RA617H end-of-season report ! I started to make some notes about what was supposedly changed between the various specs, and when the changes happened, some way into the season, as I was beginning to lose track and was curious. I also tried to dig out some points about the things that had already happened, but wasn't super-thorough about it. I also tried to stick to plausible sources, but it's hard to know what's reliable - e.g. quotes from Hasegawa-san, but these are often themselves obscured by machine-translation or vagueness in human translation. Lastly, I tried to keep track of where the snippets of information came from - quite a few were links mentioned by the posters on the autosport forum, so the references often refer to that forum (e.g. post 5#2937 means part 5 (!) of the McLaren-Honda thread, post 2937).
I can't be bothered to post this over there in the McLaren-Honda thread (which would seem to be the more natural home since many quotes came from links named in posts there), as anyone who says anything even neutral about Honda tends to get lynched
So, excuse inaccuracies etc etc, for what it's worth, here's a summary of what happened according to various press reports - may be true, may not, there are undoubtedly things missing.
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Spec 1 / 24-26 Mar / Race 1 / Australia.
Spec 2 / 12-14 May / Race 5 / Spain.
Spec 3 / 23-25 Jun / Race 8 / Azerbaijan (only tested on Fri, was not raced, will race at Race 9 / Austria).
Spec 3.5 / 25-27 Aug / Race 12 / Belgium.
Spec 3.6 / 25-27 Aug / Race 12 / Belgium (only used on Fri by Stoffel, as problem was detected, so reverted to 3.5).
Spec 3.7 / 01-03 Sep / Race 13 / Italy (only used on Fri by Alonso, preparation for Race 14 / Singapore).
Spec 3.8 / 20-22 Oct / Race 17 / USA (Vandoorne)
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Spec 2, ~+10bhp.
Spec 3, +10 to 30 bhp, depending on who you believe.
Spec 3.x, +0 to 3 bhp, aimed at low-end torque.
Spec 3.x, +27 bhp (+20kW) quali mode ?, not sure which exact 3.x.
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I incline to at least 20bhp for Spec 3 based on what Boullier said on camera, and Hasegawa's remarks of ~0.3sec per lap, but I am not doing any rigorous analysis here, others may know better. Benson's tweets seem to change day by day
Spec 3 was called Spec 2.something by press, and even Honda (I seem to recall), as it was part of some bigger revisions that are coming, but this part was fast-tracked to come a bit earlier, and so Honda and everyone else are now calling it Spec 3 for simplicity's sake.
Was going to dig around and try to see what was changed for Spec 2 and 3, but haven't done so yet. Seem to remember induction/injection for 2, and something similar mentioned for 3, but Hasegawa also said combustion chamber completely different for 3 - take those as off the top of my head, can't vouch for accuracy. Search for muramasa's translated posts if you want to find what the Japanese press reported for Spec 2 (probably the best source ?).
Spec 3.5 was penalty-free induction (bbc (
http://www.bbc.co.uk/sport/formula1/41039407)) / exhaust changes mostly aimed at boosting low-end torque (via rudex, translation of yahoo.co.jp, post 5#2937 (
http://forums.autosport.com/topic/20652 ... ?p=8071160) & 5#2942), Hasegawa estimates ~0.1s a lap (via Taylo207, translation of sportiva.shueisha.co.jp, post 5#3779).
Spec 3.6 was as 3.5 plus one penalty inducing reliability change.
Spec 3.7 is similar but with some weight reduction (via hasika, translation of yahoo.co.jp, post 5#3896), new turbo (via hasika, translation of f1sokhuo.mopito.com, post 5#4020).
At Belgium, one (some ? all?) of the 3.x specs had a rumoured +20kW 'quali mode' added, with the hope this would also be usable in races subsequently when required (think this is a quote from Hasegawa, but not 100% sure, via hasika, translation of sportiva.shueisha.co.jp, post 6#166 (
http://forums.autosport.com/topic/20733 ... ?p=8088457). Subsequently rumoured that the mode was deemed illegal by tightened FIA regulations at a subsequent event, Japan or earlier ? (
http://members.f1-life.net/race/59657/).
Spec 3.8, small improvements for reliability and performance (via hasika, members.f1-life.net, post 6#3165, and others quoting Fabrega tweet). Spec 3.8 improvement over spec 3.5 is 0.3-0.4s, improvement over previous spec is 0.1-0.2s (Hasegawa, quoted at
http://www.racer.com/f1/item/145573-hon ... ance-gains).
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