1M Widebody conversion help

[Windy5000]

Hello,

I am considering an exterior OEM 1M conversion for my CAT N 135i DCT. I have a few questions for anyone who's done this build, your help would be much appreciated!

1/ Will i need to use wheel spacers with 19" 313's?
2/ The LSD is different to the 1M, how will this affect tracking the car?

[Allmotor1m]

Hey man I did the oem 1m body on my car. Not sure what your wheel setup is now but 135 hubs will actually give you a more aggressive fitment than m3 hubs. The 1m needs room for more tire so the hubs are more sunken in. I'm running 19x9.5 front and 19x10.5 bbs rkII's and I'm just running a spacer in the front to clear the coilover.

[amg6975]

Originally Posted by Allmotor1m

Hey man I did the oem 1m body on my car. Not sure what your wheel setup is now but 135 hubs will actually give you a more aggressive fitment than m3 hubs. The 1m needs room for more tire so the hubs are more sunken in. I'm running 19x9.5 front and 19x10.5 bbs rkII's and I'm just running a spacer in the front to clear the coilover.

This is true of the rear. The front is wider than the 135.

Originally Posted by Windy5000

2/ The LSD is different to the 1M, how will this affect tracking the car?

The 135 does not have an LSD. The 1M shares an LSD and complete rear end with the E9x M3. You can swap the whole rear over to the 1M/M3 unit if desired but since you're DCT you will need a custom drive shaft.

[NGEE]

Originally Posted by amg6975

The 135 does not have an LSD. The 1M shares an LSD and complete rear end with the E9x M3. You can swap the whole rear over to the 1M/M3 unit if desired but since you're DCT you will need a custom drive shaft.

Stupid questions - when/how would the benefit of this swap justify the cost? How does the LSD swap work with existing traction control systems?

[amg6975]

Originally Posted by NGEE

Stupid questions - when/how would the benefit of this swap justify the cost? How does the LSD swap work with existing traction control systems?

In my opinion this swap does not justify the cost. Just get an aftermarket LSD designed for the non M rear end. You will want to code off the DSC parameters that mimic an LSD. See the track section for more info.

I did the M3/1M rear end on my car but only because I had a whole M3 donor car so there was no additional cost. I think it's great to have but will still probably get an aftermarket LSD at some point.

[scratchgolf135]

Originally Posted by NGEE

Stupid questions - when/how would the benefit of this swap justify the cost? How does the LSD swap work with existing traction control systems?

I couldn't justify it on my build so I just sent my (welded) diff to Whitbred and had them put in a wavetrac with a billet diff cover.

[Fishee]

Originally Posted by Allmotor1m

Hey man I did the oem 1m body on my car. Not sure what your wheel setup is now but 135 hubs will actually give you a more aggressive fitment than m3 hubs. The 1m needs room for more tire so the hubs are more sunken in. I'm running 19x9.5 front and 19x10.5 bbs rkII's and I'm just running a spacer in the front to clear the coilover.

Your youtube video just showed up in my feed lol.

The RKIIs are so old school, they look great.

[Allmotor1m]

Fishee Appreciate that brotha! They're definitely my favorite setup so far

[Marc_28i]

Hello guys i am new here, i want to show you something worth your time. I own a 128i that in its previous life was auto and has been transformed to an n54 6mt. i have some goodies on the car like an lsd m3 suspension BO and rear brakes the car has few codes I want to get rid off so I need some help
2F4A
2F80
2EE6
CDAD
2E84
2E97
2F67
all codes are obtained using inpa
the car drives fantastically well.

[Windy5000]

Thanks for all the responses, i've decided i'm going to sell the car and go for a 1M Coupe'. I do love the DCT, nothing quite compares to using the manual mode gear stick or the feeling you get from down shifting on paddles. The car will very much be missed until i decide to purchase my 1M.

Eventually i'll look into an S65 manual or auto swap for the 1M.

[scratchgolf135]

Buying a 1m and considering swaps before you even own it seems silly. You’re going to spend an astronomical amount on it and only hurt its value by swapping. You’re likely following the SixPot build thread and it’s sick but he already owned that car before prices went bonkers. Why not just convert your 135 and pick and choose all the suspension components and end up with better stuff than stock 1m? There is no reason to do the rear end swap for this conversion. Virtually any aftermarket LSD is going to be better than the 1m LSD and bushings aside (which are easy to change), the rear end is not any better (subframe isn’t improved or anything). I’d think harder about what your goals are for your car before you take that plunge assuming you can ever even find a 1m.

[amg6975]

Originally Posted by Windy5000

Eventually i'll look into an S65 manual or auto swap for the 1M.

Having done the S65 swap, there's no way in hell I'd do it to a 1M.

[Windy5000]

I'll have to think about it a little more, something just feels off in regards to welding in OEM rear quarters. I would have to find an M3 donor car for all the other stuff, a 1M comes with all parts fitted and ready to go.

There's quite a few 1M's for sale in the United Kingdom at Piston Heads, this ones on auction.

[scratchgolf135]

Originally Posted by Windy5000

I'll have to think about it a little more, something just feels off in regards to welding in OEM rear quarters. I would have to find an M3 donor car for all the other stuff, a 1M comes with all parts fitted and ready to go.

There's a quite a few 1M's for sale in the United Kingdom at Piston Heads, this ones on auction.

You don't need a donor car for a conversion, not even close. If you're set on doing a S65 swap similar to SixPot, you would likely need a donor car even if you did have a proper 1m. The only things you'd be taking off a M3 donor car for completing a straight 1M conversion (not the S65 swap) are the control arms, rear subframe assembly, and the steering rack. Control arms can be purchased as a kit from ECS/Turner for an easy swap into your 135 and they'll be brand new with brand new bushings rather than worn bushing from a donor car. The rear end seriously isn't needed in any capacity, just get a better LSD. The steering rack is easy to find on ebay or other parts sites. Buying a donor car for some used suspension components and a steering rack would be silly and add more work since you'd have to remove it all from the donor before installing. I can guarantee you that my 1m converted car with 1m control arms, spherical trailing arm bearings and solid toe links with spherical bearings along with Koni shocks and high quality AKG shock mounts is going to handle way better than a 1m at a fraction of the cost.

[amg6975]

Originally Posted by scratchgolf135

You don't need a donor car for a conversion, not even close. If you're set on doing a S65 swap similar to SixPot, you would likely need a donor car even if you did have a proper 1m. The only things you'd be taking off a M3 donor car for completing a straight 1M conversion (not the S65 swap) are the control arms, rear subframe assembly, and the steering rack. Control arms can be purchased as a kit from ECS/Turner for an easy swap into your 135 and they'll be brand new with brand new bushings rather than worn bushing from a donor car. The rear end seriously isn't needed in any capacity, just get a better LSD. The steering rack is easy to find on ebay or other parts sites. Buying a donor car for some used suspension components and a steering rack would be silly and add more work since you'd have to remove it all from the donor before installing. I can guarantee you that my 1m converted car with 1m control arms, spherical trailing arm bearings and solid toe links with spherical bearings along with Koni shocks and high quality AKG shock mounts is going to handle way better than a 1m at a fraction of the cost.

There are plenty of reasons to do the M3/1M rear end as well. Aluminum control arms, bigger axels, M3 rear brakes, factory LSD...

[NGEE]

Originally Posted by Windy5000

There's a quite a few 1M's for sale in the United Kingdom at Piston Heads, this ones on auction.

That's a crazy low price for that 1M. It would go for $90k here.

Ahhha - auction being the key word duh.

[Fishee]

Originally Posted by NGEE

That's a crazy low price for that 1M. It would go for $90k here.

Ahhha - auction being the key word duh.

This one is a theft recovery with a partially removed VIN.

[Abasissa]

Hello. Am new here , i own a 09 135 and i want to do a 1m conversion kit, any help on where can I find a good website to buy the parts from? (Platic not fiber )