bgm PRO Touring exhaust system for Vespa Wideframe
The new bgm Pro Touringbox is a well-camouflaged, high-performance sports exhaust that looks absolutely inconspicuous in the look of the standard exhaust.
The construction of bgm PRO Touring Box is designed for the greatest possible compatibility with the cylinder concepts on the market. A flat cone angle and a moderate resonance length are the main features of the box. Below we show three examples of completely different engines on which we tested the WF box.
ACMA V55
with bgm150 cylinder, (Ø57mm) bgm crankshaft (stroke 57mm), Polini CP24 carburetor, bgm Pro Touring exhaust (bgm1015TR)
It's nice to see how early and linear the engine's performance is with the bgmbox sets in and rises. It harmonizes very well with the tame control angles of the bgm150 cylinders. Despite the high and early torque, the power is maintained for a long time. This makes the engine very pleasant to drive, as it starts to 'pull' immediately and can also be revved if necessary. An ideal characteristic for a powerful everyday engine.
ACMA
with CC Corsa 160 cylinder (diaphragm-controlled), carburettor PHBL 25, exhaust bmg Pro Touring (bgm1015TR)
The CC Corsa 160 cylinder is a popular conversion cylinder for anyone who wants to build a solid but powerful engine based on the original housing. The bgm The touring exhaust also harmonizes very well with the diaphragm-controlled cylinder. This one compared to bgm150, the already significantly higher steering angle (approx. ÜS125°/AS175°) shifts the peak power by approx. 1000rpm. The harmonious, hole-free increase offers absolutely stress-free driving, the torque increasing up to the peak offers the sporty 'pull' of the engine typical of two-strokes. Here too, the engine can be revved even further after peak power has been reached, for example to save a gear change when overtaking quickly.
Engine GS150
with cylinder Quattrini M1XL (diaphragm-controlled for engine PX125/150), carburettor PHBL30, exhaust bgm Pro Touring (bgm1015TR)
A special engine based on a Vespa GS150 Wideframe Engine housing converted with a diaphragm-controlled Quattrini cylinder for a PX125/150 engine. Together with a 60mm king shaft the result is a displacement of 181ccm. The engine is in one Wideframe installed, which is why the BGM Pro Touring exhaust also attracted great interest. The cylinder here is unmachined and runs with control angles of 124/176. Here too, the BGM box delivers great performance. 21HP and 22Nm are quite impressive for a system that is designed purely as a touring exhaust system and does not have a large volume. If necessary, more would certainly be possible with a smaller control angle, but for this comparison purpose it is ideal to see that the system is absolutely easy to drive even on very sporty engines and still enables high performance. Here, too, the driving noise is very pleasant, which is why the vehicle owner had the exhaust installed directly on the vehicle.
DEVELOPMENT bgm Pro Touring box
CONDITIONS
Goal in developing the bgm Wideframebox was to design a robust, quiet, high-torque and powerful exhaust that can be used on as many engine concepts as possible.
THE ORIGINAL
In order to meet these sometimes quite contradictory requirements, a lot of time and work on the test bench was necessary. At the time the first Vespa engines were designed, there was neither the effective Schnürle reverse scavenging nor a deeper understanding of how to improve gas exchange in the cylinder using the exhaust. The original exhaust Wideframe-models was therefore in principle never much more than a silencer. He only had a marginal contribution to the engine performance, if at all. It follows that, due to the engine's low output per liter (~30 HP/l), only a small volume was planned for sound insulation (apart from the fact that in the 1950s the noise generated by a 125cc engine was not a serious problem in everyday life anyway...) .
MODERN CONSTRUCTION
Nowadays, the volume of an exhaust is not only relevant for sound insulation, but also the performance and its progression are largely determined by it. Today's designs use a suction diffuser, with the exhaust itself then being the 'virtual' counter cone. A larger volume can therefore achieve higher performance and a lower noise level.
SPACE CONDITIONS
There is room for a larger exhaust Wideframemodels are limited by the surrounding body and therefore not as variable as, for example, in the PX models. Anyone who previously installed a more powerful engine usually resorted to an adapted PX exhaust system. Although these have more volume, they are located across the vehicle and significantly reduce the ground clearance. Visually, they only match the beautiful line of the now very valuable ones to a limited extent Wideframe-models. Therefore the BGM was developed Wideframe Exhaust system ensured that it looks close to series production.
VOLUME VS. NOISE
The available exhaust volume is required for both power development and sound insulation. The more volume is used to develop power, the more power/torque can usually be generated at the expense of noise. In order not to be seen as a potential disruptive factor in today's sometimes somewhat hysterical environment, low noise was an important factor in the development phase. It has been possible to combine high performance with a pleasant sound that also suits older vehicles. Even with engines with almost four times the liter output of the original engine, the exhaust is very pleasant to drive on long journeys.
QUALITY
The bgm Pro Touring Box is mechanically very solidly constructed and is manufactured in Europe (Spain) to a very high quality level.
CONCLUSION: The development goals have all been implemented and result in an exhaust that is excellent for everyday use. It offers superior power delivery with a pleasant driving noise combined with high manufacturing quality.
