transmission upgrade for a 1988 porsche 930 ( 4 gears)

[michel930]

hello , i am from france , near Paris , and i often read your posts here at pelicans site.
first of all, i hope you will forgive my very very very bad english .

here is my question: is it true that on a 1988 porsche 930 turbo 3.3 the torsion bar tube is the same that on the 1989 porsche 930 which are with a G50 gearbox fitted ?
is it also true that on a 1988 model its possible to put in a 915 or a G50 gearbox without having to do any job on the tube in where the torsion bars are located?
may be this question has already been asked before , so i beg your pardon in this case but for me its no easy to understand all of your posts .

in fact i want to do a gearbox conversion , to have five gears , but i am scared about having to cut or change the tube where torsion bars are fitted in.

any comment or idea from you will be be helpfull for me , because here in france , only a few people have done this upgrade and i even not know where i can find them .

thanks in advance for your help
so sorry for my bad english.

thanks from france

[David]

Welcome to the forum.

I've never heard of the 88 930 being able to take the G50/50 or G50/52 without modification. I think most people cut out the torsion tubes and install coilovers.

Another option is to install a lower 8:39 gear ring and pinion. This will make the 4 gears similar to the first 4 gears in the 89 5 speed.

[michel930]

Originally posted by 125shifter
Welcome to the forum.

I've never heard of the 88 930 being able to take the G50/50 or G50/52 without modification. I think most people cut out the torsion tubes and install coilovers.

Another option is to install a lower 8:39 gear ring and pinion. This will make the 4 gears similar to the first 4 gears in the 89 5 speed.

thanks for your help , 125 shifter
and what about a 915 gearbox ?
wont it fit into my car ?
so it seems that there is no other way than cuting the torsion tube and install coilovers.
all this job seems too impressive for me , because i use to do all the job myself on my cars.

125 shifter means that you are a gokart driver?
i have been driving 125 / 6 gears gokarts for quite 20 years and i stopped driving only two years ago. ( now i am a little too old and my back and neck are not as stonger as they were when i was younger.
what is the make of your chassis ?
and the make of your engine ?
do you drive gokarts only for fun or are you a racing pilot?

best regards from france

[David]

A 915 would work for a while but it's not designed to handle the torque of the 930 so you'd be replacing it every once in a while.

I'm planning to change the R&P in my car. It will hurt top speed and fuel mileage but I don't need to go over 160mph and I don't drive it enough to worry about fuel economy.

I've got a Tony Kart chassis and a YZ125 engine. Both are getting pretty old but they still work well. I've stripped the frame down a couple times, inspected it, and welded some cracks. I've got the engine up to Honda hp levels so it's working well but Yamaha's not selling new engines anymore. This is my 5th year racing but I've only done a few races the last 2 years so I have more money to spend on the 930. I road race the kart so I run on tracks that are about 2 miles or more in length.

[dean]

I think the only G50 you can fit in your car without cutting the torsion tubes is from a non turbo model. The turbo G50/50 is too big and would require you to cut the torsion tubes. I am not positive about this though. To fit the NA G50 in your car you might have to cut the bellhousing to make it fit. I wouldn't install a 915 in your car. I think it would be a weak link.

Dean