Need help on R 50-50 ratios

[911heaven]

I have a RUF 6 speed out of my car that underwent a BTR engine conversion back in the day. The chassy was a 3.2 carrera 89, not a genuine RUF chasy WO9, but a Porsche one WOR. Nevertheless, the car I got damaged through a wrecker/ins. co 20 years ago had a title in Japan with RUF insignia, all the Ruf parts throughout the car.

I got rid of the motor years ago, but still have the transmission, even the immaculate 6 speed shift knob in leather. The car only had 8000 kilometers or about 5 thousand miles on it at the time I dismanteled it.


My question here is how to know what ratios are in the gearbox without taking it apart. Or is it absolutely necessary to take it apart to find out? I researched the other day on the net that there were some options on ratios during that BTR phase. If that is correct, all the R 50-50s out there might not have the same standard ratios.

Is there a way to find out with out dismantling the trans? I have no experience doing that yet.

Thanks for any help on this
bernard

[Bill Verburg]

Originally Posted by Bernard Plett

I have a RUF 6 speed out of my car that underwent a BTR engine conversion back in the day. The chassy was a 3.2 carrera 89, not a genuine RUF chasy WO9, but a Porsche one WOR. Nevertheless, the car I got damaged through a wrecker/ins. co 20 years ago had a title in Japan with RUF insignia, all the Ruf parts throughout the car.

I got rid of the motor years ago, but still have the transmission, even the immaculate 6 speed shift knob in leather. The car only had 8000 kilometers or about 5 thousand miles on it at the time I dismanteled it.


My question here is how to know what ratios are in the gearbox without taking it apart. Or is it absolutely necessary to take it apart to find out? I researched the other day on the net that there were some options on ratios during that BTR phase. If that is correct, all the R 50-50s out there might not have the same standard ratios.

Is there a way to find out with out dismantling the trans? I have no experience doing that yet.

Thanks for any help on this
bernard

It's possible but takes some time and careful measurement

There are 2 ways to go, lets call them forward and backward

forward
put the trans in 1st, carefully measure the turns at the input shaft and output shaft, the ratio of turns is the total gear ratio, say it's ~12 input to 1 output, the overall ratio is then 12:1, divide by the cwp ratio which is probably 3.444, the gear ratio is then ~3.448, stock would have been 12.056/3.444 = 3.5 so close enough. Repeat for each gear.

backward goes the other way

[911heaven]

Originally Posted by Bill Verburg

It's possible but takes some time and careful measurement

There are 2 ways to go, lets call them forward and backward

forward
put the trans in 1st, carefully measure the turns at the input shaft and output shaft, the ratio of turns is the total gear ratio, say it's ~12 input to 1 output, the overall ratio is then 12:1, divide by the cwp ratio which is probably 3.444, the gear ratio is then ~3.448, stock would have been 12.056/3.444 = 3.5 so close enough. Repeat for each gear.

backward goes the other way

Hi Bill! What a blast from the past. Perhaps you remember helping me 10 years ago? I was the guy trying to put a 964 full chassy loom into a 911 with all the 964 components?
I was a beginner on the forum, and so ignorant on the forum that i didn't realize each thread if long enough goes to a second page. At the time, while posting, i didn't get any replies on the first page.

As a result i thought moderators were secretly monitoring my posts and blocking them. I then posted that i would not post again and quit the forum,which i did actually for several years. Is that not funny?? I only got back on the forum about 3-4 years ago when i bought a 69'911E.

If you can dig up my old thread Bill, and post it, that would be fun. I am planning to abandon the project as i speak.

[911heaven]

Also Bill if you're still there, due to good advice from another member on the forum, I now plan to just open up the gearbox for a look on condition as well. The former idea by consensus, and as you said, quite the task. Thanks so much for the tip!

Lastly, I was wondering if you wouldn't mind looking at my thread on the marketplace forum. I'm trying to value my 3.8 motor. I know that you have a lot of expertise in that realm. I don't, and since i wasn't the person who built the motor, or the same guy who quickly wrecked the 964 car shortly thereafter, i need some help to know how to ascertain what it might have inside. Current question is are the cylinders slip in type or bore the case type?

I posted pix of the motor on my thread today. Could you have a look? Anyone else who can help, I would be grateful. I can't tell just by looking.
bernard

[Slovenia.motors]

Originally Posted by Bernard Plett

I have a RUF 6 speed out of my car that underwent a BTR engine conversion back in the day. The chassy was a 3.2 carrera 89, not a genuine RUF chasy WO9, but a Porsche one WOR. Nevertheless, the car I got damaged through a wrecker/ins. co 20 years ago had a title in Japan with RUF insignia, all the Ruf parts throughout the car.

I got rid of the motor years ago, but still have the transmission, even the immaculate 6 speed shift knob in leather. The car only had 8000 kilometers or about 5 thousand miles on it at the time I dismanteled it.


My question here is how to know what ratios are in the gearbox without taking it apart. Or is it absolutely necessary to take it apart to find out? I researched the other day on the net that there were some options on ratios during that BTR phase. If that is correct, all the R 50-50s out there might not have the same standard ratios.

Is there a way to find out with out dismantling the trans? I have no experience doing that yet.

Thanks for any help on this
bernard

Bernard,

All RUF gearboxes are custom made in order and they have different gear ratios and options like LSD etc.
Is it a R50-50 (12 bolts on side cover) or a R50-00 (11 bolts on side cover) ?
Is there the RUF tag with the serial # still present ?If so,e-mail or call RUF in Germany they have a very detailed log file for any of their builds...

[911heaven]

Originally Posted by Slovenia.motors

Bernard,

All RUF gearboxes are custom made in order and they have different gear ratios and options like LSD etc.
Is it a R50-50 (12 bolts on side cover) or a R50-00 (11 bolts on side cover) ?
Is there the RUF tag with the serial # still present ?If so,e-mail or call RUF in Germany they have a very detailed log file for any of their builds...

Thank you for the great advice Slovenia motors! As per your questions, Yes, it has the Ruf (green) badge rivoted to the underside case read R 50-50 number 0041. I'm not at home today so I would have to look as I've not looked at the badge in a decade perhaps. I could confirm the exact part no (41) by tomorrow when I get home. It has LSD, Ruf is inscribed on the case both on the side and at the rear.

I always thought that I could contact Ruf and ask, never did however. I actually thought it would be hard to do, especially since I don't speak German. If you know a number I can call or their email address, if handy, please let me know.

Thanks again,

bernard