Posted by Marlen Padberg on August 04, 1999 at 13:20:58:
In Reply to: Re: '80 528i Auto to 4 or 5 speed? posted by Troy Rudolph on August 04, 1999 at 12:55:28:
When you did your 5-speed upgrade Troy, did you change the rear end ratio at all? I have compared the ratio, and 1st to 4th in both trannys are almost identical, and 5th is overdrive, so I'm assuming you haven't changed it, correct? When you changed it, did you use the driveshaft from the 5-speed car, or get the 4-speed shortened? I asked a local machine shop about shortening my 4-speed driveshaft, and they said cutting off the flange (at the tranny end), and re-welding it carefully should keep the balance almost as good as the 5-speed driveshaft.
What do you think?
: Mine is a '79 so it came with a 4-speed. I converted to a 5-speed a few years ago. For me the advantage was highway crusing. The ~19% overdrive drops the revs quite a bit. At 80mph the thing was turning ~3900 rpm in fourth. Now, in fifth, it turns slight less than 3200 rpm. As a result, the car is much quieter and much smoother on long trip. Also, the gas mileage is much better. It went from around ~19 to around ~25 on the highway. Of course, the around-town figure didn't change.
: Since you have an automatic, you'll also get a big boost in performance. You'll most likely pick up a full second on the 0-60 time. But, if you spend a lot of time in traffic, you'll have to shift. Everything is a compromise.
: Now if you could find a way to install a 4HP22 (four-speed overdrive auto) in there, you *might* have the best of both worlds. I have no idea how to go about it though.