Specs needed for Drag Torque convertor

[StuartW]

I need to give Hauser race cars the following info to build me a custom Torque convertor and flex plate.

 

Most of the info will be a guestimate but i would appreciate some confirmation

 

I will put my guesses in red!

 

Stall Speed 3800

Full engage speed (Think thats what they call it?)6600

Vehicle weight1350kg

top revs9000

Flywheel HP800

 

Gear ratio,wheel size,diff ratio are all known quantities fank fook

 

Basic specs are

 

Built longblock with ferrera dual valve springs

PT74mm Turbo

GSC 274 10.3mm lift cams

2 speed Powerglide Gearbox

The 74mm turbo will be my restriction for the first year but in 2010 i plan on going for a 90mm type turbo :D

 

The relatively low stall is so i can still drive this beast on the road:innocent:

 

Remember i have a Transbrake to help cope with launch whilst draggin.

 

Click on the link in my sig for full specs also My garage Forum is building the story too.

 

I know all this is a bit vague but i gotta start somewhere as the Torque convertor needs to be custom made to marry the American powerglide gearbox to the 2JZ

[StuartW]

Echo...

[paul mac]

that stall is going to kill you on the strip, i know you say you want to drive it on the road but you seem to be going to a lot of effort and then blowing it on the crucial item that will get you off the line, i would have thought a 5000rpm stall would be more suited

[StuartW]

that stall is going to kill you on the strip, i know you say you want to drive it on the road but you seem to be going to a lot of effort and then blowing it on the crucial item that will get you off the line, i would have thought a 5000rpm stall would be more suited

 

Thanks for the reply..My knowledge of Auto's is minimal but growing fast.

 

I am led to believe the transbrake selects a counter gear. i.e. reverse. On launch 1st gear is manually selected. Revs are built up with transbrake powered i.e. no drive. The launch is activated by releasing the transbrake...Then you are off!.. so surely the stall is not quite so crucial?

 

the 3800 rpm mentioned is the speed the TC will start to engage power with full 1:1 drive at the higher revs, this will allow slip and the car will gain speed until full drive is felt when the engine is into its powerband.

 

My Powerglide is not a fully auto box like a BL built box or standard autobox. I have to manually change gear once up the strip

 

Discuss...

 

p.s. does anyone have a contact for Steve whitaker so I can pick his brains?

Edited December 30, 2008 by StuartW (see edit history)

[paul mac]

i wont pretend i know to much about this stuff, but i do remember Terminator was building a TH400 then i think he changed his mind, IIRC he had a custom 5000rpm stall (or he was going to get one ?) you may be better off on supraforums with this mate as you can see by the response your getting on here , i dont think anyone on this board runs a serious set up like yours, or if they do they are being a bit anti social

[Terminator]

Yes I was building a drag car using the TH400 box, but circumstances changed and I could not justify a straight line missile. I had two TCs both fully race built, the 5000 stall was a custom PHR job, the other was a rebuilt PI 3800 stall. According to the USA big power drag boys, PI's are not up to the job over 700 RWBHP as they slip at this level. As far as I know no one over here is using that much RWHP through a PI so they have not reached rebuild point. I still have my PI which was rebuilt to take around 1000RWHP, it was proven at 900RW so was more than enough for me. The guys that rebuilt the PI designed and built TC's for 6 second Mustangs, so they had a good track record in the drag field.

 

I had two TC's because I wanted to try the 3800 to see how drivable the car was off the strip. The 5000 stall was a back up if things got serious. It was my full intention to shift the TH400 manually on the strip. My target was low 9's with a possibility of 8's, the motor and box were certainly up to the job.

 

As far as I know there are two main physical factors to take into account when fitting a TC in a non standard box. The profile shape and size of the box input shaft and the distance between the flex plate and the main box seal. The TH400 used the stock supra flex plate.

 

My TH400 had transbrake, your understanding is correct. There is a solenoid, that when switched on holds reverse and first against each other, keeping the car still on the line. The engine can then be brought up to what ever rpm gives peak torque for your setup. When the solenoid switch is hit again, reverse is released and all power goes through the wheels in first. The acceleration is spine shattering. Obviously timing is crucial as there is a massive cost for such awesome acceleration, namely heat buildup. You will need some very efficient coolers and be prepared to do fluid changes very regularly. I was going to run three coolers, two with fans and one in free air mainly for a heat sink I was also looking into some high efficiency water oil coolers.

 

I would get in contact with some of the drag boys on Supra forums, I always found therm to be very helpful. The big advantage is they have done it all before, so there is now little reason for errors. You might try getting in touch with Leon Green as he has a very quick auto using nonstandard boxes, and had done a huge amount of R and D in the area.

Edited January 1, 2009 by Terminator (see edit history)