rob3379

I'm seriously considering the GTE swap into my auto 98' SC300. What I need to know is if I can use existing auto trans once GTE is in car. I was planning to build up my existing auto tranny for the abuse but I don't know if it will work electronically. With the swap do I have to use the GTE ECU or can existing ECU control engine and trans. If not what does Powerhouse and TOYOMOTO us when doing GTE swap with auto? Do they use Supra auto and ECU? Sorry for all the questions I've just been searching through the archives and have not seen this discussed.

Rob

T0ked

iTrader: (2)

I've heard mixed replies about this. Some say the standard slushbox can handle the GTE, some say it can't, or won't last very long. I know there was a year or two when the Supra TT came in auto form. Wondering what tranny it used at that time...

At the very least the stock auto can't handle too much more. So if you're planning on toying with the GTE once installed, I'd suggest doing a auto-manual swap. That's been talked about on the forums before.

I know there is Level10 which adjusts the tranny to make it "bulletproof". They change the valving, seals, etc. I talked to somebody at Toyomoto several years back and they mentioned them. They have a website, too. Expensive though.

rob3379

I would like to keep an auto in the car. The Getrag swap would cost an insane amount of money. I know the GTE motor itself will bolt to GE tranny. I just don't know the specifics on which ECU is used in this swap or which auto transmission to use.

Rob

Bean

iTrader: (1)

the stock tranny will not withstand the STOCK power of the GTE

better get it built and with a better torque converter... (same amount of money as a getrag or auto from supratt)

on stock tranny you need to keep your tranny ecu and use the GTE engine ECU... theoretically anyway...

the getrag swap is not that much money; its cheaper than the GTE swap is by at least half

Lex Luthor

Wrong. The stock trans will handle a GTE no problem, but you'll want to firm up the shifts, for the record the A340 and A341 in the SC and Supra are almost identical, the converter is different and a few other things, but it's very strong for an oe unit. T0ked, the MKIV was available in automatic every year, 93.5 to 98.

rob3379

Ok I know the trans will hold up if built properly. I need to know if I convert to GTE will I be using GTE ECU or GE ECU. If I have to use GTE ECU will my GE tranny work electronically or will I have to convert to GTE Tranny. This is for automatic only.

motorheaddown

With all due respect, just asking the question raises concerns. First the GTE motor has the obvious twins and the fuel maps to go along with it. A GE motor does not. Additionally, twins use VSV switches to control the sequential operation of the turbos that is done by the ECU. A GE motor does not. A GTE motor uses low-impedance peak-and-hold injectors. A GE motor does not (granted a solenoid resistor fixes that, but did you know that?). The MAF sensors are different, etc, etc, etc.

There are *so* many differences (aside from the interface/shift points of the tranny) that you should consider before taking on a project like this.

Please don't be offended by what I'm saying because e-mail sometimes loses its intended meaning. All I'm suggesting is do some serious research before putting $$$ on the table. In the end, you'll make the absolute *best* decision for yourself if you're well informed about the car you're trying to build :-)

best regards,
-scott

rob3379

You still did not answer my question about tranny and ECU differences. I need to know if my existing tranny will work with the conversion. I'm basically asking for opinions on what would be the better route for auto tranny, stock Supra or stock SC tranny and what ECU for trans shifting. I know that GE ECU will not control GTE engine by itself. I appreciate your concern b/c I'm still trying to gather all the details to start this project.

Rob

motorheaddown

Rob,

To answer your initial question, no. You can't use your existing ECU to control engine and tranny. The interface to your sc tranny is *probably* the same as the GTE tranny, but again do the research.

Check out http://www.mkiv.com/specifications/ncf/ncf93/ and http://www.mkiv.com/specifications/index.html. Read every page. It's the most complete source of info about the mkiv Supra. Next, get the wiring diagrams for the sc300 and see if the interface to the tranny matches the mkiv Supra.

You'll need the GTE ECU *and* wiring harness. Don't forget to get a TT fuel pump, igniter, and solenoid resistor. I'm sure there's plenty of other stuff you'll need but that should get you started.

Do some research... It'll save you time and money.

-scott

Bean

iTrader: (1)

i don't see it man... i hear stories of how the stock auto ****s the bed on the stock motor at 100k miles... and how boltup turbo kits break apart the stock tranny on the inside...


what else is different about them? i mean even the SupraTT's auto has to be built up a bit in APU range

Dew23

iTrader: (1)

It depends on the year of your car the gte tranny is told to shift by the ecu and has no kickdown cable,it been said that the gte tranny is good for about 500rwhp after that you have to upgrade.

Lex Luthor

The difference in the shift quality between the two units is electronic, not mechanical, the valve bodies are the same, so you'll probably run into a problem there, i'll try to see what other barriers await you, if I have some time i'll try to help you with the details. motorhead, take it easy on him, he doesn't have to know that a solenoid resistor fixes the impedance difference in the injectors, we're here to help teach him what he doesn't know, not bust his b@lls for not knowing it. Bean, the A340 and A341 are both plenty strong for BPU level when run with at least one aux cooler, heat is the biggest enemy of an automatic, and i'm not surprised to hear that an NA SC3 had cooked the unit by 100k, anything could have happened by then, could be the original ATF for all we know. What we do know is that tons of automatic Poopras have gone BPU on the stock auto with no problems, yes as you said it requires a stronger build for APU, but that's past 450rwhp, what do you expect brother? . What we also know is that Toyomoto went 11's in an SC3 with the stock automatic, with just Lance's 'shift kit.' While the Getrag is much more fun on the street, most guys in the know will all choose an automatic for the strip or at a stoplight, and this is the reason IMO you see scores of 600+ rwhp MKIV's running 12's and hi 11's, the Getrag. There's a guy on Supraforums that ran 11.45 with a BPU automatic MKIV, to me that is just unf#ckingbelievable....
- LL