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Mercedosaurus Rex at Indianapolic Park
Appendix 1: Specifications

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Specifications of the Mercedes-Benz 500I were hardly released up until the 500-miles race at Indianapolis. The project was carried out in secrecy, about everything there was to know about the engine remained a secret too. See for example the specifications sheet as found in the Mercedes press kit released during the month.

Karl Ludvigsen devoted a lot of attention to the engine in his books Mercedes-Benz Quicksilver Century and Prime Movers, both on sale in 1996. In Part 9 I gave a description about the engine construction, based on these two books.

The specifications as I list them here are a combination of data found in Ludvigsen's books Prime Movers and Classic racing engines and some quotes by Mario Illien in the Louis Schwitzer Award Media kit.

Ilmor type 265E
Designation Mercedes-Benz 500I
Configuration V8, vee angle 72 degrees, single turbocharger. 2 valves per cylinder, operated by pushrod system, single camshaft operated
Bore * Stroke, Capacity 97 mm * 58mm, 3429cc
Bore/Stroke ratio 0.6
Compression ratio 11.0
Connecting rod length 116.0mm
Rod/crank radius ratio 4.0:1
Main bearing journal diameter 58.0mm
Rod journal diameter 50.0
Inlet valve diameter 52.5mm
Exhaust valve diameter 39.7mm
Length pushrods "As short as possible"
Rocker adjustment "Mechanically"
Lubrication and water pumps Similar to Ilmor 265/D but modified to deal with slower crankshaft speeds
Engine control Delco GEN-IV
Boost 1.86bar (55 inch mercury)
Turbocharger Garrett AiResearch TA74, built according to USAC specifications
Peak power 1024bhp at 9800rpm1
Corrected piston speed 24.1m/s = 4.823ft/min
Maximum safe rpm level 10,500
Peak Torque 755Nm = 557lb ft at 8000rpm
Weight 123.0kg = 273.4 pounds2
Length 561mm
Width 510mm
Height 654mm

1. This 1024hp figure is corrected for temperature and atmospheric conditions. Uncorrected the power output was between 965 and 970hp.
2. Weight as listed in Prime Movers. Classic Racing Engines lists the engine weight as 132kg, so perhaps a typing error that should have read 123kg?

For good measure, the dimensions of the Ilmor/D engine normally used in the Penske PC23 during the 1994 season were: Vee angle of 82 degrees resulting in L*B*H dimensions of 561 * 555 * 566mm. The weight was 124kg. According to the Marlboro Racing press kit of 1994, the Ilmor/D produced 740hp at 12,500rpm and had a peak torque of 360lb ft (= 488Nm) at 8500rpm.

The following specifications found in the Marlboro Racing press kit (with the car being told as appearing with an Ilmor quadcam engine) were given for the Penske PC23 car:

Chassis type 94 Marlboro Penske Ilmor Indy V8
Contructions Penske Carbon Fiber
Constructed at Penske Cars Ltd, Poole, Dorset, England
Weight 1,550lb
Weight distribution (front-rear) 41/59
Wheelbase: 115in
Length 190in
Shock absorbers Penske
Radiators/Heat exchangers Modine
Wheels BBS
Front 10x15
Rear 14x15
Tyres Goodyear Eagle Speedway Special Radial
Front 25.5in x 9.5in x 15in
Rear 27in x 14.5in x 15in
Instruments Pi/Ilmor/Penske
Battery Delco
Fuel cell Goodyear Crashworthy
Fuel capacity 40 U.S. gal
Fuel Methanol, supplied by Mobil
Steering Penske, rack & pinion
Turns, lock to lock 1-1.5
Suspension:
- Front pushrod
- Rear pushrod
Brakes Alcon disc