Rover PG1 gearbox

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Pg1.jpg

The Rover PG1 gearbox fitted to the K series Elise, was manufactured by Powertrain Limited (who have now ceased trading), is a five-speed constant mesh gearbox, which employs helical gears for speed transmission and final drive. The transmission castings are full aluminium construction and all other components optimised for improved weight (36kg dry). The gearbox can be supplied with either a standard open differential or a Limited Slip Differential, presently Torsen.

Due to the modular design of the gearbox various final drive ratio and 1st to 5th gear ratio combinations have been used. Including both present and past an overall total of 21 ratio combinations, 5 speedometer gear ratios; and 7 clutch levers designs for both hydraulic and cable operation can be called on to ensure the customers requirements are met.

Gearbox type

Series number location on the bell housing

Identification is via the serial number on the bell housing housing;

Gearbox Application Table

Gearbox Code 1 2 3 4 5 Final Drive Used In
G6BP 3.250 1.895 1.308 1.033 0.848 3.938 S2 111S (WR "long" box)
C4BP 3.167 1.842 1.308 1.033 0.765 4.200 MGF VVC/Trophy (as standard but final drive 4.2)
C6BP 3.167 1.842 1.308 1.033 0.765 3.938 Elise S1 standard and MGF
B4BP 2.923 1.750 1.308 1.033 0.848 4.200 S1 111S & S1 Sports 135 & S2 135R & S2 standard (CR Box)
NA 3.167 1.842 1.308 1.033 0.848 4.200 Elise-spares
B4BPU 2.923 1.750 1.308 1.033 0.848 4.200 Exige S1 uprated (CR Box)
B4BPQ 2.923 1.750 1.308 1.033 0.848 4.200 Exige S1 with LSD (CR Box)
B6BST 2.923 1.750 1.308 1.033 0.848 3.938 Rover "BRM" 200 - CR box with std final drive & torsen LSD
340R UCR 3.000 1.937 1.556 1.273 1.043 3.920 340R LOTAC05255 Conversion
NA 3.167 1.842 1.410 1.100 0.909 3.938 Eliseparts
G4BSV 3.250 1.894 1.307 1.033 0.848 4.200 MG ZR 160 VVC
M4BSQ 2.923 1.894 1.500 1.269 1.034 4.200 MG ZR Motorsport Vehicles

Gearbox Codes

The first letter is the gearset

Letter 1 2 3 4 5
B 2.923 (13/38) 1.750 (20/35) 1.308 (26/34) 1.033 (30/31) 0.848 (33/28)
C 3.167 (12/38) 1.842 (19/35) 1.308 (26/34) 1.033 (30/31) 0.765 (34/26)
G 3.250 (12/39) 1.895 (19/36) 1.308 (26/34) 1.033 (30/31) 0.848 (33/28)
K 2.923 1.750 1.222 0.935 0.765
L 2.923 1.750 1.222 0.848 0.649
M 3.167 1.842 1.222 0.848 0.649
R 3.250 1.895 1.308 1.033 0.765
S 3.250 1.895 1.222 0.848 0.649
T 3.250 1.895 1.222 0.935 0.714
V 3.250 1.895 1.222 0.935 0.765
w 3.167 1.842 1.308 1.033 0.714


The number that follows the gear set number is the Final drive ratio

4 = 4.200 (15/63)

5 = 4.062 (16/65)

6 = 3.938 (16/63)

7 = 3.647 (17/62)


The next letter denotes the speedo gear type, always B for Lotus (note that the speedo cable is not used on the Elise). Then a clutch release code, usually P which is a type of hydraulic release specific to mid-engined cars. These may be followed by other letters, but on a Lotus only a Q or T for the type of limited slip differential:

BP = Open

BPQ = Quaife LSD

BST = Torsen

See also

External links

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