Monday, November 30, 2009

BMW E34 Toyota 1JZGTE Twin Turbo Heart Transplant

Due to heart failure of the original BMW M50B20 (520i) engine and the extremely costly experience of maintaining a Bavarian heart with original BMW parts for the past 2 years or so. As the cost of a used BMW M50B25 was very expensive and likely to cost the same to maintain, I decided to transplant a more reliable Japanese heart into my beloved BMW. I know, I know, BMW purist all over the world will be moaning about purity etc, etc. but hey, its my car and 280hp and Toyota reliability doesn't sound so bad to me after blowing a fortune maintaining my original BMW engine.

Enough about philosophy and on with the show....

BMW M50B20 (520i). Before:

Toyota 1JZ-GTE Twin Turbo. After:

The journey....

A long time ago, in a galaxy far far away.....

Wait, wrong story. I bought the BMW E34 520i in early 2007 and have tried my best to keep to its German heritage by replacing and repairing the car with only original BMW parts. I had just spend a small fortune (to me at least) to fully refurbish the gearbox (which was giving me problems) with the intention of keeping the car in stock condition for as long as possible. Unfortunately, fate had other ideas and my M50B20 engine decided to blow its top and thought mixing engine oil and coolant together would be a good idea.

This was the last straw and after finding out that a good condition M50B20 was difficult to come by and that the more readily available M50B25 (from a 525i) would cost a small fortune (to me at least), I decided that it was time for a change. After much thought and research, I decided to go with the Toyota 1JZ-GTE Twin Turbo as the engine (or halfcut as we call them in Malaysia) were about a third of the price of the BMW and after factoring in the massive amount of labor and fabrication to install a Toyota engine into a BMW, the total cost was still quite similar.

So a date was scheduled for the open heart surgery and the car was trailered to the operating theater and the offending item was removed.

The oil sump of the 'new' engine had to be modified to fit the original BMW engine bay.

The new heart being fitted.
Toyota? Yamaha?
Custom engine mountings being fabricated.

Toyota 4-speed automatic.
Intercooler. I went with a black 'stock' looking intercooler as I did not want to attract any unwanted attention.
Engine installed. Now the hard part, wiring.

The battery also had to be relocated from the engine bay to under the rear seat. Most of the E34's had their battery in this location but for some reason, mine was in the engine bay.

While the car was in for surgery, I decided to get the wheels repainted to an anthracite grey.

I also custom fabricated a panel for the boost gauge and turbo timer. Finished off with a 3M Carbon-Fiber sticker.

One of the requirements I had for the transplant was that I wanted the engine bay to look as 'stock' as possible, like it would have looked if BMW and Toyota decided to get married and have a child. As such, a lot of care was given especially to the wiring and the use of the original Toyota air intake assembly.

Overall, I am really happy with the results and the 280hp that came with it.

Some pictures after surgery.

The Toyota ECU is located in the same place as the stock BMW ECU.
The original rubber seals were reused to ensure the ECU is sealed off and the original routing for the wiring was reused.

The complete Toyota air intake assembly including the cold air intake snorkel.
The front of the engine bay had to be modified slightly to get the cold air intake to fit.
The original BMW brake master cylinder could not fit and was replaced with the original Toyota version.
The front mounted intercooler.

Stock looking front end.

The standard 520i exhaust was used for the complete 'stock' look. I didn't want to go for a custom made exhaust as I wanted it to look and sound like a stock BMW 520i.

The completed engine bay.

The original BMW gear shift was reused and the panel for the boost gauge and turbo timer installed.

Closeup of the 3M Carbon Fiber sticker.

The original BMW instrument cluster was also reused and everything works expect the meter below the rev counter used to calculate the MPG.

Some exterior shots of the car with the wheels. For a full description of the detailing work carried out check out my post on my other blog:

The new Japanese heart is smoother and definitely much, much more powerful than the original German heart but what I'm really hoping for is that it will be more reliable also.

My wallet needs a break...... or I'll be the one needing a heart transplant soon.

Just updated another post with some technical information about the 1JZ:


  1. LOL
    u dun need a heart transplant soon.

    but do more detailing

  2. Hello!
    I want to know if you can easily change an engine M20B20 to M50B20 on a E30-(1985`)

  3. HeyIam going to do the same thing in a 91 E30 convertable any advice Thaank You.

  4. where's your foreman workshop?
    any contact number? tq

  5. Hey whats up, ive been thinking about this swap for a while now, my friend is a toyota guy and hes been dying for me to do it. i'm interested, just kinda hesitant as too how much the overall cost was, and where to get the work done. any help will be appreciated.

  6. Hi. Go for it!!! You won't regret it. Very minimal reliability issues with the 1JZ if compared with the original M50 not to mention much much more power!!!

    As for the cost, for me the cost of transplanting another M50 was about the same as converting over to the 1JZ as the M50 engine was a lot more expensive.

  7. mate,
    just a got a 2j in my e46..i'd like to talk about paperwork, need someone who's in the know.
    care to TT sometime?

  8. Hey, do u mind share with us which workshop u went to, and how about his craftmanship ? Oh ya how much is the transplant costs?

  9. Thanks for all the comments. Drop me an email and I'll try to answer any queries the best I can.

  10. Greetings. As was made driveshaft ?

    1. The BMW driveshaft is mated to the exiting driveshaft of the 1JZ.

  11. Hey i hope im not too late but i recently installed a 1j into e34 and its all wired up and running but one problem my brakes were working fine before (original engine) and now it keeps switching between hard and soft mostly hard any suggestions?

    1. My 1JZ is running a modded brake master cylinder so can't comment on the way it feels but I don't have such issues. In fact, its probably too sensitive.

  12. Hello. Transmission is toyota or BMW?

    1. Hi. Transmission is Toyota. Longshaft is BMW and rear differential is BMW.

  13. Hi. I have an E34 with M20B20 and was going to turbocharge. have found 1jz vvti now but who did the transplant for you? you have a phone number for the garage? how long did it take?

  14. hi...
    interesting article. been looking for a workshop that can do conversion.
    mine is an old e36 1.8, and recently had same cc engine transplant, after the old one gave way.
    am thinking of converting to 1jz, and am searching for the right workshop that's available in klang valley. would like to know the workshop location and contact no if possible. thanks.

  15. Good day Seech!

    Can You please answer for my on any questions.
    We have bmw e34 1988 year, 535 M30 mech trans left hand drive
    We want implant in bmw body 1jzgte vvti with ATM from JZX100 car.
    Was purchase in assembly 1jzgte vvti with ATM from JZX100 car, also we buy vacuum brake tank with cylinder, ECU, MAF and other components for proper instalation
    New motor was fit in bmw and we can't understand why set vacuum brake tank if it thrust in steering shaft which exit from motor panel, if we can see at you pictures you set from original bmw vacuum brake tank other vacuum brake from jzx90? or not? Can you explain how we can fix vacuum tank in our bmw E34
    Also we can know how you measure center in motor section? you new motor was fixed on center? or not, if we fix motor on center by crankshaft wi have a problem with unscrew oil filter his interfere steering mechanism, may be you incline 1jz? or shift center of crankshaft?

    Big thanks!

  16. change the 1jz gte engine to e34 and you also change the master cylinder then how the ABS ? ABS got function ?

  17. Where can I find 2jz Mount Swap Kit for bmw E34 , M5??

  18. Hey I have a 1990 525i and I just bought a 2jz gte vvti , I'm looking for engine mounts. CN you guys please help me. Thanks

  19. Hi May i know where is the workshop.I like to have a transplant for my old Bm..thank you very much

  20. Do you use 1JZ ECU or stock BMW ECU? If you use 1JZ, how about the standart electrical such as A/C and other stuff?