Talk:Toyota TTC

レス TTC

I was going through an old 1970s Crown JDM parts catalogue and found some cars were listed with a "LTC" option from Oct 1974 to Nov 1975, which the glossary expanded to "レス TTC". The same manual shows Oct 1975 onwards as having "TTC", which the glossary expands to the expected "トヨタ トータル クリーン システム". Also note the one month overlap, presumably while production lines were being switch over. I'd guess that レス TTC could be read as "lesser TTC", i.e. sort of a first effort that would just pass the 1975 emissions laws but that Toyota knew wouldn't be good enough for the upcoming, tougher 1976 laws. Does anybody know how レス TTC differs from the later TTC ?  Stepho  talk  22:55, 28 June 2013 (UTC)

That sounds reasonable. I know that the TTC-V was updated in March 1976 for the 76 emissions standards, here's the text from the 1977 JAMA Buyers Guide:

トヨタ自動車、コロナ２０００、カリーナ２０００の複合渦流方式TTC-Vによる５１年適合車発表。セダンのみならずハードトップにもTTC-V採用。カリーナに希薄燃焼方式TTC-L・１６００モデル追加。５１年規制適合。（即日発売）

I'm afraid I don't have anything more specific, but maybe I shall have to scan and share the Crown pages?  Mr.choppers | ✎  03:07, 14 October 2013 (UTC)

Oh, I found more text regarding changes made in October and November 1975 - maybe it will shed light. I will be back after another agonizing bout with Google translate and my dictionary.  Mr.choppers | ✎  03:08, 14 October 2013 (UTC)

75.10.24: トヨタ自動車、コロナ２０００／１６００、カリーナ２０００／１６００、セリカ２０００／１６００、カローラ１６００、スプリンター１６００をTTC-C（エンジン改＋酸化触媒＋２次空気供給＋エンジンによってはEGRなど）により50年規制適合化。カリーナとセリカはホイルベースとトレッドを拡大しシャシの改善、フロントエンドとダッシュボードをマイナーチェンジ。セリカLBにLTとGTVを新設。DOHC・２lエンジンも存続。（コロナ、カリーナ、セリカは１１月１日発売、コロナのー部車種とカローラ、スプリンターは遂次発売）

Which I read as meaning: "24 OCtober 1975. Toyota introduces Corona 1600/2000, Carina 1600/2000, Celica 1600/2000, Corolla 1600, and Sprinter 1600 with TTC-C. This revised (kai, 改) system has an oxidizing catalyst, a secondary air supply (?), and EGR for some engines. The Celica and Carina have an extended wheelbase and tread, as well as minor changes to the front end and dashboard. The Celica Liftback gains an LT and a GTV model, the 2-litre DOHC engine remains available. Corona, Carina, and Celica go on sale 1 November, while Corolla, Sprinter, and some Corona versions follow later." I don't know if that's any help?  Mr.choppers | ✎  04:34, 14 October 2013 (UTC)

My interpretation (with some help from Google and some from my own knowledge) is: "24 OCtober 1975. Toyota introduces Corona 1600/2000, Carina 1600/2000, Celica 1600/2000, Corolla 1600, and Sprinter 1600 with TTC-C to comply with the 1975 (50年) regulations by using an oxidising catalyst (2 way or 3 way catalyst?), air injection (pumps air into the exhaust port to burn up any unburnt fuel), and EGR for some engines." Skipping other model intros, bits in parenthesis are just my explanation rather than direct interpretation.

Eiji Toyoda in his "50 Years" book mentioned that Toyota had to swallow its pride and buy rights to use Honda's vortex system. After they paid for it they discovered it only worked on smaller engines - ie the typical Honda engine. I'll look it up when I get home tonight.  Stepho  talk  05:33, 14 October 2013 (UTC)

I think your interpretation matches the text (2-way catalyst would make sense), but I don't know how much of this is what differs from the earlier TTC. Good job with the citation! I'm going to remove the refimprove tag, I think it's fine now although more couldn't hurt.  Mr.choppers | ✎  22:50, 14 October 2013 (UTC)

Doh! I should have known that oxidising catalyst is a 2-way catalyst. Also found more info in "Against All Odds", pages 185-195, 198-203, with particular attention to CVCC and Honda on p194-195 and p199-200. CVCC was enough for 1975 regulations but not enough (by itself) for 1976. And Honda sold only the basic info to Toyota, not quite enough to pass the regs without more research by Toyota.  Stepho  talk  07:17, 16 October 2013 (UTC)