One decisive reason why modern two-strokes are so superior to the 4-stroke engine is the exhaust. While a four-stroke still needs valves, camshafts, exhaust and turbocharger, the two-stroke gets by with the exhaust alone. It doesn’t need much more than a bit of shaped sheet metal perfectly adapted to the overflow and exhaust. Thus, it determines the removal of the old gases, but also the inflow of the fresh gases through the suction and charging effect.
Exhaust construction – a science in itself
This may sound very simple at first, but the design of the exhaust is a science of its own, with huge differences in quality. If you want a really good and high-quality exhaust, you have to search a little and dig a little deeper into your wallet. There are only a few really good exhaust manufacturers and the systems are usually only available in small numbers at high prices.
If you are looking for a racing exhaust system for classic Vespa and Lambretta scooters, you will inevitably stumble across Tobias Rußmann’s company NORDSPEED. The company from near Bremen sets standards with its systems, especially in the area of 200cc large-frame models. Rußmann is an artist when it comes to interpreting the tight space between the stud bolts of the cylinders. With his design, he manages to tease out the absolute optimum under difficult conditions.
SIP Scootershop and NORDSPEED have already brought several exhaust systems onto the market in cooperation. They are characterised by powerful design and modern equipment. All models from SIP by NORDSPEED have the following technical features:
- O-ring flange, suitable for all common cylinders
- Connection for EGT
- Connection for Lambda/AF
- Flange plate to accept many common silencers
The Mustang 2.1 – a true powerhouse
The latest creation from SIP and NORDSPEED is the Mustang 2.1 racing exhaust, which is one of the most powerful in this market segment. With a sheet thickness of 1.5 mm, it is more stable and the bracket is also built more robustly and more accessible. For better vibration absorption, the metal sheets for the bracket are hard-soldered. A clear matt coating instead of a glossy paint makes the surface even more heat-resistant. The unit has a very wide rev band and is capable of very high peak power. This makes the Mustang 2.1 the perfect middle ground between systems designed for maximum power and pure torque systems.
The exhaust’s strengths are at their best when fitted to a matching engine. A large carburettor, reworked intake and tuning cylinders with larger cross-sections at the ducts should therefore be included.
It is important that the timing of the cylinder used matches the layout of the exhaust:
- Overflow times: 130°-138°
- Exhaust timing: 188°-198°
The Mustang 2.1 racing exhaust fits the following Vespa models:
Vespa 200 Rally, P200E, PX200 E/, Lusso ->’94/, Cosa 1 200
Attention: The racing exhaust is a tuning part that is not approved within the scope of the German Road Traffic Licensing Regulations (StVZO), but may only be used for racing purposes.
By the way: To ensure that the exhaust works as it should for a long time, regular cleaning is recommended. This article explains the best ways to clean the Vespa exhaust.