[SC_B5X]

8HP70 Swap

Introduction
As many people know I recently blew up my stock HP50 transmission in my 340i. Rather than swap in a stock transmission I went ahead and did an HP70 swap out of a diesel 430d. I followed the writeup from F30MGM to do this swap as well as advice from Peter Olesky (works for Pure Turbos in Europe) who has also done this swap.

Everything was done by Josh Pickell at Upstate Performance and Automotive Repair.

Overall this swap is extremely straight forward and requires little modification and it is also a cost effective upgrade.

List parts needed:

- 8HP70 Transmission (330d, 430d, 535d)
- N57 Flywheel
PN#: 11228506670
- 328i Transmission Support Bracket
PN#: 22326796605
- AT Service Kit (New Pan/Filter + Fluid. I recommend buying 9 Liters to be safe, 7 was not enough for mine)
- Custom Exhaust Hanger (Image 4, Box 1)
- Swap HP50 ground cable to HP70 as the one on HP70 is shorter (Image 4, Box 2)
- BMW Coder capable of resetting the ISN as well as programming the HP70.

Where can I source an HP70 from?

I got mine off of eBay. Luckily you can find them everywhere in Europe and for pretty cheap ($500-$1400). All you have to look for is 330d/430d transmissions.

Why do I need all these different parts?

I'll go down the list and explain why each part is needed.

N57 Flywheel
Stock B58 Flywheel wont fit, it'll rub against the starter. Therefor you need to buy an N57 flywheel, luckily these can be found cheap on eBay ($50-$100 from overseas, or more expensive in the US from scrapyards, $100-$200). See Image 8 for comparison between stock B58 Flywheel & N57 Flywheel.

330d Transmission Support Bracket
The HP70 is slightly shorter than our stock HP50 transmission, so it doesn't perfectly line up with our transmission supports (shown in Image 5,6). Technically it still works, as i've been running mine like this for over a week as i'm still waiting on mine to come in. But seeing how cheap they are at only $38, there is absolutely no reason not to get the correct part so you don't run into headaches down the road.

AT Service Kit
Self explanatory. Most transmissions will come with the fluid already drained, and in my case a crack on the transmission pan. Even if it comes with an intact pan and filled transmission, you might as well just give it a fluid change with fresh oil and filter while your at it. Remember to buy 9 Liters of ATF fluid (FCPEuro kit only comes with 7), as when I did mine it took 8 Liters.

Custom Exhaust Hanger
The HP70 exhaust hanger is designed for the diesel exhaust, which is apparently completely different from ours (See Image 4, Box 1). The hanger that comes on it will not work with our exhausts. Also the mounting points for the exhaust hanger are different, so unfortunately we can't just swap on our exhaust hanger and call it a day. I presume any exhaust shop or someone who does fabrication can easily make a new one inexpensively, I haven't gotten around to doing this yet.

Swap HP50 Ground Cable To HP70
Honestly, i'm not sure if this is really necessary or not. But when we noticed the HP70 had a shorter ground cable (Image 4, Box 2) we just went ahead and swapped the cable from the HP50 over to the HP70 to be safe so we didn't have to deal with it once it was in the car.

BMW Coder
You will need someone to be able to reset the ISN codes as well as program the transmission to your car. I personally went through BimECU.com, they were able to do it for $300 and completely remotely. All you need is an OBDII to ENET Cable and a Windows laptop with Teamviewer. Levan (owner of bimecu) did a great job and helped work out any kinks. I would highly recommend them.

Does XHP work with the HP70?
Yes! XHP will actually detect that it's a 340i with a HP70 swap (see Image 1,2).

What was the end cost?

List Of Costs:

- HP70 $1014 + $1200 rush shipping from the UK to SC, USA
- N57 Flywheel $150
- 330d Transmission Support $38
- AT Service Kit + 2 Extra Liters of ATF $182
- Transmission Coding by BimECU.com $300
- Install by Upstate Performance $580
- XHP $370

Total Cost: $3,834
Note: You can do this swap for much less if you are not in a rush as I was. I could have saved on transmission shipping if I didn't need it ASAP, as well as ordering flywheel from eBay rather from somewhere in US. Also you can find the HP70 for much less than $1000, but I found one with only 2400 miles on it so I paid extra.

Theoretically you could do this swap for less than $3000 if you take your time and find better deals than I did.

Things To Note:

XHP
Currently i'm having an issue where when I flash XHP Stage 3 to my car, the transmission doesn't recognize the different drivemodes (Comfort, Sport, Sport+, etc) and is stuck in comfort mode shifting. So far we haven't been able to figure out why it does this. When I flash back to stock the transmission goes back to being able to determine weather to use comfort mode or sport mode shifting (soft vs hard shifts). XHP is working directly with me to figure out what's going on and how to fix it. It seems like this is a problem only i'm having, as Peter Olesky is running XHP on his HP70 swapped M140i and has not run into this issue.

Transmission Cooler Lines
Since the HP70 is slightly shorter than the HP50 the transmission lines don't line up perfectly, it was a pain in the ass to get them to connect but we were able to do it. Just keep this in mind if you do the swap and be careful not to break them. Not really a problem, but worth noting.

Images

Image 1


Image 2


Image 3


Image 4


Image 5


Image 6


Image 7


Image 8

[Supr3me]

You're a fucking G for taking the time to write this out for the rest of us that are inevitably gonna blow our HP50.

[SC_B5X]

Originally Posted by Supr3me

You're a fucking G for taking the time to write this out for the rest of us that are inevitably gonna blow our HP50.

Thanks bud! Hopefully everyone finds this useful.

[Glemm1970]

Thank you for information. Where else to find out about the problems with such a replacement for X-drive.

[njdangelo]

Wow Awesome write up! I'm surprised by the flywheel picture. It looks like the one you swapped in is lighter weight with all those cut outs. Have you noticed any difference in torque delivery because of the flywheel change?

[weehe126]

Did you check the weight difference between the 50 and 70? Same with the flywheel as mentioned above.

[T_H_O_M_A_S]

according to leebmann24 , 89 kg for the 70 and 81 kg for the 50

[SC_B5X]

Originally Posted by njdangelo

Wow Awesome write up! I'm surprised by the flywheel picture. It looks like the one you swapped in is lighter weight with all those cut outs. Have you noticed any difference in torque delivery because of the flywheel change?

Wouldn't really be able to notice seeing how the entire trans got replaced and there's too many variables including higher stall torque converter, slightly different gear ratios, etc.

[SC_B5X]

Originally Posted by Glemm1970

Thank you for information. Where else to find out about the problems with such a replacement for X-drive.

Can't guarantee anything, but I would imagine picking up an xDrive trans and swapping it in wouldn't be too much different.

[TemjinX2]

great write...we need more these kind of write ups on the forum

[Glemm1970]

The F20 was never equipped with an HP70 at the factory, unlike the F30 and the like. There will be a problem with the driveshafts, from which they will fit, the transfer case itself also differs in the year of manufacture, despite the same model ACL35, perhaps something else will go crooked))

[SC_B5X]

Originally Posted by Glemm1970

The F20 was never equipped with an HP70 at the factory, unlike the F30 and the like. There will be a problem with the driveshafts, from which they will fit, the transfer case itself also differs in the year of manufacture, despite the same model ACL35, perhaps something else will go crooked))

There's not going to be any issues with driveshafts lol. As for xDrive components I can't speak for that. But Peter Olesky swapped an HP70 into his M140i RWD no problem.

Originally Posted by TemjinX2

great write...we need more these kind of write ups on the forum

Thanks man.

[RBT-Tuning]

The "Stuck-in-Comfort" mode issue should be now fixed for all cars. We uploaded the update 10 minutes ago!

[Levanime]

Originally Posted by RBT-Tuning

The "Stuck-in-Comfort" mode issue should be now fixed for all cars. We uploaded the update 10 minutes ago!

that is awesome

[SC_B5X]

Originally Posted by RBT-Tuning

The "Stuck-in-Comfort" mode issue should be now fixed for all cars. We uploaded the update 10 minutes ago!

Can confirm. Issue is now fixed!

[Devil doc]

Silly question, but is this a comparable upgrade to the likes of the new pure drivetrain solutions 8hp50 transmission?

[SC_B5X]

Originally Posted by Devil doc

Silly question, but is this a comparable upgrade to the likes of the new pure drivetrain solutions 8hp50 transmission?

Pure's built transmission is probably the absolute best option for upgraded transmissions we have right now, but also the most expensive coming in at $6000 for their Stage 1 transmission.

HP70 has proven it can take 700whp+ (Peter Olesky) no problem at all. Honestly the good thing about an HP70 swap is that it's a cheap and capable upgrade option compared to the Pure. You can do an HP70 swap for $2400-$3800 including the shipping costs, install, parts, etc. That's half the cost of the Pure's $6000 trans, which doesn't even cover the cost of shipping them your trans and paying someone to install it.

To sum it up:

If you want the absolute best transmission upgrade available and you don't mind paying for it: Go Pure Drivetrain's built HP50.

If you want a capable and cost effective upgraded transmission: Go HP70. And the best part is if you decide you want a built transmission down the road, Pure Drivetrain offers a built HP70 option which actually holds a lot more power than their built HP50.

Pure Built HP50

Pure Built HP70

[Devil doc]

Originally Posted by SC_B5X

Pure's built transmission is probably the absolute best option for upgraded transmissions we have right now, but also the most expensive coming in at $6000 for their Stage 1 transmission.

HP70 has proven it can take 700whp+ (Peter Olesky) no problem at all. Honestly the good thing about an HP70 swap is that it's a cheap and capable upgrade option compared to the Pure. You can do an HP70 swap for $2400-$3800 including the shipping costs, install, parts, etc. That's half the cost of the Pure's $6000 trans, which doesn't even cover the cost of shipping them your trans and paying someone to install it.

To sum it up:

If you want the absolute best transmission upgrade available and you don't mind paying for it: Go Pure Drivetrain's built HP50.

If you want a capable and cost effective upgraded transmission: Go HP70. And the best part is if you decide you want a built transmission down the road, Pure Drivetrain offers a built HP70 option which actually holds a lot more power than their built HP50.

Pure Built HP50

Pure Built HP70

Thank you so much for taking the time to write such a well thought out response, I appreciate it, and I'm sure lots of other people in the forum like myself will too. The 8hp70 option sounds like a GREAT option if you’re not interested in paying the big bucks for the heavier duty pure transmissions, or your power goals are less aggressive than four digit HP set ups; however, if you wanted to go nuts on a “budget”, then the pure 8HP70 would be a bang for the buck for the quadruple ratings and then some.

[TheFanatic]

Great to know about the Pure transmissions. Definitely something to go with for X-drive just on the ease of install/programming alone. Although cost is higher you'll be getting a new built transmission and not a used one. Depending on power goals it's really a pay now or pay later type of thing... Anyone know if they offer the build kit for us to build the trans ourselves?

[luchocamp]

very informative, thanks

[J3Vr6]

Saw this post linked from the 6MT trans limit discussion. May have been posted elsewhere, but is the actual limit of the stock automatic transmission on the 340i? I think SC_B5X was pushing around 650whp?

[TheFanatic]

Originally Posted by J3Vr6

Saw this post linked from the 6MT trans limit discussion. May have been posted elsewhere, but is the actual limit of the stock automatic transmission on the 340i? I think SC_B5X was pushing around 650whp?

it depends on how it's used but most people start noticing slip around 700