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Ever since Danny Humphreys watched Tom Cruise outrun a pimp in a 928 Porsche during the iconic chase scene in Risky Business, Danny has wanted the car for himself. In addition to wanting a 928 Porsche, Danny is also a long-time drag racer who views the sport as a progressive disease. Naturally, as soon as he did get his Porsche, he pulled the engine and the horsepower has gone up from there.
Today, Danny’s 928 Porsche has a supercharged 572 cid SMX engine in it from Steve Morris Engines, complete with a “shark fin” blower hat that really puts this car and engine combo over the top. We were able to catch up with Danny during day one of Sick Week 2024 at Orlando Speedworld to get the full scoop on his “shark.”
“I’ve owned this car for 23 years,” Humphreys told us. “I bought it, drove it home, pulled the motor out, put a big block in it – just a 540 cid pump gas deal – and had it like that for a few years. I’ve always run supercharged stuff and ran Top Sportsman back 500 years ago, and we started doing some back half stuff, so I went with the supercharged combination.”
Seeing this car and engine in person is the only way to do it justice, but there’s no denying it’s unique, and in the drag-and-drive scene, it’s even more unique.
“I always wanted to be Tom Cruise in Risky Business, so I figured if I got the 928 it was a good start,” Humphreys says.
A good start indeed, but what really makes the Porsche “no substitute” is Danny’s choice to stuff a Steve Morris Engines’ supercharged 572 cid SMX engine in the car.
“This is a Whipple 9.8-liter supercharger that was originally designed to run in an alcohol Funny Car – they’re like an anvil, you just can’t screw ’em up,” he says. “It is a screw blower using an 8mm belt. We’re only running like 32-lbs. of boost so we’re not leaning on it too hard.
“I had Steve build me a 572 cid SMX because I wanted a 4.500” stroke in it, so I didn’t have to beat the snot out of it. I’m getting old and I don’t want to work on it all the time.”
Inside, the SMX engine features a billet Sonny Bryant crankshaft, billet MGP rods, a Steve Morris Engines’ piston package, and Manton valvetrain components.
“I had the supercharger intake custom made,” Humphreys says. “This is the only supercharged SMX, so it’s kind of a unique deal.”
Running the engine using 32-lbs. of boost, the SMX made 2,600 horsepower on the Steve Morris Engines’ hub dyno. The engine utilizes a wet sump oiling system, which is again unique among other SMX engine combos primarily being dry sump.
“We’re the only wet sump SMX, which is due to a packaging issue for me,” Humphreys says. “As you can tell, it’s 10-lbs. in a 5-lb. bag, so we needed a wet sump deal. I do have an accumulator on it and haven’t had any issues with it, so it seems to be working well.”
On the fueling side of things, Danny’s SMX runs pump gas on the street courtesy of eight injectors under the intake, and methanol on the track courtesy of another 16 injectors.
“It’s completely segregated so there’s no switching valves or any of that stuff,” he says. “Holley EFI runs the whole thing – I just switch the tune back and forth. The injectors are kind of a unique situation because for packaging issues on the supercharger it’s always a little difficult to get the injectors working. I’m actually running mechanical nozzles with a check valve that has a 15-lb. check valve in it, so there’s always pressure in the lines. Whatever comes in this end goes out the other end, so that’s a little bit different.”
If you’ve seen this car in person or looked at it via video or photos, you’ll inevitably ask yourself, “How does Danny see while driving?” The answer is quite clever and simple actually.
“My buddy actually designed and built these blower hats for truck pulls and it’s really a pretty unique design, but obviously it’s not very good for certain lines of sight,” Humphreys admits. “I mean the supercharger itself is big enough. What I did was I have a camera mounted on the passenger side with a monitor on the dash, so I can see traffic on the other side. That’s how I’m able to see to my right.”
At Sick Week 2024, Danny was racing in the Rowdy Radials 1/8th-mile class and hoping his supercharged 572 cid SMX-powered 928 Porsche could make some 4.50 ETs. Unfortunately for Danny, his week ended early on day one due to issues with the car, but he did run a 4.89 at 165 mph. Here’s hoping we see Danny and his 928 Porsche out again later this year.
Engine of the Week is sponsored by PennGrade1, Elring – Das Original and NPW Companies. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].
