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The project started last year when Shane discovered this car for sale in Green Bay (86.5 Automatic)
Long story short, the car was prepped at Page Auto (timing belt, water pump, hoses, vacuum lines, A/C overhaul etc…). Once complete, moved to Tim Murphy’s house where Tim, Mike Schmidt (Z), Todd Tremel, and I proceeded to develop an intercooled setup for the 85/86 928.
IMO the intercooler is the shining star of this development. Todd never ceases to amaze me. He was handed the largest air / water IC core we thought would fit (within reason) and he made us an intercooler.
How good? On the dyno from idle to full boost (under load) to the peak of 10ish psi the air temperature rose less than 10 degrees!!!
Stage 1
This is still a work in progress, the setup we tested is a stock fuel system using a Vortech FMU to raise fuel pressure as needed under boost.
Next step will be to develop this kit using 42lb injectors with shark tuned fuel / ignition maps. This setup will retain stock fuel pressure.
In the beginning we had no intentions of using Shane’s car for stage 1 testing. We had a window of opportunity so we took it. The guys at the dyno were very impressed when we arrived less than 24 hours after the base line run with the stage 1 kit installed ready to go.
Stage 3
Fuel system is 100% stock except for 42lb injectors.
Air / Water IC using the windshield washer tank as a reservoir with a heat exchanger mounted in the nose of the car. This is the same setup as the S4 kits, with a different IC design. The core sizes between the two kits is very similar
Only modification to the car other than the supercharger is a Motorsports X-Pipe. Stock mufflers are still in place.
Stock – 271.48rwhp
Stage 1 – 370.35rwhp (16.48hp per pound of boost @ 6psi)
Stage 3 – 473.61rwhp (18.38hp per pound of boost @ 11psi)
I was concerned the stock mufflers would be restrictive. This was confirmed with a pressure gauge connected to a bung in the x-pipe. 7psi of maximum back pressure in the exhaust. We are losing power here.
The dyno owner / operator (and boosted guru, just finished an 800whp 2.2 liter mitsu pushing 50psi) made a comment this was a neat setup. All the advantages of a supercharger with some of the backpressure of a turbo!
Shane’s #1 item on the “to-do” list is an RMB. I have no doubt he will pick up serious hp uncorking the exhaust.
The Dyno:
Our local speed shop, Beyond Redline, recently removed their Dynocom due to issues with replacement parts. They now have the latest generation Dynojet with AWD option and dual eddy currents.
This dyno is 100% enclosed within the shop so all elements are well under control. This helps keep some consistency between runs since you don’t get the outside air blowing directly onto the car like other dynos.
This can be an issue if there is any difference between the outside, ambient air temperature & pressure versus what the dyno is reading inside. This is very common at some shops and can cause erroneous results.
Two days after the car was tuned for the stage 3 setup – Shane left Green Bay for Las Vegas Nevada.
Green Bay to Las Vegas = 1,800 miles
Fuel mileage = 19 miles per gallon (yes, even with 42lb injectors)
The entire trip without a speeding ticket = priceless!!
Back row: Mike, Adam, Tim, Shane, Paul, Todd, Jim
Front Row: Andrew, Jim, Tony, Luke (dyno owner / super tuner), Erik
For the record, the Llama and I never hooked up. But then Shane and Tonay stayed an extra night, so maybe there was some action after all.
The car stuff was a blast. I had so much fun despite my car's harness giving up the ghost. I hope to have that fixed soon and get it dynoed as well. Fun times - fun people. Thanks for letting me join in.
I made it all the way to Vegas without feeding the bears...
Not for the lack of trying on the part of the revenue collectors of Utah though, they tried like hell to get me. One UHP even road in my blind spot for more then five miles trying to get me to screw up.
Crossing my fingers for the trip to WA State in hopes that I can get her home without any tickets.
My Hearty Thanks goes out to Erik, Mike, Todd, and the Murphy Family for putting together such a great masterpiece!! It drives smooth and sweet and should you ask it to, like a demon on meth...
to the Green Bay crowd!
Supershark in Utah taking a breather from out foxing the UHP:
Wow, makes me wish I lived near Green Bay. Excellent 928 support and seems like a great bunch of guys. A few more years of getting my car sorted and I hoping I can add a little Murph magic.
Finished Supershark waiting for its' registration paper to be faxed.
I must say that Tim and his Family were excellent hosts. They made me feel right at home and made sure that I didn't want for anything. My face is just now getting back to normal from smiling and laughing the whole time I was there.
Supershark crossing the rockies, i meant to cut south from Denver and go through New Mexico and Arizona, but the morning rush hour traffic was so bad that I took I-70 just to get out of there sooner.
As it was I really enjoyed the twisty canyon roads that I encountered there, the S/C really helped equalize the thin air at those elevations and the air/fuel stayed right in there between 12.5 to 14.7, depending on throttle position.
I managed to average 19 mpg with the whole trip of about 2000 miles, with about another 2000 miles to go to get back to WA State.
04-24-2008, 10:15 PM
Murf 928 85/86 Supercharger update & Dyno Charts (aka - Shane's new car)
