engine and drivetrain Has anyone ever seen a 02 with one-piece drive shaft?

[geokai]

Hi all, Im doing a m20 conversion and have installed the engine and trans from a donor 325i. Since the tranny is e30 and the diff out back is 320i, i will need to have a custom driveshaft made. Does anybody see a problem going to a one piece alloy drive shaft?

any thoughts ?

thanks, Geoff

http://home.comcast.net/~geoffkai/bmw.html

[Tommy]

I had problems with one piece shaft in my racecar. I'm going back to two piece. The reason was that it goes to a resonance at certain rpm and would break if continued at that speed or faster. You probably have lower ratio differential so it may be ok. Also larger diameter shaft would help. It can be calculated by a competent shaft specialist if it works or not. You have to know how fast you want to spin it. Mine was on the limits and it didn't work.

[NickVyse]

This thread might interest you - roughly same length as the 02 shaft depending on your gearbox.

http://www.s14.net/forums/showthread.php?s=beb76b0f200f3a6855b0eef4e647bfe0&threadid=20369&highlight=carbon+AND+driveshaft

[geokai]

Thanks for the good advice.

Im probably going to keep the 2-piece and merge the 325i front half-shaft onto the rest of the 02 drive-shaft . I dont want to run into vibrations; it was mostly a idea of simplicity i was interested in.

Tommy, your car rocks! I found lots of motivation to do my car after looking through all the pics on your Goodfellas web page.

Thanks for the input guys, Geoff

[winstontj]

Hi all, Im doing a m20 conversion and have installed the engine and trans from a donor 325i. Since the tranny is e30 and the diff out back is 320i, i will need to have a custom driveshaft made. Does anybody see a problem going to a one piece alloy drive shaft?

any thoughts ?

thanks, Geoff

http://home.comcast.net/~geoffkai/bmw.html

CD posted a while back all the specs of a stock driveshaft. Operating torque was up in the 600's and max torque/shear limit was up in the high 700's IIRC. Stock driveshaft is fine for just about everything - up to and including everything. Alloy CroMoly may be an option for weight savings but CF is going to cost you (regarding Nick's post). At least with alloy steel they could weld it to the stock u-joints. A one-piece CF shaft would be cool but fitting the ends would be an issue. I'm sure they have perfected this now but I toyed around with one a few years back and we could never figure out how to attach the ends. We used shear pins and they never held. I'm sure a custom shop would know but then again that's where you'll pay $1,200 too. The extrusion can be had for under $200 but attaching the ends is another story.

Why not just use the 2002 d-shaft? Run the stock rear and shorten the front and weld on the E30 flange. Are the E30 and 2002 tubes different diameters? If they join in the middle with the same spline (doubt it) you could just run the forward E30 section - probably still have to shorten it - and stock rear 2002.

How much HP/torque are you going to get? Guys blow up diffs all the time but I've never heard of a d-shaft blowing up from an M20 conversion.

[c.d.iesel]

..maybe you can use one of these BMW shafts and

stay with 2-piece - check the dimentions>

[punchesdfw]

How did you get the stock tranny in your 2002? I assume you cut-out the tranny tunnel?

[geokai]

Yes, i did cut the trans tunnel out first. Im currently at the point where i need to cut the tunnel in half and then add a little metal to the middle to widen it. It also will be about an inch higher than stock. so it will have a step-down a few inches after the shifter hole.

For the speedo im planning on buying a nice digital unit that runs on HALL effect. I will have to place magnets around the driveshaft or rear axle.

-Geoff

[geokai]

Yes, i did cut the trans tunnel out first. Im currently at the point where i need to cut the tunnel in half and then add a little metal to the middle to widen it. It also will be about an inch higher than stock. so it will have a step-down a few inches after the shifter hole.

For the speedo im planning on buying a nice digital unit that runs on HALL effect. I will have to place magnets around the driveshaft or rear axle.

-Geoff

[NickVyse]

For the speedo im planning on buying a nice digital unit that runs on HALL effect. I will have to place magnets around the driveshaft or rear axle.

-Geoff

I did the same - mounting the magnet on the output flange of the diff. I then took the old speedo apart, removed the old workings and cut a rectangle out the middle of the speedo face and mounted the digital speedo. You don't even notice it until it lights up, and where the trip and mileage readout used to be, I printed out BMW and 2002 in white out of black and stuck them behind the cut outs. Looks quite neat.

It's a rubbish picture, but you can just about make out what I'm poorly describing!

[geokai]

Nice job on your car!

I think you can also get what looks like a conventional speedo; it IS digital, but looks like an anolog unit.

[NickVyse]

Nice job on your car!

I think you can also get what looks like a conventional speedo; it IS digital, but looks like an anolog unit.

Yep, that's another option. I got mine from spa in the UK:

http://www.spa-uk.co.uk/design/gauges.asp