Engine Firing Order, Improved Traction

[gingernibbler]

Have any of you noticed the Merc engine sounds like a Ducati V twin on videos? Do you think they're running a "big bang" engine to improve rear grip and tyre wear. The Ferrari engined cars seem to be more wayward on acceleration.

Also if they are running a different firing order it may help rear tyre life as the power pulses have bigger gaps between them allowing the tyre to regain traction/cool down rather than spin away the tyre.

Can't really say anything about renault's rear grip yet as we're yet to hear them at full pelt but seems like a regular firing order

[Jersey Tom]

I've always thought the firing order and grip thing questionable at best, unless there's a paper floating around out there with some more concrete evidence.

[Tommy Cookers]

@ ginger
firing order and firing intervals are anyway in principle two unrelated things
and ....
at eg 12000 rpm these engines are firing 600 times/second
basic dynamics says that torque impulses at this 600 Hz simply cannot propagate seperately from the wheel through the tyre
(which would be necessary for there to be any traction differences from firing interval differences)
the torsional frequency of the tyre/car system being eg less than 10 Hz (as can be seen from slo-mo TV footage)
the same reason why your road car's engine running vibration cannot propagate through the elastomer engine mount system
both cases are effective isolation systems
if the tyre was filled with rigid foam instead of Nitrogen there would be less isolation

any differences in firing order or firing intervals will be for other reasons
crankshaft design or maybe power curve reasons
Yamaha attempts to make clear its crankshaft design reasons for its 'big bang' engines

[tanmay324]

when yamaha first introduced big bang inline 4 to motogp, everybody thought the engine provides better traction. but later Yamaha themselves confirmed that the crossplane doesn't help in traction but is for reducing the vibrations which occur at very high rpm. Thus giving the rider a better feel of rear wheel. But this configuration in inline 4 means need of extra balancing shaft, eating power.

[Tim.Wright]

I've always thought the firing order and grip thing questionable at best, unless there's a paper floating around out there with some more concrete evidence.

Same here. To me, sending oscillating loadings through a tyre is a grip killer not a helper.

[Holm86]

We've already talked about this in the engine thread here.

[Tommy Cookers]

.... the crossplane ..... But this configuration in inline 4 means need of extra balancing shaft, eating power.

is there evidence of a balance shaft (in either the road or MotoGP machine) ?
(FWIW I assumed there was no such shaft)
the cross-plane crank is like two 180deg twins coupled at 90deg (no force imbalance, only moment imbalance)
as used by the Sidecar WC winning URS (no balance shaft)
the Japanese by reducing vibration transformed road motorcycles in 1960s with 180 deg twins both 4 and 2 stroke (no balance shafts)

[tanmay324]

.... the crossplane ..... But this configuration in inline 4 means need of extra balancing shaft, eating power.

is there evidence of a balance shaft (in either the road or MotoGP machine) ?
(FWIW I assumed there was no such shaft)
the cross-plane crank is like two 180deg twins coupled at 90deg (no force imbalance, only moment imbalance)
as used by the Sidecar WC winning URS (no balance shaft)
the Japanese by reducing vibration transformed road motorcycles in 1960s with 180 deg twins both 4 and 2 stroke (no balance shafts)

i once read a paper published by yamaha motogp. it showed presence of a balance shaft in their 1 liter motogp engine. according to them this firing order creates an imbalance thus requiring balance shaft. And according to many its the main reason they are down on power compared to honda V4.