On the test bench: Polini 133, PWK35, Franz


Today Jonas was our guest on our dynamometer.

With a Polini 133 in the gray cast iron version did the young man with our testFire magic After all, the exhaust already achieved a very impressive 28,3 hp.

In addition to the gray cast iron Polini, which Jonas worked on more than neatly, one can help Polini membrane and a 35 Keihin PWK Carburetor the engine to its performance.

After a few small changes, we checked again today whether it managed to break the magical 30HP limit.

The first attempts with one Franz, Jonas own exhaust, looked very promising compared to the last P4 session.

The change from the red to the blue curve is rather simple. The cylinder was mainly lifted with a 0,5mm thick spacer at the cylinder base.

It is nice to see from the two curves that the increased control angle and the resulting smaller discharge has a greater effect on the functioning of the exhaust than the reduced compression and the lower mixture acceleration due to the larger squeeze dimension.

Sometimes less is more.

Unfortunately, the crankshaft gave up in the course of this series of tests, and the crankshaft stump on the pole wheel side sheared off.

28PS were probably a bit much for the simple racing wave in the long run.

The aluminum chips in the boost port do not bode well ...

Hoping it will Motor housing didn't catch too much, we already have Jonas with a new one BGM crankshaft 51mm stroke and 105 connecting rod equipped - with this the new attack on the big 30 will be carried out in the near future.

From our side - Jonas succeeded a lot !!

If you are also interested in finding out which exhaust makes a bullet out of your engine or is better suited for the big tour, then we can offer you a small selection of exhaust systems for testing on the test bench.




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