How does the ECU determine to pull timing?

[jtmp3]

is that what the msp ecu uses to pull timing in relation to boost?

 

[jtmp3]

Or is there ohter factors that make the MSP pull timing?

 

[jtmp3]

What boost is too much on stock timing??

 

[TurfBurn]

And people wonder why I talk about piggy's not being able to rein in the stock ECU and that timing can move....

lots of factors involved and alot of things that can cause issues with the timing and output. I'm having issues getting your curves to load... but we'll see...

 

[jtmp3]

uh,what??

 

[TurfBurn]

LOL... didn't follow my post???

I did look at your curves finally.. was having adobe problems before... the bumps are evident... hard to say what they are but they are definitely tune related.....

My other point was that people argue about piggybacks not having drift issues and that the stock ECU doesn't "drift" much... but your dyno's are showing a 10+ horsepower shift that is either fuel or timing related and if you have a tune that is "good" in one case... and you get that same shift again you are back to still losing the power.. that is one of the "bummers" of piggybacks that is a fact of life whether people will admit it or not.

 

[DSMConvert]

The afc adjusts maf and o2 signals via a % not a set value. Adjusting values via a set value is very dangerous to do. When I get back to the office I'll have to take a look at our initial dyno runs but your numbers seem slightly low...not suprising though as the map generally yields a 10whp gain when tuned to the specifc vehicle. Ours was done in a low humidity 76 degree CA day on a relatively stock car. However when we did our runs we did 3 runs spaced 45-1hr a part. Doing runs any sooner than this does not give the car proper time to cool down and will contribute to drifting as turf noted. The biggest contribution to timing retard, excluding the knock sensor, is the coolant and iat temps. As we know detonation increases with heat linearly so the ecu is preprogrammed to increase retard at higher rpms with it received higher temp signals from the coolant and iat sensors... however changin the value of one of these sensors, say for example moving the iat location, doesnt really do much as the ecu just extrapolates from the coolant sensor and knows something is up. Mallard if you can get me the a/f chart to go with that dyno chart I can take a look and make some suggestions on tuning.

 

[TurfBurn]

It's just odd (referencing his car/dyno... not the application) that there are "hiccups" in it... lacks a good explanation

the DSM works very well and is easily my favorite of the piggy's well worth the pennies... I don't know/get what the hiccups are other than oddities the stock ECU is introducing.. and the question is why the hiccups are popping up. I know the DSM does a very good job of getting AFR's moved around so I do doubt that it is an AFR thing and with how flat the boost curves looked I do expect it to be a timing issue or so forth..

 

[Mallard]

Mallard if you can get me the a/f chart to go with that dyno chart I can take a look and make some suggestions on tuning.

This is a very old thread that was revived from the dead. My car was sold in November.

 

[jeffmsp]

since its revived was the good run the first run? Maybe your coolant and intercooler where hotter after the 1st run. Also, something like a rattling in the engine bay could cause your knock sensor to detect knock it works on a 1-5 v i believe so if something is rattling near it timing could be affected. Also the intake manifold could have heatsoaked, turbo got hotter, pipes warmed up and expanded causing efficiency drop etc. the first run would be the best if nothing gets changed throughout the runs i would imagine.