Vespa exhaust test
As part of our development of the 125cc cylinder for the PX80, different exhaust systems were tested on a completely original PX80 in order to have references available for comparison.
We tested the following exhaust systems:
Original Piaggio (green curve)
SITO Plus (red curve)
SIP Road (blue curve)
It is remarkable how brave the Sito Plus does against the strong Road. Up to 4500rpm, the original pot is not only at eye level but even a little bit stronger to then say goodbye to the other two in a spectacular way.
As expected, surprises cannot be expected from an exhaust change on such a tame cylinder. The absolute numbers only result in a difference of a maximum of half a horsepower.
However, it is more important to consider the performance curve here. So the engine with the Sito Plus at 7000rpm still has a remarkable 5HP on the rear wheel, the original pot only has 3,5HP.
The 7000 rpm correspond to approx. 80 km / h in fourth gear (the diagram shows measurements in third gear). So there are only 2,5 HP more on the rear wheel by changing the exhaust with the Sito Plus.
The result is that the motor can maintain this speed much better without being forced to its knees by increased driving resistance such as an incline or headwind.
The SIP Road, on the other hand, has more torque in absolute terms, but this is applied much earlier and, in direct comparison to the Sito Plus, is only noticeable in the draft or mid-speed.
Here, the final translation might have to be lengthened somewhat in order to utilize the full potential of the system.
