Thread: JB3
View Single Post
      01-05-2009, 09:26 AM   #78
dcafs
Private First Class
18
Rep
149
Posts

Drives:
Join Date: Sep 2008

iTrader: (0)

Quote:
Originally Posted by dadasracecar View Post
My posts don't make sense? You're delusional. What the hell does CHANGE mean to you? It's either retarded or advanced from the stock position. Read the quoted posts that you made.

I'm saying the JB3 increases boost and fueling but, until shown otherwise, it does not change timing. The speculation is that it relies on the car's knock sensor to pull timing when the car knocks at high boost on the stock timing map. That's why it may be dangerous. It would be if that speculation is true.

The general rule of thumb is that you pull timing when significantly increasing boost to mitigate knock. If you're just raising (doubling) boost and adding fuel any car will knock. Relying on the knock sensor to pull timing after the fact is reactive and bad because your engine will suffer that knock event - possibly every time you go into that max boost situation. If a piggyback pulls timing when raising boost the car (hopefully) won't knock under high boost and the ecu controls the timing as normal. It may advance or retard the timing but it will do so using it's full range rather than immediately pulling a bunch from a big knock event caused by doubling the boost and leaving timing as it were.
Already explained on post #55 - I think he is saying the ECU adapts to the changes and remembers them for the next time the same conditions are encountered.......BUT as a secondary backup, it is still listening for knock all the time and fine tuning accordingly.

The tuner's answer is:
"The ECU "remembers" the multi-dimensional timing table it builds. So just to expand on that thought in a theoretical sense, taking out say 2 degrees via the CPS the first time you give the car gas the first time you install a piggyback, you are being proactive for that first 3 seconds. But from that point on its 100% "reactive" based on the knock sensors. Yes, the engine is ALWAYS checking for knock conditions and adjusting accordingly. No matter what CPS offset you have. The only way it can do this is by advancing the timing up to the point just before actual knock"
Appreciate 0