Exhaust Tail pipe size

[Rodders]

Query about my 1938 16/70 DHC
The front pipe from manifold to silencer is 2" (51mm) diameter
The rear tail pipe out of silencer is only 1.5" (38mm) diameter
Is the tail pipe large enough?
Met an ex AC owner at the weekend, he thought it was on the small side & possibly reducing the engine power output.

[B.P.Bird]

Yes it does appear to be small, especially thinking about the twin tailpipes on the post war Ace. You need to find a chum with a 16/70 and compare notes. Maybe have a word with the Registrar ?
Barrie

[Flyinghorse]

I was thinking somewhere there would some science behind this and found this useful calculator.https://www.firgelliauto.com/blogs/engineering-calculators/exhaust-diameter-calculator

Rpm ( and hence gas volume) is critical. I assume the older 6 cylinder wellers have a lower rpm
Using 3000rpm I got 2" diameter