TeufelHei

Anyone here know about installing the superior Borg Wagner 5 speed unit? I'm contending with a tranny re-build right now on my 81 928 US spec, and the cost vs longevit is in question. Are they interchangeable and to what degree? What adaption has to be done to make it work? Please advise if you can.

Tim

Jim bailey - 928 International

bolt it into a 81 ..... plug and play the difficulty is finding one at a reasonable price plus adjusting to the different final drive ratio 2.20 (85-88) rather that the 2.75 of the early car .

rjtw

Hi Jim,

Pardon me for a stupid question, but can you define final drive ratio?

And what adjusting are you referring to? I hope you only mean in driving style (I assume the later boxes are generally "shorter" geared all round), not in the need for a different differential or some such thing!

Just curious should I ever need to pursue the option.

Thanks
Rick

Jim bailey - 928 International

the later trans is a taller ring and pinion gear ratio less rpm acts more like "overdrive" there is more space between gear ratios more rpm drop when you shift but as Marc Thomas has proven you can go 210 mph with enough power .

TeufelHei

Thanks Jim, you have answered my prayers.

Next question, can you change ratios? Were there any comparable (interchangable) components from any other model/year Porsche cars?

Tim

Jim bailey - 928 International

you can only use 928 parts ..... The rare GT box for 1989 had a 2.75 ratio for better acceleration closer gears . That has been a 3.09 made but is it thousands for a ring and pinion and has some issues with manufacturing tolerances .

TeufelHei

Thanks again Jim, I'll play the custom gearbox game some other time then.

Tim

Gary Quayle

Sterling,
From 928 Specialists' web site -

84-86 S - 4-Speed Automatic (Euro)
2.36 (2.54 - Optional)

84-86 S - 5-Speed Manual (Euro) 2.73 (2.27 - Optional)