| Xtrac has developed what managing
director Peter Digby calls a world gearbox in that it can be either transverse
or inline with up to 80 per cent common parts. “We manufacture 200
at a time to keep the cost down.”
The progenitor was the British Touring Car 406 gearbox that came out about
five years ago, The European Touring Car Championship 416 version of the
gearbox was then installed into the JAS Honda Accord in addition to the
private Honda Civics that ran in the ETCC while more recently Xtrac has
developed the 426 gearbox carrying over 70 per cent commonality of parts
with the 406 and 416. The 426 has wider gears and final drive to offer
teams the capability to deal with more torque and/or endurance events.
A diesel final drive option is also available, this gearbox being installed
in an Alfa Romeo 147 diesel that not only won its class in last year’s
Nürburgring 24 hour race but also finished 24th overall in the field
of 220 competitors.
“We have to make sure that the diesel gearbox accommodates the vast
change in rpm compared to that of a petrol engine,” says Digby.
“Then there is the massive increase in torque and there is the implication
of a potentially slower gearchange. They are all things we are enjoying
playing with, but our diesel transverse box has done quite a number of
24 hour races now.”
The Xtrac 436 drag gearbox has been gaining success after success in the
Hot Rod Class of the NHRA Sport Compact series. This 4-speed gearbox with
spooled differential is capable of short durations of immense torque and
yet keeps a majority of commonality with the 406/416 original gearboxes.
One 436 gearbox has already completed over 100 standing starts in one
of the 1,100 ps cars which previously would use one gearbox for only two
runs.
In addition to the extensive family of these gearboxes, Xtrac also offers
longitudinal versions of this family of gearboxes for rear-wheel drive
cars. The 407, which has been available from the autumn, shares the majority
of components with the 406/416 but carries the wider cluster of the 426.
The 437 gearbox carries 20.5mm Xtrac sports car gears for use in the most
powerful machines.
Xtrac is also an official partner of Megaline and so can offer the well-proven
assisted gearchange system as seen on the Audi Le Mans cars for many years
as part of a comprehensive package that includes Xtrac designed and developed
peripheral components. These include differentials, driveshafts, gearlevers
and even starter motors.
For the US market Xtrac has developed a rear crown wheel and pinion. While
these are produced very cheaply in mass volume in the US, they do not
always fit the bill and can fail under extreme pressure, so Xtrac has
completely re-engineered the way that they are manufactured. “We’ve
gone for a much more efficient, low friction and very, very high quality
finish. They are substantially more expensive,” concedes Digby,
“but in fact the initial testing proves that not only are they far
more efficient but it is far cheaper buying those than finding extra horsepower
from the engine – and they last far longer. This means that they
do not have to be set up again, saving up to half a day, the diff doesn’t
have to be taken out of the car and so on.”
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