Talk:Big-bang firing order

The major edit today was me. sorry I wasn't logged in. Sandersjoshua (talk) 14:59, 20 April 2010 (UTC)

I propose to name this page Big bang engine instead of Big bang firing order. As firing order is not the only thing you need to make a big bang engineSandersjoshua (talk) 14:59, 20 April 2010 (UTC)

Errata

Not sure the protocol for this, but:

1. Right now the introduction for the Big Bang firing order says it leads to more rear-wheel instability (which is incorrect)

2. The introduction section of the I4 screamer engine claims the exact same rear-wheel instability, but stated for the opposite reasons as the intro.

This seems to be due to a misunderstanding of what is actually causing the instability: compression/decompression from the regular interval engine, not the paradoxical smoother firing intervals giving rise to unpredictability.

Ming —Preceding unsigned comment added by 76.210.66.163 (talk) 07:27, 28 November 2010 (UTC)

@Ming: Please make changes as you see fit. I have been watching this article for over a year and very little has changed. Sandersjoshua (talk) 12:28, 13 March 2011 (UTC)

I have tagged the article as self-contradictory because of this. --142.205.241.254 (talk) 23:14, 20 October 2011

(UTC)

According to an article in the magazine sport-bikes (february/march 2012) the big-bang firing order was a revolution in GP race, because the increased time interval between the explosion (and so delivery of power) allow the tires to recover the grip — Preceding unsigned comment added by 130.223.173.122 (talk) 14:59, 4 April 2012 (UTC)

The big-bang firing order provides greater overall traction and acceleration at the rear wheel. A rear tire has a given amount of hysteresis of energy absorption before the force applied overcomes available traction. When the big-bang firing order is utilized, a much larger force is applied to the rear tire, using all of the hysteresis available to the point it may exceed the traction available, giving the maximum acceleration possible for that tire. The long interval until the next "bang" allows the tire to regain traction and to recover to it's state of no power applied before the pulse occurs. This also makes it much easier to modulate wheel spin trough a corner. In a "screamer" firing order, the amount of power applied per pulse is smaller, but occur much more rapidly. The tire may not have time to recover to a no power applied state by the time next pulse occurs, if the available traction is exceeded by the next power pulse, wheel spin occurs and traction is not regained as subsequent power pulses occur quickly, unless power is reduced. It's more difficult to modulate wheel spin with this type of power delivery. This effect was put to good use by flat track racers for years using Harley-Davidson XR-750's converted to a"twingle" firing interval, where the interval was changed to 45º, making the power delivery much like a single. More advanced multi-cylinder motorcycles that made more power had trouble keeping and regaining traction on the dirt tracks, while the very long interval of 675º until the two cylinders fired again allowed the H-Ds to easily regain traction and accelerate. Twowheelsonly (talk) 03:37, 8 April 2012 (UTC)

Is there a reliable source laying out the elastic material properties you just described (I think this is what you mean by 'hysteresis')? — Brianhe (talk) 06:20, 8 April 2012 (UTC)

I don't interpret this as a contradiction; rather it highlights the differing rider techniques of cornering under power and the differing characteristics of different configured bikes operating at the edge of their limits.

A 270 engined bike is better cornered whilst powered throughout the corner so as not to upset the suspension with +/- torque forces acting between the swing-arm and frame; this sudden change in geometry can cause loss of tyre traction, not the torque effects on the tyre which are moderated by the firing order.

A 180 engined bike has a less abrupt effect of torque between swing-arm and frame, but is more likely to lose tyre traction if powered throughout the corner because of torque effect on the tyre.

The comments made about Mick Dohan and his style of cornering suggest that he came into a corner fast and decelerated late, nearer the apex, before applying sudden acceleration to exit the corner; the 270 engine did not suit his technique because it would upset the suspension in the corner and he was unable or did not want to change his technique. His technique was developed on the 180 engined bike and he championed using that combination. A 270 engined bike would require all or most deceleration to be completed before entering the corner, but would allow for a more powered traverse of the apex and more controlled cornering overall. — Preceding unsigned comment added by 58.170.240.160 (talk) 05:32, 25 April 2012 (UTC)

Graphical box

It seems that the details in the table are suspect and need both correcting and explaining. Arrivisto (talk) 06:29, 22 October 2011 (UTC) a.) The tables describe Big-bang and non-Big-bang motors without positive indentification, and are quite confusing. b.) There are many theories about loss-of-traction, several (evidently) conflicting are presented here. talk --Puddin' Man (talk) 23:48, 13 October 2012 (UTC)

I agree that the Graphical column is insufficiently explained. As a reasonably sophisticated lay reader, I have no idea what the ones and zeroes refer to. 99.46.179.29 (talk) 14:54, 28 April 2019 (UTC)

In the 4-cylinder table, I'm left wondering which (if any) of those configurations is the Yamaha YZF-R1/YZR-M1. Does anyone know? — Preceding unsigned comment added by 2605:A601:A994:B600:7285:C2FF:FE8C:A7B (talk) 19:52, 23 December 2019 (UTC)

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90° odd-fire V6 graph

The 90° odd-fire V6 graph is wrong. If possible, someone please fix it. ABSOLUTE CIPHER (talk) 13:44, 29 August 2021 (UTC)

Issues with the V4 section

Per https://web.archive.org/web/20170909103206/https://www.neunelf.blog/2017/06/a-24h-winner-is-the-heart-of-your-718/, which cites Alex Hitzinger, the 919 V4 (at least in the form that was raced - Motor Sport Magazine cited Hitzinger regarding an earlier configuration not working, and him changing to the raced form) used the same configuration as a boxer four - four crank throws 180° apart from one another, which would mean piston pairs in opposite banks reach TDC at the same time which would mean it would actually have a similar behavior to a 180° V4 crank in a 90° bank angle (although with two cylinders 180 degrees off from where they'd be on a normal 180° V4 crank, but AFAIK this has no real effect), with 180-90-180-270 timing.

How do we want to document this? Also, it looks like it's not what the Zaporozhets or even-fire Wisconsin engines used (which did use 90° split crankpins as far as I can tell, so in each bank of cylinders, one of a pair was at TDC and the other was at BDC, and the other pair was the other way around (the opposite of a boxer).

Additionally, I found a pic of a Ford V4 in an eBay listing showing the opposite of what the article describes - the piston pairs in opposite banks do not reach TDC at the same time as in a boxer. Bhtooefr (talk) 13:54, 3 November 2024 (UTC)

...and now I've found other sources on the Porsche 919 engine (Race Engine Technology issue 124) that indicate a 90 degree crank for the unraced gen 1 (such that firing alternated banks), and something like a 180 degree crank with 90 degree offsets (presumably with firing not alternating banks but still 180 degrees between firing events) for gen 2. So maybe the article was correct already... Bhtooefr (talk) 18:45, 3 November 2024 (UTC)