Mazda Rotary Port Timings

Mazda Rotary Port Timing

Applications	Model Years	Overlap	Exhst Open	Exhst Close	Intake Open	Intake Close	2nd'y Intake Open	2nd'y Intake Close	Aux'y Intake Open	Aux'y Intake Close
10A 0813 Cosmo	'68-'72	23ｰ	75ｰ BB	48ｰ AT	25ｰ AT	45ｰ AB	-	-	-	-
10A 0820 R100	'70-'73	6ｰ	75ｰ BB	38ｰ AT	32ｰ AT	40ｰ AB	-	-	-	-
10A 0866 RX-3	'71-	6ｰ	80ｰ BB	38ｰ AT	32ｰ AT	40ｰ AB	-	-	-	-
12A North America	'71-'73	16ｰ	80ｰ BB	48ｰ AT	32ｰ AT	40ｰ AB	-	-	-	-
12A North America	06/73	ｰ	ｰ	ｰ	32ｰ AT	50ｰ AB	-	-	-	-
12A North America	'74-'75	ｰ	ｰ	ｰ	32ｰ AT	50ｰ AB	-	-	-	-
13B North America RX-4, Cosmo	'74-'75	ｰ	ｰ	ｰ	32ｰ AT	50ｰ AB	-	-	-	-
13B REPU	'74-'78	ｰ	ｰ	ｰ	32ｰ AT	50ｰ AB	-	-	-	-
12A North America	'76-'78	6ｰ	75ｰ BB	38ｰ AT	32ｰ AT	40ｰ AB	-	-	-	-
13B North America	'76-'78	ｰ	ｰ	ｰ	32ｰ AT	40ｰ AB	-	-	-	-
12A Australia	'78-'80	6ｰ	75ｰ BB	38ｰ AT	32ｰ AT	40ｰ AB	-	-	-	-
12A Europe	'78-'85	16ｰ	75ｰ BB	48ｰ AT	32ｰ AT	50ｰ AB	-	-	-	-
12A North America	'79-'85	6ｰ	75ｰ BB	38ｰ AT	32ｰ AT	40ｰ AB	-	-	-	-
12A Australia	'81-'85	16.5ｰ	75ｰ BB	48.5ｰ AT	32ｰ AT	50ｰ AB	-	-	-	-
13B North America	'84-'85	16ｰ	71ｰ BB	48ｰ AT	32ｰ AT	40ｰ AB	32ｰ AT	30ｰ AB	45ｰ AT	70ｰ AB
13B North America NA	'86-'91	16ｰ	75ｰ BB	48ｰ AT	32ｰ AT	40ｰ AB	32ｰ AT	30ｰ AB	45ｰ AT	80ｰ AB
13B North America Turbo	'87-'95	16ｰ	75ｰ BB	48ｰ AT	32ｰ AT	50ｰ AB	-	-	-	-
Factory Race Peripheral Port	-	151ｰ	73ｰ BB	65ｰ AT	86ｰ BT	75ｰ AB	-	-	-	-
Racing Beat Street Port	-	23ｰ	84ｰ BB	48ｰ AT	25ｰ AT	60ｰ AB	-	-	-	-
Racing Beat J-Bridge Port	-	172ｰ	88ｰ BB	57ｰ AT	115ｰ BT	72ｰ AB	-	-	-	-
13B RX-8 Renesis (from SAE 950454)	'04-	-55ｰ	50ｰ BB	23ｰ BT	32ｰ AT	40ｰ AB	32ｰ AT	30ｰ AB	45ｰ AT	80ｰ AB

AB = After Bottom Dead Center
AT = After Top Dead Center
BB = Before Bottom Dead Center
BT = Before Top Dead Center
Overlap = Period when both exhaust and intake ports are open on the same working chamber
Note - Peripheral exhaust ports are always open, 360ｰ duration.

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