Thema Gear Box

[geoff gibbs]

DOES ANY BODY KNOW THE GEAR RATIOS FOR THE 16v TURBO. ANY HELP MUCH APRECIATED.:)

[DJ]

The only information I can find is:

Top gear ratio - 0.91
Final drive ratio - 3.11 (1988 Turbo 16V), 3.17 or 3.18 (1993 ie Turbo 16V) Not sure which one of these is correct for the 93.

[1,6 HF]

Weernink lists the following for the 16V turbo, from 1989-:
3.500/2.176/1.524/1.156/0.916/R.3.545
Final Drive: 3.111 (3.176 for the Wagon)

[geoff gibbs]

Many thanks for gear ratio figures. Im told this box is very strong, would you agree? What HP & torque would you think it could handle?

I would be running it on a chevy ls6 racing, but only aprox 4 minutes at a time, in 3rd gear only.
Regards geoff gibbs

[ncundy]

I don't think many have put that much power through that transmission. The only person who has tuned a Thema significantly that I am aware of can be found on this thread :

http://www.viva-lancia.com/lancia_fora/read.php?f=17&i=1607&t=1607

As you will read he bought my old Thema Turbo.

A better bet for getting hold of him may be via evocorner :

http://forums.delphiforums.com/evoforum

But I guess you are putting more power and torque through than that - particularly at start up ?

[1,6 HF]

Many thanks for gear ratio figures. Im told this box is very strong, would you agree? What HP & torque would you think it could handle?

I would be running it on a chevy ls6 racing, but only aprox 4 minutes at a time, in 3rd gear only.
Regards geoff gibbs

I really don't know the gearbox at all--I just have a reference for the factory ratios--so I don't have a useful opinion about its strength.

But you want to strap this onto an LS6 small block w/ about 400 lb ft of torque? That's nearly twice the torque of the original engine. If you don't mind my asking, what is it that you're doing that involves only 4 minutes at a time in 3rd gear?

[geoff gibbs]

Hi
Thanks For The Reply.:)

[www.deltahpe.nl]

Hello,

The type number of that gearbox is C.503.5.29 and it should have a Viscodrive on it.

C503 = model gearbox
5 = number of gears
29 = torque in KgM

So this gearbox can handle (factory specs) about 285Nm (which is i think 210 lb ft?)

Ratio´s:

Gears - Transmission

1: 3,750 - 11,910
2: 2,176 - 6,911
3: 1,524 - 4,840
4: 1,156 - 3,671
5: 0,917 - 2,912
R: 3,545 - 11,259

This car has the same gearbox as the Lancia Delta Nuova (II), Fiat Croma and more models...