Cat Killer

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POSTED ON October 30, 2017

Back in Volume 9, Number 1 of Perth Street Car Magazine, five years ago to be exact, we covered the build up of a very unique Windsor engine being put together at A1 Hi Performance in Myaree..

Engine Essentials.
The engine was built by proprietor, Leon Withnell, for his own TE50 Falcon as an R&D project and featured some very hardcore parts. At the time it was revolutionary because no tuning existed for AU EFI Fords and as a result modifications to these cars were often limited to cold air induction and exhaust upgrades. Leon took a stand and built a highly modified engine that had our readers frothing at the mouth. The engine was dubbed Cat Killer because it was designed to take on Holden’s 300 kW GTS Commodore. Our road test from Volume 9, Number 4 proved that not even the Callaway enhanced GTS was in the same league as this blue oval monster. In fact, the car accelerated so hard that the tacho and speedo needles collided with each other! Hidden inside the Ford Motorsport R-Series block is a Moldex/Cola 4340 steel crankshaft, Eagle H-beam rods with 230,000 psi ARP L19 rod bolts and custom JE forged pistons.

The combination of a 4.125-inch bore and a 3.40- inch stroke gives 363 cubic inches or 5.90-litres of displacement. A Competition Cams solid roller camshaft was used in the original engine but Leon has tried several in the past few years. The camshaft used in the current configuration was ground especially for the engine and only arrived days before the dyno test. Cylinder head choice was a pair of highly modified Edelbrock Victors, which are modelled on the 18-degree Chev head. These flow 340 cfm of air on the intakes and 279 cfm on the exhausts at 32-inches of water. Even more impressive is the fact that they do this with a minimum port restriction smaller than a Dart Chev or a 2V Cleveland. The intake port actually flows 137cfm per square inch at 28-inches of water. Consider that the theoretical maximum a perfect 1-inch orifice can flow at that pressure is 143cfm through a straight pipe – not a curved port with a valve stem running through the middle!

Offset roller lifters were required because of the valve offset in the head, these feature a tiny oil hole to provide lubrication to the roller which runs on the cam lobe. At high rpm this roller can be spinning at 30,000 rpm so a little oil adds life. Jesel built a custom set of shaft-mounted roller rockers for the engine with a 1.70:1 intake ratio and a 1.60:1 exhaust ratio. Five years ago the engine was running a 95mm throttle body and a one-off BXR cross ram intake manifold but that has since been replaced with a Victor Jr. single plane manifold and a 1000cfm square-bore throttle body. Leon was keen to test the engine with the Victor’s shorter runners and also to see the effects of using a throttle body with four smaller butterflies. In the real world, the shorter runners and bigger camshaft would combine to wash off some of the engine’s bottom end torque, resulting in less wheelspin and greater acceleration on the road. The progressive nature of the square bore throttle body also makes the car more driveable than the huge single throttle plate.

The engine uses a Petersen wet vac external oil pump. Two coil packs are triggered by an MSD distributorless ignition module.

Oiling is courtesy of a Petersen wet vac pump which scavenges from the sump and supplies oil to both the main bearings and the rear of the lifter galleries simultaneously. The system is essentially an externally-mounted oil pump with an in-built two-stage vacuum pump. The wet vac pump has the added benefit of producing a vacuum in the crankcase which helps rings to seal and dramatically reduces windage, resulting in more available power at the flywheel. Restrictor plugs are used to limit the amount of oil that travels up the pushrods onto the rocker gear, keeping it below to feed the crank and rods. Controlling the MSD distributorless ignition (DIS), the two wasted spark coil packs and the 50-pound fuel injectors is a Motec M800 unit with self-learning enabled. This helped to quickly establish a base tune in the early days. For the recent dyno session at C&R Motorsports, in Walliston, well-known local tuner, Andrew Jordan, was on hand to work his magic. Andrew monitored the engine’s vital signs and was able to use the real time data logging to deliver exactly the right fuel and ignition trims to extract the absolute maximum from the wild Windsor.

Engine Run-In.
As the engine had been freshened just prior to its dyno day, Geoff Chaisty, from C&R Motorsport programmed the Superflow 902 dynamometer to run the engine in over a 60-minute period. During these break-in cycles, the engine was cycled up and down, at first from 2500 to 3500 rpm in 5-second ramps, for ten cycles at varying throttle openings from 20 to 60 percent. A quick glance at the torque curves generated during this period shows that they become closer and closer as the engine begins to bed-in. While the running-in process was being carried out, the EFI fuel curves were being gradually mapped by Andrew on his laptop computer, providing a base for future adjustment. Air/fuel ratio information from the oxygen sensors was used in conjunction with data from pyrometers located in each header pipe to build a picture of how each cylinder was functioning. After the run-in was complete, the oil was changed and the filter checked.

Dyno Testing.
The first few runs included a part throttle (60%) acceleration test from 3800 to 5000 rpm which was performed to check the fuel map at a faster acceleration rate. This resulted in a maximum of 382 lbs/ft of torque and 367 hp – both at 5000 rpm. The first full-power acceleration test was then programmed to run from 3500 to 6000 rpm, the ignition timing was set fairly conservatively at this early stage and resulted in 423 lbs/ft at 5750 rpm and 481 hp at 6000 rpm. The power curve was still climbing steeply at 6000 rpm. In the next test, the upper test limit was raised to 6500 rpm and no other changes were made. Power jumped over 40 hp to 522.5 hp at 6500 rpm and was still rising.
Andrew then tweaked the fuel map a little and with the next test run set to 7000 rpm we saw 430 lbs/ft. at 5700 rpm and 559 hp at 7000rpm with no sign of the curve leveling off. At this point the ignition timing was adjusted from its base of 28-degrees to a new maximum of 30-degrees. With the rise in total timing the starting rpm was lifted to 4500 rpm and the upper limit also lifted to 7500 rpm.

Adding an extra litre of oil created measurable windage losses. Opening up the exhaust tappets effectively reduces cam duration which helps low and mid-range performance.
Advancing the ignition timing to 32-degrees made significant gains.

After Andrew raised total timing a couple of degrees higher to a new maximum of 32, the engine again responded favourably by producing 608.2 hp (453 kW) at 7550 rpm – a sensational effort. All the tests up to this point had been carried out at a coolant temperature of 160 degrees F. The next two runs were conducted at 130 and 180-degrees F respectively to determine the engine’s sensitivity to heat. Very minor differences were noted, indicating that this engine was fairly insensitive to coolant temperature change, which is an excellent quality for a street engine. Often engines can demonstrate large power differences across a 50-degree change in coolant temperature.
The following dyno run was mad after a litre of extra oil was added to confirm or disprove what was believed to be an issue in the oil pan. Even though the oil was still below the recommend level, the extra oil caused a loss of as much as 10 hp at some points and this was with light synthetic oil. This demonstrates how much power can be robbed by oil windage in the crankcase.

Geoff from C&R Motorsport and tuner, Andrew Jordan, monitor the engine on dyno.

The engine had cracked the magic 600 hp mark with only 363 cubes aboard and matched that with just under 450 lbs/ft of torque. But Geoff and Leon felt that the camshaft was a little too big, as indicated by the engine’s ability to make power to just under 8000 rpm without dropping off noticeably. To confirm this theory, the exhaust tappets were opened up 0.006-inch; this resulted in a power increase at all points below 7000 rpm and by as much as 14 hp at 5200 rpm. Only a couple of horsepower were lost above 7000 rpm after this change. The engine pulled strongly all the way to 7750 rpm and at this point had only just started to level out. With enough road and enough faith in the conrods and other internals the engine would easily turn well past 8000 rpm and not fall off. Not many street engines can boast such credentials.
This engine not only produces strong power, it does so very efficiently. Brake-specific fuel consumption is a measure of the engine’s efficiency and is defined as the ratio of the rate of fuel consumption to the rate of power production. Calculating BSFC requires measuring the rate of fuel usage as a function of the mechanical power generated. Reviewing the data from the dyno, the Brake Specific Fuel Consumption (BSFC) average between 4500 and 7700 rpm was a very low .365; indicating that the engine uses very little fuel to generate its horsepower. In fact, BSFC figures in the mid .3s are normally reserved for highly efficient race engines. Complimenting the engine’s efficiency are its manners. Despite its 600 hp pedigree, the Cat Killer still idles like a kitten. So, after five years of research and development, the Cat Killer has served its purpose as a very valuable test mule. The TE50 will be equipped with a genuine 600 hp, 8000 rpm street weapon, capable of slaying the opposition with potential 10-second quarter mile times. Oh, and thanks to the trick exhaust system, Leon will be able to listen to the CD player in comfort while the scenery flashes past!


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