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So. I guess I need a new tach as well as a new speedo.

 

If you have a 74-77 tach, there is some chance the BMW ECU will drive it. It won't hurt to give it a try.

 

 

...and will mount it on the gear box rear ears to pick up the 3 lobes on the output flange.

 

I had exactly the same thoughts, early on. I think a Honeywell 1GT101DC Hall Effect would do well, mated to an aftermarket speedo. That was my original plan, since I had intentions of using an aftermarket ECU. However, it may be troublesome with the BMW ECU. In my M3, there are a couple of obvious speed related 'things' going on... speed sensitive stereo, speed sensitive wipers, and gear based rev limiter (which uses info from the VSS). Obviously the first two are irrelevant, but the third item would be affected if the pulse count was off by much. Also, I can only guess at all the EFI related variables BMW may influence with the VSS. It's not something I've researched and it may be nothing to care about, but I would look into it before pushing the ignore button.

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Ron.

 

Im just going to use the Speedhut sender to drive the speedo, nothing else.

 

The S50B32 does require a road speed signal, otherwise it goes into a reduced power mode and wont rev past 7k. This road speed signal originates at the VSS and goes to the instrument cluster to drive the speedo but then is modified from its simple square wave form into something else before it sends it to the ECU. Problem I have is that I dont have access to a car or a scope to see what the final signal that goes to the ECU looks like. Not having the VSS signal from the BMW diff or the dash to modify the signal Im likely going to have to purchase one of these http://www.kempower.be/Electronic%20devices/BMW%20M%20speed%20simulation.htm Pretty expensive .......unless you would like the challenge of making one for me Ron!!!

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Hell at this point it almost seems cheaper and easier to install an E36 diff.

 

 

I've been seriously considering just that. Taller butt gears, very tunable LSD, VSS, CV half-shafts... and no need to machine a diff adapter.

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No joke, if you're not running a 6 speed it almost seems required.

 

The back mount would be pretty easy to mount up (might actually be able to attach something off of the normal mustache bar, or just make a custom on out of aluminum or something)

 

The front is really the part I'm hesitant about. You could probably hack up the rear subframe of an E36 to make some sort of front mount that attaches to the Z though.

 

I'll look into more and see how much of a pain it might be.

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Ive got both the medium case diff from the early E36 M3 (same as the version you get in the US) as well as the large case diff used in the Euro Evo version. I would love to use the large case diff and CV's as they are just about unbreakable but cost and availablity of higher ratio gears and the amount of mods to fit make this unatractive vs low cost and vailability of R200 options.

 

 

 

 

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I looked at using a BMW diff, but it is wider than the Z diff and looked like a lot of trouble to swap.

 

Summit has an adapter for the tach for $78.95. Not cheap, but cheaper than a new tach and much cheaper than the speedo converter.

 

I may try a dash from pull-a-part. If I am lucky, I could even put replace the guts of the Z speedo with the BMW speedo. Fat chance.

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I thought they almost all used the 205mm gear sets.

 

If I've got my facts straight, the stateside E36 M3 uses a 188mm ring gear, the Euro diff is a 210mm ring.

 

 

 

BRAAP and I went to the JY tonight. I found this 1995 M3 diff (3.15:1)...

 

 

M3Diff4.jpg

 

 

M3Diff3.jpg

 

 

M3Diff1.jpg

 

 

M3Diff2.jpg

 

 

M3Diff5.jpg

 

 

I looked at using a BMW diff, but it is wider than the Z diff and looked like a lot of trouble to swap.

 

 

Flange to flange is about 11.5"... about 2.5" wider overall than my R180. Yes, it would take some creativity to adapt, but I see nothing scary... yet. The axles would probably be the biggest expense/effort.

 

 

...but cost and availablity of higher ratio gears and the amount of mods to fit make this unatractive vs low cost and vailability of R200 options.

 

In the States, R200 CLSD's cost far more than Bimmer CLSD's. The diff pictured above has 80K miles on it and I can pick it up for $300 (about 1/2 the price of a comparable R200). It's not the large case diff, but I see no need for it in our cars unless you plan on boost and slicks.

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Q45_Rear_Diff_Install_0011.jpg

 

This is a Q45 diff in an S30. I just measured the one in my garage and from flange to flange it's approximatly 13". So I really don't think the diff is going to be too wide.

 

I'm gonna go to a picknpull tomorrow and yank the front diff mount and maybe just the whole damn subframe out of a 325 or 328 or something, then go find me an M3 diff off Craigslist or something (3.38 would be FANTASTIC!).

 

Considering that I was gonna have to get custom cv shafts from Dutchman or something anyway, I'm 100% going to be going the Bimmer route...

 

 

...especially now that Ron is and I might be able to get some help....

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...especially now that Ron is and I might be able to get some help....

 

I'm not yet committed. Hughdogz gave me a set of half-shafts last weekend, so I'm good for a while. On my wish list is CV's and taller gearing, so I'm just daydreaming right now. But, I'd be happy to lend you a hand with yours.

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The GPS speedo has a built in 0-60 timer. Don't know how accurate it is, but I thought I'd give it a try. I only made one run and botched the launch a little. 4.48 seconds...

 

 

First0-60.png

 

 

 

I can't make it in 2nd gear, gotta use 3rd for the last few MPH. That never helps.

 

I think wrapping up the tune and a little better launch, I should be able to get pretty close to 4 seconds flat. Not too shabby for a little NA motor that also makes useful torque @ 1200 RPM.

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  • 2 months later...
  • 5 months later...
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I've built another set of mounts for one of our members...

 

 

NeverdoneA.jpg

 

 

 

NeverdoneB.jpg

 

 

 

 

I have 3 more sets laser cut and formed. Just need to weld them up. 1 set is for another HZ member. The other two will go up for sale here.

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  • 3 weeks later...

Looks like you got the 6bolt CV flange on the diff flange. Most 95 M3s had the black sheep diff with the CV joint at the rear of the driveshaft. Any other year of the e36M3 will have the same case, but with a 4 bolt flange. The Auto M3s had a 3.38, which is a pretty common upgrade, but as far as taller gearing you may want to check out some 5 series diffs.

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Looks like you got the 6bolt CV flange on the diff flange. Most 95 M3s had the black sheep diff with the CV joint at the rear of the driveshaft. Any other year of the e36M3 will have the same case, but with a 4 bolt flange.

 

As you mentioned, the '95 M3 diff I have came with a CV. It was a manual coupe. My '98 M3 coupe w/manual trans came with a U-joint. BRAAP's '97 M3 sedan w/manual came with a CV. Another friends '98 M3 w/automatic has a U-joint. To be honest I haven't figured out the pattern, but I can't say I've tried, either. If you have the magic decoder ring, don't be bashful :-)

 

 

Are you going to keep producing those mounts?

 

I don't have any plans to keep making them.

 

 

If so how much are you selling them for?

 

See next post.

 

 

I've always thought a boosted s52 would be an awesome swap.

 

You and I think alike :-D

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FOR SALE

 

I finished up all four sets. Three are spoken for and shipped. I have one set left...

 

 

S52toS30Z.png

 

 

 

First $150 in my Paypal account takes them. Shipping is included in the US. If outside the US, PM me and I'll get you a quote.

 

P.S. The black paint is a very light coating just to protect them until you're ready to install. It will remove quite easily.

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