zcpowereddx

hey guys whats up
heres my setup 440 blue top injectors vafc timing all the way retarded runnin bcpr6es spark plugs on a d16a6 on 8-10 psi. my problem is its pinging at around 4,000 rpm in any gear and im runnin hella rich 3,000 and above set at -27 and it still ping I live in las vegas Nevada if that matters any help would be great

boosted_dc2

how do you know your rich??? what are the plugs gapped at???

Landon

bluesiTYPER

Improper ignition timing can cause detonation also..Let me try to explain:

Detonation is caused by excessive intake charge temps..instead of a progressive burn near TDC, it becomes a violent explosion (detonation)..

Basically, by retarding your ignition timing, you are preventing the cylinder pressure from reaching peak too close to TDC (telling the spark plug to start the fire later in the combustion cycle)..

Most engines perform best OVERALL when cylinder pressure peaks at 12-14 degrees after TDC, and is usually acceptable between 18-20 degrees after TDC..At these points, piston acceleration away from TDC is relatively slow so when pressure from combustion is peaking, the combustion space is not increasing rapidly..because of this, the pressure holds at a higher level and gives the crankshaft a good push, making high horsepower..

Since by you saying that you retarded your ignition timing all the way, you are prob well past 20 degrees after TDC..Now to understand how this can cause detonation by itself:
What you are doing is slowing combustion so much that the exhaust valve is already opening while the burn from the spark is still going, consuming fuel..This increases your exhaust valve temps as the fire passes the valves into the exh manifold..This also causes the exhaust side of the combustion chamber and piston crown to get hotter..Then the intake valve opens to bring in the fresh air/fuel mixture, but all the hot parts previously mentioned heat the intake charge, which causes the density of the mixture to go down (power decreases because of the lower density charge)..

At worst, which is what it sounds like in your case, you've got combustion continuing so late on the downstroke that the exhaust valve, piston crown, and combustion chamber haven't had enough time to cool before the next induction of air/fuel enters the cylinder..this retained heat is enough to get combustion going long before the spark plug fires again..this causes detonation, or in the worst-case scenario can cause pre-ignition (basically much like a blow-torch that can melt thruogh the crown of the piston, burn valves, etc (you get the picture)..

SO, I would go tune your car on the dyno..higher boost levels do not necessarily mean higher horsepower if you don't have the correct setup.. You need to find the happy medium between ignition advance/retard, and boost level..

With optimal timing, the cylinder pressure will be able to stay high(remember what I was saying about combustion space not increasing to rapidly when the spark fired), you will make more power..

Basically more cylinder pressure = more push on the crankshaft = more hp..

If you are retarding too much, the spark is fired as cylinder is already moving pretty quickly down the cylinder wall increasing combustion space volume quicker, which in turn makes cylinder pressure go down..

Basically less cylinder pressure = less push on the crankshaft = less hp..

SORRY for the long explanation, but I didn't want to give you a half-*** answer that you might not understand..Good luck with your setup ..