When we caught wind of a raucous triple rotor being debuted for the first time in the USA, and visible to prying eyes for the first time we had to corner the creators for the inside scoop. At PRI 2016 in the Turbosmart booth, we met Rocky Rehayem of PAC Performance and had a look at his monster rotary powerplant.
“So many firsts, I’ve been in business for 25 years, PAC Performance in Australia – we build rotary engines. Drag racing is our form of motorsport to show off our product and the rest is history,” Rehayem introduced himself.
PAC performance may be known for their drag racing campaign but they pride themselves on their in-house craftsmanship and competence with the whole spread of rotary applications.
“We build 10-15 cars a year, and we service and maintain anywhere from 7-15 cars per race event. We do drag racing as our major motorsport but also we do some road racing, rally, drift stuff and the street car scene,” Rehayem continued.
“We fabricate, we wire, build the engines, do all the machining etc. The majority of our work is on early model Mazdas – Rx3s, RX2s, R100s, RX7s all that stuff. We’ve got two dynos, we use Mainline DynoLog and have a four-wheel-drive tire dyno for up to 2,000 horsepower, and a 2,500 horsepower hub dyno.”
Development of these temperamental powerplants started nearly 30 years ago for PAC Performance. In traditional experimental hot-rodder fashion, they began modifying and found the weakest link in the chain, again, and again.
“We’ve been pushing these engines since 1991 and exploring all the avenues. With the factory Mazda cast iron plates we reached a level where we couldn’t push them anymore. Being cast iron they became obsolete,” Rehayem explained.
“Mazda stopped making the center plates 6-7 years ago, so in order to keep racing the 3-rotor engine we had to find an alternative. We started machining our own, this was done in conjunction with the guys at Turbosmart – we sat down and made all the drawings, plans and started making these plates. It took us about three or four years to get them to a point where they were sellable.”
With the cast iron plates sorted out and in production trim, the weakest link moved to the front and rear plates that capped off the Wankel design. In all this exhaustive R&D, PAC has engineered a product with a shining track record.
“Once we had a strong center plate the front and rear became the issue. We developed a front and rear plate and have been testing them since 2006. We haven’t lost a single plate in racing ever. Every plate we’ve ever made is still in use because they can be repaired, welded and reground,” Rehayem boasted.
On the horizon, PAC has some lofty power goals, and to achieve them, stock internals are not going to cut it. Rehayem hinted at the future saying;
“We use all stock internals, as we started to outgrow the power potential of engine components we began fabricating. Now we make our own cranks and our own billet plates. Next thing on the agenda is probably going to be rotors and rotor housings.”
The engine we had our eyes on powers the PAC Performance Mazda6 SP, the company’s latest car has been campaigning since 2012 and holds a shocking best ET of 6.263 at 223 mph to its name.
“At the moment this engine makes about 650 horsepower per rotor, and we can do that quite reliably. The plan is to try and make 700 horsepower per rotor, and we’re doing that still with stock stationary gears and rotors. This engine makes 950 lb-ft of torque, and between 1,900 and 2,000 horsepower depending what boost we’re running, and we rev it to about 11,000 rpm,” Rehayem detailed.
“We use a 100 mm throttle body blade and we’re using a Garrett 98 mm Gen II turbocharger running about 45-50 pounds of boost. We run an external dry sump, an Enderle fuel pump and 18 fuel injectors (it’s on alcohol).”
To manage all that boost Rehayem and Turbosmart have teamed up to test a new blow-off valve that we expect to revolutionize turbocharger drag racing.
“We’ve been doing testing with a Turbosmart blow-off valve, this late-model valve does two things; one, when you get off the throttle it lets all the boost pressure out so we don’t spin the turbo backwards. Two, when it’s on the two-step and we want to get our boost pressure ready for launch, it will open up just enough to maintain the boost we want for launch. We keep our turbo speed right up there, and as soon as you let go of the clutch the turbo is spooled up,” he explained.
Engine management and electronics are an important part to the success of this exotic package. A Weber IDA isn’t anywhere in sight of this tuned up Mazda.
“We use a home-grown product; a Microtech LT32 for our engine management, with 32 injector drivers so we can drive the injector with proper peak and hold. Additionally, every racecar we do at our place uses MoTec data acquisition,” Rehayem emphasized.
Reliability is undeniably the first question that comes to mind of engine enthusiasts when it comes to high-strung rotaries, but Rehayem and PAC Performance live their mantra;
“Our motto is; we’ve got to first finish to finish first. The last thing I want to be doing is replacing engines, and I know these things have a real bad reputation. As PAC Performance, we pride ourselves on the reliability of this engine and we work damn hard to make sure it’s reliable,” he assured.
“At 1,800 horsepower the engine is fairly reliable, we can do a whole weekend of racing and torture it the whole weekend. It comes down to good tuning, good engineering practices and basic stuff you’d do with a normal piston engine. If you get that right, these things are reliable.”
Rotaries have a cult following, one largely perpetuated by the Australian contingent of enthusiasts. They may have a gotten a bad reputation over the years, but maybe we need to look down under for a little inspiration.