Marcos Mantis – Evolution of a British Sports Car

Phase 1 1997-2017: Original Marcos factory specification with the Ford 4.6L Quad Cam V8

PERFORMANCE

Acceleration
0-60mph in 4.1 seconds
Maximum Speed
In excess of 170 mph
(Performance times achieved on test tracks in ideal conditions and NOT the M62 m’lord…)

ORIGINAL ENGINE

Type
Ford modular V8 Quad Cam 4.6 litre 32 valve
Construction
Light alloy block and heads, five bearings
Bore & Stroke
90.2 x 90.0
Displacement
4600cc
Compression Ratio
9.9:1
Valve Gear
Four valves per cylinder, operated by dual overload camshafts, roller tipped rockers, hydraulically adjusted individual timing chains
Max Power
Approx 352 bhp @ 6,000rpm
Max Torque
Approx 330lb ft @ 4,800 rpm
Fuel System
Sequential multipoint fuel injection, staged dual bore throttle body
Fuel
Unleaded only
Ignition
Electronic engine management, twin coils

TRANSMISSION

Gearbox
T45 5 Speed Borg-Warner
Type
Five speed manual gearbox 1st 3.371, 2nd 1.993, 3rd 1.325, 4th 1.000:1, 5th 0.672, Reverse 3.221
Final Drive ratio
3.23:1 LSD (BTR from Holden)
Emissions
Dual three way catalytic converter, EGR

BODY/CHASSIS

Type
Square section tubular steel chassis with glassfibre composite two-door, two seater body, convertible in Spyder

RUNNING GEAR

Steering
2.5 turns lock to lock
Turning Circle
34 feet
Suspension
Front – MacPherson struts and lower link arm. Rear – Independent with upper and lower wishbones, coil springs & adjustable telescopic dampers
Brakes
Front/Rear – Ventilated discs, 4 pot front calipers
Wheels
Front – Two Gates 9″ x 18″ Rear – Two Gates 9″ x 18″ 
Tyres
Front – 235/40 ZR 18 Rear – 255/35 ZR 18

DIMENSIONS & WEIGHT

Length 168.00″ 4263mm
Width 72.00″ 1828mm
Height 40.00″ 1016mm
Wheelbase 89.96″ 2285mm
Track Front 63.75″ 1620mm
Track Rear 61.42″ 1560mm
Ground Clearance 4.75″ 120mm
Kerb Weight   1078.0 Kgs

Phase 2: 2017-2021 re-engined to General Motors LS376/480 with Fast Road cam 

2017 conversion to the General Motors LS376/480 ENGINE

Type

LS-Series Gen-IV Small-Block V-8

Construction

Cast-aluminium with six-bolt, cross-bolted main caps, nodular iron-camshaft, powdered metal connecting rods, hypereutectic aluminium pistons & hydraulic roller camshafts

Bore & Stroke

103.25 x 92 mm (4.065″ x 3.622″)

Displacement

6162cc (376 cu in)

Compression Ratio

10.7:1

Valve Gear

Hydraulic rollers, Lift: 0.551″ intake/0.522″ exhaust, Size: 2.165″ intake / 1.590″ exhaust

Fast Road Cam

Duration @ .050” Lift (deg) I: 219 E: 228.
Maximum Lift (in) (1.7 rocker) I: .525 E: .525.
Lobe Separation (deg) 112.

Max Power

Approx 495 hp @ 6200 rpm. Est 525 hp following custom mapping

Max Torque

Approx 473 lb-ft @ 5200 rpm

Fuel System

Sequential multipoint fuel injection, staged dual bore throttle body

Fuel

Unleaded only

Ignition

Electronic engine management, twin coils

Engine weight

183kg

TRANSMISSION

Gearbox
Tremec TR6060 (92246731) six speed manual transmission, rated to handle 420 lb.-ft. of torque
Type
Six speed manual gearbox 1st 2.66, 2nd 1.78, 3rd 1.30, 4th 1.00, 5th 0.74, 6th 0.50, Reverse 2.90
Final Drive ratio
3.23:1 LSD (BTR from Holden)
Emissions
Custom dual catalytic converters from JP Exhausts in Macclesfield

 

Phase 3: 2021 onwards General Motors LS376/430 standard cam 

2021 conversion to the General Motors LS376 ENGINE

Type
LS-Series Gen-IV Small-Block V-8
Construction
Cast-aluminium with six-bolt, cross-bolted main caps, nodular iron-camshaft, powdered metal connecting rods, hypereutectic aluminium pistons & hydraulic roller camshafts
Bore & Stroke
103.25 x 92 mm (4.065″ x 3.622″)
Displacement
6200cc (376 cu in)
Compression Ratio
10.7:1
Valve Gear
Hydraulic rollers, Lift: 0.551″ intake/0.522″ exhaust, Size: 2.165″ intake / 1.590″ exhaust
Standard Cam
204/211 duration
0.551/0.525 lift
117 lobe separation angle
1.7:1 rocker arm ratio
Max Power
Approx 495 hp @ 6200 rpm
Max Torque
Approx 473 lb-ft @ 5200 rpm
Fuel System
Sequential multipoint fuel injection, staged dual bore throttle body
Fuel
Unleaded only
Ignition
Electronic engine management, twin coils

 

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