Chris' 1989 3.0L Stroker Cab



I’m a roadster guy at heart, but when it came time to find a “family” car in 2001 we were lucky to find this 1 owner 1989 320i Cabriolet. Alpine White colour, bone stock, automatic and a slug but it still drove great….like a BMW.

This ’89 320i Cab had only 90,000km and was in great condition aesthetically, but the auto gearbox failed soon after I purchased the car. Not a great start to E30 ownership, but this sparked my new passion……….modding!

My Progess:

As mentioned above the auto gearbox failed within 5mths of ownership, and since I had never modded a car before I did the unheard of and bought a new reconditioned auto gearbox from BMW AG…..yuck!! Only then did I find BEN and other online forums where I was quickly enlightened that it was very easy to convert to a manual gearbox.

The information on modding started flowing straight to my bank account and before I knew it the stock suspension was replaced with Eibach ProKit springs & Sachs Performance (Reds) dampers. Then soon after a re-spray in Diamantschwarz, an M-Technic 1 front spoiler and a very rare Racing Dynamics exhaust I decided to do the manual gearbox swap and pick up some Racing Dynamics RGP rims in 16x7.5” wrapped in 225/45-16 Dunlop SP-9000 tires. As you can see I was overtaken by the urge to modify and in 1 year the lowly 320i Cab had undergone a real transformation.

While I enjoyed the car immensely it still lacked power, and let’s face it 129hp in a 3000lbs car sucks. Hence, I began looking at ways to get more power and the Rotrex supercharger kit looked appealing, but I finally settled on the 3.0L stroker. This was great timing since Dave Adams was nearing the end of his stroker project and he was very helpful in fielding my questions.

The Ireland Engineering kit was chosen due to Dave’s experience with them, but I fortunately ended up with a free upgrade to their custom made forged Cosworth crank. The pistons ended up coming from Ross Racing as opposed to the JE pistons mentioned on their site. Along with the kit I also picked up some 8mm plug wires and an Adj. FPR. I felt the new engine deserved a different label so in keeping with the other mods, I found a new Racing Dynamics valve cover. Other goodies included a Schrick 272/272, headers, larger injectors, M30 AFM, Alpina B3 2.7L chip & Ed Mazula big bore throttle body were acquired to help the engine achieve it’s potential.

Work on the stroker began by my engine builder up north and after 2-3 weeks it was complete. Two days later it was in my Cab and the raw power during the drive to the exhaust shop blew me away. I then realized that this was the perfect power for this car……pity BMW never did it this way from the factory.

Obviously there were small problems, as expected from a built engine, but through a few months of changing this and replacing that, the car was tearing through the streets via the huge amount of low-end torque. Thankfully, I was still convinced there was more potential in this engine so I took the car to a Unichip piggyback tuner and put the car on the dyno. The HP results were much lower than expected but the Torque results were pleasing. The Unichip piggyback was fitted and then the car was tuned on the dyno at every 1000rpm with an end result of 10-15rwhp & rwtq gained throughout. I was sold on the proper tuning of an engine and highly recommend the Unichip piggyback to anyone I come across….modded engine or stock.

After a while I learned of the MAF swap and decided to try it out since I already had ability to tune. The throttle response was great but the gains were minimal showing to me that when folks do the MAF swap it is actually the proper tuning of the engine that yields the big gains.

Now with the power sorted I concentrated on aesthetics and found a 2nd hand OEM M-Tech 2 bodykit and fitted it without delay. Next came E30 M3 running gear which gave me needed larger brakes & 5 lug hubs, which led to the rims I always wanted for the car….16x7.5 & 16x8.5 3pc Hartge’s.

Many folks would think the car is complete…but us E30 nutters know it never is complete. What I’ve learned through all of this is that I love the 3.0L stroker E30 Cabriolet, and I love modding cars. We all know, especially here at, there is never enough power and the modding bug never seems to die, so of course I have plans for more power, more aesthetic changes, more handling changes.


Below are my dyno graphs that show the following:

1 st Run: raw 3.0L stroker w/ Alpina B3 2.7L chip

2 nd Run: after the first Unichip piggyback tuning

3 rd Run: after the 328i Siemens MAF was installed and tuned by the Unichip


Known Performance: (as of 06/19/05 )

3.0L stroker M20B25

Rear wheel HP: 188


Rear wheel Torque: 207



Engine Modifications:

Ireland Engineering 3.0L stroker Kit w/ Forged Cosworth 3.0L crank & Forged Ross Racing Pistons 9.8:1

Schrick 272/272 cam

Carbon Fibre barrel type shielded cone air filter (similar to BMC)

E36 328i MAF

Custom aluminum elbow

Ed Mazula Big Bore Throttle Body

Mild ported head

IE larger injectors

Stainless steel headers

Racing Dynamics rear silencer


Drivetrain Modifications:

Getrag 260 gearbox & driveshaft

Z4 2.5L shift lever

Sachs clutch

3.64 LSD w/ 40% lock

Electronics/Engine Management:

Alpina B3 2.7L chip

Unichip piggyback


Diamantshwarz re-spray

OEM M-Technic II bodykit


Ellipsoid (smilies) as standard w/ Philips Premium bulbs

Front fogs w/ Philips Vision Plus bulbs

Rear fogs as standard

16x7.5 & 16x8.5 3pc Hartge rims

205/50-16 & 225/45-16 Dunlop SP-9000 tires

Shadowlined trim

Rolled rear fenders

Complete restoration of leather seats with Leatheriqe dye

M-Technic II steering wheel (replaced next week w/ a MOMO Prototipo)

Racing Dynamics pedals

BMW leather shift knob

Blaupunkt Los Angeles stereo & no idea what speakers


Eibach Pro Kit springs

Sachs Performance (Reds) dampers

10mm rear spring pads

E30 M3 front struts

E30 M3 front & rear hubs

E30 M3 front sway bar & links

E30 M3 offset control arm bushes














E30 M3 rotors

E30 M3 calipers

OEM Texstar pads



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