Kent Racing Letterhead
MERKUR XR4Ti PROJECT

IMSA GTU

UNDER 2.0 L FOUR CYLINDER, 2 VALVE, FUEL INJECTION,  TURBOCHARGED WITH INTERCOOLER
1.0 PRINCIPLE DIMENSIONS

Wheel Base                                       101.0
Front Track                                         56
Rear Track                                         56-1/2
Overall Width at Front Axle              68 inches
Overall Width at Rear Axle              70 inches
Ground Clearance (Front)              3.0 to 3.75
Ground Clearance (Rear)              3.5 to 4.25
Overall Height to Roof                     50-1/2 at 3.75 in. grnd. clearance
Weight Dry                                         2,100 lbs.
Weight Distribution                          50/50


2.0  FRONT GEOMETRY AND DETAILS

Roll Center Height                           2.0
Virtual Swing Arm Length               2.2 x track
Bump Travel                                      3.0
Droop Travel                                     2.0
King Pin Inclination                          0 ░
Caster Angle                                     2.5 ░ to 3.5 ░
Scrub Radius                                    2.0 inch
Camber Characteristic                   Bump Travel       Camber Angle
 
  Bump                                                          +3                          -1.5
                                                                       +2                          -1.0
                                                                       +1                          -0.5
                                                                         0                            0
                                                                        -1                          +0.3
  Droop                                                           -2                         +0.8

Wheel Size 16" Dia. x 11 Rim Width
Tire 22.0 x 11.0 - 16
Brakes, Disc  Lockheed CP 2261, 11.97 Dia. 1.1 inch thick
Brakes, Caliper  4 - Piston Lockheed CP 2279, 1-3/4 inch dia. piston
Shock Valving  As specified by ÍHLINS
Wheel Rate  350# / inch
 
FRONT SUSPENSION DESCRIPTION

Wishbone upper and single lower link
PROFAB front hub, NC machined alloy upright
Adjustable stabilizer bar
ÍHLINS shock absorbers - adjustable gas pressure
Adjustable ride height


3.0  REAR GEOMETRY AND DETAILS

Roll Center Height                           Adjustable 2.0 to 4.0 inches
Virtual Swing Arm Length               2.2 x track
Bump Travel                                      3.0
Droop Travel                                      2.5
Camber Characteristic                   Bump Travel       Camber Angle
 
  Bump                                                          +3                          -2.5
                                                                       +2                          -1.6
                                                                       +1                          -0.7
                                                                         0                            0
                                                                        -1                          +0.3
                                                                        -2                          +0.5
  Droop                                                          -2.5                       +0.5
 
Wheel Size  16" Dia. x 12 Rim Width
Tire   24.5 x 12.5 - 16
Brakes, Disc  Lockheed CP 2261, 11.97 Dia. 1.1 inch thick
Brakes, Caliper  4 - Piston Lockheed CP 2271, 1-1/2 inch dia. piston
Wheel Rate  350# / inch

REAR SUSPENSION DESCRIPTION

Independent rear suspension
Kent Racing differential with Hewland ring & pinion
Fabricated steel upright
Unequal length upper and lower arms
Parallel equal length locating links
Center lock hub
Coil springs over ÍHLINS gas pressure adjustable shock absorbers
Wheel rate adjustable by changing coil springs
Ride height adjustable by threaded collars on shock
Cockpit adjustable rear stabilizer bar
4.0 STEERING

Rack and pinion with capability of addition of power steering.


5.0 TRANSMISSION

Weismann 5-speed with quick change output ratio.
Center mounted in chassis.


6.0  DRIVE SHAFT

Steel tube


7.0  AIR JACKS

Grant King - 3-1/2 inch diameter x 13 inches


8.0 AERODYNAMICS

Semi-ground effects underpan
Rear wing
Front Spoiler
Internal ducting between front spoiler and firewall


9.0  BODY

Merkur XR4Ti sheetmetal
Fiberglass by Hartman, Costa Mesa, CA, hood, front fenders, rear fenders, doors, front spoiler, rear bumper, rear deck frame (hatch),
rear wing.


10. CHASSIS CONSTRUCTION


Space frame constructed from 1.50 inch diam. 4130 seamless tubing.
Main hoop, left side bracing, left side door beam, lower fore and aft
tubes - wall thickness .090 inch.
All other tubing - wall thickness .065 inch.


Notes: Brake calipers and rotors were changed by Dave Kruse in the 1988 season to take-offs from the Brabham Nissan GTP Car.


11. ENGINE SPECIFICATION


Engines by Drake Engineering, Irvine, California, based on Ford Lima 2.3 liter, 4 cylinder, 2 valve motor, with fuel injection, turbocharger, and intercooler.

Displacement reduced to under 2 liter per IMSA GTU rules.

Displacement                        1981cc (std),  1996 (+.015")
Bore                                         3.785"
Stroke                                      2.685"
Compression Ratio              7.5:1
Rod Length                             5.5"
Pin Diam.                                23mm
Big End                                    2.0"
Crankshaft                              Velasco (4340 billet)
Rods                                        Carrillo
Oil System                               Weaver Brothers multi-stage pump
                                                  with dry sump
Water Pump                           Offenhauser
Clutch                                      Tilton multi-plate
Bellhousing                            Zakspeed
Injection                                   Bosch mechanical unit (Porsche
                                                  924 GTR Carrera Turbo)
Ignition                                     Bosch

RPM                                         6 - 8000
Horsepower                           350 hp at 1 bar boost for endurance races
                                                  400 hp at 2 bar boost for sprint races