[N111CUK]

Originally Posted by AWSAWS

Is the intent to use this as a track car?

That's a lot of hard work! Well done. Impressive!

It's actually easier than installing new turbos.

Currently the car is undergoing major performance upgrades

RB stage 2
TFT intake
Setrab 25 row oil cooler
JB4 G5
MHD backend flash
New meth control
New Decated exhaust

Hopefully it will run 550whp reliably or 600whp if I can get some e85 in the UK

[AWSAWS]

Originally Posted by N111CUK

It's actually easier than installing new turbos.

Currently the car is undergoing major performance upgrades

RB stage 2
TFT intake
Setrab 25 row oil cooler
JB4 G5
MHD backend flash
New meth control
New Decated exhaust

Hopefully it will run 550whp reliably or 600whp if I can get some e85 in the UK

My only thoughts are:

1. Our terrible roads! Uneven and holes all over the place
2. Even a lightly modded 335i can get you into trouble after 3 seconds of WOT

Don't worry, thanks to green initiatives we'll have E85 or similar soon enough. I can't wait too. Ethanol fire supplies at £2.25 a litre is way too pricey!

[idnan]

As Nick said, it is a pretty simple procedure. Apart from the custom propshaft, it is a case of bolt on and bolt off with the m3 parts. I've done this one two cars now, mine and an e91 and both of us are happy with the upgrade. I do recommend an m3 steering rack although without servotronic it is quite heavy in low speed situations.

[N111CUK]

Originally Posted by Fishayyy

Did you ever take any pictures of what your finished hybrid looked like?

Might have some on the hard drive. I'll look tonight

[N111CUK]

Originally Posted by AWSAWS

My only thoughts are:

1. Our terrible roads! Uneven and holes all over the place
2. Even a lightly modded 335i can get you into trouble after 3 seconds of WOT

Don't worry, thanks to green initiatives we'll have E85 or similar soon enough. I can't wait too. Ethanol fire supplies at £2.25 a litre is way too pricey!

Yes it's all about excess. The standard car is plenty good enough but piston heads always need more. If you have to ask why you don't understand.

[Fishayyy]

I looked into it more and it turns out that the DSS one-piece carbon shaft will fit the 335i with an M3 differential. So I think Im gonna wait for VAC motorsport one piece shaft and use that.

[N111CUK]

Originally Posted by Fishayyy

I looked into it more and it turns out that the DSS one-piece carbon shaft will fit the 335i with an M3 differential. So I think Im gonna wait for VAC motorsport one piece shaft and use that.

Sounds good mate. Make sure you share pics and details with all.

[Fishayyy]

Originally Posted by N111CUK

Sounds good mate. Make sure you share pics and details with all.

I normally don't post much on this forum, but when I finally get my hands on all the parts I need, I'll make sure to put up a thread or at least post on this thread. Thanks for the help!

[AWSAWS]

Originally Posted by idnan

As Nick said, it is a pretty simple procedure. Apart from the custom propshaft, it is a case of bolt on and bolt off with the m3 parts. I've done this one two cars now, mine and an e91 and both of us are happy with the upgrade. I do recommend an m3 steering rack although without servotronic it is quite heavy in low speed situations.

In that case do mine next

[Fishayyy]

So just to check is this all I need? I already bought the Subframe and LSD.
Driveshaft
Axles
Brake rotors
Wheel Carrier (Upright)
Camber Arm
(Semi-)Trailing Arm
Steering Arm (Toe Control Arm)
Wishbone (Upper Arm)
Guide Rods

[N111CUK]

Originally Posted by Fishayyy

So just to check is this all I need? I already bought the Subframe and LSD.
Driveshaft
Axles
Brake rotors
Wheel Carrier (Upright)
Camber Arm
(Semi-)Trailing Arm
Steering Arm (Toe Control Arm)
Wishbone (Upper Arm)
Guide Rods

Not sure mate

My m3 rear subframe was 100% complete. It bolts up with 4 bolts.

I also bought front end m3 gear to match up the breaking systems and suspension upgrades

Also now would be a good time to decide whether you want bushings or stick to OEM m3 bushings

Plus you can upgrade all break lines with braided all the way to the copper plumbing. Makes a difference.

My advice Measure twice and then measure again

[Fishayyy]

Originally Posted by N111CUK

Not sure mate

My m3 rear subframe was 100% complete. It bolts up with 4 bolts.

I also bought front end m3 gear to match up the breaking systems and suspension upgrades

Also now would be a good time to decide whether you want bushings or stick to OEM m3 bushings

Plus you can upgrade all break lines with braided all the way to the copper plumbing. Makes a difference.

My advice Measure twice and then measure again

When you say you bought front end M3 gear do you mean the front subframe with axles and everything?

Damn there's a lot of parts.
It's going to take me a lot of research putting this project together because I'm going with all aftermarket upgrades instead of OEM so I have to make sure that I get all of the parts I need including the bolts and other bits to hold them together lol.

I feel like I'm going to spend a good deal of time just assembling the suspension off the car before I decided everything is final and ready to go.

[N111CUK]

Regarding the front end

I only installed hubs, carriers, top mounts, and rotors + calipers from the m3.

I also installed a H&N ARB. Including new bushings

The 335i front end is good on the rest of the parts.

[johanh13]

Originally Posted by N111CUK

Regarding the front end

I only installed hubs, carriers, top mounts, and rotors + calipers from the m3.

I also installed a H&N ARB. Including new bushings

The 335i front end is good on the rest of the parts.

I am very interested in upgrading my 335i to m3; I would like to get the brakes and suspension, front and rear! In the rear, can I put in all the arms, shocks, carrier, and brakes, from the m3 but keep my diff and subframe?
In the front, arms, shocks, carrier, brakes from m3, but keep subframe and steering rack?

[N111CUK]

Originally Posted by johanh13

I am very interested in upgrading my 335i to m3; I would like to get the brakes and suspension, front and rear! In the rear, can I put in all the arms, shocks, carrier, and brakes, from the m3 but keep my diff and subframe?
In the front, arms, shocks, carrier, brakes from m3, but keep subframe and steering rack?

You can do as you say for the front but in the rear you are better off with just installing a complete m3 subframe as it is easier and better.

[Eagle1oh7]

Quick question, minus LSD, nothing has to be done to the drive shaft if only swapping our the rear subframe?

[ellz]

This is mighty interesting. Could be a good way for me to go with my 335i touring, I would presume all the chassis points are the same from saloon to touring ?

A quick look on ebay and it seems there are quite a few E9* M3 being broken down for parts.

[E92 420]

Originally Posted by ellz

This is mighty interesting. Could be a good way for me to go with my 335i touring, I would presume all the chassis points are the same from saloon to touring ?

A quick look on ebay and it seems there are quite a few E9* M3 being broken down for parts.

Not my thread I know. But yes all mounting points are the same

[russjonesr]

Originally Posted by N111CUK

Not sure mate

My m3 rear subframe was 100% complete. It bolts up with 4 bolts.

I also bought front end m3 gear to match up the breaking systems and suspension upgrades

Also now would be a good time to decide whether you want bushings or stick to OEM m3 bushings

Plus you can upgrade all break lines with braided all the way to the copper plumbing. Makes a difference.

My advice Measure twice and then measure again

I don't suppose you have the measurements Adam? I have the same configuration 2007 335i auto to m3 dct

Cheers Russ

[YO335vert]

Originally Posted by N111CUK

335i project M3

Now before I start let me just answer the question most people put to me. Why don’t you just buy an M3? Well because I prefer the N54 engine the 6AT transmission and how it drives daily. I also believe this car can make a great weekend arrive and drive track car and overcome its heating issues.
What mods on my the 2007 335i 6AT M Sport

• Vishnu Procede V5 £500
• Vishnu PWM Methanol Injection trunk mounted £800
• PLM 3” De cat Down Pipes £200
• Custom cat back exhaust using OEM back box £400
• Injen Dual Cone Intake £200
• Spearco FMIC £300
• HEL braided brake lines £95
• M3 Rear sub frame including disks brakes hubs etc.. £500
• M3 Front brakes with M3 hubs and carriers £150
• KW V3 coilovers M3 spec £1450
• H&R Anti Role Bar Front £75
• Original Cost of Car £14,000

Total spend £18,670

The main mod which is of most interest is my M3 rear sub frame transplant
The complete M3 sub frame fits 100% into the 335i and requires a modification to the Prop shaft.

Why use an M3 rear instead of the Quaife? Well this route IMHO is better as I get all the clever suspension bits from the M3, stronger axles and prop including better brakes and for less money.

I must offer my gratitude to another e90post member IDNAN who had already completed this conversion before and helped me overcome some major questions. THANKS!

ALSO a big thanks you to MVG Engineering in Dartford Erith for all their help in getting this Installed. 01322 342699 speak to John he is very knowledgeable

Combinations of parts for the M3 Differential install

• M3 E92 DCT Rear sub frame with FD of 3.15
• M3 E92 DCT Prop shaft
• 335i 6AT Prop Shaft

As I mentioned before the sub frame is a straight fit. The considerations you will have to take into account are the final drive of the differential you choose.

335i gearbox transmission ratios
• 335i 6MT OEM Diff gearing FD 3.08
• 335i 6AT OEM Diff gearing FD 3.46
• 335i DCT OEM Diff gearing FD 2.56
M3 gearbox transmission ratios
• M3 6MT OEM Diff gearing FD 3.85
• M3 DCT OEM Diff gearing FD 3.15

Now armed with this information you can decide what FD you end up with. Choosing a lower number than your OEM setup will give you longer gearing and picking a higher number than OEM will shorten you gearing. This will not throw up any CEL codes but will be important to overall performance output.

I picked the DCT M3 diff as this would lengthen my first gear which was a little short IMHO and means my 1 gear launches are more usable with all the performance mods. I also can cruise on the motorway freeway at lower revs and higher speeds improving MPG.

If you have a DCT 335i and install a 6MT M3 diff you would be way out and you could take off in 3rd gear which would be crazy. I would go with as close a ratio as OEM and maybe go longer if you have mods making the car more powerful with more torque.

Now once you have the Diff you need to modify the prop. You could get a new prop built but so long as you have the M3 prop you can use this with your OEM prop and create a new prop for this application.

The best way to create the new prop is to combine the 335i prop and the M3 prop. Use the 335i tri bolt flange plus gimbal plate (rubber bushing with 6 holes) and the 335i centre bearing(this is vital to keep everything in line as intended by BMW OEM). You then mate this to the M3 prop creating a very strong custom prop which is mostly M3 but is 100% OEM fit.

Measuring this was simple. The measurements are split into two parts.
1. Diff to Centre bearing
2. Centre bearing to Transmission

The first measurement on the M3 prop is spot on. This part of the M3 prop remains constant because we share the same monocot chassis as the M3. What we need to measure for cutting and attaching is the second measurement. This measurement is from Centre Bearing bolt hole to rear side of the tri bolt flange. To get this absolutely right you should provide the prop builder both of the measurements because they will need to remove the centre bearing and attach the 335i bearing and therefore they need to know where all three points will be in relation to each other.

What I did was to attach the 335i prop to the transmission (make these bolts tight) and centre bearing (locate only one bolt) and take a measurement from the centre bearing bolt hole (one without the bolt) to the face of the flange attached to the 335i prop (your tape measure will be at an angle that’s OK). Then once you have this take it off and attach the M3 prop to the diff and then to the centre bearing again put all 6 bolts tight on the diff and only one bolt in the centre bearing. Then take another measurement. You now have both measurements for the Diff builder. Get a good shop to make this up for you. I used JW Engineering in Erith Dartford, they build racing props for kit cars and touring cars so they know there stuff.

NOTE: It is important to understand at this point that any prop has expansion movement at one of its halves; the 335i prop has movement at the front portion near the transmission where by the M3 prop has its movement at the rear at the diff. You should only keep one movement when building a prop
Some other challenges and choices that comes to light when doing this.

1. The M3 rear sub frame comes with all the M3 suspension arms etc.. (GREAT!!) but this also means you need M3 shocks and Springs as the 335i shocks won’t fit . At this point I decided to get new coil overs and opted for KW V3. I ordered the M3 version.

2. Now you have M3 rear brakes they are actually bigger in diameter than the 335i fronts and also drilled. You could just keep the 335i fronts but I opted to keep the OEM theme here and get some cheap M3 front Disks Callipers hubs and Carriers. This also makes the M3 KW coil overs fit. So I’m stopping a lot better now.

3. Depending how your sub frame turns up you may need some extra bits from the dealer. Bolts were the main bits that I needed. Prop bolts, Calliper carrier bolts, M3 Rear spring lower bushings, M3 Front strut plates etc….
The whole project took a week but with better planning and this info I’m providing you could get this done in two days tops. I had a lot of stop starts as I would run into a parts shortage or the above challenges and I needed to stop working.

What’s she like to drive. Well I can say that it’s better than the OEM M3 and very committed into corners. Traction is never an issue and no noises or issues with the conversion. If I had gone the Quaife route I would have not gained better breaks suspension and M3 components so I think I got a better deal and car in the long run.

The car is no wider at the rear than with the 335i rear sub frame so no concerns with wheel clearance.

I’ll try and help any of you guys with this conversion you may want to take your own route to complete this.

Thanks for reading my post all the best
Adam




I'll post loads of picks when I can

Hi, I'm trying to do this same swap and I got a m3 rear end complete all i need now is the driveshaft and how to put them together, I have a 2010 auto, how do I go about putting the 2 together any pic would help thanks

[ChawenHalo]

Fantastic stuff, well done for going through with this! it will be great to get some pics.

You'll have to upgrade radiator and pump though to avoid thermal stress issues. Same for gearbox although from memory the ZF auto is rated for higher torque than the MT.

The LSD has an incorporated rad as well.