What is it that the stock ECU "learns"?

[BruceW]

What is it that the stock ECU \"learns\"?

I have been trying to find some detailed info. on this and have had no luck. How and why does the ECU adapt itself based on your driving? A lot of people recommend that if you want your car to really perform you need to reset the computer and then drive it hard. What is the computer adapting? I am guessing it's the fuel and spark but why did Dodge do this? I would love to get my hands on the flowchart for the ECU programming (that would answer all of my questions). To get the most out of the engine how hard and how long do you need to drive it? Do the add-on units like the VEC override this? I have never seen this feature in aftermarket fuel injection systems, I suppose it has something to do with improving the emissions or fuel economy.
TIA

 

[Jack B]

Re: What is it that the stock ECU \"learns\"?

There is lot of bogus information on the adaptive ability of the viper computer. Talk to Sean Roe he knows far more than anyone at this time.

Basically you have short and long term adaptives for left/right engine sides. The short term adaptives are constantly being changed by the external input (air temp, coolant temp, O2 feedback, etc). The long term adaptives are being changed by the short term adaptives. The tug and pull by the short term adaptives is a 150 second period, in affect, the long term will change after the same average value is requested for 150 seconds. This is an over simplification since the computer algorithms control the process.

Most of this is not meaningful under WOT. Adaptives are only in effect when in closed-loop, somewhere between 0-80% throttle. All of the adaptives are locked out and the car reverts back to a preprogrammed/fixed algorithm (MAP) when you go WOT. Some cars remember the long term adaptives when they go WOT, not the viper.

All this relates to the problem of modifying the viper. Due to the inability to change the MAP, a modded viper cannot realize its full potential. A case in point is my car. I did a series of modifications. I subsequently found that it was running too lean to achieve full hp. You have to able to change the MAP and that is where you use the Roe VEC2.

 

[DrumrBoy]

Re: What is it that the stock ECU \"learns\"?

Thanks for the info. I have the same problem. On most dyno pulls, I start out at 17/1 A/F and almost linearly drop to 11/1....but that's at 5800. I don't get into the 13/1 zone until 4500 or so. I believe this costs me 50+ RWHP. You mentioned that a VEC 2 will aloow you to adjust the MAP, will a VEC 1 allow me to remap the fuel delivery, maybe not as well or conveniently but will a VEC 1 help me any?

 

[Qualitywires.com]

Re: What is it that the stock ECU

I think the Vec 1 may help out a tad bit but not as much as the Vec 2 would. I am planning on getting a Vec 2 system here shortly. I am just deciding on the Splic Sec vs. the Roe Vec2. I wish I could get a hold of a windows base program for the Vec2 so I can see the features and play with it first before I buy it.

 

[PhilC]

Re: What is it that the stock ECU

Drumrboy:

You would be fine if that POS tuner in Chicago didn't break into and ruin your after market DFI. You definately have to get either a vec 2 or another programmable add on to get those numbers right. As previously stated, the stock comp is not going to help at wot, which in my opinion is when you need it the most. Let me know if you would like my assistance. Now all you have to do is get your wife's approval to spend more $ on the beast.

Phil

 

[Jack B]

Re: What is it that the stock ECU \"learns\"?

Drumboy:

don't bother with the VEC1. You cannot change timing and fuel independently

AB:
All you have to do is ask Sean for the software, I would think he would gladly let you use the software prior to buying. The software initially looks difficult, however, after a few hours the light goes on and it really is intuitive. The use of the smart cards allows a quick change of parameters, such as from NA, to NOS.

I just took my WOT 14.5 a/f and dropped it to a nice flat linear 12.75. If you have any mods, you are running to the lean side. I have done that with the aid of the Innovative A/F logger. The next step is to take it to the dyno and start adding advance.

 

[STUGOTS]

Re: What is it that the stock ECU

i just bought a vec 2 (there on backorder right now) i was asking Sean about the softwear and he said the same thing Jack said it looks hard to figure but after a few hours it clicks