Purple Means Performance cont'd

Royal Purple also excelled in ‘independent’ testing, and certified data is available from the manufacturer. We decided to conduct some tests of our own. Recently we visited the dynamometer facility at Riverside, California’s K&N Engineering, manufacturers of the finest automotive air and oil filtration products on the planet. Our test subject was a stock, 22,000-mile, 4.6L two-valve Tremec TKO-550, five-speed Bullitt Mustang (serial #00019) factory rated at 265 horsepower with 305 1b.-ft. of torque.

First we had to arrive at a baseline with the car, K&N technician Curt Swanson strapped the Bullitt onto the dynamometer and conducted a series of pulls.

Third gear: 228.7 hp at 5,200 rpm, and 261 lb.-ft. of torque at 4,300 rpm.

Fourth gear: 237.3 hp at 4,900 rpm, and 277.4 lb.-ft. of torque at 4,100 rpm.

With a baseline horsepower and torque figure established, the Bullitt was driven over to K&N’s Race Shop, where its engine, transmission and rear end fluids were drained. In their place, K&N Race Shop Manager John Hudson substituted Royal Purple XPR 20W50 motor oil (which is similar to Royal Purple XPR 10W40 except that it rates a 20W50 viscosity) along with Royal Purple’s Synchromax Manual Transmission Fluid and the Max-Gear rear end gear lube. To ensure an absolutely clean baseline, we also replaced the stock OE Motorcraft filter with one of K&N’s Performance Gold oil filters (P/N HP-2010).

K&N’s Limited Lifetime Warranty Performance Gold oil filters are considered the finest in the industry and feature heavy duty case construction (with easy spin-off 1-inch nut feature) and can withstand 550 psi. Performance Gold also has a flow-rate of 12-16 gph and internally features high-tech filter paper capable of trapping 10-20mm micron contaminants.

Third gear: 227.1 hp at 5,000 rpm, 263.0 lb.-ft. at 4,000 rpm.

Fourth gear: 239.7 hp at 5,000 rpm, 280.4 lb.-ft. at 4,000 rpm.

While the third gear numbers fell slightly short, Swanson pointed out that the oil had yet to be really run in. However, the torque number showed that Royal Purple was starting to work. At 4,000 rpm we gained 2 lb.-ft. torque a full 300 rpm sooner than stock, a strong indication of Royal Purple’s friction fighting properties.

On our fourth gear pull we gained 2.4 hp and 3 lb.-ft. torque. Again, a full 100 rpm sooner than stock. What’s more noteworthy is the fact that useable (street driven) horsepower in the 2,500 - 4,500 rpm power band is significantly increased with the substitution of Royal Purple. Would you believe? A 4.7 hp gain at 2,500 rpm and a 5.5 hp gain at 3,100 rpm, in third gear!

And when you talk about engine torque, the new gets even better. Significant increases in third gear engine torque using Royal Purple came in immediately at 2,100 rpm (13.4 lb.-ft.) and gains continued up to 3,400 rpm.

In fourth gear, horsepower figures started climbing on our Royal Purple-ized Bullitt Mustang. They were within 2 hp all the way up to 4,300 rpm, and torque increases were also parallel to horsepower increases at those rpm operating ranges.

Then came the installation of a K&N Million Mile Warranty, High-Flow Filtercharger (P/N EO-945). The K&N High Flow Filtercharger is a direct OE snap-in replacement filter.

Third gear: 234.9 hp at 5,000 rpm, 252.3 lb.-ft. at 3,200 rpm.

Fourth gear: 240.9 hp at 4,900 rpm, 283.0 lb.-ft. at 4,100 rpm.

With the addition of the K&N High-Flow Filtercharger, we gained 7.8 hp at 5,500 rpm as well as 2.7 lb.-ft. torque at the 4,100 rpm operating range. Of course, these numbers are on a freshly oiled engine. We feel that after proper drive-in time we could have improved those numbers. On our 65-mile drive from Riverside back to Los Angeles, we felt that the Bullitt’s 4.6L ran smoother and exhibited better throttle response. We also noticed that in fourth and fifth gear, especially at lower rpm operating ranges, we could get into the throttle, and the car exhibited less of a tendency to lug and appeared to accelerate quicker.

Of course, performance numbers will differ from vehicle to vehicle. But in closing, our question is, When was the last time you were able to gain 5-7 hp and 2-3 lb.-ft. torque for the price of an oil and filter change? You be the Judge!

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