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Gear box help?

A

aquazi

Lifer
Derby + N. London
As far as i know the M and non M (N52) use the same transmission. But the gear ratio's are totally different. Even the N52 roadster and coupe have a different final drives!

Quick comparison google comparison i had (when i was thinking about getting a cayman s!)

Transmission 6-speed manual 6-speed manual
Gear/Ratio/Overall/(Rpm) Mph
..........Z4M..................................... .............CaymanS.........
1st,:1 4.35/15.75/(8000) 38 .................... 3.31/12.84/(7200) 44
2nd,:1 2.50/9.05/(8000) 66 ......................1.95/7.57/(7200) 75
3rd,:1 1.66/6.01/(8000) 100 .....................1.41/5.47/(7200) 103
4th,:1 1.23/4.45/(8000) 134 .....................1.13/4.38/(7200) 129
5th,:1 1.00/3.62/est (7500) 155* ..............0.97/3.76/(7200) 150
6th,:1 0.85/3.08/est (6400) 155* ..............0.82/3.18/est (6950) 171
Final drive ratio 3.62:1 .............................3.88:1
Engine rpm @ 60 mph
in top gear 2450 rpm ................................2400 rpm
*Electronically limited.

Gear/Ratio/Overall/(Rpm) Mph
6-speed manual
........Z4 coupe (non-M).........
1st........4.35/13.35/(6500) 36
2nd ......2.50/7.68/(6500) 63
3rd........1.67/5.13/(6500) 94
4th .......1.24/3.81/(6500) 126
5th........1.00/3.07/est (6450) 155*
6th........0.85/2.61/est (5475) 155*
Final Drive ratio .....3.07:1
Engine speed @ 60 mph = 2100 rpm




Sent from my iPhone 5s using Tapatalk
 
You could do, but the gears won't be as long, most likely.

It'd probably top out at 120 or whatever your current top speed is.
 
+ the gearing will be set to utilise the best performance for the engines power band and make sure its not hitting flat spots when changing gear etc.

For example you don't want to be accelerating and when you're reaching the prime of the power band, you run out of gear. Once you change it hits a flat spot and you need to build up the power again.
 
ben g said:
You could do, but the gears won't be as long, most likely.

It'd probably top out at 120 or whatever your current top speed is.
Click to expand...

The facelift final drive for a 2.0 is not that different from a facelift 3.0si final drive.
It's 3,38:1 versus 3,23:1, so that is not such a big deal. (gearbox internals are the same throughout the six speeds)

The problem is probably the clutch and/or the propshaft. Clutch is different (so maybe also the gearbox bell housing, or pressure plate etc etc), but the propshaft too (the flange). So an 3.0si gearbox does not bolt on to that.
Also that might become a very weak point when upgrading to an engine with more power. The 2.0L flex disc is smaller.
If you want to do a swap, try to get a complete engine (with ecu etc obviously), gearbox and propshaft. So basically get a totalled donor car, then you can probably get whatever you want (buying lots of tiny new parts because numerous things don't line up right can get expensive really fast).

On the other hand a 3.0i is so cheap in the uk.... sell your 2.0i (minus the upgrades) and buy a 3.0i might be more sensible.
 
GuidoK said:
On the other hand a 3.0i is so cheap in the uk.... sell your 2.0i (minus the upgrades) and buy a 3.0i might be more sensible.
Click to expand...

:thumbsup: is there a Echo in here? :rofl:
 
Of course, Alpina's are different again. The RS uses a 6-speed ZF gearbox, with the final drive changed from the Z4 3.0 - 3,23 instead of 3,07.
 
Jonny essex said:
I'll get the gear box, propshaft and LSD to play it safe then, basically EVERYTHING,
Click to expand...

If you want basically everything, you also have to get the driveshafts/outputshafts (so the shafts from the diff to the wheels).
The n46 uses a thinner shaft (30mm versus 38mm) with smaller flanges (the flange where the shaft bolts to the diff): 80mm bolt circle versus 86mm bolt circle.

I don't know how experienced you are as a mechanic and how much in dept knowledge you have on specific bmw parts, but there are a lot of things different.
They look similar, but when it finally comes together..... they might not line up.

Swapping an engine is 'easy' as long it's the same engine. But when you're swapping for another model.....you will learn a great deal about your car :rofl:
If you're planning to pay someone to do this work for you, expect them to loose a lot of time on figuring out the small details (and they'll charge you for it, or they'll cut some serious corners)

If you want to know all the differences, start by examening the details on all the parts of the driveline, engine, engine mountings, subframes etc in the ETK (realoem, bmwinfo etc), and look at what models those parts are also used to get an idea about their relevance and possible places to source.

I mean you talk about the engine. But what about the cooling? aircon? brakes? (Yes, brakes are connected to the engine.... :roll: )

That's why having a totalled car on hands might be useful. Provided that the parts you need are still in tact.
 
Yep and a company that do this type of work quoted. And Jonny said they where robbing mugs!! Afraid not buddy they just know what's involved I am afraid they have a better idea than you. I don't like being harsh in posts but it's not just buying all the big bits and then fitting. There are 100s of other things you and I haven't thought of.

As an idea I brought a LSD diff for my car ( a direct replacement ) I then had to buy new bolts for the output shafts new bolts for the prop shaft, new output shaft oil seals new oil a whole list of other stuff. And then the bushes I forgot about. So after spending about £1000 on new stuff to do the job (plus a few extra bits) I then had to spend another £200+ And I am doing it all myself.
 
(about the bolts: tbh I always use the old (driveshaft) bolts (on the diff flanges) although TIS prescribes that bolts should be replaced once removed. Just like the front alu subframe... I always use the same old bolts. :roll: (I know it's not in accordance with BMW's advice))
 
I hear you I did exactly the same before. But I had a little niggle at the back of my mind. So I just thought screw it I only plan on doing this once I will do it right.
 
Jonny essex said:
aquazi said:
As far as i know the M and non M (N52) use the same transmission. But the gear ratio's are totally different. Even the N52 roadster and coupe have a different final drives!

Quick comparison google comparison i had (when i was thinking about getting a cayman s!)

Transmission 6-speed manual 6-speed manual
Gear/Ratio/Overall/(Rpm) Mph
..........Z4M..................................... .............CaymanS.........
1st,:1 4.35/15.75/(8000) 38 .................... 3.31/12.84/(7200) 44
2nd,:1 2.50/9.05/(8000) 66 ......................1.95/7.57/(7200) 75
3rd,:1 1.66/6.01/(8000) 100 .....................1.41/5.47/(7200) 103
4th,:1 1.23/4.45/(8000) 134 .....................1.13/4.38/(7200) 129
5th,:1 1.00/3.62/est (7500) 155* ..............0.97/3.76/(7200) 150
6th,:1 0.85/3.08/est (6400) 155* ..............0.82/3.18/est (6950) 171
Final drive ratio 3.62:1 .............................3.88:1
Engine rpm @ 60 mph
in top gear 2450 rpm ................................2400 rpm
*Electronically limited.

Gear/Ratio/Overall/(Rpm) Mph
6-speed manual
........Z4 coupe (non-M).........
1st........4.35/13.35/(6500) 36
2nd ......2.50/7.68/(6500) 63
3rd........1.67/5.13/(6500) 94
4th .......1.24/3.81/(6500) 126
5th........1.00/3.07/est (6450) 155*
6th........0.85/2.61/est (5475) 155*
Final Drive ratio .....3.07:1
Engine speed @ 60 mph = 2100 rpm




Sent from my iPhone 5s using Tapatalk
Click to expand...

Thansk mate, still unclear so could i use my 6 speed 2L manual gear box with a 3L M54 engine?
Click to expand...

I might have a 2.5L M54 gearbox sat in my garage with around 40k miles on it, gathering dust....
 
Jonny essex said:
Guys im greatful for your help, and i know it wont be cheap, once i source everything i think i need i will let who ever does the work what i have and ensure i have plenty of cash when its done. :thumbsup:
Click to expand...

Surely it's not going to be very reliable once it's done?
 
2.5 is a 5 speed, so you still beter take the 6 speed from the 3.0.
switching gearboxes is stil on my list, but as i have a M54B25, i should only need the gearbox and driveshaft to make the M%4B30 gearbox fit.

@johnny, you're talking about LSD, so you're gonna switch that into the normal diffhousing ? as non of the non-M cars have an LSD only the M has an LSD.
 
Machine monkey said:
Yep and a company that do this type of work quoted. And Jonny said they where robbing mugs!! Afraid not buddy they just know what's involved I am afraid they have a better idea than you. I don't like being harsh in posts but it's not just buying all the big bits and then fitting. There are 100s of other things you and I haven't thought of.

As an idea I brought a LSD diff for my car ( a direct replacement ) I then had to buy new bolts for the output shafts new bolts for the prop shaft, new output shaft oil seals new oil a whole list of other stuff. And then the bushes I forgot about. So after spending about £1000 on new stuff to do the job (plus a few extra bits) I then had to spend another £200+ And I am doing it all myself.
Click to expand...


I've been there and done that multiple times with engine transplants in the past. Set a budget, then double it + the never ending trips back to the garage for tweaks, adjustments and constant problems.
Would I do it again? Nope. Ended up hating each car. Got worried about driving a long distance because they became cars that normal garages wouldn't touch to repair, had to keep going back to the same garage that built the cars. After investing thousands, the cars became garage queens and a trophy photo of what I built, but couldn't use.

If it ends up being a show car being taken around on a trailer then do it. If not think again.
Go do research in real modification forums, you'll see pages and pages of endless pain. This forum only shows the usual modifications, wheels, suspension, wrap dashboard and bodywork etc.
 
+1 this is so true.

It's not cool to try and recreate something that already exists either (a 3.0lt Z4).




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