Stoffi freely admits that his pipe is largely a
rip-off of the PM 55 Mk2 with a few small changes
in the header pipe length and silencer design.
Apart from the obvious changes in respect of the
carbon muffler, the two pipes do look near
identical, right down to the fitting brackets.
Personally I think that straight copying of
other people's designs is out of order, but
there seems to be very little that can be done
about it from the originator's point of view,
apart from ensuring that their original is also
the best quality. Stoffi's Italian - built
version is marginally cheaper at 305 Euros
(approx £190 at today's exchange rate),
but obviously you need to add delivery from
Austria on top of that. Performance is
improved - like the PM - all
through the engine's speed range.
Peak power is 1.5 hp higher, but from
65 mph up to 75 mph there is a gain of
almost 3 hp which will help the scooter
hold it's top speed up hills etc.
DIG are a new name to the UK, with an importer currently being
setup in Bristol to distribute their huge range of scooter pipes.
Their Runner 180 exhaust is the only one that is supplied with
a replacement rear pulley spring and calibrated
variator rollers, and as such we left it last
to fit. Unusually (apart from the Polini) the
DIG features a pressed header pipe, rather
than one rolled from cones. The fitting
design using two rubber bobbins is both
awkward to do up, and didn't line up very
well. Nothing new there then from the
Italian aftermarket parts industry. We
tried the pipe first on standard transmis-
sion settings, and ended up with a
curve much like that of the Malossi
pipe, with the power output slowly
climbing until the machine reaches
70 mph. With the stronger rear pulley
spring and lighter rollers supplied
however, the DIG pipe did show
some small advantage. Peak power
is up by 0.2 hp, but thanks to
the pipe's revvy nature, it holds
on to the power longer. At 80 mph
the DIG is still making over 15 hp,
when both the PM and Stoffi boxes
have dropped to significantly less.
The downside of the transmission
mods and the revvy delivery is that it harms initial acceleration.
The DIG makes less power than standard right up to 40 mph,
but if you value top speed over acceleration then this may
still be worth a look. Fitting a gear kit to your transmission
would do much the same thing.