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Sigh... memories...

The Euro version ,,,,,,,,but at the expense of HP.
Excellent summary!

I'm jealous, the driving experience of the Euro version was significantly better than the US. Mine was an 87, so it had the even extra luxury stuff, in terms of full leather dash. Those had a tendency to lift in the corners, and not wear well....dumped for 88 when they also changed the bumper trim etc....

Ug... just remembering the TRX rims too.

Beautiful car, with absent B pillars, and classic good looks. The Euro M635CSI was so much more fun to drive with more power and less weight. I believe most people converted to dual timing chains, this doesn't rob that much power, and can save an expensive rebuild. By now I'm sure you upgraded to the S50B32 chain tensioner etc.. Did you go for the Fahey crank hub?

I sold my car very shortly after a test drive in a used E34 M5. The extra power was eye-opening, and I realized I'd want one of those eventually, or something similar, a bit more practical with 4 doors.
 

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Excellent summary!

I'm jealous, the driving experience of the Euro version was significantly better than the US. Mine was an 87, so it had the even extra luxury stuff, in terms of full leather dash. Those had a tendency to lift in the corners, and not wear well....dumped for 88 when they also changed the bumper trim etc....

Ug... just remembering the TRX rims too.

Beautiful car, with absent B pillars, and classic good looks. The Euro M635CSI was so much more fun to drive with more power and less weight. I believe most people converted to dual timing chains, this doesn't rob that much power, and can save an expensive rebuild. By now I'm sure you upgraded to the S50B32 chain tensioner etc.. Did you go for the Fahey crank hub?

I sold my car very shortly after a test drive in a used E34 M5. The extra power was eye-opening, and I realized I'd want one of those eventually, or something similar, a bit more practical with 4 doors.
The TRX rims were a pox on all the BMWs of the mid-80's era. Remember they were on 5 series and 7 series as well. The Euro M635s were supplied with special 3 pc BBS TRX rims which were prone to cracking and were recalled by BMW/BBS. The replacements (I still have a set of these) were single pc forged BBS rims that took the 415 mm TRX tires. The tires are still available but are outrageously expensive.

You can see a summary of my car in the other post (M6's on the Board). Frank Fahey rebuilt my Dinan stroker a few years ago. The Dinan stroker motors were supplied with a special run custom SCAT crank, which provided even more stroke than the E34 M5 cranks did. Since it was custom for the Euro M635s, it fit a single row sprocket for the cam chain, and I did not have to convert all the cam gearing to dual row. We did replace all the tensioners/chain/sprockets during the re-build, and using the updated cam chain tensioner I have had no problems since. The stroker crank really transforms this motor, providing a large amount of mid-range torque that you really can use.

And of course, I have been using the Fahey crank hub for a many years. It was the first mod I did to the motor, even before Dinan stroked it.

I consider the Euro M635 the only real performance 6 series. At 3300 lbs (with a modded motor over 320 HP) it breaks (under) the 10:1 LBs/HP criteria which I think is essential to consider it a real performance car. The US model 6 series were nice cruisers, comfortable and capable of high velocity autobahn running. But at a stoplight, forget it. And nothing matches the sound of those Euro M635 tubular headers at full song.

The E34 M5s are a nice improvement but still don't have the power/weight ratio of my stroked Euro M635.
 

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yes you are right,the sounds and power of a m88 is very nice to drive.(high reving is a addiction)haha,the best thing I have did on my euro was placing a 3.91 diff from a us version m6.its transforms the car completly.the same with the tuning and 3.6l to 7200 max rpms.I can not waite until ist back good weather.cruising full powah,hoping to get a lot of traffic light,so I can launch the car full trottle.its strange,but fast accelleration is with my car very tricky,I have 275 tyres,but to much trottle and I lose grip,but when I got it right its is very nice,my friend have a z3m roadster,and every summer its the same,I can not take him and he can not take me.aah I miss summer time.
 

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Well, the euro M635csi like the Euro M5 had a slightly different engine, 286 vs 256 HP.
The Euro's had the m88, while North America got the s38. Single v. dual chain as dhl93449 highlighted.

The valve cover on the m88 also had a Rondel that we didn't get on the s38.
 

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yes you are right,the sounds and power of a m88 is very nice to drive.(high reving is a addiction)haha,the best thing I have did on my euro was placing a 3.91 diff from a us version m6.its transforms the car completly.the same with the tuning and 3.6l to 7200 max rpms.I can not waite until ist back good weather.cruising full powah,hoping to get a lot of traffic light,so I can launch the car full trottle.its strange,but fast accelleration is with my car very tricky,I have 275 tyres,but to much trottle and I lose grip,but when I got it right its is very nice,my friend have a z3m roadster,and every summer its the same,I can not take him and he can not take me.aah I miss summer time.
Tire slippage under accel is probably due to some decent HP plus the 3.91 diff. I am using 240/17s (so I can rotate tires) and I have a Quaiff LS diff and get a considerable amount of slip, esp in the rain or on dirty pavement.

BTW what top speed have attained in your car? I have suspected that the MTechnik skirt kits lower the top speed of the car, especially due to drag at the rear valence (its like a large parachute back there).
 

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I never drive faster then 200km,I hate the dead fly's on my front.hahaha
I only do fast accelleration.fast driving in belgium is not possible.to much traffic and to much crappy roads.
and the good places where you can drive fast there are the cops standing with there speedgun.
to much risk.my car's are a investment.fast driving is good,but on a track.I must check that in the gear ratio calculator.

I am building a turbo e24 on this moment,in csl mode.special build for accelleration.
I will post pics soon.
 

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Hello,

like Ruben:
It is same car:

called M635csi in Europe and M6 elsewhere....:cool:
Well, no. There are a number of small but significant differences. Did you know that the quarter panels on the Euro will not fit the US car and vice versa? The hood is different, as are the bumpers/bumper mounts, air dams, rear trunk spoiler. The ECU and air flow meter are different. European cars came with options like manual Recaro sport seats, water buffalo hide and trim, a magnetic key central alarm systems (in the trunk) you will not find on any US or NA car. Even the valve clearance spacers are different for M88 vs the S38. The M88 can use convention VW pucks while the S38 uses special (meaning $$$$) BMW ones.

If you ever wreck a Euro M635 here in the US, you had better have a body shop that knows what they are doing. If they order parts for a US 635 they may not fit your Euro body!
 

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forgot to tell,after the tuning the accelleration was not possible on full throttle.
the m technic rear springs where too soft.when accelleration the rear wheels are jumping up and down very fast.
this was not fun.

I solved this with something very simple,I orderd in the uk some greystone spring rubbers.(towing a heavy load)
with that the rear suspension keeps original,but the becomes stiffer under load or heavy accelleration.(when pressed)
it was day and night.
 

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that is the first time I hear that,the the quarter panels and the hood is different.do you have a pic of the us hood and trunk spoiler?I only knew those other things.
what is different?
what do you mean with pucs,are those the plates under the cam lobs?
 

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I never drive faster then 200km,I hate the dead fly's on my front.hahaha
I only do fast accelleration.fast driving in belgium is not possible.to much traffic and to much crappy roads.
and the good places where you can drive fast there are the cops standing with there speedgun.
to much risk.my car's are a investment.fast driving is good,but on a track.I must check that in the gear ratio calculator.

I am building a turbo e24 on this moment,in csl mode.special build for accelleration.
I will post pics soon.
200 kM is about 120 mph, so I don't think the skirts are in effect yet. My car pulls like a train to 140-145 MpH, then "stalls" out very gradually increasing speed thereafter. Like in your country, these are "go to jail" speeds here in the US, so I have not run long enough to get to max speed. But given the HP in my car, it should be able to get to 165 just based on HP. I think even the US 256 HP M6 was measured by Road and Track at 156 mph (Road and Track, World's fastest cars 1988). But that car did not have MTechnik spoilers. I suspect that rear valence creates a lot of downforce, but at the expense of a large amount of drag.

Talk to Frank Fahey about your turbo. He built a 600 Hp turbo 635 (modded straight 6 3.5 L motor) with alcohol injection back in the eighties.
 

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that is the first time I hear that,the the quarter panels and the hood is different.do you have a pic of the us hood and trunk spoiler?I only knew those other things.
what is different?
what do you mean with pucs,are those the plates under the cam lobs?
The difference are very minor, but enough that if you are welding in new panels, they are not interchangeable. You can tell by the different part numbers in the ETK for the M6 vs the M635. It looks as if on you car, you have the later version M6 style trunk spoiler. Compare yours with the photos of either of my M635s in the other post and you will see the difference:

http://www.m5board.com/vbulletin/e31-850-csi-e24-m635-csi/202873-how-many-e24-m6-m635csi-owners-forum-4.html


Yes, the cam adjustment shims on the M88 are different than the S38. On the hood I believe one of the differences is the cutouts for the windscreen washer nozzles and perhaps the mounting location for the gas springs that open the hood.
 

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It's about the timing

Very simple answer Mike about what they are referred to differently in Europe and the USA. It's about timing. When the M635csi was launched in Europe in 1984, BMW was using the model naming nomenclature they had used with the M535i. For whatever reason they decided to change that soon after and called the mechanically very similar E28 car the M5. It w only later of course that the E24 in M car guise was launched in the USA. By that time the model naming rules had changed and it was called M6 for that reason. BMW, being good German traditionalists, never changed the name in European markets. As a matter of interest they called the car M635csi in my home market of NZ as well despite that fact that no cars were sold there until 1986 or so through dealers. This was because NZ was using UK spec cars so the name remained in accordance with the UK rules. As a matter of interest 20 of the UK spec cars came to NZ and were sold new. Mine was probably the last sold in 1990 even though it was a chrome bumper car delivered to the NZ dealer in 1987. Blame the recession. So in a nutshell there is nothing more to it than timing. The engine numbers and so on are not, to the best of my knowledge linked to the naming. It was just different markets over time and the changing nature of the value that BMW AG saw in the emerging M brand. All the best. Kiwiphil
 
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