Manual tranny question

[jrhaile]

Did finished the auto to manual swap. Everything went great, took about 10 hours total to do. I didn't change the differential though. My question is, should I? at about 70mph, my car is hitting about 4000rpms, is this normal for those of you who manual trannies? if I should change it, what ratio should I change it to and where can I get it? Don't send me to zionautosport or whatever either, too damn expensive!

Btw, I love my bmw even more now. Car absolutly jumps off the line and it it's 100x more responsive which I love.

[Kevin325i]

4k at 70mph seems a little high for me. I think it should be closer to 3200, but I'll go check tomorrow.

I do know the gears top as follows. 1st should be about 35mph, 2nd should be around 53 mph, 3rd like 75-80 (not possitive on that one)

If you can pick up a 3.15 LSD off a manual 325i that'd probably be best. But if you don't mind the high revs on the highway your car will be quicker with the shorter gearing.

Kevin

[El Presidente]

the revs will be much higher due to the different gearing. 4k is high for 70 (my 1.8 is around 33-3400), but normal given it has 3.91 gears. If you are into acceleration, and don't mind the revs, I say keep it. Your top speed will be between 90-100 though.

[TeeUp]

my 1.9 -----


mph rpm
70 - 3200
75 - 3400
80 - 3700

[BlantonG13]

Same here...on the 318i as Prez and Tee...I don't hit 4k rpm until I am going 85mph...I would get the differential changed. If you can, look up a used parts dealer or something, find a manual differential off a used BMW. This will save you some serious cash. But make sure to have it inspected or checked out by a mechanic...you don't want to put broke parts on your baby.

[dutchbmw]

My car:

2950 rpm @ 70 mph (112.6 km/h)

[frank3]

Unless I misread...did you say what gear you're in at 70? Is it 4th or 5th?

Also...tire/wheel size will make a bit of a difference also...but not too much.

[dutchbmw]

Mine is in 5th gear with the values above.

[frank3]

My 94 325i has the same rpm's as dutchbmw at 70 in 5th gear: 2950. In 4th gear at 70 it's around 3800.