1987 Porsche 928 S4 Supercharged Track Car
Vehicle Details
- Year: 1987
- Make: Porsche
- Model: 928 S4
- VIN: WP0JB0922HS861215
- Mileage: 0
- Transmission: Manual
- Title Status: Bill of Sale
- Color: Blue (Yellow Wrap)
- Seller: JPD
- Seller Type: Private Party
- Location: Macomb County, MI 48094
- Lot #: V-0010009
Now up for auction is this custom-built 1987 Porsche 928 S4 supercharged track car. Over the course of four years and with no expense spared, this 928 S4 was converted into a highly competitive HPDE track monster by its owner, an avid track-goer and engineer by trade. Described as a fast and reliable performer, this 928 weighs in at less than 3,000 lbs. and features Bilstein adjustable coil-overs, custom body modifications, a stripped-out lightweight racing cockpit, a rebuilt 5-speed manual transaxle with custom 8-plate LSD, and a supercharged V8 engine estimated to produce over 500 HP at the rear wheels. Meticulously built and diligently maintained by the seller over the last four years, this 928 is now being offered for auction on a bill of sale out of Michigan.
Sporting a custom yellow vinyl wrap over Blue paint, this S4 has also been modified with air-exit louvers atop the hood and both front wings, NACA ducts, slim profile racing mirrors, custom-designed and fabricated steel protection plates, a mechanically adjustable dual-element carbon fiber rear wing, a front splitter, a single driver’s side windshield wiper, and lightweight Lexan rear window. The sunroof has been deleted and protective stainless-steel grating has been placed over all air inlets and outlets. It rides on a set of three-piece aluminum racing wheels (front 18” x 11”, rear 18” x 12”) which were media blasted and resealed in 2019. Pirelli racing slicks are currently mounted and hub-centric 25mm H&R wheel spacers have been placed on all four corners along with extra-long wheel studs.
Inside, the cabin has been completely stripped for weight savings and fitted with a full welded roll cage. Dual Kirkey racing seats have also been added along with RJS 5-point racing safety harnesses, a Lifeline fire suppression system, a removable MOMO racing steering wheel, and short-throw solid ball mount shifter linkage. Other additions include a Roadkeeper 2 camera video logging and data logging system, and an extensive array of gauges for monitoring vehicle data. Real-time data logging is controlled and recorded via a removable Panasonic Toughbook mounted to the passenger floorboard with a docking station. Only the brake lights have been retained, this 928 is not legal for street use.
With its virtually perfect weight distribution and innovative “Weissach Axle” passive rear steering system, this 928 offered the perfect basis for a high-performance track build. The original 5.0L V8 engine in this example has been fitted with a Pro Charger D-1SC custom mounted centrifugal supercharger, custom Mishimoto intercooler, G-Reddy modulated blow-off valve, custom fabricated dual 2.5” stainless-steel exhaust with x-pipe, and an Electromotive “Tec 3” dual ignition electronic control system. With a maximum boost pressure of 15psi, this 928 is estimated to send over 500 HP to the rear wheels through its 5-speed manual transaxle which was rebuilt in 2019. The seller notes that the 8-plate limited-slip differential was rebuilt in 2020 along with rebuilt half-shafts and new boots. The timing belt, drive belts, and water pump was also replaced in April of 2020 with approximately 15 hours of total run time since. A recent HPDE inspection was carried out in preparation for sale including a fresh oil service and brake fluid flush. An image of th eHPDE inspection sheet is posted in the photo gallery. The following list details an extensive amount of additional performance upgrades equipped by the owner:
Engine
- Clewitt Engineering Ignition Wires
- Upsized 42lb. Bosch Fuel Injectors
- Bosch 44 Motorsports Fuel Pump
- Adjustable Engine Rev Limiter (Set To 5700 RPM)
- Full Aluminum Racing Radiator
- High Flow Volume Thermostatically Controlled Electric Radiator Fan
- Dual Water Pumps
- Integrated Fender-Mount Radiators
- Precision Motorwerks Windage And Crank Scraper System
- 3-Qt. Accu-Sump Engine Oil Supplement System W/ Automatic Valve Deployment
- Modified Oil Pan With 928 Motorsports Extended Capacity Internal Cloverleaf Baffle
- Special Oil Inlet Suction Tube System
- Supplemental Porsche GT2 Engine Single Pass Oil Cooler
- Custom Extra Length Insulated Inlet and Return Fuel Delivery Hoses by Precision Motorwerks
- Solid Aluminum Billet Engine Mounts By 928 Motorsports
- Coolant Quick Drain Valve on Engine Block
- Crankcase Vent Catch Cans with Filtered Vents
- Magnetic Drain Plug on Engine Oil Sump
- Porken Timing Belt Tensioner
Drivetrain
- Heavy Duty Carbon Fiber Racing Clutch
- Racing Clutch Hose Assembly by Precision Motorwerks
- Magnetic Drain Plug
- Custom Designed and Fabricated Transaxle Oil Cooler
- Dual Electric Cooling Fans
- Electric Pump for Oil Circulation (Filtered)
- External Pressure and Temperature Gauges
Chassis, Suspension, Steering, and Brakes
- Bilstein Adjustable Coil-Overs (front springs 950 lbs., rear springs 600 lbs.)
- Fully adjustable Sway Bar Links by 928 Motorsports
- Rebuilt Steering Rack with Solid Aluminum Mounting Bushings by 928 Motorsports
- Custom 3-piece frame cross member by 928 Motorsports
- Stainless Steel Brake Flex Lines by Precision Motorwerks
- Rebuilt Stock Calipers with New Pistons, Seals, Red Powder Coating (2019)
Electrical
- Optima Yellow Top Deep Cycle Battery (2019)
- 90 Amp Lightweight Alternator (2019)
- Lightweight Starter (2018)
- Emergency Electrical Master Switch “On-Off”
- Permanently Mounted Battery Tender
- Plug-ins for GoPro, Roadkeeper, Cell Phone, Toughbook
This 928 will be accompanied by a collection of records and documentation as well as a bill of sale. For any avid track-going enthusiast in search of a highly competitive Porsche, this painstakingly developed HPDE track monster is not to be overlooked.
Auction Results
- Highest Bid: $22,928
- Auction End: Apr 30, 2021 07:10:00PM UTC
- Number of Bids: 3
Comments (20)
Bid in the amount of $22,928
Bid in the amount of $15,000
Regarding street legal tires, I do have a extra set of wheels and tires that I used as quasi-wets. Used perhaps 3 times, they are like new. Tires are G-Force, date coded 2018 (I purchased them new). I will include these with the sale. These wheels and tires would meet the DOT street legal requirement.
Good luck and thanks for the questions!
3. Shipping – I am retired. I would be pleased to personally deliver the vehicle in my enclosed trailer anywhere within the lower 48 for ONE WAY fuel costs, tolls and $100 per diem expenses (you insure the vehicle prior to departure). Further, should you be interested I would be pleased to personally attend a track day with you to shorten your learning curve at your location of choice, if the time-line works out. If the time-line doesn’t work, perhaps we can make other arrangements. Regardless of the track day scenario, and should you choose for me to personally deliver the 928 I would be pleased to brief you on the 928 to share with you my specific knowledge.
2. Education on maintaining, the build components and driver training? This car is well sorted. Should you be the successful bidder I would be pleased to accommodate the new handler, personally personal training (in person, phone or online) with all of the aforementioned. This 928 is fully prepped, ready to ship, and is ready for it’s first track day of the 2021 season. Fresh AMSOIL Racing Oil and filter, Motus 600 brake fluid flush, Pirelli slicks, and a signed off local SEM PCA tech form / car inspection was completed on Apr 22, 2021.
c. Some states as in Michigan, allow registration of historic vehicles. In Michigan, if the vehicle is 26 years or older it can be registered as historic.
Hello Folks,
I have received numerous private offline messages with questions. Inasmuch I thought it would be fair to publicly address the common themes of the queries.
1. What would it take to make this car street legal?
I can only speak to my home state of Michigan where we can legally drive a vehicle as long as it is deemed safe (brakes, steering etc.) and has brake lights and DOT street tires. However, your state may differ????
a. Smog Test - this car will not likely meet a legal smog test if your state requires it to pass for registration. This car has dual shorty magnaflows, no catalytic convertors and blue flames exit the 2-1/2” exhaust when hard off the throttle at the end of the straight into the corner. This issue, though not impossible to solve would be an obstacle.
b. Lights – Some states require headlights, tailights, brake lights and turn signals. This car has brake lights only. It would not be much of a challenge to fulfill the balance of these lighting requirements. However, the original 928 hideaway headlight pods are out of the question as the storage space on the drivers side is filled with a K&N oblong air filter and the passenger side space accommodates intercooler piping. Alternative LED mini headlights would be an easy work around.
Bid in the amount of $1,987
And something further, for those who might ask, no nannies on this 928! NONE! It's all you!
The time has come for me to release this track monster to a new handler. My ownership of this 928 has been a challenging and rewarding experience. An experience I will reflect upon for years to come.
My hope is that it will go to a new owner who will appreciate this 928’s heritage, share the passion, treat it with caution and care, and exercise it regularly as it so deserves.
Should the new handler wish, I will be pleased to facilitate communication after the sale (short and long term as desired) to assist with questions.
Cheers!
This car is truly remarkable; it is fast, reliable and predictable. It is simple to service, obsessively clean everywhere (above and below), easy to maintain, economical to operate, has been meticulously cared for, runs on 93 octane & Amsoil 15W-30 Dominator Racing Oil. However, I will warn you that this car will drain you of all the adrenaline you can muster. Unequivocally, this car will put a smile on your face time after time, regardless of your driving skill level.
I would best describe this car as very much unlike any 928 GT street car I have owned or driven (alot). This car is light and nimble, much like the 240 Z cars I drove when a younger man. But, 928’s have gobs of bottom end torque, in this cars case further and exponentially torqued up with the supercharger forced induction, creating an overwhelming and instantly available torque to launch you out of the apex. When this torque is combined with the 928’s passive Weissach rear axle steering, it sets you on track through the straight, to brake late and hard into the next turn entry.
If you are a track day enthusiast, or a “want to be”, whether you have already dipped your toe into HPDE with your daily driver, or have a “pristine” car that you don’t want to trash on track days, or just getting started and want a car that you can handle with opportunity to grow, or hard core looking to up your game with a precision track tool, this car will challenge and build your driving skills. For beginners, you will be pleased the car is fitted with that extra Kirkey seat. It will allow you to get proper driving instruction to tame this beast and grow your skill rapidly. Don’t be intimidated, with proper HPDE and other coaching instruction you will grow into this car.
Track times were my benchmark to demonstrate my continuous improvement, of both the car and my driving skills. Today, this 928’s reputation for track performance is well known here at our local Michigan tracks; Waterford Hills, Grattan and Gingerman.
This is a car that raises eyebrows as it preys upon and passes GT3’s, GT4’s, GT350R’s, ZL1’s, Z06’s, M3’s and many others at PCA HPDE events and OTD (open track days). A word of caution though, GT2’s and ATR’s are not to be messed with.
I never wheel to wheel raced this car, nor did I ever have intent to do so. There is no evidence of ever being damaged from either a street or a track incident. The unibody on this car is rock solid.
Ambient temperatures in excess of 95, hard on the power at 15 psi of boost on short courses, with limited straights for recovery, and full 20-minute track sessions……. Now, no problem. Drive it as hard as you want! Or can……
Further, I considerately and meticulously continued to modify this 928 S4 into a track performance monster. All the work performed on this car is top shelf, backed up with the component build documents. Data acquisition on the floor mounted Toughbook laptop has been key to making this 928 track car a reliable, overperformer.
When I purchased the 928, it was a car that was 90% done, yet with 90% to go. It required significant technical refinement to bring it up to my standards and expectations. As my driving skills grew at track days, I began to push further and further into the car’s drivetrain and handling performance envelope. With hard throttle tracking sessions, on short tracks, I was probing further into all that extra supercharged horsepower, and the car was confronted with heat rejection issues. This required proper management and an engineered bulletproof solution. I set out and conquered those heat issues as you may clearly observe in the track video and detailed photos. Open frontal area, dual wing radiators, secondary electric water pump, fitted oil cooler; all were integral to this reliable solution.
With confidence, I can state that this 928 has been a fulfilling and rewarding experience in all respects. Having purchased this car from a PCA track chairman, caged and with the supercharger and Tec-3 ECU already fitted and tuned, this 928 was already remarkably fast. The previous owner had dyno records, but they were long lost. I never felt the need to dyno the car as the track yielded comparative data in the cars I passed and those I could not.
Welcome Porsche aficionados and all others to the auction of my highly modified dedicated 928-S4 track car. This is not a race car. It a highly developed track car. Want to race it, certainly it is capable.
As a gearhead I would argue that you haven’t lived if you haven’t heard the thunder and felt the resonance of power passing through the unibody of this supercharged 5-liter 32 valve V-8 Porsche; with the instant bottom end torque launching you out of the apex and down the straight.
For the past 4 years I have developed this car; to build, challenge and develop my track driving skills. Money, time and labor input all took a back seat to optimizing this car’s performance on the track.
Love it!