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| Tech Specs - Test Car at a Glance | | Car | '84Mustang: Project Pro Tree Mustang | | Engine | OEM '91 5.0 H.O. short-block | | Cylinder Heads | '71 351W, 1.90 intake, 1.60 exhaust | | Camshaft | FRPP X-303 | | Carb | Carb Shop 750 Holley | | Intake | Weiand Stealth, port-matched, with 1-in four-hole spacer | | Timing | 40 deg total | | Exhaust | Equal-length shorties, 2.5-in H-pipe, Flowmaster three-chamber mufflers | | Rear | Dana 44 with Detroit Locker | | Gears | 4.27 Precision Gear | | Suspension (front) | Koni adjustable struts and four-cylinder coils | | Suspension (rear) | Koni adjustable shocks, Moroso Trick springs, Steeda aluminum lower control arms, FRPP upper arms, airbag | | Lubricants | Amsoil 10W-30, engine; Castrol Type F, C4; Redline Lightweight Shockproof, Tremec; Amsoil 75W-90 gear lube,rear | | Tires | P165 radials, front; M/T 26x10, rear |
On-Track Comparison: C4 vs. Five-Speed | C4 | | Date | 60 FT | 330 FT | 660 FT | 1,000 FT | ET/MPH | Comments | | | 6/28 | 1.596 | 4.840 | 7.648 | 10.112 | 12.214 /107.22 | Shift 6,000, 90 deg, 56%. 29.93, 2,400 ft. Engine 150 deg | | 1.602 | 4.830 | 7.630 | 10.085 | 12.179/107.62 | Shift 6,200, 86 deg, 63%, 29.92, 2,207 ft. Bogged. Liked higher shift point. Air change should equal 12.20. | | 1.602 | 4.847 | 7.648 | 10.102 | 12.195/107.69 | Shift 6,200, 86 deg, 63%, 29.92, 2,200 ft. 11.75 psi in slicks | | 1.592 | 4.829 | 7.626 | 10.078 | 12.167/107.86 | Shift 6,200, 83 deg, 68%, 29.93, 2,054 ft. 12 psi in slicks | | 6/30 | 1.578 | 4.792 | 7.578 | 10.024 | 12.109/108.00 | Shift 6,200, 80 deg, 47%, 29.96, 1,550 ft, 150 deg. Air change should equal 12.137 from last pass on 6/28. | | 1.588 | 4.808 | 7.590 | 10.026 | 12.099/108.68 | Shift 6,200, 77 deg, 45%, 29.98, 1,300 ft. Air change should equal 12.093. | | 7/7 | 1.595 | 4.811 | 7.602 | 10.048 | 12.129/108.35 | Shift 6,200, 74 deg, 69%, 30.14, 1,300. Higher humidity hurts, increased barometer seems to help offset e.t. loss | | 1.599 | 4.819, | 7.607 | 10.050 | 12.128/108.45 | Shift 6,200, 72 deg, 75%, 30.15, 1,000 ft. Air change should equal 12.108 | - All tests with C4 were with 4,700-rpm transbrake launch, 11.5 psi in slicks, 25 psi in airbag. Engine at 40 degrees timing, 85 Max Jet, 160 degrees water temp. Car weight 3,030 lbs, with approx. 47% on rear tires. Struts and shocks full loose.
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 The first outing with the...  The first outing with the stick exposed a serious problem with our rear lower control arm bushings (right). The resulting axle movement broke a rear shock a split second before the 1-2 shift, yet it produced the quickest pass of the night. New bushings (left) and fresh adjustable shocks cured the problem.  Project PTM launches hard...  Project PTM launches hard from the Raceway Park starting line. The stick was a little quicker and provided more fun, while the auto was consistent and just the ticket for weekly bracket racing.  The engine is a 302 using...  The engine is a 302 using a stock roller block and old-school 351 heads. It makes just over 300 hp at the wheels and can propel our Mustang into the 11s. | Tremec Five-Speed | | Date | 60 FT | 330 FT | 660 FT | 1,000 FT | ET/MPH | Comments | | | 8/11 | 1.547 | 4.837 | 7.583 | 9.969 | 11.991/111.55 | Shift 6,200, 84 deg, 34%, 29.84, 2,000 ft. Nose bouncing on launch | | 1.542 | 4.843 | 7.598 | 9.987 | 12.015/111.25 | Launch 5,500, Shift 6,200, 80 deg, 47%, 29.84, 1,750 ft. Air should equal 11.975. No change in 60 ft. | | | 1.567 | 4.800 | 7.535 | 9.908 | 11.926/111.69 | | - Launch 4,700, shift 6,000, 68 degrees temp, 70% humidity, 29.88 barometer, 1,000-foot corrected altitude. Air should equal 11.924. Broke rear shock.
- Used same 4,700-rpm launch, 11.5 psi, 25 psi airbag (too much body roll). Engine 40 degrees timing, 85 Max Jet, 160 degrees water temp. Car weight 3,050 lbs, with 48.5% on rear tires. Koni struts one turn tight, shocks full tight.
- Video showed nose bounced on launch and 1-2 shift. Left rear shock broke prior to 1-2 shift on last pass.
| | 8/23 | 1.577 | 4.810 | 7.535 | 9.910 | 11.930/111.65 | Launch 4,700, Shift 6,000, 92 deg, 32%, 29.85, 2,390 ft. Air change should equal 12.019 from last pass on 8/11 | | 1.560 | 4.799 | 7.519 | 9.880 | 11.889/112.21 | Launch 5,500, Shift 6,200, 87 deg 40%, 29.85, 2,100 ft. Air change should equal 11.910 from previous pass | | 1.578 | 4.809 | 7.559 | 9.936 | 11.953/111.94 | Launch 6,000, Shift 6,200, 81 deg, 45%, 29.85, 1,679 ft. Spun bad. Air change should equal 11.861 | | 1.558 | 4.760 | 7.497 | 9.883 | 11.908/111.45 | Launch 55, Shift 62, 73 deg, 53%, 29.89, 1,267 ft. Spun, but pulled wheels. Shift light broke. Air should equal 11.834 | - Replaced damaged LCA bushings, installed new Strange adjustable shocks. Car weight 3,056 lbs. Rear tires at 12 psi
- Airbag now 30 psi (body roll eliminated), Koni struts 1.5 turns tight, Strange shocks on Pos. 6 (out of possible 8). No changes to engine
- Shift light broke on last run, no signal for Third or Fourth gear shift. Overshifted by unknown amount
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| Conclusions | - The five-speed is quicker using the identical launch and shift rpm, but how much?
- At 2,000 feet, the five-speed is 0.176 second and nearly 4 mph better, including 0.05 quicker in the 60-foot; all with destroyed LCA bushings
- With repaired bushings and new shocks, and better suspension tuning for stick launches-at 2,400 feet-improvement was 0.284 second and 4.5 mph over the C4.
- All this was accomplished with 20-30 lbs additional weight.
- The car now runs the same e.t. at 2,400 feet elevation that it ran with the C4 at 600 feet below sea level.
- The potential for the five-speed is 11.70s in better air.
- With traction and suspension tuning, further gains are possible.
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