Here's a chart with the duration and overlap for series 4 Rx-7 through Series 2 Rx-8, including 4 and 6 port engines:




I used this calculator: http://www.wallaceracing.com/camcalc.php

and here's the source material:


series 4


series 5


series 6


series 1 and 2 Rx-8

 

sweet! i did that on the last HD, but i looked up the timings of the early 10a, and the PP's as well.

since its lost, i don't recall exact numbers but the PP is like 330/303 or something, its like the rx8 in terms of the intake/exhaust timing relationship.

 

where'd you get the information for the 10A and PP motors? Is there some kind of service manual or Mazda document you found?

 

both, some was in the FC yamaguchi book, and i have a bunch of old manuals around too, google..

actually http://foxed.ca/foxed/index.php?page=rx7manual he's added some new ones

 

Are you sure that "ATDC" means "AfterTDC" and not "AboveTDC"? It seems odd that there'd be such a large difference in the port durations between the FC and FD motors when the ports don't look that much different.

 

This thread should be stickied.

 

the timings are given like its a camshaft, so its AFTER tdc, like a cam.

you're right though, typo on the FD?

 

this is a great thread, man. i like it. let me just say thanks for taking the time to compile and post your chart.

nice catch. according to the other documents posted, they are identical open and close timings.

 

More port timing data
visual port timing

 

They're very different. Read through it all again, the FD opening is very different because it is in BTDC, not ATDC. Put the numbers into the calculator I used.

I thought it was a typo myself, but I cross referenced all the sources and the numbers were the same. The FD port timing is much different from the FC turbo motors. I wish I had specs on the Cosmo 2 and 3 rotor engines.

93 FSM


93 service highlights


94 FSM

 

just looking at some of those other links that have been posted here... all those other sources seem to think that the opening time of the FD ports are similar to the FC ports, even though the service manuals say otherwise.



And here is a diagram out of the Renesis SAE paper, and it lists the FD as having 16 degrees of overlap (just like the 13BT). So maybe it was a typo that was propagated throughout Mazda's documents at the time.

 

ask and ye shall receive

can't believe i missed the ATDC/BTDC changeover though...

 

FSM for the FD is wrong. It should be in values of ATDC, not before. Degree wheel don't lie.

 

^ I'm just surprised that the 93 FSM, 94 FSM, and service highlights are all wrong