So i know a lil bit about ignition timing and when the pcm senses knock it retards the timing. So im running pump gas w 100% meth, ive ran meth for months and the pcm advanced timing on its own. I then did 3rd gear pulls and advanced timing from 3k-7k according to knock or lack there of. So my end result is 35.5-36* of timing at wot full boost. Zero knock showing. So is this too much timing. I mean im not knocking so i should b good rite? Im running 28psi w my 50trim.
thats way to much good luck with that. 22-25 is ideal with big turbo, i ran 31* on 25 with no way of controling it, thank god nothing happen
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I still to this day have no idea how you are running that much timming and not knocking. but ANYWAYS. do you know what advancing timming does??? Do you know if you have TOO much timming that its firing WAY BEFORE TDC and you can actually HURT your power? Your motor actually starts working against its self, more heat, more pressure on rods and pistons= fail. To tell you the truth i cant believe it has not given up yet. Most guys on big turbos run 15-20 pump 25 meth. I ran 31* 26 psi (gt35) and my rods did not like it. If i had DSP i would have been runnign 25, Yet i had ZERO knock (meth) does not mean your motor is gonna hold. More timming is not always better.
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PTP when you fedex man gettin this block?
Lets make sure we understand a little about timing before we ask about it:
Spark advance, which is optimally timed to achieve best torque by producing peak cylinder pres at about 15* ATDC, increase octane requirements by half to three quartes of an octane number per degree of advance. Spark advance increases cylinder pressure and allows more time for detonation to occur.
So to be safe i would say 1* of timing for 1octane point.
Next, peak torque is = to peak VE(volumetric efficiency). Do you know when peak torque is achieved in your power band, that may make the next set of notes easier to compute.
The optimal amount of of timing advance varies inversly with VE because because denser mixtures burn faster and require less lead time to achieve the 15* peak. Therefore, engines need more advance at low-load, narrow throttle settings when VE is poor. VE is poor at idle, but engine engine speed is low, 8-20* of timing typically works well.
The on set of boost is increases the effective compression ratio, and combustion speeds up dramaticly, requiring less timing, and simultaneously increases the risk of detonation. Max timing at 1.0 bar boost is typically in the range of 23* at any engine speed, and 2.0 bar should be arround 21-22*.
All things being equal, bigger engines need more timing advance because it takes the flame(spark igniting fuel/air) longer to burn its way across the larger bore than the smaller one.
Does this make any sence?
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The purpose of ignition advance is to account for the lag time following spark ignition for combustion pressure to peak at 15 degrees AFTER TOP DEAD CENTER. A little fyi !
Lets make sure we understand a little about timing before we ask about it:
Spark advance, which is optimally timed to achieve best torque by producing peak cylinder pres at about 15* ATDC, increase octane requirements by half to three quartes of an octane number per degree of advance. Spark advance increases cylinder pressure and allows more time for detonation to occur.
So to be safe i would say 1* of timing for 1octane point.
Next, peak torque is = to peak VE(volumetric efficiency). Do you know when peak torque is achieved in your power band, that may make the next set of notes easier to compute.
The optimal amount of of timing advance varies inversly with VE because because denser mixtures burn faster and require less lead time to achieve the 15* peak. Therefore, engines need more advance at low-load, narrow throttle settings when VE is poor. VE is poor at idle, but engine engine speed is low, 8-20* of timing typically works well.
The on set of boost is increases the effective compression ratio, and combustion speeds up dramaticly, requiring less timing, and simultaneously increases the risk of detonation. Max timing at 1.0 bar boost is typically in the range of 23* at any engine speed, and 2.0 bar should be arround 21-22*.
All things being equal, bigger engines need more timing advance because it takes the flame(spark igniting fuel/air) longer to burn its way across the larger bore than the smaller one.
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How much timing is too much timing
a th-----scope
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