jibbby

Hear it goes - I have lost races because of my stock tranny and I have just about had enough with it..., What do you guys think the best most cost effective way to get the auto tranny shifting to perfection in these older SC's?.....Upping the tranny line pressure and shift kits, is not the answer... Hate the delay or untimely shifts under the juice....Example, If I am cruising the car at 30mhp and hit the juice the car rev's like crazy and doesn't down shift unless I release the gas a bit and then floor it again.....Major delay and it pisses me off...From a dead stop start the tranny performs decent under the juice through all the gears...I want to be able to hit the gas at any speed and move immediately. I don't want a manual tranny either in LA traffic...Any suggestions? I am trying to avoid the expensive R154 or V160 manual tranny swaps if possibe... What can be done? I also hear the built stock trannies kinda suck and only help with hp holding capacity and not better shifting times... I hear a stand alone ECU helps with tranny performance and shifts to some degree.....Anyone know about this stuff?

skeet94

Seems like your tranny is slipping, which is why it revs before going into gear when you perform a kickdown. I suggest you look into a Built TH400 conversion with a GV OverDrive unit which will definitely cure all your transmission woes .

jibbby

Isn't the TH400 a 3 or 4 speed transmission? So what the means top speed is reduced and freeway driving at 80mph or more you will probably be close to redlining...The newer Vette and Camaro auto trannies are probably the best choice for swaps. However hooking those up with the Lexus motors, ECU, and drivetrain is oh so challenging...If I were to do that I would also go with the LS1 engine and ECU swap as well in my SC4...That would make twice the N/A power, front end weight would be the same and all in all would probably be an easier swap altogether...Instrument integration would be the hardest part.....I have seriously considered that huge swap for some time now......Looking for something a little more cost effective for now....

Has anyone done a Th400 swap on an SC before? I would love to see that and how it was worked out? I couldn't find anything on through the search engines on any of the forums...Just a lot of R154 and V160 swaps.....

SCV8

You will find that as your mixture changes, so will the vacum signal to the tranny ECU that controls the shifts. It's a delicate balance to obtain, but worth the effort once it's all sorted out.

mitsuguy

iTrader: (2)

I had a friend that had his auto supra tranny built in Austin, TX (boost logic, I think)... car made around 500 whp, and the tranny was just awesome to drive...

anyone know the differences between the transmissions???

he also had a 4k stall, which was just beautiful...

even the shoddiest of drivers could get that car into the 11's and he was on stock turbos and side mount ic...

dinhNER

iTrader: (5)

oo interesting

BLK13X

How much for the TH350/400? I was going to suggest to rebuild the stock A341E to withstand your HP output, add in a throttle-sensitive shift kit and ATF cooler.

PHLSingle

Unless this guy is seriously looking to race that SC400 - suggesting a TH400 is some bad advice. You're not making that much power...I would seriously look into getting the SC400 auto built to handle the additional HP and TQ you are making - combined with your upgraded TC. A reputable shop should be able to take care of your tranny. Its a combination of clutches, line pressure, etc & proper cooling.

A 350/400 tranny with no overdrive is not going to make you happy driving around, esp with the rear end gearing your car has.

skeet94

It was me who gave him that advice about the TH400. If he is looking at HIGH hp in the future then that's the recommended route I'd say. If you look on www.supraforums.com alot of Built Supra trannies tend to break, it's not how much power it can handle it's how much abuse it can handle. It's determined by your driving style...also if you could read my reply, it clearly states you'd have to have a GV Overdrive Unit too to make it drivable .

If you're looking at high horsepower and tons of abuse on the tranny, pick up a TH400 with GV OD unit, otherwise rebuild your tranny. If it dies, then you'll do it again and again...then after about 2-3 times of doing that, you'll have spent enough money to get yourself a TH400 in the first place .

PHLSingle

supraforums...what's that? Skeet, I'm assuming you have a 400 in your car?

High HP, like what? 600, 700 or more to the tire? Sure, if that's his goal AND he wants to stay auto...then sure, pursue a 400. But unless he is going to either 1) try and turbo his sc400 or run a 400 shot on the car...I don't see him getting to that power level.

Jibby also said he's trying to avoid the high $$ w/swapping to a 6spd. Do some numbers on 1) th400, 2) converter, 3) adapter plates, 4) GV unit and IMO 5) dumping the 400 rear end gearing.

It comes down to budget and your realitic goal with the car.

hemogoblin

I dont know how strong the automatic tranny is off of a 2JZGTE, but ill have one for sale in a month or two. I'd assume its stronger then the NA trannys.

skeet94

No I don't have a 400 in my car .

Supraforums? If that's not self-explanatory then I don't know what is. www.supraforums.com I suggest you read up alot on built transmissions .

Also Jibby, do a search on there to see what you can come up with for Auto tranny controller / computers / ecu's. You might get some interesting info .

skeet94

The limits for those are at 500rwhp ... that'd be a much more viable swap. Although IIRC they are electronically controlled so you'd have to sort out the electronics to mate the transmission to your ECU.

PHLSingle

Oh, so you're just feeding this guy stuff second hand...from what you read, right?

This argument is pointless...I'm giving Jibby some real world feedback. I've had built stock auto's and have been racing on a th400 for almost 3yrs now. Perhaps you'd like me to come to your garage and show you how to build one? I've been a member of supraforums, most likely, longer than you've even owned your Lexus.

The stuff I've suggested in this thread is now from what I read, but from what I've built, raced and street driven over the years - making alot more power and driven harder than his sc400 is.

skeet94

Good for you!! Yes I'd like for you to come over and build my stock 2JZ-GTE Transmission to handle ****loads of power, where if I even abuse the **** out of it, it won't give me no problems whatsoever! I've specifically bugged the **** out of sponsors of supraforums.com, to do research research research!! before I go and spend money on something that isn't going to work out. If he wants to sort out his transmission and sluggish changes etc, a simple rebuild is NOT going to work. An option is the TH400, instead of starting a little mini war on me, why not just say agree to disagree as what I stated about the TH400 with a GV OverDrive unit is an option, but not within his budget! Oh and since you know alot about rebuilding transmission I suggest you rebuild his transmission to handle what he wants to do with it...see how far he gets and how he likes it. NO NOT a SHOP, you yourself! As you're clearly volunteering to teach me how to build one up, I guess you can build it up for him.

If you really want to turn this into a "I'm bigger than you thread" then fair enough. Also I suggest you do a bit of reading into my posts...where I specifically STATE!!! "WITH GV OverDrive UNIT!" if you're talking about drivability.

I'm looking at doing a TH400 conversion though, so yeah I can only go off based on others experience.

I don't care how long you been a member of supraforums, I've owned my Lexus for two years now, paid for it by myself and am proud of that fact since it's my first ever car that I worked for myself and paid for myself at the age of 21, coming from a not so rich background so before you know anything about me don't go around stating **** you know nothing about...want to get personal take it to PM...so for your information I'm sorry but I don't give a flying **** about how long you been a member of supraforums. I'm giving him information that I honestly believe myself, based on what I've read from other people's opinion. If you think there's something wrong with it then how can you expect him to rely on your experiences, if me stating other people's experiences are not good enough?

Also I guess now you're going to say the A340E from the 2JZ-GTE is not good enough and he should still rebuild his transmission?

As I said, lets see you try to build his current stock transmission up since you know so much about it and are clearly boasting/proud of that fact .

Having something in your car, and building something that is IN your car are TWO different things .