Bob's 1989 S50 Powered 325i



I have been exposed to BMW’s as long as I can remember. My father had numerous cars throughout my childhood, but it was always the BMW’s that I was drawn to. I bought my first BMW in 1990, a 1981 320is with 100k on it and in very nice condition. It was a great car, Alpine White, Factory Recaro’s, BBS wheels, and LSD. I drove that car for a few years and ended up selling it because my parents didn’t feel that it was appropriate while I was in College. Regretfully, it would be 10 years before I owned another one.

After owning a couple of E36 M3’s, I met Steve Petersen. At the time, I was planning to do a S52 swap into a 318ti. That was until I saw Steve’s car, a 1987 325I with the S52 swap. I knew right away that was the route I wanted to take.

I set out to find a clean late model E30 with plastic bumpers and didn’t look any further than Ben Carufel’s car in San Diego. Ben was a member on Bimmerforums and I had seen his car posted and knew that it was the perfect car for my project. I flew to San Diego and purchased the car from Ben in July of 2003.


My Progess:

I brought the car home and immediately began on my new project. I ordered the suspension, seats, and wheels for the car and took it to the track in late September 2003. The car was great on the track, just a little underpowered compared to the S52 in Steve’s car.

I began my search for a donor motor and finally tracked one down from a shop in Washington State. The motor came out of a 95 M3 with front-end damage and had approximately 60k on it. I received the motor in late October and began to acquire parts for it. I wanted to get he most power possible out of the motor, but focus on reliability. I proceeded to order the performance mods for the motor and started to tear the motor down. The S50’s have a well-known weakness in the pre 10/95-build cars. BMW won’t admit it, but they have weak valve retainers. BMW never officially put out a technical bulletin on this, but the part number in the ETK changes for the 96 and up cars. I chose VAC Motorsports for the headwork and went with their Stage 1 head and opted for the BMW Motorsport dual valve springs.

In Late October 2003, I took the car to David Raye Engineering for the Roll cage. DRE specializes on chassis fabrication and cages for all sorts of cars, primarily Circle Track. DRE had the car for about 2 months and delivered it right before Christmas.

In January, I finally began work on the car. My friend Steve was kind enough to offer the use of his garage for the conversion and I couldn’t pass it up. We began by pulling the M20 and stripping the car. Once the motor was out, I began to clean and prep the engine bay for the conversion. I also began pulling the suspension and subframes off the car in preparation for a full rebuild and bushing replacement.

With the motor in the car and all of the front suspension work done, I moved the car back to my garage in March 2004 to start on the wiring, interior, and the rear suspension. The car became more of a weekend project was not a priority. At the time, I still owned my E36 M3 and was satisfied having that to drive around. I worked on the car on and off all summer long and finally got it to the point where it was driveable in early October 2004.

I drove the car around town to get the bugs worked out and with 17 miles on the car ran into some serious issues. I noticed that there was a fair amount of oil in the coolant and a large amount of oil leaking from the front of the motor where the head meets the block. Feeling extremely frustrated and the lack of freetime due to a new job, I shelved the project for the following spring.

I started on the car in March of 2005 and began by pulling the head off. I replaced the Head gasket and checked for any signs of problems and didn’t find any. I put the motor back together and headed out to put some miles on it. I drove about 20 miles and pulled over to check for any leaks and much to my disappointment, I had oil leaking from the front half of the motor again. I drove the car home and began to investigate the leak. It turns out that it was a 10 cent o-ring that seals the camshaft sensor. All the work over a 10-cent part! After flushing the coolant a couple times over the next month, I realized that the oil in the coolant was the result of oil getting into the water jackets during the tear down phase of my rebuild.

With all of that grief behind me, I continued to work on the car finishing the interior and adding things like the aluminum radiator, lap counting, and the onboard fire system.

In July 2005, after putting some miles on the motor to break it in, I finally got the car to the track. The car ran flawlessly and I put on over 300 track miles running amongst Porsche’s, Ferrari’s, Corvette’s, and even a Carrera GT. The car was a little under-powered compared to the other cars, but it was a blast nonetheless…

I have recently decided to swap almost everything over to an E30 M3 after finding one that I couldn’t pass up. I will be flying out to New Hampshire to pick it up and drive it back to Minnesota in the next few weeks and begin the transformation. Fortunately, I have found a buyer for the 325 and it will be shipped to Massachusetts in the coming weeks where the new owner will drop in a motor of their choice. I will miss this car, but the new owner is extremely enthusiastic and I know it will be in good hands.


Engine Modifications:

S50 and 5 speed tranny out of a 95 M3 with approximately 63k on it

VAC Motorsports Stage 1 Head with BMW Motorsport Dual Valve Springs

VAC Motorsports Timing Chain, Cam Chain, and Oil Pump Chain

Welded Oil Pump nut

Fan delete with 318ti thermostat and Motorsport nut.

Spal 16 inch Electric pusher fan

ARP Head Studs

European spec 3.5 inch HFM

24lb. Injectors

Schrick Cams

Ground Control Green Gizmo

Brand new S52 Primary Tensioner

Benfer Powdercoated Valve Cover

Metal water pump

Metal Thermostat Housing

PWR Aluminum Radiator

Aluminum catch can for coolant overflow

OBD2 Headers with ports welded and Headers wrapped

Custom 2.5 inch exhaust, no cat, Dynomax Muffler

All brand new parts used for the conversion: E34 oil pan, Motor mounts, motor mount arms


Drivetrain Modifications:

UUC 8.5lb. Flywheel

E34 M5 clutch

Rogue Engineering WSR


UUC TME’s (red)

UUC Underdrive Pulley’s

E30 M3 Driveshaft, Guibo, Shift carrier

3.73 LSD and 3.46 LSD Differentials

M Coupe Finned Diff Cover

Redline fluids for tranny and diff’s

Electronics/Engine Management:

Turner/Conforti Software

Brand new Vanos and Solenoid


Recaro SRD’s with Sub hole

BMP Gauge Cluster’s (Instrument and vent)

VDO Vision Gauges (Speedo, Tach with recall, Oil Pressure, Oil Temp, Volt, Gas, Water Temp, Diff Temp)

Sparco Wheel

Auto Technique Quick Release hub

Turner Motorsports Shift Knob

Factory Interior completely stripped and replaced with lightweight carpet

Onboard Lap Counting

Alpine Stereo system(very discrete)

Factory IS Front Lip

Euro Bumper Moldings

French Headlights

Smoked Front Turn Signals

Evo Hood Seals  

David Raye Engineering Roll Cage

Sparco 5 point belts

SPA On Board Fire System


Turner Motorsports J-Stock Kit with Specially valved Bilstien’s and H+R springs

Dinan Fixed Camber Plate(front)

BMW Offset Front Strut Mount

Turner Motorsports Rear upper Strut Mount

Turner Rear upper Reinforcement plates

Suspension Techniques Swaybars

Turner Motorsports Front Swaybar reinforcement

Turner Motorsports Rear Swaybar reinforcement

Ireland Racing Front Adjustable Sway Bar links

Suspension Techniques Rear Adjustable Sway Bar links

Turner Motorsport Rear Trailing Arm Sway Bar mount reinforcement

Powerflex Front Control Arm Bushings

Ireland Racing Rear Subframe Bushings

Ireland Racing Rear Control Arm Bushings

M3 Aluminum Front Control Arms

Sparco Front Strut Bar

Roll cage is tied into rear towers and “Boxed out” to reinforce rear towers




Zimmerman Cross Drilled Front and Rear Rotors, Cryogenically treated

Rebuilt Calipers with Turner Motorsports guide pins(rear)

Braided Stainless Brake lines

Motul 5.1 Fluid

E21 Brake booster






Street-16x7.5 Kosei K1’s with 215-50-16 Falken Azenis

Track-16x7.5 Kosei K1’s with 225-50-16 Avon Tech R’s



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