BassVirolla wrote: ↑17 Sep 2025, 18:13
Tommy Cookers wrote: ↑17 Sep 2025, 14:46
... but a 120 deg V6 is possible with paired firings so behaving like an inline 3
(exhaust pulses arriving at the MGU-H/turbo at the ideal 240 deg intervals)
Why not a single turbocharger? Nothing not solvable with a hot V, I think. Even if the "twin 3 inlines" is not ideal (which a 90⁰ V6 also is not), I cannot see any inconvenience with a flat plane V8.
an exhaust pressure pulse is productive for about 240 deg rotation and counterproductive for about 60 deg rotation
so 3 cylinders (per bank) is ideal in capturing high pressure and 2 or 4 cylinders (per bank) is inferior
ie a V8 of 90 degree bank angle should have 3 exhaust pulses per rev per bank at equal (240 deg) intervals
2 cylinders per bank firing at 240 degree intervals (first firing 0 deg second firing 240 deg)
then 2 cylinders per bank firing simultaneously (third firing 480 deg) will do this ....
a bit like a V12 cut down to V8 (of course that would give some engine frequency vibration)
but if the bank angle was 90 deg (with correct counterweighting) there would be no engine frequency vibration
yes there's a (smaller) vibration at twice engine frequency (about the same as the conventional flat-crank V8's)
this engine might only need 4 main bearings and 6 crank throws
all this assumes there's intent to maximise turbine work
eg for a so-called MGU-H or enabling leaner running than hitherto (this might depend on a higher explosive range fuel)
anything with a wastegate or a multiple-entry nozzle isn't trying to maximise turbine work