5.3 maggie PTB help?

[SilverBullet6.0]

Hey guys, been playing with my maggie setup on my 2011 sierra with a 5.3. So far ive done away with maggies pathetic IFR table and installed zr1 injectors, a slightly smaller pulley for 8.5-9psi, dialed in the maf and pe with a wideband and dynamic airflow disabled above 1000rpm. My truck is lifted with oversize tires. Cruising on the highway i regularly see 2psi of part throttle boost and up to 5psi when cruise control pulls the truck up a hill. Should I be worried about running lean during closed loop ptb? How can i correct it to partially enrich the afr for ptb?

[gn2beatu]

If your in closed loop you should not be running lean - as the load value on the engine isnt that great and the airflow going through the engine shouldnt be enough to spike EGT's or worry about KR as the O2's will keep you at stoich. Being at stoich @ low load even with light boost isnt an issue as long as its LOW LOAD. But 5psi does seem high, how steep of a hill are we talking about, like mountain steep? And what is the max boost you run, as you might want to change some settings. If it is mountain steep, then you might want to kick in open loop and enable PE a little earlier by KPA. But at 2psi, normal closed loop is fine as long as its light throttle. Keep the PE for when you want the power, otherwise your gas milleage will go to away, which has always been an issue with the stock maggie tunes.

You also have the ability to vary your AFR by RPM, and that is something I like to do under light/medium load around 3-5 psi range. If it was mine, I would taper the PE AFR curve from stoich @ 4psi to around 13:1 by 5psi for the hill, then after 5psi taper from your freeway high rpm AFR of 13:1 to 11.2 by the time you get to ~3500rpm, and from 3500 to redline taper it to 11.4 to 11.5 by 6000rpm and higher. Make sure whatever RPM your shift points are at when under WOT that the AFR is still 11.2 as this helps reduce KR. Some trucks with big tires I have even gone to 11.0 at shift points and in that same RPM area you may need to pull 2-3 degrees of timing IF YOU HAVE KR.

G/L

[SilverBullet6.0]

Not mountain steep, but something like a 50-75ft change in elevation in a short run without downshifting. I had the pe table tweaked to command a decent afr at loaded cruise rpms, but once it downshifts my rpms come up enough that it goes to full enrichment. The tps is usually around 40-50% in the situations Im describing.

[SilverBullet6.0]

Also, with any wind at all, im sitting at roughly 2psi @ stoich just cruising on flat land at 60-70mph. I know 2psi isnt much to worry over, but the fact that sometimes it sits there for a while (40min drive to work every night) worries me.

[SilverBullet6.0]

Well, i went in an lowered the enable tp for pe and its greatly resuced the time im in boost at stoich on hills. However, i towed a s-10 on a featherlight trailer weekend and was still in boost at stoich a few times. I just dont want to hurt my engine running too lean.