Keith13b

iTrader: (3)

I've heard it as well, but not sure of the reliablility of the source.

Bean

iTrader: (1)

ebanks,

do you know how much power twin T3/T4s would be on a 4.0L motor? you're talking at LEAST 800-900rwhp

Twin 16Gs (TD05) would be fine. on a 300zxTT they will make around 600rwhp at high boost levels... and on the 4.0 they will spool very fast

twin 60-1s is WAY too big

with 16Gs or T28s you don't need external wastegates as the internal ones that come with the turbos do just fine; it would save $1000 in wastegate money

Please respond and tell me you're reading this; twin 60-1s would be a big no no... that would be in the 1000-1100rwhp range and spool VERY slowly

imagine a 60-1 spooling on a 2.0L 4cyl

machinegt

is there anyway to ask toyota themselves what kind of range the sc400's auto trans can take? or would they look at us like a buncha freaks.

if we could get an official word from toyota that would be nice.
i would think the engineers there would have tested it and had some test results on the transmission.

someone who worked on our transmission should have some kind of interest in helping us with this, or are we totally in the dark?

oh by the way, i am completely happy with 400-450 RWHP, that is highly pleasurable! im excited about the buzz of turbos on the v8. its time we unleashed the true power of our engines onto the streets.

lex400sc

Yeah, I'm sick of getting crapped on by Grand Ams, V-6 S10s, and other inferior cars.

SCV8

I posted a question over on the Supra forum awhile back,and my general feedback was that the Supra/SC auto trans are good to around 450 hp before you need to start modifying things inside.
This info was from owners who'd fried trannys before and knew from that horrible experience what the limitations were.
I was toying with the idea of a blower when I did this,which was planned to produce around 390 hp.
I think that the only way that this kind of thing would happen successfully is that an offering of a lower powered (440 hp?)version would be offered to start,not suggesting to sacrifice any engineering quality or anything,but a fully tweaked 550+hp monster is just going to create a lot of wierd problems for most people.If someone wants more power,then they can go about the extensive additional control components and tuning/programming associated with a fully tweaked out turbo on a street car.
A fairly quick spool would be so much fun also.

Lex Luthor

OK, sorry to join in two days after starting this thread, been away on business. Here's the answer for everyone, the SC4 trans is basically the same trans as the Supra unit, different converter and a few minor differences, but a very solid source informed me that the internals are basically the same. Several sources have told me that the SC4 trans is good into the 400's no problem, past that we can have the trans built, I have several options for that, Paisley said to use Select, they build the trannies for his Supra, said they can do ours no problem. There are other places that will do it, I think the ballpark for the upper limit is around 650hp with a built unit, I remember Brian 'VeilsideRSPsc' saying how the physical size of the clutch drums limited the unit to that hp level supposedly. By the way, he was running a 60-1 with plenty of other equipment, on a bone stock auto, not even a shift kit or converter, for months and months of hard abuse before going to a built unit, he said it slipped trying to smooth out the shift, but it never blew after like 10 months of boosted abuse, worked until the day he yanked it out. Ethan, yeah, the converter will be the first to go, it's definitely a weak unit from the factory, but it'll actually flash to around 2100-2200 rpm, not too terrible. A Precision 9.5" unit w/ the anti-balloon plate will do wonders, and will probably stall in the low 3000's with the 8, could always have it tweaked to 3500+rpm for bigger turbo(s). As we start to get into the 700hp range, a GM 3-spd conversion like on your car will definitely be in order, and I can think of many benefits. First of all, a GM TH350 takes muuuch less power to drive than the Lexus auto, even a TH400, which we'd be using i'm sure, would still sap less power than the Lex unit. The Chevy Turbo 350 and Turbo 400 trannies are very abundant ( not referring to 'BOP' units, Buick/Olds/Pontiac, different bolt pattern, can work, but the top two bolts don't line up the same), easy to find one and have it built, or you can get a unit from TCI that'll handle decent power and costs around $600 for the entire unit sans converter! Like you said Ethan, an adapter plate can be made, PHR also has one available. For serious power, which we'll be making by the time we need to do the 3spd swap, we'll want a fully built unit capable of handling over 700hp, but that's easy with the GM 3spd, plenty of places will do it, and for much less than the Lexus unit. Problem is, you'd be losing the overdrive fourth gear. Since the SC4 has a 3.90 rear, the loss of OD would be close to unbearable on the highway.
This leaves three options:
1) Deal with it, but no more top end runs on the expressway
2) Gear Vendors overdrive unit, can even do a dbl overdrive if you've got good life insurance to take care of the kids after you're gone. Seriously, a built GM 3spd and GV OD has been proven behind worked big blocks, it would be the best of all worlds and would provide a drastic e.t. reduction with the right converter.
3) This is that murderous *****, a built GM 4spd auto, i.e. TH200-R4 (GN) or TH700-R4 (F-body/C4 Vette). The 200R4 is weak, cooked plenty of 'em in my GN, the quick GN guys go with the 3spd. So, that leaves the 700R4, or it's newer version 4L60E. This is a pretty strong trans, yes I blew for or five of 'em, but only on spray and Hoosiers. These units can be built to handle serious horsepower, and may be a great option. Also, the 700R4 has a very low 1st gear, 3.05, between that and the 3.92 rear, spooling won't be too much of a concern, shifting before hitting the rev limiter and resulting fuel cutback is more of a concern. It's a computer controlled unit, but it can be swapped in, the rod guys love to use this trans. For instance, you can wire a switch to lock up the converter, which you would want anyway, it's worth a tenth or two by the time you get to the end of the track to be able to manually lock it when you want. The stock 12" converter with these units is somewhat strong, but only stalls to about 1800rpm (Vette units stall to around 2200rpm). So, a built 700R4 with Precision 9.5" converter and Fairbanks or SLP servo (Verrry positive upshifts/downshifts) would be a great way to go.

Far as the rest of the issues, Ethan, for the applications that don't have a return-style fuel system, like you said, no big deal to convert that over, all the new Celica guys going turbo are all dealing with it. I agree with Bean, twin 60-1's would be extreme, but that would definitely allow for unbelievable potential. I'll tell you what I would like to personally see. Definitely quality components, i'm big on doing it right the first time, because i hate to repeat myself. I think twins would definitely be easier to plumb manifold-wise, but i'd rather see a decent-sized single, less plumbing up top, one less turbo to worry about, and the kit could be done for less $$ with the same power potential, a bit more lag. I'm looking for serious power, maybe 400's rwhp from the entry-level kit, but potential to go towards 700+ rwhp with a built motor, fuel system, and stand-alone. Far as the stock bottom end Ethan, it's as overbuilt as the 2JZ in there, 6bolt splayed press-in mains, big-@ss oil pickup, forged crank, rods, pistons, nice webbed alloy block, real trick. The Aussies are boostin' the crap outta the 4.0, it'll take it, my biggest concern is the head gaskets. Oh, and to answer your question, they're all dual-distributor.

-- Jon

Static911

At our meet this Saturday (or I may just forward this thread to him), there will be 5 technicians from Lexus to answer all our technical questions...I am printing this thread out and showing him it.

edit: hi Ethan. I'm Ethan too.

Static911

Lex Luthor

Awww, the two Ethans, how cute. Wanna take him out for ice cream? I think it's a solid idea to show this to the Lex techs, you should also get in touch with sc400turbo and blown_sc400.

MadMaxSC400

I probably won't be able to make the meet, I'll be out of class too late in the day.
I'll spend 6-7 g's for 500 rwhp.

lex400sc

I won't be able to make the SF meet either (license suspended), but do post follow-ups on the boards just for archieving purposes in case this project arises again two years later. And do take lots of pics at the meet! Lots!!

Lex, I can probably get my hands on any GM tranny pulled from part cars if you don't mind used ones. Are we settling on the 700R4 then?

All I have to say is if this thing goes through, we're going to have some fast *** frame-torquing SC400s around here! :eek:

Bean

iTrader: (1)

Richmond makes a 6-speed tranny replacement for the TH350 and TH400...

take a look at a summit catalog; there's usually an ad for it; i've read an article on it and it seems pretty nice...

And you can always get a T56 Borg/Warner to work with it; hell they got it on the Viper, Fbodies, and Cobra now

As for turbos, a single would be nice but I don't know if it can fit A single T66 would be NICE; it would spool quick and offer lots of power.

healerhand

Sorry to jump in so late. I dont know much about imports. I have been modifying my mustang since the day i got it. I am too interested in a turbo kit for my LS400 (first generation). I was wondering where would the twin turbos located? As far as LS, everything is so tight. If Ethan going to build a kit for the SC, GS, and LS. He would have to do a lot of modifications on pumpings, wirings, an holes to keep them form melting.

Twin Turbos - The best place to put it would under the car. Next to the tranny. Where the header ends. This place will be heat proof from other components. The problem would be spooling. It so far from the intercooler and engine. Otherwise, it would be a great place.

Single Turbo - For single large turbo, the best place is to relocate the battary and fuse box. There you can put in a large single turbo to minimal heating problems.

So, please count LS owner in. I would like to build a sleeper with 550 RWHP.

healerhand

As far as tranny goes Ford have a stronge one. Its Tremac TKO Plus. Its a 5 speed. It can handle around 550-600 rwhp. If you you auto, C4 is up to 1000 rwhp. Domestic tranny is easy to get, but bell housing might be a problem. Driveshaft can get it custom.

healerhand

Hey Eric (edogg), How are you doing? anyway, i thought about that area in the right side of the engine bay. There are a lot of AC lines and accessories. I affraid the heat will melt all of the stuffs.

Lex Luthor

Bean, that Richmond 6spd is a strong unit, not quite as smooth as the Getrag or the BW T56, but better than the ZF 6spd IMO. Someone here may choose to put a stick behind the 8, but an automatic would be the better choice once we approach serious hp. A single T66 is exactly what i'd like to see. Healerhand, once the kit is done for the SC, it will fit the LS, everything is layed out basically the same, and you actually have a good amount more hood clearance. I would not recommend a Tremec unit, and definitely not a C4, no way i'd use a C4 for anything close to 1000hp, a built C6 would have a hard time at that level. I was hurting C4's with a little 289 K-code motor in my '67 Mustang Shelby pkg. Next someone will say to put an AOD in there, hehe.
Regardless, let's not worry about the trans right now, the oe automatic is good into the 400's, let's worry about making everything fit right now, then we can work out drivetrain plans for each person on a case-by-case basis.
- Jon