Quote:
Originally Posted by NoDOHC
For future reference, this is my daily driver. I do want reliability. I ran 13,000 miles with very advanced timing and had no problems with it, so I thought that I had a reliable tune.
.
|
it depends on the drive cycle, with our race car, for 3 years, our drive cycle was WOT for 25hours at a time! which is almost the opposite of the drag racers, their season is less than 15minutes of run time. the honda guys expect to rebuild the engine at least once in that 15 minute season too.
so there is a HUGE difference between an engine with a 25 hour design vs one with a 7 minute lifespan. if the engine runs in like 7, i minute increments, they can run cardboard apex seals...
a street car yet again is different, as it needs to do stop and go and things, and the WOT cycles are short, at least here in CA.
i've been looking at the timing curves of various engines mazda has built over the years and i must say its surprising. the 85 and earlier timing curves are all in the FSM's, so i was interested to see what timing they ran in like a non emissions engine.
the answer? its like 15 degrees@wot. the later 70's engines with reactors run about 20, the catalyst engines run more like 27... i suspect the non reactor/non cat engine still runs 15 degrees because of emissions still, but more isn't always better, as you just found out.
the FSM's are all at
www.foxed.ca the REALLY weird ones is the late 70's rx4/cosmo, its runs a normal mechanical advance, so there is a 15 degree timing split, and L&T advance together, but it ONLY has a vacuum advance on the trailing. so the vacuum advance ONLY changes the timing split.
the other weird one is the 74? rx3, its got a timing retard box, so whenever this box is on, leading timing is retarded 20 degrees. it MUST be to get the reactor warmed up fast, but when this is on, the trailing fired before the leading....
anyways, start small, and work your way up...