E34 'Ronin'

[A Chad 18]

Hi Team,

I've been lurking on here for a while but never committed to writing up a project summary for my Beamer, so here it goes.

I picked up my 1993 E34 back in 2015 for the grand sum of $3000 with north of 250,000Km on the clock. It was not running very well, it leaked all kinds of colors and the clutch was poked as was the suspension. The positive points were that it had a manual transmission and an M52B28 fitted instead of the original M50B25.

Thanks mainly to the color, the car quickly earned the nickname 'Ronin' after the Dunkelblau M5 'getaway car' that features in the movie of the same name. This Ronin however was not getaway ready, but I think I've rectified that deficiency.

The first job was to fix the tired clutch, which I sorted by going to an E30 race series favorite carbon-kevlar unit. I matched the new clutch with a single mass flywheel from a 318i E30 and this combo is still going strong today.

 

To rectify the driveline challenges in the car I have replaced the tired G240 E30 transmission with a G220 E46 unit. This also required the change from a 3.92 differential to a 3.19 ratio unit which results in 2,700Rpm @ 100Kph which feels ideal.

After the gearbox swap I put some effort into the shifter connection which required some modification to work with the newer gearbox. I have gone with a Turner Motorsport shift bush kit and an Ruf adjustable short shifter. Topped off with a leather Msport knob & boot it feels incredible to row through the box.

Regarding the tired suspension, this received a full refresh as did the steering linkages. I went with Bilstein HD shock absorbers and H&R sport springs which seems to be a good combo for decent stiffness whilst retaining relative comfort.

Now that the driveline is sound and the suspension is sorted, it's time for some power. As it sat, the power delivery was very 'lumpy' with holes in the torque band and lost torque. I fitted the larger M50 intake manifold and matched it up with a set of M3 injectors, I then fitted one of those trick LINK ECU E36 G4X computers. Luckily the 93' E34 525i ECU is identical to the 325i E36 which made the LINK ECU a direct plug in job. After a dyno tune I've ended up with a claimed 234Hp and 300Nm, which is a healthy step up from the original output and more than enough to really enjoy hustling the car. Most importantly the power delivery is now beautifully linear and  plenty of torque is available from 2,500RPM, so the larger intake manifold has not hurt the bottom end appreciably. I am also impressed with the car's performance considering it is still breathing through a decat M50 exhaust and manifold from the original engine configuration, perhaps something to look at in future.

After the engine tuning I decided to finally get the whole thing engineering certified, which it passed with flying colours.

The latest round of modifications have been purely aesthetic. I have made up some BMW dealer plate surrounds, fitted some EU spec yellow high beam tints and installed clear indicator lenses. I have also recently fitted some staggered Hartge 17"wheels (reproductions I believe), wrapped with 235 wide rubber in the front and 255 wide rubber in the back. This has been a very worthwhile modification, as the original 225/55 R16 rear tires, even with Bridgestone RE003 rubber made first and second gear difficult to utilize fully without breaking loose. I can now get off the line and give full power in dry conditions without loss of traction, which is very rewarding.

Interior wise I have kept the car quite basic. It has full black leather seats robbed from a 540i which are in excellent condition, the dashboard is crack free and the AC blows cold after replacing a few aged components and re-gassing the system.

Thanks to all the weight lost from the front end due to the combination of an all alloy engine and manual gearbox, turn in is brisk and the car changes direction with ease and feels very precise on windy roads. It does feel more like a comfortable 3 series than a 5 series when I compare it to E34s that I've driven with either six or eight cylinder power. The modifications that have been made to the 2.8L engine have resulted in enough power to really make the car scoot when needed, but not so much so that I can't enjoy revving it through the gears without losing my license. In all a pretty tidy package and I still enjoy owning 'Ronin' 8 years down the line..

I hope this wasn't too long a read...

Edited June 27, 2023 by A Chad

[Driftit 2093]

Nice work.  I'm getting closer to getting started on my neglected E34.  Bringing it back up to scratch for race events.
Some good motivation seeing other people working on E34's.