Power Enrich

[jlbjr]

Hello,

I have a 2016 ZO6 Auto w/ KN Air Intake. No wideband yet. I have been messing around with Timing, Idle, MAF and Fuel Trim hystagrams. I've been comparing my scans to others that I can find, I think it's pretty good. I'm not a pro. Some of the compare runs, the PE kicks in earlier, mine is 5,000rpm which I believe is stock. So, how does the ECM adjust the fuel, I'm only in PE for 1,500rpm and a very short period of time. Also, how does it ramp and change those values if I bring PE in earlier. Why doesn't the whole PE table ramp/ go from a lower PE 1,000rpm then max out at higher PE 6,500rpm. If the AFR has to go up and down through the rpm range, does it really get to those values so fast? The scan I'm comparing with, I didn't see the tune, just the scan. He's(Crawford Racing from 2016) about 30hp more than me, at the same specifics. His PE comes in at 3,000rpm. His car is a manual trans.. I've heard that some people start the PE Table with one value across the board and make small changes up or down and scan, then compare. I hope this makes sense? Again, not a tuner. Just learning. Buy wideband, or email tune? I like to do my own remodeling at the house, then I learn. Thanks.

[TriPinTaZ]

The 5000 RPM value means PE can be delayed, not that PE starts at 5000. The delay is so that you don' dump fuel right away that doesn't get used and wasted out of the exhaust contributing to emissions. It really isn't necessary, in stock form, for PE to start immediately after stomping the gas. As for the PE table itself, you don't need super rich PE at low RPM's nor do you need it at low RPM high load, and it causes additional emissions to be sent into the atmosphere. And the other parts of the PE table have to do with what stoich ratio makes the target power and helps cool the combustion chamber along with COT cooling the catalytic converters off.

I've seen some tuners set the PE Lambda target the same across the board. In my opinion you don't need to set the low RPM PE that way. My tunes start a bit leaner in that area and then ramp up to where the PE should be. I'm not saying they are wrong and it isn't dangerous, I just see it as unnecessary. You can also influence peak Torque and peak HP values with lambda changes depending on the setup. NA motors actually like things a bit richer at peak torque and slightly less timing and then lean it out and increase timing towards redline. Supercharged motors and Turbo's are different. But in reality all of this is a mute point unless you strap the car to the dyno and test what makes more power.

On the 2015 Z06, if your only mod is the K&N intake, there isn't a ton of power to find. You can lean out the fueling if you have a wideband in the car, and adjust the timing in some areas but without headers you wont get anymore timing in it, past about 5000 RPM, without causing knock retard. If you change the PE curve you should reduce the PE Delay values so that it doesn't delay going into PE. The OEM settings are safe with the commanded PE and MAF curve, but once you change WOT fueling and add an intake that skews the MAF's reading, such as the K&N, the OEM PE delay logic is no longer optimal.

[jlbjr]

Tripin, I think i'm looking at a stock PE Enrich EQ Ratio chart. Say wide open at 3,500rpm, when it gets to the top of 4,900rpm, then it riches up 2 points. Then leans 3 points to 6,200rpm, then richens 1 point until redline. What is the ECM using to make that adjustment? A MAF, LTFT, O2 volts or a VE value, or both? When the value is 1.195 at 5,120rpm, how is the 1 value calculated? I appreciate the help, I might sound like a goofball. Thanks

[jlbjr]

My Log. 04172022am pe stock.hpl Is this decent? The fuel trims are set from a couple months ago. The knock is on a throttle close or shift, not sure if it's real.Thanks

[ZeroBoostBuick]

The reason for the delay could be the "Enable Torque" & "Enable Pedal" tables under Fuel - Power Enrich.

Enable Torque table ,... I would change the whole table to 30 % or 25 or 20 %

Enable Pedal table stock is set to 70 %,... set to 35 % is more ideal.

Also under Power Enrichment - Enrichment rate Ramp In and Ramp out from factory is set to 1.0000... It's much better to set those 2 table to 0.0100

That Should help with the delayed PE.



PE enable torque & throttle 16' ZO6.png

[TriPinTaZ]

I disagree with setting Enrichment Ramp In/Out rate to 0.0100. You want to increase this value to 1.5000 or 2.0000 so that it ramps in faster, no slower. A value of 0.01 would likely be problematic if it would indeed reduce the enrichment rate to 1% of the OEM value.

As for the PE values it is an EQ Ratio. There is an extensive explanation on it on this forum.
https://forum.hptuners.com/showthrea...EQ)-Discussion

[jlbjr]

Thanks, Could you guys look at my scan when you have a minute? Tell me if it's decent or any advice? Thanks.

[TriPinTaZ]

There isn't enough channels logged to provide much insight.

[ZeroBoostBuick]

I disagree with setting Enrichment Ramp In/Out rate to 0.0100. You want to increase this value to 1.5000 or 2.0000 so that it ramps in faster, no slower. A value of 0.01 would likely be problematic if it would indeed reduce the enrichment rate to 1% of the OEM value.

As for the PE values it is an EQ Ratio. There is an extensive explanation on it on this forum.
https://forum.hptuners.com/showthrea...EQ)-Discussion

You're totally right. Brain fart. Thanks for catching that. higher ramp in/out values = less PE delay.

Thanks !