1991-1992 Jaguar XJR-14

Images copyright Bob Chapman @ Autosport Image, Paul Ajari, David Lynn, and Michael J. Fuller 
Text copyright Michael J. Fuller

Jaguar XJR-14The office.  Surprisingly uncluttered considering the size.  Note the left hand, straight-shot, gear lever.  "Straight-shot" inasmuch as it shot down the car's centerline (and through anything in its path), reducing the linkage complexity and length (and weight).
Jaguar XJR-14The XJR-14's engine intake was just above the cockpit.  Note the slit inlet just below the main engine intake.  This siphoned off any thickening boundary layer, but more importantly helped bleed additional cooling air into the cockpit through the three inlet holes.  

At the XJR-14's debut at Miami, IMSA made TWR alter the design of the engine inlets.  IMSA cited their chassis regulation which stated the highest point of the car could not be the engine intake.  As such, the TWR crew created a field modification that made the car legal.  
“This was one of the areas that we thought that NPTI had a hand in!” says Tony Dowe, TWR Team Manager, in referring to arch-rival Nissan and potential gamesmanship.  “We had shown Raffauf the car and it had been given an ok. Then when we arrived at Miami it was suddenly not ok!”  The team ended up Jaguar XJR-14, Laguna Seca 1992installing two “Mickey Mouse ear” inlets in place of the original single engine intake.  These would become permanent throughout the rest of the IMSA season.  Dowe continues, “The revised inlet helped the mid range power and the rear wing! So we were not too unhappy about the change other than the way in which it was forced on us.”  The guys at TWR Valparaiso created a legality blister to the peak of the roof making it the high point and the Mickey Mouse engine intakes were placed either side and to the height of, though not above, the blister.
Jaguar XJR-14A period shot of the XJR-14 with most of the bodywork removed.  Note the large muffler just behind the radiator.  IMSA regulations stipulated a 108 db maximum which necessitated a muffler to reduce dbs from an unimpeded 130+.  The muffler also meant a re-routing of the exhaust exit.  So it moved from exiting just ahead of the rear wheel, out the side pod, to actually being plumbed into the tunnel section for aero affect.  In the image you can see the exhaust loop rewards post-muffler and then behind the silencer can.  It's there that it is plumbed into the vertical face of the outer diffuser wall.
Yes, that's a Bentley LMGTP in the background...The main protagonist.  The well developed, reliable, light-weight-yet-stout, and powerful Jaguar-badged Ford HB gave the XJR-14 an advantage during the early part of the 1991 season inasmuch as it was one less thing to worry about.
Jaguar XJR-14The TWR designed magnesium 6-speed gearbox had the gear cluster oriented longitudinally and ahead of the rear wheel centerline in order to move mass lower and further forward in the car as well as making for a simpler yet stiffer gear casing.  The starter installation was unique as well in that it acted directly on the back of the gearbox input shaft through a two-stage epicyclical gearbox and sprag clutch.  This kept its mass low and it was easily accessible from underneath the car.
Jaguar XJR-14The gear shift linkage emerges from between the engine inlet trumpets, having started its travels by going straight through the center of the fuel cell, to continue on to the (and through) oil tank reservoir and then to the gearbox.  The gearbox was also unusual for its left hand gear change.  With the driver on the right hand side of the cockpit this allowed for a direct route down the center of the car for the shift rod and reduced the number of joints making for a light and sensitive gear change.
Jaguar XJR-14The rear suspension consisted of conventional spring dampers mounted to the bellhousing and operating off of bell cranks attached to pushrods.  The only element of the rear suspension in the underfloor airflow was the lower A-arm.  

ęCopyright 2009, Michael J. Fuller