22 March 1996

DIESEL TWEAKS

MAKE A USEFUL DISCOVERY

In most minds, tuning normally goes with petrol engines. But diesels too can be tweaked to good advantage, as Andrew Pearce finds on a visit to Lincolnshire

LAND Rovers diesel Discovery comes close to being all things to all men – sorry, persons. Its comfortable, roomy, well thought out (in parts), frugal and goes just about anywhere. Family transport or work tool, itll oblige.

But its not a bundle of fun to drive. Some cars are better than others but none are swift, for neither the 200Tdi or 300Tdi motor shines in such a weighty home. And while the ride is comfortable, handling is pretty much ho-hum.

So there is scope for improvement. Warwick Banks has been in the business of making 4x4s go faster, go round corners and stop for umpteen years, and has developed a packet of changes intended to cheer up a standard Discovery. Engine, suspension and soundproofing can all have the treatment; see box for options.

More go, less noise…

Nothing drastic is done to Land Rovers direct-injection clatterbox. The cylinder head is modified to give more swirl and a better burn, the turbocharge wastegate is reset to allow more boost and the injection pump is recalibrated to suit rather than simply opened up.

According to the man behind the mods, thats quite enough to lift power by 34hp, torque by 30lb ft and pare almost four seconds from the 0-60mph time. More important for day-to-day driving, the mid-range 50-70mph time improves by 38%. Fuel consumption in manual cars should be 25-30mpg; in automatics, 1.5-2mpg less.

Sounds pretty good. To see how good we drove the firms 1994 300Tdi automatic demonstrator, which started out with an 111hp engine: the latest autobox cars come with an uprated 120hp unit. Apart from engine changes the test car carried extra soundproofing, a handling kit and a lower stall speed torque converter. The idea behind the latter is to let the engine spend more time powering the car and less time churning oil.

At idle theres still the direct injection Tdi knock, but its much muted. Like the standard car the Banks version needs a good prod on the throttle to get it moving, but once the turbo wakes up the differences quickly become clear. Diesel rattle smoothes out to a mid-range hum and theres more urge.

Speed builds decidedly faster than with the standard product, so its no longer necessary to find a mile straight before overtaking – the engines extra urge shortens the whole business and the driver spends less time exposed to risk. In a manual car its likely that less stick twiddling will be needed on hills and minor roads, thanks to the modified motors extra torque.

On motorways a healthy cruise is easier to hold and the car punches forward more willingly from 75mph. The only fly in the test cars ointment was a low frequency boom from 3000rpm on, which Banks says has been with the car from new.

…And better handling, too

Progressive-rate springs, gas dampers and different thickness anti-roll bars replace the standard items. The Banks car keeps the originals compliant ride, but feels tighter. Roll is subjectively less and the vehicle feels very stable through sweeping bends, in a straight line and during direction changes. Mid-corner manholes still send a quick tremor through the steering, but thats the only negative. All told, this £2490 package is a good way to inject some fun into Discovery motoring.


Engine modifications

(200Tdi, 300Tdi) (fitted) £1495

Hush kit, incl engine/bulkhead blankets£279

Fitting£75

Handling kit£795

Uprating kit for standard suspension£650

Fitting above£150/£175

Note: Modified parts are warranted for six months/6000miles. As power is still less than the petrol V8, drivetrain reliability should be unaffected.

&#8226 Warwick Banks Handling (01778-590500)


THE BANKS OPTIONS

Above: Engine mods lift power output by 30% and torque by 15% – enough to make a big difference on the road. Below: Power at the rear wheels on a rolling road (front propshaft disconnected). Modified car is substantially stronger from 1600rpm on, with power peaking earlier.

No visual changes, but this Discovery

is quieter and

faster than the standard

offering.