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BMW 6-speed box users: What are your impressions?

Harlard

Harlard

Hurlurd?Harland?Bueller?
300+ Club
Joined
May 11, 2007
Location
Niketown, OR
You know, as another alternative, to compare to the CD009. More expensive new (like $5000 from the dealer), so choices are limited to used boxes.

If you have a -37BZ or -53BZ box, post your experiences.
 
Excellent. Aside from a 3-axle gearbox on a non-dual mass flywheel rattle noise at idle (I had the same in my '69 Camaro when I swapped in a T56, and Cam has it with the M90 in his 940) and maybe some coast down, it's as factory. Shifts great. Clutch we chose is a bit heavy but I've been over that and it's not a gearbox problem. The clutch and flywheel are where the struggle is with this swap, especially if you don't want sinterlamell.

Gear ratios are aggressive with the -DZ variant. 1st is pretty useless with the 3.73s the car has now, we have a set of 3.31s, they're on the "later" list. 3.15s would be very good.

Fit in the tunnel of a 240 is EXCELLENT. It's easier to put this 'box in than an M47, no joke. Except weight maybe. We did have to have the front shaft shortened 20mm, $80.

If you have the means, I highly recommend it. It's so choice.

Do you have specific questions?
 
Mostly in terms of refinement and resonance. I swapped one in my E39 and am really liking the ratio spread and lack of noise. It has a single mass Valeo comversion flywheel and N47 pressure plate and disc. The idle rattle is nearly imperceptible, but the inline 6 engines are also smooth.

I’m sweating the flywheel situation for sure. So far TTV seems to be the popular option. I want to run a full weight flywheel with a 707 disc. Seems to be the easy option.
 
We used a Tenaci modular flywheel, but had to have Cam's friend modify the inner ring on a CNC as it wouldn't clear the springs on the clutch disc. Had to open up the inner portion of the pressure plate to clear the center hub on the clutch disc also, it needed about 4mm larger diameter. They were easy operations, but they were on a CNC mill.

We also used the organic Sachs disc MKM sells, and a Sachs E39 540/E46 M3 Sport pressure plate, I forget the part numbers on these. It's heavier than I expected, but I don't think the regular pressure plate for these applications will hold the torque value we're expecting when the engine is finished.

I prefer to use off-the-shelf stuff whenever possible. Sometimes, it's not, and you gotta do what you gotta do.
 
Harlard said:
I’m sweating the flywheel situation for sure. So far TTV seems to be the popular option. I want to run a full weight flywheel with a 707 disc. Seems to be the easy option.
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This may be the most logical thing I’ve heard from you in months :-P

Also, the TTV quality is amazing for what it costs.
 
Yes, it's very good with the refinement. No, it's probably not as good as an inline 6 because nothing is. When we made the pro and con list for transmission choice between T5/M90/S6, the fact that no one seems to say that their T5 doesn't buzz or vibrate weighed heavier against that transmission than the cost of the S6 did. We're too old for that shit, and have the understanding of what "You're only at full throttle 1 percent of the time" really means.
 
You'll want as long an axle ratio as you can muster. I don't know if there are smogtastic Dana 30 ratios that would fit a 1030. It rattles. I thought it felt like a lot more than my car but that could be 240 vs 940 also.

I think the 53BZ doesn't fit without tunnel bashing.

I'm not old I'm just special.
 
redblockpowered said:
Maybe someone is throwing out one of those B230 dual mass flywheels as we speak. The key to vibration damping.
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Problem with those is they are a wear item, and they are NLA. Tried buying one already.

Going to TTV: they are 6 Kg. Bit too light for an old fart like me. Gonna see about getting a clutch disc made for my yoshifab flywheel.
 
Harlard said:
Going to TTV: they are 6 Kg. Bit too light for an old fart like me. Gonna see about getting a clutch disc made for my yoshifab flywheel.
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Don’t they make a heavy FW? Or is that only in the smaller clutch disc diameter?
 
I want to say there's one around 8 or so but it's for "Homologation" use with a smaller clutch. Either way I love mine, even though I'm mostly driving around in Massachusetts traffic with stock-ish suspension and such. Certainly doesn't feel like a racecar or even a pretend racecar, otherwise I'd probably be driving around in an E46 instead.

Evil rattle is very manageable. 16v might be better. Maybe insulate the transmission tunnel like 960/late 940?
EDIT: I expected to merely tolerate this thing when I bought it. Unforgiving clutch/FW is an easy way to totally ruin an otherwise streetable car.
 
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