[Donnie2000]

n53 330i owner here too. I also installed a racing diffs lsd set followed by a blackline lsd. Mine had a 3.15 ratio as standard. I put the racing diffs conversion into a 3.23. It worked fine and was perfectly civilised in daily use but i felt i wanted something a bit more aggressive in its action and lockup and i was sorry i didn't go more aggressive on the ratio too, which led me to put a blackline lsd in a 3.38 diff. I would also say it seemed to fit very precisely and resulted in similar backlash to the original. I had to swap the input flange and set the pinion preload, which seems to have worked well, as I haven't had any problems with it. What value are you setting the pinion preload to? Your markings on coast are certainly looking good but i'm not sure which you need to adjust for you drive markings, as it's been a while since i worked on mine. It looks close though.

It is definitely noticeably more aggressive in lockup. Even around slow 90 degree corners in my estate, if you put some power in, you can feel it lock the axle and scrub the inside wheel. Driving reasonably quickly on small roads you can really feel it help to rotate the car from the rear around bends.

I installed a dimple magnetic diff plug and changed the oil a few months ago. It had more mileage than they recommended for that first oil change. There was plenty of metal gunk on the plug but the oil looked reasonably clean otherwise. I've heard Quaife units produce some metal wear also. I guess it's to be expected.

To tackle the front end ploughing i installed the m3 arms and Ian's camber plates but the biggest difference was the m3 rear roll bar. I think it's 22.5mm or so, hollow. It totally changes the balance of the car on turn in, so it's more playful.

I would love to get rid of that throttle lag. It's one of the only really annoying things about the car now. I thought i read multiple places about these ecu's locking out if you try to tamper with them?
btw it's a great thread

[Dormermike]

Throttle lag on an n53? cant say ive noticed any on mine

[tim_s]

Originally Posted by Donnie2000

n53 330i owner here too. I also installed a racing diffs lsd set followed by a blackline lsd. Mine had a 3.15 ratio as standard. I put the racing diffs conversion into a 3.23. It worked fine and was perfectly civilised in daily use but i felt i wanted something a bit more aggressive in its action and lockup and i was sorry i didn't go more aggressive on the ratio too, which led me to put a blackline lsd in a 3.38 diff. I would also say it seemed to fit very precisely and resulted in similar backlash to the original. I had to swap the input flange and set the pinion preload, which seems to have worked well, as I haven't had any problems with it. What value are you setting the pinion preload to? Your markings on coast are certainly looking good but i'm not sure which you need to adjust for you drive markings, as it's been a while since i worked on mine. It looks close though.

It is definitely noticeably more aggressive in lockup. Even around slow 90 degree corners in my estate, if you put some power in, you can feel it lock the axle and scrub the inside wheel. Driving reasonably quickly on small roads you can really feel it help to rotate the car from the rear around bends.

I installed a dimple magnetic diff plug and changed the oil a few months ago. It had more mileage than they recommended for that first oil change. There was plenty of metal gunk on the plug but the oil looked reasonably clean otherwise. I've heard Quaife units produce some metal wear also. I guess it's to be expected.

To tackle the front end ploughing i installed the m3 arms and Ian's camber plates but the biggest difference was the m3 rear roll bar. I think it's 22.5mm or so, hollow. It totally changes the balance of the car on turn in, so it's more playful.

I would love to get rid of that throttle lag. It's one of the only really annoying things about the car now. I thought i read multiple places about these ecu's locking out if you try to tamper with them?
btw it's a great thread

Cheers! Happy to hear your thoughts on the diff and the rear ARB, I was hoping for as much! I did consider an m3 rear ARB but they're dearer and the difference from the 13mm to the 15mm is massive as you can see in the pics so reckon it will be enough. What did the 3.38 come out of? Did you just use the cw/pinion or the whole casing? How do you find the ratio?

Interesting you managed to get the RacingDiffs to fit, I wonder what's going on there, it's a shame they didn't want to investigate further with me really, mine def had the side gears too close together for the one they sold me.
As for the diff, I've added a 0.05mm shim to increase pinion depth and try to make the pattern a bit more central, was a bit toe(drive)->heel (coast). Did that on the final pinion bearing, it ended up giving a bit more backlash than before which suggests it's not sitting exactly the same as the mock up bearing as that wasn't expected! Gear pattern looks ok, still too far to toe on the drive side, but seems a pretty big contact area. Going to run it around a bit more and try a bit of gear marking in different places, it's reaching the point where I'm thinking I'll just bolt it back up as it looks ok, they're used gears anyway, it's a ballache and would need input seal number 3 to adjust it again and probably new shims as they get trashed driving the outer race out. As it is it's using the original shims off the 3.23 diff in the same position and giving good carrier preload and 0.08mm backlash, all of which I'm happy with and implies it's pretty close to where it ought to be.
I set the pinion preload to just over 1ft/lb / 12 inch/lb in the end. I ended up re-using a crush sleeve as didn't have another, put 100ft/lbs on the nut and it didn't have enough preload so used the buzz gun on it.
I'll let you know how I get on with the blackline and swarf and how the throttle lag mapping works out. You can map these ecus easily enough, when they first came out it was challenging but ways and means were found and there are quite a few tools that will read/write them.

[Donnie2000]

I had one of the earlier racing diffs conversion sets. The one where you had to machine the gears to fit. I think now it is supplied with the pin, so avoiding the machining. There must be some variance in the diff inner gears. For example I had to machine more from the axle ends than they instructed, because I could see they weren't going to work. When fully inserted they would have made contact with the friction disk.

I used a spring balance and string to measure the bearing drag on the pinion bearing, rather than torquing to a specific value. It was difficult to find information on the value, but I had 2 other diffs I could measure for reference and both were similar. Iirc it is about half the drag you would typically find on tapered roller bearings (which values are much easier to find for older models).

My diff is the 3 bolt variety, so I think yours may be completely different? The interior of the diffs all seemed to be the same for me. But all three had different input flanges. Although 2 of them looked slightly different, the pcd of the 3 mounting bolts was the same. Then the 3.38 had a different pcd. I swapped only the input flange from the original 3.15 over to it. Otherwise I used the complete 3.38 diff. So I didn't remove pinion at all. Supposedly it came out of a low mileage 320d.

With regards to the ratio, it definitely feels perkier. Interestingly It just reachs 60 at the very top of 2nd! Which the juvenile in me had to test. However I find on small roads bends, 2nd is a bit low and 3rd almost feels a little high but it's pretty close. So I do wonder if I should have gone even further with the ratio. But then as others have pointed out you run into the problem of drone when cruising on the motorway.
I think mine has a gs6-37bz transmission. So your gear ratios may be slightly different to mine. I think at about 80 on the motorway it runs about 3150rpm in top.

I'd recommend the magnetic plug. It's surprising how much gunk it picked up. The Blackline has been a great addition though. No more wasteful spinning if the inside wheel but you have to be more attentive with it, as it can step sideways much easier.

[tim_s]

I used a spring balance and string to measure the bearing drag on the pinion bearing, rather than torquing to a specific value. It was difficult to find information on the value, but I had 2 other diffs I could measure for reference and both were similar. Iirc it is about half the drag you would typically find on tapered roller bearings (which values are much easier to find for older models).

Oh crap, I've got too much preload on the pinion bearing then! The diff's on the car now but I ran out of time today before it started snowing! Will have to back the nut off, estimate and hope for the best. Better now than trash the bearing...
I'd gone for 12 inch pounds - well it actually was nearer 10 inch pounds in the end, which was a fair bit more than on the original bearing (which I'd assumed had broken in). I've just found a figure of 0.4-0.6nm for a 188l - a fair bit less.

[Donnie2000]

Originally Posted by tim_s

Oh crap, I've got too much preload on the pinion bearing then! The diff's on the car now but I ran out of time today before it started snowing! Will have to back the nut off, estimate and hope for the best. Better now than trash the bearing...
I'd gone for 12 inch pounds - well it actually was nearer 10 inch pounds in the end, which was a fair bit more than on the original bearing (which I'd assumed had broken in). I've just found a figure of 0.4-0.6nm for a 188l - a fair bit less.

Sorry i'm a little hazy on info, (ignore my mention of half the torque, as i'm not sure if that is correct) but i do have notes where i measured both differentials bearing drag with a string wound around the shaft (25mm radius).
At 25mm radius i measured 3 - 3.5 pounds of drag. So i just set the preload to give me the exactly the same drag as before (3.5 pounds on the 3.38 diff), as i was reusing the bearings.
Interestingly i also marked the shaft face and nut as a guide to how far to tighten and the drag was correct when tightened exactly to the mark. You see some people saying that using a mark is a valid method and others saying it's not, but in my case it appeared valid and has worked correctly since.
I would imagine you should be setting to a slightly higher drag with new bearings and spacer as there will be some relaxation or freeing up with use.

so actually my measured value works out at approx. 0.4nm, if i worked it out correctly.

[tim_s]

Thanks, makes sense. There's no point in me pulling it all apart now, I think I'm going to back off the nut , which currently has loads of torque on it, and torque it back up to around 120ft/lbs which was about as much as I could easily with my wrench and gave around the amount of drag youre talking about. It may not be perfect but think it will be ok despite the crush sleeve undoubtedly being a bit over-crushed now. Hopefully I can do this in situ with the prop out of the way

[Donnie2000]

if you have a torque wrench that can accurately measure 0.4-0.6nm of drag, i think you'd have enough space to get enough of a turn to measure it. Because you have new bearings, i'd aim for the upper value in the range.
Be interesting to see how it works out long term.
The difficult part will be trying to get the required torque from underneath the car. I remember i struggled with it even off the car!

[tim_s]

It's all back together now and have taken it for a few runs dropping off and collecting the little one from nursery and it is silent so far. I couldn't get any real indication of torque with the crownwheel still in there, but I'm confident from having setting it up a few times on the bench that I have a decent idea on the relationship between the torque I put on the nut and the drag on the pinion, so it should hopefully be ballpark correct just from torquing the nut. I'm not going to lose any sleep over it!
Having driven it, I'm feeling 3.23 is still too short, so at some point I may consider a shorter ratio.
A few pics, they always seem grotty, I suppose the underside of cars generally do.
I did a few fixes like the below on the heatshield that was on its last legs around the bolt holes - I intended to buy another but only remembered when I was putting it all together, so this will have to do:


Did some general flapwheeling, kurust and dinitrol to clean up the subframe etc.
url=https://postimg.cc/PvmLfZDy][/url]







General impression is the ARB and suspension bits at the rear make it much tighter, the eibachs sit perfectly and are noticeable both in terms of ride height and ride - from what I'd read I was expecting them to basically be the same as oem sport springs but am glad that they're a bit more sporty and a touch lower. The diff is noticeably shorter but I'm annoyed I didn't go 3.38, I think it would have been better still and it still feels a bit long. The LSD has definitely improved traction but I've not really had chance to push it.
Maybe at some point I'll consider selling the diff complete and try a 3.38, no rush though!

[Markos ZimZimma]

Originally Posted by tim_s

It's all back together now and have taken it for a few runs dropping off and collecting the little one from nursery and it is silent so far. I couldn't get any real indication of torque with the crownwheel still in there, but I'm confident from having setting it up a few times on the bench that I have a decent idea on the relationship between the torque I put on the nut and the drag on the pinion, so it should hopefully be ballpark correct just from torquing the nut. I'm not going to lose any sleep over it!
Having driven it, I'm feeling 3.23 is still too short, so at some point I may consider a shorter ratio.
A few pics, they always seem grotty, I suppose the underside of cars generally do.
I did a few fixes like the below on the heatshield that was on its last legs around the bolt holes - I intended to buy another but only remembered when I was putting it all together, so this will have to do:


Did some general flapwheeling, kurust and dinitrol to clean up the subframe etc.

General impression is the ARB and suspension bits at the rear make it much tighter, the eibachs sit perfectly and are noticeable both in terms of ride height and ride - from what I'd read I was expecting them to basically be the same as oem sport springs but am glad that they're a bit more sporty and a touch lower. The diff is noticeably shorter but I'm annoyed I didn't go 3.38, I think it would have been better still and it still feels a bit long. The LSD has definitely improved traction but I've not really had chance to push it.
Maybe at some point I'll consider selling the diff complete and try a 3.38, no rush though!

Good to see it all back together Tim, but was expecting to see the undercarriage as clean as the examples by this Dutch guy!

https://www.facebook.com/51648536175...529866429/?d=n

[tim_s]

My diff is the 3 bolt variety, so I think yours may be completely different? The interior of the diffs all seemed to be the same for me. But all three had different input flanges. Although 2 of them looked slightly different, the pcd of the 3 mounting bolts was the same. Then the 3.38 had a different pcd. I swapped only the input flange from the original 3.15 over to it. Otherwise I used the complete 3.38 diff. So I didn't remove pinion at all. Supposedly it came out of a low mileage 320d.

Yeah the 325 has the 4 bolt input flange that bolts directly to the prop without a rubber donut, which I think means the pinion shaft is different and doesn't have a pilot on it - you can probably see that on some of the previous photos. I'm not actually sure what diff I could use to get 3.38, but I suppose changing the prop isn't out of the question, esp as I have to drop the gearbox at some point. I'd imagine if the diff came from a diesel that also runs the gs6-17 gearbox, the prop would probably mate up. I should probably forget about all that for now and enjoy what I've just done. I need to change the flash to reflect the diff ratio, that and do some datalogging on the current map so I have a baseline to compare against the remap.

[tim_s]

Originally Posted by Markos ZimZimma

Good to see it all back together Tim, but was expecting to see the undercarriage as clean as the examples by this Dutch guy!

https://www.facebook.com/51648536175...529866429/?d=n

That would last about a week with the roads around here! I did consider cleaning it all up, I did give the underside a proper clean when I first bought the car, but I really couldn't see the point especially at this time of year...

[Markos ZimZimma]

Originally Posted by tim_s

That would last about a week with the roads around here! I did consider cleaning it all up, I did give the underside a proper clean when I first bought the car, but I really couldn't see the point especially at this time of year...

Oh I think you did more than enough by giving the subframe some TLC in Jan/Feb! I stumbled across the Stipt Polish FB page a few weeks back and have been wowed by the level of detail he goes into even on the underside of cars... OCD at its finest!

[Donnie2000]

Are the gear ratios listed for the gs6-17 in yours the same as listed for that gearbox in this document (pages 33-34). If so, the ratios seem a lot longer in general than in the gs6-37.

https://www.google.com/url?sa=t&sour...=1612287776442

Hopefully that link works.

[Donnie2000]

Originally Posted by tim_s

I couldn't get any real indication of torque with the crownwheel still in there,

oh yes, i completely forgot about that!

you might find it easier to find a 3.45 or 3.46 ratio in 4 bolt rather than 3.38.
I'm pretty sure i've come across them before.

[tim_s]

The ratios aren't the same as in that doc, they're around the same as the 37 - 1:1 5th and something around 0.83 6th!
A 3.46 ratio is in 325i autos I think.

[Donnie2000]

Originally Posted by tim_s

I need to change the flash to reflect the diff ratio,

Do you mean the ratio itself has to be entered in the flash? Is this something i should have done when i changed the ratio? what does it affect? thanks

[tim_s]

Yeah the ratio is stored in the flash, and the gear ratios of the box. It seems to run fine without changing it, (as I'm sure you've found!) but it's used for the dme to calculate which gear you're in, which in turn is used on quite a few maps.

[Donnie2000]

Originally Posted by tim_s

Yeah the ratio is stored in the flash, and the gear ratios of the box. It seems to run fine without changing it, (as I'm sure you've found!) but it's used for the dme to calculate which gear you're in, which in turn is used on quite a few maps.

ah interesting. Do you use a kess v2 to flash the dme?

[4foothill]

Originally Posted by Donnie2000

ah interesting. Do you use a kess v2 to flash the dme?

I've used a kess v2 clone for my n53 and it works fine.

Why would the ECU need to know about the ratios? I'm told it uses the wheel speed sensors for the speedo.

[Donnie2000]

Originally Posted by 4foothill

I've used a kess v2 clone for my n53 and it works fine.

Why would the ECU need to know about the ratios? I'm told it uses the wheel speed sensors for the speedo.

that's good to know regarding the kess clone. I assume some type of charger to stabilise the battery voltage is a must?

No idea on the ratios...but the dash can tell you when is optimum revs to change gear for efficiency, so maybe something to do with that...

I can confirm my speedo became more accurate when i upped the tyre sidewall profile, so yes speed would appear to be from the wheel sensors.

[0l0dom0l0]

Speed is from the wheels - there's two versions, true and corrected. Dash shows corrected which is true speed plus a bit, about 3-4mph. You can chose which you want to display on the dash with Carly or NCS. I have coded the digital speedo to show the 'true' speed.

Regarding gear/ diff ratio in the ECU - Manual cars don't have a gear position sensor, just a neutral sensor. So for the ECU to know what gear the car is in it uses wheel speed, engine speed, gear ratio and final drive ratio.

As Tim said, the ECU will use different maps or parameters depending on the gear that the car is in.

On a side note I had a 130i before the 330i with about a year inbetween. The 130 has the same gear ratios I believe but a much shorter final drive (3.45). I'm sure the diff would bolt straight in, I'm 99% sure its still a 188L diff.

Personally I found the 3.45 a bit revvy. Would only just make 60 in 2nd. It did feel much punchier in the higher gears though. I think somewhere around 3.30- 3.35 would be the perfect ratio, the 3er is noticeably longer, especially 3rd/ 4th which feel like they go on forever.

I'm following with lots of interest - also interested to hear how you got on with the NOX mapping. This is something I need to look into also, I would really rather avoid the NOXEM unless I have to.