Anyone done an A/B dyno test with flipped pistons?

[BCjohnny]

This subject crops up from time to time so I'll give the example I always offer

No A/B test, there was no budget for such a luxury, and it introduces other variables as well, so make of it what you will .....

Small capacity four cylinder 1800cc + 'stock' component engine, approx 120 bhp, 1/4 mile asphalt oval

Very competitive formula, maxxed out 'stock' wise, so latest incarnation used offset bores & 'flipped' pistons also, which I believe was fairly unique amongst the class

Car was night and day faster than any other in the field especially the latter half of the straights, won 6 of 9 races IIRC and placed in the rest ...... fourth meeting car wasn't even let off the trailer with the reasoning that the engine was "not illegal under the rules, but couldn't race anyway" ...... loose lips etc

Went back to the previous 'stock' spec ...... no offset bores or 'flipped' pistons ...... and the same car was merely competitive again

So, I think in certain restricted lower powered applications there can be tangible gains and, while accepting most of the other caveats posted, might be worth a try ...... as long as the customer can keep his mouth shut

[rebelrouser]

Engine masters just did a test on piston swapping https://trakt.tv/shows/engine-masters-2 ... pisodes/24

[FishFry]

I flipped the pistons on my Chevy 261 a while ago.
Sounds a bit different, feels a bit different, is a bit more responsive - but nothing revolutionary.

Frank