Ok, so.. what issues will I have with timing when I tune for 27lbs of boost? Will I need to start figuring out the MSD box and retard the timing? Im simply unsure of what is going to happen at high boost. What exactly happens to cause the timing to advance?
#76844, "RE: timing conerns..." In response to Reply # 1
I understand how an ignition system works. However, when you force a motor and electrical system to do something its not designed to do what will happen? My question was more specific towards the 420a motor and my current setup. Not a generalization of all motors and how they are built to work. Thanx for the link though.
#76846, "RE: timing conerns..." In response to Reply # 2
Theres really nothing to figure out w/ the msd. Its as easy as plotting it out and telling it to retard x degrees at x rpm or x psi. Its cut and dry.
You kind of need to see whats going on w/ some dyno time and taylor you timing to whats going on. What type of fuel do you plan on running? Our ecu just goes to 17 degrees advance at wot so its not really a situational occurance like it is w/ cars whos ecu make the decisions based on air flow/injector pw and things of that nature. You also have aftermarket cams if i'm not mistaken right?
#76848, "RE: timing conerns..." In response to Reply # 3
He is right, I'm sure if you do a few dyno passes and post the sheets there are some people here who can give you an idea of what type of adjustments to make.
#76851, "RE: timing conerns..." In response to Reply # 3
Originally posted by MR BLUNT 2gnt Theres really nothing to figure out w/ the msd. Its as easy as plotting it out and telling it to retard x degrees at x rpm or x psi. Its cut and dry. You kind of need to see whats going on w/ some dyno time and taylor you timing to whats going on. What type of fuel do you plan on running? Our ecu just goes to 17 degrees advance at wot so its not really a situational occurance like it is w/ cars whos ecu make the decisions based on air flow/injector pw and things of that nature. You also have aftermarket cams if i'm not mistaken right?
I only have a 6211, not a 6212 MSD box, so I think it will take me a little while to get used to for adjusting. I believe you can only adjust it by RPM, but its late and I forget. Id like to run plain old 93 octane with portfueler. I do have crower stage 2 cams and adjustable cam gears. Any more advise?
IVe been reading some posts that Ive searched for.. Basically it seems that you just need to hook up a logger and find out whats going on with the timing and adjust it accordingly. What advance level should I try and stay around?
#76855, "RE: timing conerns..." In response to Reply # 4
You'll need to retard a couple degrees up top. I can do ~24 PSI on the 20G using 93 octane unleaded without pulling any back. When I push it past 24 PSI, I use leaded C16 and pull just a couple degrees. Make sure you watch your EGTs *very closely* at those boost levels. It'll get real hot with too much or too little timing advance.
Also, I'd recommend tuning your A/F ratio in the low 11:1-11.3 on the dyno (11:5-11.7 on street) range at points above 20 PSI. The extra fuel helps prevent detonation.
#76857, "RE: timing conerns..." In response to Reply # 5
Originally posted by siueclipse Id like to run plain old 93 octane with portfueler.
Then don't push it to 27 PSI. You can't run that kind of boost through a 420A on stock ignition maps without melting your pistons. Maybe soon you'll start to realize why you can't "pass 400whp with ease". Doug
#76859, "RE: timing conerns..." In response to Reply # 7
Originally posted by dougie2
Originally posted by siueclipse Id like to run plain old 93 octane with portfueler.
Then don't push it to 27 PSI. You can't run that kind of boost through a 420A on stock ignition maps without melting your pistons. Maybe soon you'll start to realize why you can't "pass 400whp with ease".
I have the equipment to take me over 400whp, its just going to take awhile to get through that last phase. Ill be hitting the dyno up late next week. Ill post the techedge wideband logs.. exactly how I set the cams up, how i setup the msd box, what fuel i was running etc.. and then Ill even post the dyno sheet so everyone can debate if its real or not.
#76862, "RE: timing conerns..." In response to Reply # 9 Sep-24-04 07:03 PM by siueclipse
Ill throw in some higher octane gas for the dyno just to be certain that everything will be fine. HRC made 382whp at 27lbs of boost on the 20g with the portfueler system. I wonder what octane they were running.
