Gearing for subie

[Eatoniashoprat]

Hi, I've got my Ej20 turbo and its gonna be around 230hp in my '72 super. It will be running at full weight with subaru engine/rad. I'm getting a type 1 box built for it but I need to figure out which gear ratios to use. I'm thinking start with a 3.88 R/P and 4th gear to be around 0.82-0.89. With a 24" tire that will put me at 62mph at 2800-3000rpm. Now I have heard to just use the stock 1-3 with this setup but I have fears that first gear will be too low. Has anyone used this box with this setup on here and what works for you? Thanks

[Bugat5speed]

Hi,

hope that you do not spend too much money on building the type 1 gearbox, cause it will probably break. The Subi Turbo gives a torque of more than 300 Nm and this is far too much for the type 1 tranny. We always use Porsche 915-gearboxes for the EJ 20T. Even the 901/914 will not stand the torque.
Porsche 901/914 won´t stand more than 270/280 Nm. The type 1 is much weaker than the 914.

Hope you choose the right way with investing.

Martin

[Eatoniashoprat]

Originally Posted by Bugat5speed

Hi,

hope that you do not spend too much money on building the type 1 gearbox, cause it will probably break. The Subi Turbo gives a torque of more than 300 Nm and this is far too much for the type 1 tranny. We always use Porsche 915-gearboxes for the EJ 20T. Even the 901/914 will not stand the torque.
Porsche 901/914 won´t stand more than 270/280 Nm. The type 1 is much weaker than the 914.

Hope you choose the right way with investing.

Martin

Thanks Martin, There are many success stories using a type 1 box based on the type of driving I will be doing. There are type 1 boxes of similar spec to mine that run 11 sec. passes (fairly) consistently. My car won't be that fast or have the shock load of a dedicated drag car. With the right tire, clutch choice/management I think it should be okay. I agree that Porsche or a bus box would be the 'right' way, however I added it up and its not in my budget right now. I can get what I need out of a type 1 box for much less than a Porsche unit.

Now, how about those gear ratios? Even if I had a good first gear ratio I could split 2nd and 3rd since I think I have a good choice for 4th... Anyone?