whp without any issues at all. Above 400whp, I would definitely recommend an upgraded transmission cooler. They will usually fail around 450whp if not upgraded/built.
As these cars have gotten older, and have been abused by previous owners, sometimes there is latent damage or wear inside a transmission (or engine) that can't be detected, but will cause an earlier failure at a lower HP level.

How much HP are you planning to make with your rebuilt engine? Are you planning on drag racing, etc?

 

Hello and thank you for your quick reply Wreckless.
I am not sure how much i want to do with the engine yet. Right now i got a 3inch dp and intercooler, would you recommend me replace to a better transmission oil cooler now when i got the front bumper off?
I have been thinking of 550injectors, lexus afm, upgraded ct26, wideband and of course getting it tuned by proffessionals on dyno.
And no no no, no drag race and such abuse.. And its not gonna be a daily driven car at all, maybe a few times a month.
But im not sure how much hp i will get by these upgrades i listed above i was thinking about, i would like to have 350whp that is my goal..

 

Just found this video on youtube, unbeliveable i havent seen this yet.
http://www.youtube.com/watch?v=Z9OVp6dVwM4

He made 340whp with 550 and upgraded ct26.. So the upgrade i listed above with the items i already got installed will make around 350whp does that sound realistic? And the transmission will hold?

 

I would still install a cooler even now the biggest one you can fit. Also shimming the accumulator wouldnt hurt.
Im running a 1JZ Soarer auto on my 7M supra with shimmed accumulators and a 11x11 cooler. I do recommend changing the filter out, and flushing the trans fluid. Im running Toyota T-IV

 

Filter is changed with brand new oil.
Not sure what you mean by accumulator?

 

Here's a great link that offers a good walkthrough on shimming the auto trans accumulator, as well as a lot of other tips & tricks to keep it alive under higher HP.

http://www.supraforums.com/forum/showthread.php?267655-How-to-make-a-a340-last(56kers-take-a-nap)

JSPEC's recommendation to stick to Toyota Type-IV auto trans oil is absolutely good advice. Also, there's no time that's 'too early' to add a large transmission cooler, as that is always an improvement regardless of your HP level - it's just not truly necessary if you had a more stock engine build in mind.
With 550cc injectors, Lexus AFM, upgraded fuel pump, and a 57trim CT26, I'd simply acquire an SAFC and wideband O2 and tune it yourself. That is well within the limits of what can get good results on an SAFC setup, and SAFC's are easy easy easy to tune yourself especially if you have a wideband O2 sensor. But if you've got a local professional that does good work for a good price, there's no harm in letting a pro deal with it, either.

If your 3in downpipe doesn't replace the turbo 'elbow' that bolts to the back of the CT26, I'd definitely recommend having that elbow ported ,or better yet, replace your existing elbow or downpipe with a DDP such as the BIC unit, which permits much better wastegate flow and vastly reduces turbulence in the exhaust leaving the turbine housing. On my old 62-1 CT26 (not a recommended upgrade - they don't last!!) I gained close to 15whp and 20tq by going from the HKS DP and stock elbow to a DDP with an external wastegate dump. If I were to do it again, I'd get the same DDP, but a recirculated model.

With all of those parts installed and a upgraded 57 trim CT, 340whp is very much within reach and even 350whp isn't unheard of. To that end, though, you might consider one of the bolt-on PTE turbos that Sound Performance offers for the 7M-GTE that's a 100% bolt replacement for a CT26, which would yield even better power with all the same hard parts & fuel upgrades described above.
If you take the time to reinforce the auto trans as well, all of those parts will easily support 400+whp. It's a Supra, after all, and 400whp is about where it really starts getting fun

 

Thank you so much for your reply Wreckless, good to hear rhose simply mods can support that kind of power. I will also need another elbow then, i just got the stock right now.
Maybe you could link me that one you bought once?
The transmission oil can be bought at any toyota dealer?
Ill just let the pro taking care of the tune.
Those items listed above with my intercooler and dp with new elbow etc will be a good reliable build if i shim the transmission and larger cooler?
I want a fast and reliable car not some junk which could blow up anytime.

 

My downpipe & elbow elimination was an ugly one-off part that did the same job as a DDP, but wasn't as pretty.

There seems to be two options available that I can find - first, the Titan Motorsports downpipe for the MK3, which uses a 'bellmouth' style inlet from the turbo and eliminates the elbow restriction as a result.
http://www.titanmotorsports.com/defdowwturel.html

The second, and the one that looks more like what I had, is the BIC performance DDP, available from BIC's product page:
http://www.bicperformance.com/products.htm

I would definitely add the $52 option for the DDP recirculation, as the open wastegate noise will attract a lot of attention, and I've heard from other Supra owners in Denmark over the years that aftermarket modifications are illegal, so that kind of attention would be bad, I'm assuming. The second part is that the BIC pipes are built to order and I'm not sure if BIC ships parts to Europe, so I'd send an Email first before buying it.
Since Titan Motorsports ships all over the world on a daily basis, and they usually stock their own parts, the Titan would likely arrive much sooner with much fewer headaches shipping it to Europe.

I suspect the DDP might edge out the Titan DP in overall performance, but I also believe that you'd need to be running a MUCH larger turbo in that tiny CT26 exhaust housing to ever notice a significant difference.

Yes, the Toyota Type-IV ATF should be available at any Toyota dealership.
Yes, so long as the rest of the car is in good shape and the maintenance has been addressed, and your local pump fuel can support that much boost safely, yes, that should be a reliable setup. If you decide to get one of the Sound Performance bolt-on PTE turbos for the 7M, I'd suggest the addition of an adjustable fuel pressure regulator, as that will help extend the capabilities of that fuel system once you've got a high pressure pump in place.

With the shimmed accumulators, fresh Type-IV trans oil, and a large trans cooler setup, yes I do believe that would perform reliably at the HP you'll be making So long as there isn't anything wrong already with the transmission, or the transmission isn't excessively worn. These cars are getting old, after all.

Hope that answers all of your questions! :beer:

 

I work at Toyota as a mechanic so gonna be easy getting the oil.
Performance isnt exactly illegal in Denmark, you will need to get confirmed that brakes and whatever there is are capable to handle those kind of powers, if they say good for it and you got some papers on it it isnt illegal.
Unneseccary sound performance is illegal, but they dont really do anything about it here where i live, so i think ill go for the bic ddp
Ill get an upgraded fuel pump aswell
Ill go do what you said with the transmission, its fully functional and shift perfect.
Had the bottom of the transmission and noticed the magnets wasnt dirty or had any signs of metal sticked to it, im not that much into automatic transmissions yet but will come.