Janspeed Ltd - UK

Janspeed Engineering Ltd, Salisbury, Wiltshire, UK

          Range Rover Turbo
 Janspeed Turbo - Range Rover
From Janspeed Turbo brochure (1980):
Range Rover Janspeed Turbo
The British Leyland Range Rover has now been with us for some considerable time, and over the years
much has been done to improve its looks and general appeal. However, little has been done to improve
the power output of the lazy V8 Rover engine. The standard car performs perfectly adequately under
normal driving conditions but try towing uphill or driving in a head wind and you will discover that you
require a lot more power than the normally aspirated 126 b.h.p. engine produces.
It is in this field that Janspeed excel, not only producing a highly successful turbocharger conversion
but also having a full range of conventional tuning equipment available.

In keeping with modern technology Janspeed have now uprated and redesigned their old draw through
turbocharger conversion for the Range Rover series. The new second generation blow through turbo-
charger system does away with the standard Stromberg carburettors and utilises instead a modified 
down-draught Weber carburettor mounted on a reworked standard inletmanifold. Both the single and
twin turbo variants are retained, though there is no appreciable difference in performance, both
conversions producing in excess of 200 b.h.p. which is enough to propel Leyland's all terrain vehicle
from standstill to 60 m.p.h. in 12 seconds with a top speed of over 100 m.p.h.                                             Range Rover twin turbocharger installation by Janspeed
With the introduction of the new system, turbo lag has now been completely eliminated and hence
the installation can be recommended for use on the very high geared automatic versions.

On the single turbo installation the nearside (RHD) standard exhaust manifold is retained and a link 
pipe is used to duct the exhaust gasses under the engine and into the new higrade cast iron turbo
manifold. The turbo manifold not only carries the Roto Master T4 turbocharger but also houses the
wastegate which senses boost pressure and allows exhaust gasses to bypass the turbine when necessary, in this way preventing an over boost situation by slowing the rotor. The wastegate is not
the only engine safeguard there is also a sophisticated engine management system which retards the ignition under the boost condition, hence preventing detonation, has an over-rev and over-boost cut out
facility and has transistored ignition built in.

The turbocharger unit draws fresh air through a highly efficient air filter compresses it and passes it through a shorter crossover pipe and in turn into a cast alluminium plenum chamber over the carburettor. It is partly the presence of this adequate plenum chamber that gives the installation its
quick trottle response. There is also a pressure modulating valve fitted over the carburettor so that
when the carburettor butterflies are closed the pressure build up is not great enough to slow the
compressor wheel, hence the compressor will always have enough inertia to supply pressure at even
the smallest trottle openings.
                                                                                                                                                       Discreet installation of 200 bhp Janspeed turbocharger conversion
All the standard components of the engine, transmission and cooling system are adequate to cope
with the extra power produced, though an oil cooler is fitted to maintain the correct sump temperature.

For those Range Rover owners not requiring the power increase of the turbocharger installation Janspeed
also manufacture a range of conventional tuning equipment to suit all needs from a quick road car to a 
long distance competition car. A stage I conversion for the Range Rover will produce about 25% increase
in power with the bonus of a small fuel saving. The conversion kit consists of a pair of stage I cylinder 
heads (gas flowed, polished and ported but retained standard size valves) an exhaust system and a 
pair of extractor manifolds, 2 new needles for the standard Stromberg carburettors and a pair of highly
efficient air cleaners. The cost of a fitted stage I kit is £ 1,148.00 plus VAT. (1980)