The gear ratios from the F80 (M3/M4):
1. 4.806
2. 2.593
3. 1.701
4. 1.277
5. 1.000
6. 0.844
7. 0.671

I?m pairing it with a Q45 (3.54) diff.

So 1st would be useless with a 3.92....or anything shorter than a 3.43 or something. 6 and 7 would be an overdrive regardless. The rest seem to fall in line with the cd009 ratio

Wow that sucks. Now I have to do some gear ratio calculations.

Nissan Pathfinder rear diffs are 3.13.
Nissan Armada/QX56 rear diffs vary came in 3.36 and 2.94 ratios as well.

Or, add 1000 rpm to your engine speed :)

E9x M3 DCT Gear Ratios E92 V8

1st - 4.780
2nd - 3.056
3rd - 2.153
4th - 1.678
5th - 1.390
6th - 1.203
7th - 1.000

with a 3.33 auto final drive on 255/40-17 tires

8500RPM 39.77 62.2 88.29 113.28 136.7 158.01 190.08
RPM 1st 2nd 3rd 4th 5th 6th 7th

with the 3.54 same tires
8500RPM 37.41 58.51 83.05 106.56 128.64 148.64 178.81
1st 2nd 3rd 4th 5th 6th 7th

With a 3.13
8500RPM 42.31 66.18 93.93 120.52 145.49 168.11 202.23
1st 2nd 3rd 4th 5th 6th 7th

Can't format it right for the forum

Hi guys,

I just finished with this swap which took me maybe more than 1 month since i did everything all alone at my parking spot .

Parts i purchased:

GS6-53DZ gearbox
Pmc gearbox adapter plate + flywheel
Pmc chassis mount shifter
Flex plate from auto sr20
Sachs oem clutch
Gearbox seals

Everything else was custom made by me. ( except the driveshaft)

Process i can say was pretty straight forward but i had some issues ( i still have).

The spot

https://i.imgur.com/DRDYvRp.png


Adapter plate on . I believe no one has mentioned that now you can't remove starter without having to remove the gearbox.

https://i.imgur.com/mC4sqHf.png

Gearbox on .

https://i.imgur.com/wS4LqKM.png
https://i.imgur.com/gXAAys5.png


Took me maybe half an hour to align and install it , most difficult part was to put the damn gearbox on the floor jack.



Then when raising it i realized that the gearbox touches the firewall. :picardfp:

Removing it and bang the firewall was not an option so i placed some small pieces of wood between the firewall and the gearbox and started to raise it slowly and carefully .:bigok:
You could hear the 30 year old metal bend very easily. :spank: Didnt really need a lot to be honest.

Also the 2 top gearbox allen bolts took me i don't even now how many hours since there was absolutely no space to put any tool and torque them down.

https://i.imgur.com/YkWQlF1.png

https://i.imgur.com/ANgan1c.png

https://i.imgur.com/fXtYkrb.png

After that it was time for the gearbox mount which may look super ugly but i believe it does the job.

https://i.imgur.com/PnDKDPR.png

Ugly also but stiff selector rod. This one i may order it to be cnc cut because i dont believe its welded 100% straight .

https://i.imgur.com/pFyQBij.png

For shifter i chose the shortest option that was available because i dont really like those long ones.

https://i.imgur.com/KN3p9My.png


For driveshaft i used the original one with adding a 3 bolt flange and i didnt use the bmw rubber coupling. I didnt take a photo of that.:-/

After installing everything and thinking i am done , the real nightmare begins.

Clutch bleeding = impossible.

Clutch would only engage half and gears didnt go in. Pedal would start to feel stiff only after 40% of the total travel.

I then changed the slave cylinder which was new and thought maybe its defective, and also removed the rubber clutch line and made a stainless steel one.

Did manage to bleed the system , no air coming out all, but still the pedal didnt have the best feel.

The last option that did the job( still not 100%) was to adjust the master cylinder rod that goes on the pedal so it pushes a little more fluid on the system.

I believe the problem is the clutch bearing position and clutch is not pushed 100%.

Pmc says to use the 28.5mm but in my situation i think the 33mm position would work better?
I have emailed them but no reply so i dont know.

https://i.imgur.com/umoUcw5.png


Anyway today was the first ride which didnt go as planned and i need your opinion- help.

Gearbox makes a terrible sound which i did notice when i first started the car when was on jack stands and thought it will go away when i install the driveshaft etc.

https://www.youtube.com/watch?v=pf_VHvrCMiM

When driving its sounds very bad when decelerating with gear in. :down:

Any help would be appreciated.

*update*

Looks like i'm experiencing harsh gearset rattle on deceleration, and certain RPM's where the engine NVH is at its worst. After doing some research it seems that some people have this issue after installing lightweight single mass flywheels in their bmw's.

I assume having no rubber guibos on the driveshaft , in combination with how rigidly I have the transmission mounted to the chassis is going to cause some unwanted NVH from the GS6-53dz transmission.

Bmw guys suggest changing the fluid , a mix of 75w140 with atf which i wait to be delivered and see how it goes. Also i think to remove the polybush gear mount and put some normal rubber mounts .

Haven't push the car yet since im trying to break in the clutch and figure out these noises but in general gearbox feels amazing. The gear changes are so smooth.

The only issue is that its very short because i have a 4.36 diff. 1st gear is like it doesnt exist , i dont even use it.

I'll put the old 3.9 crown wheel i have next week and i hope it will be better.