|Chassis||Carbon fibre and Aluminium honeycomb monocoque|
|Suspension (front)||Double wishbone, pushrod activated inboard Bilstein spring / damper|
|Suspension (rear)||As front|
|Axle track||Front: 1,841 mm (72.5 in)
Rear: 1,676 mm (66.0 in)
|Wheelbase||2,794 mm (110.0 in)|
|Engine||TAG-Porsche TTE PO1, 1,496 cc (91.3 cu in), 90° V6, turbo (4.0 Bar limited), mid-engine, longitudinally mounted|
|Transmission||Getrag 5-speed manual|
|Weight||540 kg (1,190 lb)|
|Notable entrants||Marlboro McLaren International|
|Notable drivers||1. Alain Prost
2. Stefan Johansson
|Debut||1987 Brazilian Grand Prix|
The McLaren MP4/3 is a Formula One racing car built and run by McLaren International during the 1987 Formula One World Championship. It was designed under the leadership of American engineer Steve Nichols, after John Barnard quit the team in August 1986. It was the first all-new chassis design for McLaren International since the successful MP4/2 series of cars debuted at the start of the 1984 season.
The MP4/3’s aerodynamics were completely different from the MP4/2, and the car appeared much more low-slung, to take advantage of the maximum fuel capacity limit of 195 litres, rather than the 220 litre limit in effect from 1984 to 1985. With addition of side-ducted radiators, the car’s basic exterior shape was all-new and sleeker than its predecessor. However, it carried over the suspension geometry and gearbox design from the MP4/2. The engine was the same 1.5 litre TAG-Porsche twin-turbo V6 that had so successfully powered the MP4/2, but with slight changes in compression and engine balancing, to cope with not only the new reduced fuel limit, but also with the FIA's mandated pop-off valve which restricted turbo boost to 4.0 Bar after turbo charging was unrestricted prior to 1987.
There were three wins in 1987 with the MP4/3 by Alain Prost at Grand Prix of Brazil, Belgium, and Portugal. Stefan Johansson managed a few podium places, but he would be replaced in 1988 by Ayrton Senna. McLaren still managed to finish 2nd overall, with 76 points, in the Constructor's Championship. The MP4/3 is the pinnacle of the development of the McLaren TAG-Porsche partnership. The Porsche-TAG engine featured an updated Motronic 1.7 engine management system, and now produced 960 bhp (720 kW) in race trim and 1,060 bhp (790 kW) in qualifying. These horsepower figures put it closest to Porsche's all-time most powerful racing engine, the 5.4 litre 12-cylinder in the 917/30 which produced over 1,500 horsepower (1,100 kW) in qualifying.
Even today the MP4/3 is still considered to be one of the most powerful F1 cars ever made, since turbo boost pressure would be further reduced to 2.5 bar in 1988, reducing the power output of the turbo engines to around 650 bhp (480 kW) in a bid to make the naturally aspirated cars more competitive. Turbocharged engines were then banned completely in 1989, so the turbo era in Formula One may remain possibly the high-water mark for horsepower levels in Formula 1.
The MP4/3 was also the car with which Prost won the 1987 Portuguese Grand Prix to become the driver with the most wins in Formula One history beating Jackie Stewart's record of 27 wins which had stood since Stewart retired at the end of 1973.
Chassis Log History
Five new MP4/3 cars were moulded from carbon fibre with assistance from Hercules Aerospace, as since the creation of the all-new MP4/1 in 1981. The chassis numbers, 1 through 5, were used throughout the year, with three new cars ready for the first race in Brazil.
Two MP4/3s were destroyed during 1987, but three complete MP4/3s still exist: Chassis #4 is on display at the Donnington Museum, chassis #5 is still owned by McLaren, and chassis #1, the only one in private hands, belongs to a Porsche collector in the United States and will be auctioned on March 9, 2012 at Amelia Island, FL by Gooding & Company.
#1: Used as a spare car at Rio, Imola, Spa, Monaco, Detroit, Circuit Paul Ricard, Silverstone, Hockenheim, Hungaroring, Monza, Estoril, Jerez, Suzuka, and Adelaide. This chassis only raced once, at the aborted start (1st) at Österreichring by Stefan Johansson.
#2: Raced by Johansson at Rio, Imola, Spa, Monaco, Detroit, Paul Ricard, Silverstone, Hockenheim, and Hungaroring. The car was written-off in practice at Österreichring by Johansson, after a deer struck the car, and crashed.
#3: Raced by Alain Prost at Rio, Imola, Spa, Monaco, Detroit, and Paul Ricard. Car modified for Johansson for race use at Österreichring. It was originally a spare car at Mexico, but then raced by Johansson, but written-off in 1st-lap accident.
#4: New car for Prost to race at Silverstone, Hockenheim, Hungaroring, Österreichring, Monza, Estoril, Jerez, Suzuka, and Adelaide.
#5: New car for Johansson at Monza, Estoril, Jerez, Mexico, Suzuka, and Adelaide.
The sixth car, known as the MP4/3B, was a test mule for the Honda turbo engine that would power McLaren's hopes for 1988. The MP4/3B never raced, but was tested by Prost, and later his 1988 team mate Ayrton Senna, until the all-new MP4/4 made its track debut at Imola a week before the start of the 1988 season (Prost lapped Imola over 2 seconds faster in the MP4/4 than he had in the MP4/3B. The MP4/4 would go on to be the most dominant single season car in F1 history, winning 15 of 1988's 16 races, as well as claiming pole in 15). After finishing the role, the sixth car went to Argentina and is on display at the Juan Manuel Fangio Museum in Balcarce.
Wheel Diameters (front/rear): 13in/13in
Wheel Rim widths (front/rear): 11.75in/16.30in
Disk brakes: McLaren/SEP
Steering assembly: SEP
Fuel Tank: ATL
Wheelbase: 111in (2794mm)
Width (front/rear): 72.5in (1841.5mm)/66.0in (1676.4mm)
Gearbox weight: 121.3 lb (55 kg)
Chassis tub weight: 154.3 lb (70 kg)
Formula weight (dry): 1190.5 lb (540 kg)
Fuel capacity: 42.9gal (195L) 
Complete Formula One results
(key) (results in italics indicate fastest lap)
|1987||Marlboro McLaren||TAG Porsche TTE PO1