Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Crossover for M3W

I've always wondered why the M3W doesn't have a crossover like almost all V2 engines. So I had one custom-made. Visually, I think it turned out really well, and the results are phenomenal: better torque in the low and mid-range RPMs, smoother engine operation, a fuller, more refined sound, and lower fuel consumption. Some pics:

Looks pretty but please explain the theory to me if you can.

On a V-twin with separate exhaust systems, the two cylinders do not operate evenly. Each cylinder generates pressure waves that propagate through the exhaust. A crossover connects both exhaust headers, allowing these pressure waves to support each other.

The main advantages are:

More torque in the low and mid-range RPM band: Thanks to improved use of the pressure waves, the cylinders are scavenged more effectively. This often makes the engine more responsive and flexible.

Smoother engine operation: The pressure pulses balance each other out to some extent, resulting in a smoother-running engine.

Slightly more peak power: Usually only around 1–3%, provided the rest of the exhaust system is also tuned accordingly.

Reduced heat buildup: Depending on the design, the exhaust gas flow is distributed more efficiently.

Changed exhaust note: A matter of personal preference. Sound often becomes fuller and deeper, though sometimes slightly less "harsh."

Lower fuel consumption – an expected reduction of about 1 L/100 km.

Thank you so much for going to the trouble of explaining this, the benefits seem to make this necessary really.

Is the Siamese exhaust system on parallel twins a sort of halfway house answer to the problem.

Congrats and nice welding!

In essence the exhaust pulses of one cylinder aid scavenging of the other. Moto Guzzi V twins had a crossover on the front pipes or via an H section under engine or both.

Looks very nicely thought out for layout and well engineered joints, looks much neater than the KH version

What I however need is a new air filter cover. The standard one has its scoop only between 5 and 7pm on teh clock and breathes warm air just on the top from the balancing pipe. So better would be one which is wider open. Any suggestions?

Great idea and nicely executed!
What exhausts are you running? Just wondering if the crossover pipe would have more effect on a car with standard (i.e. restricted) exhausts than it would on a straight-through system.
Also, can the crossover pipe be removed without disturbing the headers?
What diameter is the crossover tubing?
Thanks,
Bunny