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Bruce's 928 | Episode 6 - Risky Business

See some great scenes from Risky Business featuring the 928. In this episode I focus on wheels and what wheels came on the 928. I also explain wheel off-sets and how that affects fitment. This series documents the restoration of my 1990 Porsche 928 s4. The 928 was my teenage dream car. I first fell in love with the 928 when it was featured as the hero in Risky Business. The 928 was a 5 litre Porsche with a V8 and was my teenage dream car. I first fell in love with the 928 when it was featured as the car from Risky Business. With its 32 valve V8 the Porsche 928 s4 was a true supercar breaking the land speed record on the Utah Salt Flats at 172 mph in 1987. This series follows the process of mechanical, paint and body work, and interior restoration. It also looks at some of the unique features of the car and the history behind it.


Movie Clip:



I think I can take him.

I think I’m going to throw up.


A great iconic movie featuring a great iconic car. Risky Business was the classic coming of age movie that every teenager of my time loved…and it featured some great scenes of the 928…

Movie Clip:

Porsche, there is no substitute.

Fuck you!



Well there were actually 3 other cars that were substituted for the main car used in the movie. All of the 928s used them were slightly different and were various model years but the car that was shown in most of the scenes was a 1981 Platinum Metallic 928 rented from the owner in Chicago for $500/day.

Here’s a little known fact, the car that went into the lake, known as the “dump car”, came from a Props Broker in California and was painted to the right colour and then stripped down before being dumped into Lake Michigan. You can actually see in the scene that the front end of the car is sitting high because the engine and drive train had been removed. You know, to this day, I can’t get out of my 928 without firmly applying the hand brake.

This episode is all about wheels. The 928 had a number of stock wheels over the years. The early cars, including the one in Risky Business had what are known as Phone Dial wheels. They were the stock wheel from the introduction of the car in ‘77 until ‘82. Most of the Phone Dials were 15” but cars with manual transmissions got a 16” version of the same wheel. After that there was the Flat Dish wheel. The Flat Dish was the stock wheel on the 928S & S4 from ‘83 until ’91. These were the wheels that came with my car. I have to admit that I was never too crazy about these wheels. Mine were chrome and in pretty good shape but it was always something I wanted to change. The question was, what wheels to change them to?

Other stock wheels on the 928 included Club Sport wheels on the GT models from ’89-’91 and then once the GTS models came along in ‘93 & ’94 the cars got 17” Cup 1 wheels. And in the last year of production the 928 finished its run with 17” Cup 2’s.

I have always thought that the cup style wheels looked the nicest on the 928 but finding a set at a decent price is not as easy as you might think. Cup style wheels were used on other Porsches, but the widths and the offsets varied so not all cup wheels fit the 928.

The offset refers to the distance between the mounting surface of the hub and the center line of the rim. In this diagram you can see that a wheel with a zero offset has the mounting surface directly in line with the centre line of the wheel. A wheel with a negative offset has the mounting surface closer to the inner side of the rim. These are commonly referred to as deep dish rims. And positive offset wheels have the mounting surface closer to the outer side on the wheel.The offset is measured in millimetres and is indicated by the letters ET.

The offset on the S4 is ET52 on the rear, and ET63 on the front. That’s a positive offset.

Shortly after I got the car, I looked online for a set of wheels but I couldn’t find any Cup style wheels for a decent price, so I settled on a set of 17” Boxter wheels. They fit the car nicely and had a similar look to the Cup2 wheels that I really liked. I guess I shouldn’t have settled because I have never given up my search for the cup style wheels. I’ve also contemplated other styles of Porsche wheels that fit the car. Some of the more popular wheels that people put on their 928’s are 18” Turbo Twist or Carrera III wheels. I liked the Carrera III’s but I decided that my preference was to stick with one of the original 928 wheels so I started a serious search for a set of GTS cup style wheels. I probably looked online every 2nd or 3rd day for about 4 months and then finally, I found them. A beautiful set of 17” GTS Cup 2 wheels in polished aluminum. They even came with tires and centre caps which was a nice bonus considering 4 centre caps alone can cost between $200-$300.

Now one thing I want to do to the wheels prior to putting them on the car is polish the aluminum and have them coated with a protectant to reduce the amount of brake dust that sticks to the wheels. Kurtis Martin is an auto detailer that has done lots of work for me. When I got the 928 he did a full cut polish and paint correction on the car and got rid of all the circle scratches and really brought the paint back to a beautiful mirror like shine.

Kurtis is going to completely polish the wheels and then apply a ceramic coating.

Kurtis Martin:

So what we’re doing to these wheels is first cleaning off all of the contaminants, removing the oxidization from the polished metal. Following that, we want to protect them. We’re going to use a Ceramic Pro coating which is a 9H hardness that is going to give us long-term protection for easy care and maintenance of these wheels. So it’s going to protect against things like oxidation. It’s going to protect against pitting. It’s going to protect against acid rain. It’s also going to mostly help keep the brake dust off the wheel.


So now the wheels are polished and protected and waiting until the rest of the car is done. I think the polished aluminum is going to look fantastic with the black car.

But let’s get back to the Risky Business Car… After being used in the movie, it wasn’t in high demand, in-fact they drove the crap out during the filming of the movie and most people thought it was actually dumped into lake Michigan. At that time Tom Cruise was relatively unknown, so the car wasn’t expected to ever be valuable so no one kept track of its whereabouts. A few years ago, a fellow by the name of Sam Johnson tracked it down through the help of a private investigator. He then had it repainted back to its original colour and it sold at auction in 2012 for close to $50,000. Not bad considering its icon movie status. There’s a couple of great articles about the filming of the movie and all of the cars used to create the film which I will post on Bruce’s 928 Facebook Page.

In the next episode I’m going to show you the process of tearing down my car and prepping it for paint. Thanks for watching…

Movie Clip:

A couple of boys in daddy’s car. Wanna race, come on pussy.

Hit it.

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