abutler696

Alright guys.....I have a question here....tonight I went out gteching again(its an addiction) and with the ECU upgrade I have now I can brake torque twice as much as I could before. But then again....what's the advantage of it? All it does is spin out my tires which loses time. Now I was thinking about the torque converter upgrade but I can understand me having some slicks it would take off 3/4 of a seconds which would be badass but on the street...would I just spin through a few gears and be 5 cars behind by the time my wheels catch? I mean I have some damn sticky wheels(NItto NT555 Extremes) but there is too much power behind it. My best times come from only brake torqueing at 1200 RPM instead of 2400. Any answers?
Thanks, Adam

Keith13b

iTrader: (3)

Installtng the TC would eliminate the need to "Torque Brake". Besides, t-breaking is really only necessary for launching at the track, where there is plenty of traction. You can power break a Pinto and spin its tires, so doing it w/ a lex is just a waste of rubber, ands yes, it really slows you down.

The TC will raise the stall speed of the tranny, so when you hammer it, your rpm's will go higher before the trans locks up. Putting you in your optimum rpm range from the get-go.

I have a bone stock SC400, w/ a TC and a sudden hammering of the gas from a standstill will just light up a set of Firehawk 285's, and send the car spinning into a donut pattern. I couldn't imagine what it would do w/ intake,exhaust, and ECU mods.

Good luck, and waste a few sets of tires for me.

Keith

Red93sc400

Keith:
Which Torque Converter did you use? How expensive was it to get it installed? Did it change how the transmission shifts? Is the inter-gear smoothness still there with the torque converter? Can you share with us the RPM shift point in ETC as well as Normal with the torque converter with OD off and TRAC off in both cases?

You are the only person I know of who has the SC torque converter in place. Your feedback would be greatly appreciated.

Lex Luthor

Keith, I wouldn't mind having access to that info as well. I'm doing my converter in a week or so, probably the Precision Industries 9.5" unit. It's virtually bulletproof, even with slicks and a shot of juice right out ot the hole, you can't pop that thing, had their unit in my GN, which used to pull the left front wheel on the launch, and I never had a single problem. Do u have the Vigilante as well?

Red93sc400

Hey Lex:
What is the total damage in $ on this going to be? How much for the TC and how much for the labor or better yet any estimate of how many labor hours this changeover is? How intrusive is it to rip out an old torque converter and replace it with a new one. Once you are in the trannie, what else could or should be changed out at that time (ie things that take wear and tear). I would imagine this to be the time to do the rear main seal on the engine for sure. Your thoughts on this...

Lex Luthor

Hey, Red. Where in NE are you? I'll be headed your way on business pretty soon, just waiting for them to deliver my truck. Okay, let's take it from the top. I've done some pretty decent business with my local Lexus dealer, so they agreed to install whatever parts I ordered for the trans. Labor to change the torque converter is 7hrs @ $85/hr, $595 total. A new replacement converter (which is 2100-2200 stall) from Lexus is $934.22 (!!), bringing the grand total to $1529.22 if my mental calculator is functioning today. At 'reasonable' power levels, these transmissions are pretty strong (same basic unit as the Supra auto, some minor differences such as converter bolt pattern, etc.). They don't generally break, but the converter is more prone to failure, especially if the fluid isn't changed at regular intervals. That being the case, upgrading the clutches, increasing line pressure, and generally bolstering the internals is not really worth it unless you plan to make real horses. Let me interrupt myself by letting you know that I have big plans for power production, and I will keep you posted as to the limits of this trans, and what needs upgrading and what does not. Changing out the rear main seal on any car is a good idea while you're in there, as you know, but to be honest with you, my motor doesn't have much mileage, so if it's dry as a bone when I inspect it, i'll probably leave it. Of course change the fluid and filter, and I recommend an external, auxilliary trans cooler anytime a higher stall unit is utilized. Note that while you are staging (torque-braking, as it were) the 'slippage' within the unit will cause heat to rapidly build up, but an aux cooler will not really alleviate this situation, so keep that in mind (that's with any converter, stock or otherwise). I plan to use the Precision Industries 9.5" unit, which as I said earlier, is the best out there. They claim their unit does not require an aux cooler, but you can take that with a grain of salt. Other units are reworked stock cores (manufacturers play with stator/rotor angles and distances, etc, to manipulate stall speed, let's not get too technical) while the Precision 'Vigilante' unit has a completely proprietary casing with anti-balloon plate, etc. Stall speed is directly affected by the specific torque output of the engine, so it will vary car-to-car, but you can expect somewhere around 2800-3200rpm stall speed, which is right around the limit of how high you want to go with these cars (on the street, that is). Depending on who you purchase this unit from, pricing is $900 and change (just raised their prices), but Chris (Smooth8) can take care of you when you're ready. I also know the owner of a well-known local shop, and I can get you guys 2700-2800 stall units for $395, no BS! PM me if you like.

Lex Luthor

If you get a chance, post a pic old man!

Red93sc400

Lex:
Thanks for the very informative post. You have thought out this change well. I hope that you will be able to GTech your car both before and after the TC change so we have some data. My trusty digital camera is out for repairs. I kinda knocked it over when it was on a tripod down in the cellar. Alot of nice little pieces resulted. It has been back to the mfg. now for a month with no end in sight. I hate to see what the bill will be or how they will charge me for this. Here is a picture of my car when it was in the previous owner's driveway..... since then I have Zaino'ed it and man does she shine, shine, shine.... I have about 5 coats of show car polish on it now. The big aggessive Bliz Nur_Specs are on the ***. It is fun to drive with those cans on. The 4.5" orafaces are wild. She runs better with them. The engine seems to happily rev up quicker and free'er, maybe I am imagining this, dunno. Have no real data. My gas mileage has gone up from an average of 24 to an honest 26. No idea if this is a result of the new mufflers or the colder weather. I pretty much drive with a full tank of gas in the winter.

I am up along Route 15 (you know this as the Hutch, here we call it the Merrit Parkway) which is about 60 miles up the line from NYC and along the coast. Drop me a line, would love to have you over to "Casa RED93SC400". You can see my new rotors and wheels and tires and whatnot, most of this stuff is coming in and may be here someday?. Am waiting for the springtime thaw before they are installed. Too bad you missed the big CT CLubLexus rally in Berlin. There were perhaps 24 cars there. I was the only SC and so utterly stock compared to the IS300's that I actually felt square (and old). We had fun.

What kinda truck you getting BTW?

Keith13b

iTrader: (3)

1. I used the Precision Industries unit from Swift Racing

2. $800 shipped was what I paid

3. TC won't change shifting at all; just off the line performance

4. See #3, still Lexus shifting throught the gears - nothing changes.

5. See #4

Dealer boned me 8 hours to install. I got screwed. The unit is easy to install for a do it yourself'er. I want to hit myself over the head for having them install it. I also had the rear seal replaced while it was open.

My advice is get one; you will not believe the performance gain you get - unbelievable. You will need new tires shortly there after.

Keith

Red93sc400

Keith13b:
That is great news and nice to hear. When you say you could have performed the change of the torque converter yourself, what do you mean? Is it just bolted to the front of the trannie inside the main bell housing?

Please forgive my questions, It should be obviouse that I do not know nor can visualize much about the configuration of a torque converter in the Lexus SC. So I did some research and found a web site that explains how a torque converter works in general....

http://www.howstuffworks.com/torque-converter.htm

BTW... Did you add a trannie fluid cooling system?

Keith13b

iTrader: (3)

Drop the transmission, and the TC is bolted to the flexplate by 8-bolts. If you can change a clutch in any car, you can swap ot the TC in a Lexus. I did not add a cooler, but I plan to in the future.


Keith

Lex Luthor

Yeah, it's not too bad, but it's cold and i'm without a lift. 7 hrs from my dealer, but i'll forget all about that as soon as I drive it. The converter was ordered today, Precision raised it's prices unfortunately, but u gotta pay to play, I guess. By the way, I've joined forces with lexussc400.com and will be representing them on the East Coast, so feel free to hit me with any tech questions. Keith, Precision claims you don't need an aux cooler with this unit, but I think you and me know a bit better than that. I also picked up synthetics for the diff and motor, M1 filter, new Lexus plug wires, caps, rotors, PCV, fuel filter, DexCool, etc, just want to make sure it's tuned before I dive into the motor. Red, it's very common for a more efficient exhaust to give u a couple MPG, it may actually pay for itself over time. Aaah, the Hutchinson, gotcha. Sorry I missed that meet, I was in Orlando on business, had Lex withdrawal for days. I'll be up your way sooner or later, thank you for the invite. To answer your question, i'm picking up a 4dr Explorer, not my first choice, but my company is picking up the tab, so who's complaining. I guess I could always slap a blower on it, errrr, bad bad bad.