Quote:
Originally Posted by misfitsfreak81
well it has a brand new cas, had brand new acl race bearings and was running full synthetic oil. the assembly was done by me, by the fsm and everything was tripple checked. all the clearences were within factory and only a little on the tight side.
i realize that the only time you really see 15deg is at vac <2000. thats what i was wondering about. the timing in the haltech was locked at 15deg via the timing lock function and we went out and made 3 or 4 3rd gear pulls from 3000rpm to about 6500. then made one pull to 7500rpm and the bitch let loose. what im trying to figure out is if there should be more advance in the timing. from everything that i know, the more rpm and the more load the motor is seeing the more advanced the timing should be. on decel the timing is gets retarded. the thing that first tipped me off mere minutes befor the motor popped was the afr's going nuts. on boost they werent too bad, maybe 12 was the leanest i saw. however on decel it was litteraly puking fuel to try and stop missfires, i mean i saw 8.0 on my wideband. also the oil temps were steadily rising quite fast.
when i tore down the motor on sat. i found the #4 rod bearing to be smashed and then spun. it was literally mushroomed over the edges of the rod. im guessing that that could only have been from detonation, however correct me if im wrong.
please everyone feel free to chime in on this. im trying to figure out if i fucked up or if someone else did. if it was me then thats fine, i can bite that bullet, but if its someone else then things are different. thanks in advance.
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no, no, no, no!
The more "advanced" the timing is, the earlier before TDC the spark plug fires.
The more "retarded" the timing is, the later it fires.
As you can probably imagine, under boost, you want to fire later - this minimizes stresses and potential for detonation. If you fire early, then the mixture is burning while the piston is still compressing, which makes for higher combustion temperatures and pressures.
These higher temperatures/pressures make for more power, but more stress on the engine as knocking develops.
Timing and AFR are for our purposes unrelated. AFR is dependent purely on injector pulse width. The fact that you're 8:1 on decel means that your high vac, high RPM portion of the map is too rich.
Might be a good idea to post your fuel and ignition maps up here in screenshot form.
As far as blowing the motor, if you were timing locked to 15deg, my bet is that your base timing was incorrect, meaning that in actuality you were locked to a value greater than 15deg.... or you had a boost spike.