| Item | LC Gearbox | Rating ***** | Comments |
|---|
| Weight | V Good | **** | 11g lighter |
| Durability | Excellent | ***** | Bigger bearings |
| Shifting | Smooth | ***** | Smoother |
| Adjustability | V Good | **** | In position |
| Spur options | Excellent | ***** | Colour coded |
| Cost | Expensive | ** | Over priced |
I hadn't originally intended to buy the LC Gearbox because the original 2 speed was exceptionally
strong and had caused no reliability problems, although it was heavy because it was designed
around the 1/8th scale cars which meant that it is over engineered for the Impulse. However, I
wanted the adjustability of the Centax II clutch and as the two components had been designed
around each other I elected to purchase both. Along with the LC Gearbox which came with a 48 tooth 1st and 45 tooth 2nd gear spurs,
I also purchased 46 tooth 2nd gear along with 49 and 50 tooth 1st gear options, in addition to
these you also need the Layshaft
and Brake/Pulley adaptor to
complete the installation.
As with most Serpent products the quality of finish is 1st class, there are some minor bits of
flashing to remove from the spur gears, but as to be expected all the components fitted perfectly
with no slop and smooth operation. The original carriers with the left and right threaded retaining
nuts have been replaced with lighter weight carriers that are fixed to the spur gears with three
small countersunk screws, this is where the bulk of the weight has been saved, the clutch shoe
carrier has also been slimmed down and the tension springs have done away with the nyloc nuts
and rely on self tapping screws into the clutch shoe itself, again reducing weight further. These
measures have resulted in the gearbox assembly shedding 11g of rotating mass compared to the
original, this is offset slightly by the addition of the Brake/Pulley adaptor although this weight
is closer to the centre of the axis which means it's not as hard to spin because it's not acting
like a large flywheel.
 |
The new gearbox appears to be smoother in operation than the old version, and when the car changes
up to second gear there is not so much of a pronounced dip in the engine revs, this is what makes the
change smoother and the acceleration more linear, this is really all down to the reduction in
rotating mass. The smoother gear change should help the car in damp conditions because your not
getting that sudden burst of acceleration as the car changes up and comes back into the powerband.
The lighter weight will allow the gearbox to spin up quicker, this improves acceleration off the
line and out of hairpin corners. The engagement point can still be adjusted in position using two
tensioning screws and springs, but to be honest I actually find it easier to remove the 1st gear
spur and then the shoe assembly to gain access to the adjusters, at least this way you can be
certain that you've adjusted both sides equally.
