Where the Rubber Meets the Road

By Rob Fusi & Colin Mazzola, edited by Charlie & Katie Boyer

Performance data is one of the most coveted pieces of information an automotive enthusiast seeks for their steed. For newer stock Porsches, you have a relatively good idea of how much power the car is making…or do you? The twelve members of GTC Motorsports own a variety of different cars in various stages of modification, and inevitably car comparisons are made in quite a few conversations. Some proud owners boast about the theoretical power his monster is making. Other drivers declare talent allows them to perform only so well, given their limited power. The same holds true for the weight of the car, which is an often overlooked, but extremely important ingredient to performance.

This is Ags before we realize he’s a cheater, and Rob is skeptical

After years of debate, GTC Motorsports partnered with Powertech (www.pwr-tech.com) to learn the truth. What is the REAL peak horsepower of each car? How smooth is the torque curve? Is the air to fuel ratio too lean or too rich? Too lean a mixture risks damage to the engine, and too rich allows horsepower to fall through the cracks! Powertech’s brand new Dynapack (www.dynapack.com) dynamometer is considered by many to be the best chassis dynamometer available, with repeatable and consistent results. A “dyno day” was set-up to analyze the power of each car in one bay, while overall and corner weights were measured with accurate scales in another bay. This would surely put to rest any uncertainties, and more importantly, it would show whether those expensive modifications actually have increased the power.

Part of the crew

Seven cars were set for the day, three stock and four modified. The stock cars were essential to the mix to help set a baseline, since factory specs provided power ratings and could be used as a benchmark for the modified cars. The list included a 1997 993S, a 1995 993, a 1994 911 Turbo 3.6, a 1978 911SC (with a Euro stroked 3.0 engine), a 1977 911S (with 3.6 varioram engine), a 1974 914 (with a high compression 3.2 engine), and a 1971 914 (with a meager 2.0 four cylinder engine).

Flynn stays hydrated and nourished

The event was to start promptly at 8:00 a.m., however, most of the attendees were, shall we say, just a wee bit tardy. Keith, Brian and Jake of PowerTech used this time preparing the first car, while John Flynn stalked arriving doughnuts or other breakfast treats towards the front of the shop. At about half past, the rest of the crew finally started to wander in. Katie Boyer, a.k.a. “Food Angel”, sent Charlie along with many tasty treats for all to enjoy (thanks Katie!) and Bob Wonsetler provided the crew with bagels and cream cheese for those who wanted a healthier breakfast option. Finally arriving with the highly anticipated “Box of Joe” were John Agogliati and Rob Fusi. In addition to those partaking in the dyno-ing, fellow GTCers Shawn Crews, Adam Crews, and Nick Albrecht were in attendance. Shawn’s 944 Turbo, aptly nicknamed “Cicada” (as we only see it every seventeen years), was still undergoing a top end rebuild…a procedure that has been underway since last May (mental note, do not let Shawn work on your car). Nick’s Boxster “Flo’” was experiencing clutch issues, so the vehicle could not attend. Adam, though his Boxster had no actual issues, complained that sun spots and paranormal activities had rendered his vehicle too scared to show up.

Colin considers supercharging…

The first car up was Colin Mazzola’s 914-6, affectionately known as “Pesky”. Just about the only original part left on the car is the floor pan, and even that is questionable. It has a high compression and twin-plugged 3.2, and the car sounds fantastic! After a few minutes of warming up the oil, Keith revved ‘er up for the first run. The result: 204 rear wheel horsepower (or just “rwhp” for those of you familiar with dyno speak). This was lower that the 235rwhp that a previous dyno excursion had produced, but Keith thought we’d get some more power since the oil was only at 185 degrees. A general number used to estimate the horsepower at the crank is 15% loss through the transmission to the rear wheels. Using this formula, 204rwhp is approximately 240hp at the crank, well shy of what the “butt dyno” says about the speed of Pesky. The next two runs proved Keith right, with the best power number coming in at 216 rwhp. Everyone was a little surprised at the final result, but assumed that maybe the high humidity and relatively high temps were not helping the result (even though the dyno does compute an SAE horsepower rating to compensate for atmospheric differences). However, as we would find out, there would prove to be a far simpler answer than barometric pressure or relative humidity.

Hippy White screams to redline

The next car was Bob Wonsetler’s 1997 993 S, known as “Hippy White”. With Hippy hooked up to the dyno, the anticipation was high. Would Hippy be able to put up a better number? Was Pesky’s reign of terror atop Mount Dyno going to come to an end so quickly? Unfortunately, Bob had the GHL mufflers on for the upcoming Lime Rock event, as opposed to his supercup setup which has just an absolutely nasty sound (and in this case, nasty is good). After four runs, Hippy ’s best was 219 rwhp. All of a sudden, Pesky’s results didn’t seem so bad! Perhaps this dyno simply reads low? Time would tell…

The results are in for the Twisted Pumpkin!

Those suspicions were disproved by Rob Fusi’s 1977 911S. Powertech performed an engine conversion on this car over the winter from a stock 2.7 (that dyno’d at 115rwhp) to a 1997 3.6 varioram engine. This was the real unveiling of the “Twisted Pumpkin” (what else do you call an orange car with 3.6 in it?). Rob has been planning this upgrade for quite some time, so he was quite eager to see how all of the modifications would test out. Well, after three nearly identical runs, the results were impressive: 253 rwhp. Using the 15% loss guesstimation for crank horsepower converted from rear wheel horsepower, the engine is approximately 298hp. Apparently that Rennsport chip, open airbox, and custom exhaust help quite a bit! With the upgraded power and the light weight of an early 911, this will be one potent pumpkin at the track and autocross course.

Once Rob’s car was finished, Bob and Colin both began to wonder if something was wrong with their respective cars. Pesky’s problem turned out to be two disconnected plug wires (not as noticeable as you would think on a twin plugged engine). Mike Daino helped Bob out with the Bosch “Hammer” tool that reads the codes from the vehicle’s computer. Bob’s car did in fact have a couple of codes resident that suggested a bad mass airflow sensor or faulty oxygen sensor.

Ags is like a proud father with his “exceptional” 3.6 peak power

Moving down the line was John Agogliati’s 1995 993, affectionately know as “White Rice”. This is a 3.6, but it is rated at 271hp rather than 282hp of the 1996-1998 varioram-equipped 993’s. The group was guessing somewhere in the low 230’s for rwhp for this supposedly stock 3.6, and we were all shocked when it produced 247.5 rwhp! This equates to roughly 291 crank hp using the 15% loss calculation! John’s shrieks of joy were quickly followed by many comments from the gallery: “With that power, you should be driving MUCH faster” quipped one “friend”; “Stock class huh?” replied another suspicious member.

Slow White’s results always bring a reaction

Next up, John Flynn’s monster 1971 914 with a slightly modified 2.0 was bolted up for its set of runs. The car, known as “Slow White”, was the only four cylinder in the group. Could Slow White break into triple figures digits for horsepower? Rob Fusi’s 2.7-powered 911 tentatively held the trophy for the lowest HP engine ever tested on Powertech’s dynamometer. Could John’s white 914 steal the record away? Before the run, Keith asked John what to use for the maximum RPM value. John, who normally shifts when the valves start bouncing off the pistons, suggested a conservative 5400. Keith replied “well, let’s go to 6000 and see if it is still making any power up there.” As Slow White began the run, the air was thick with anticipation. Could Slow White hit 100 rwhp? Could it actually have more power than a standard issue yellow school bus (the short variety)? No, it was not to be. The result was a whopping 82 rwhp. Look out Yugo’s and 3 cylinder Geo Metros! Slow White’s results were hindered by an absurdly rich mixture, which was in the 9:1 range. Keith suggested re-jetting the carburetors might bring another 10-15 horses, but that would be a task for another day.

Charlie, looking like a true tourist and awaiting “the news”

Tubbo weighing in with Charlie & John available as spotters

Two contestants were left, one of which was Charlie Boyer’s 1994 911 3.6 turbo with an engine freshly rebuilt by Powertech. Charlie purchased the car in January, and it was supposedly stock. The factory specs state his car should produce 355hp at the crank, which is approximately 302rwhp. Though the turbo is new to the GTC family, it has already been nicknamed “Tubbo” for its rather portly profile. For the turbo charged cars, an extra device that measures boost is hooked up. In addition, an extra fan was placed directly over the intercooler in order to provide nice cool air for the intake. Unlike all the other cars that had been on the dyno to that point, as Tubbo revved up, it actually squatted about 4 inches. Clearly this was one powerful car. As the banshee cry of the single turbo and normal din of the flat 6 finally started to dissipate, the results were in. Wait just a minute…did that say…no it couldn’t be. Oh yes, THREE HUNDERED AND SEVENTY NINE. “This has got to be some kind of mistake”, we all thought, as the 3.6 turbo is only rated at 355 ponies at the flywheel. Well, turns out Tubbo was not running the stock 0.7 bar of boost, but instead 0.9 bar. With the 379.5rwhp translating into roughly 447hp at the crank, clearly Tubbo needed a new name. The group complied, quickly re-dubbing it “Silverbird” after the famous Ruf “Yellowbird”. Considering how quick Charlie was in his 250hp Boxster S, we are all expecting great things at the track of Charlie and his new steed.

Stiffmeister shows its stuff!

Last but not least (of course, there’s no need to worry about being “least” after Slow White’s big numbers!) was Dave Stoesser’s 1978 911SC. It has a European 3.0 stroked with a few other modifications, and Dave was hoping to break the 200+ rwhp range. “Mr. Softee”, as it is known, has the distinction on being one of the few cars with a stock suspension that runs in the red run group at the track. I can tell you from experience, that there is nothing quite like watching Dave four wheel drift his car through the bus stop at Watkins Glen…all while the car leans at about a 45 degree angle. It’s actually less of a turn and more of a hard tack to starboard. Nonetheless, it is a work of art. As the dyno was hooked up just aft of the mainsail, Dave began to wonder what the results might be (Dave is actually upgrading the suspension this winter, so sadly the nautical jokes will soon come to an end). The car revved up nicely, developing a deep and throaty note as it hit redline. The final tally on the soon to be “Mr. Stiff” (hey now!) was 192 rwhp. Not at all bad considering the car still has the original CIS injection (I smell a Motec upgrade!).

For the last run of the day, Pesky was back on the dyno for a run with all the plug wires connected. The difference was quite large, with the final result coming in at 236 rwhp.

All in all, dyno day was a huge success. We discovered two performance issues in Pesky and Hippy White, found out that Ags sandbags more at the track than he does on the golf course, and foiled “Cheatin’ Charlie” Boyer’s evil plan of stomping all over folks at the track while still claiming to be driving a “stock” 3.6 Turbo (granted, he “claims” he didn’t know there was a 0.9 bar spring, but let’s not let facts confuse the issue…). Thanks again to the entire Powertech crew for hosting the event and doing such a great job. See you and your rwhp at the track!