1st time WOT Tuning questions

[Intenseblue]

Bone stock 5.3 E38 Silverado. K&N CAI, 212/218 111lsa cam. Otherwise stock.

I'm finishing up tuning on vve and maf today for sub 4000rpm driving. Up until now I've tuned off of Ltfts multiplied by half in paste special. Knowing what I know now I wouldve used short trim averages and began with direct paste pct without halving.

I've just purchased an AEM can bus wideband for wot tuning and have some newbie concerns that I'm seeking understanding on.

I'm assuming I'll tune VE first, then MAF. My question regards the PE table and lambda both. Not necessarily together. If I'm in speed density logging and hit ve on WOT will my error percentages reflect the PE interceding? Or will I be looking for .85(generality) and the pe multiplier cause me to go way rich?

Interjection, I feel like I'm answering my own questions on this lol. I've exhausted the gen 3 and 4 forums searching but have found little clarity, at least under my keywords.

Also with the PE Table. My stock is active at 5000rpm and 87pct tps. Is this an either/or to activate, or are both required? If both are required, where does that leave me from a low rpm roll stomp in first gear at 10mph? I'd hope not stoich until 5000rpm.

Lastly, are there any PE tables that need to be modified for performance safety such as generalizations mentioned already or even for part throttle to wot transitions? Is it standard practice to lower the tps pct or rpm? 5000rpm seems excessively high, so does 87pct throttle. Usually if I'm over half throttle I'm "playing", and as for 5000rpm, That's already past torque peak.

Forgive me if the vve table is already on top of that for me as well. Just looking for more clarity that I've not came across yet.

The truck will be final tuned back with the maf. Same thing here, would I want to activate it sooner afterwards?

I'd honestly expected more wot wiriteups or info than anything and there seem to be way less of those than anything else. I've found 1 that's way dated, but seems to be from a credible source on the forums. And two others referenced with dead links.

Last question, and this is me pushing my boundaries possibly, but target a/f seems to be all over the place here as well. 12.3-13. I'm not seeing anyone talk about ramps though. I'd imagined shooting for about 12.3-4 til peak torque then 12.8 after. Are yall ramping these transitions. Or going from one to the next, or just a straight afr across the board. I've seen that used AND recommended as well but cant wrap my mind around it being optimum.

Many thanks.

[village_idiot]

Your AFR Error/EQ Ratio Error (whichever you are using) should be a reflection of Commanded AFR/EQ vs Actual. So, when you enter PE, the error will not factor stoich at all. It's whatever the current commanded vs wideband is off. I have my AFR Commanded, EQ Ratio Commanded, and WBO2 all next to each other on my channels so I can see them all.

PE has to see both values just like a shift point. So, if you go WOT at 2000 RPM in your example, it will only go into PE after seeing over 87% AND over 5000 RPM. I personally lower the delay RPM to 0 or up to around 2000-2500 depending on the vehicle and mods, and will taper my TPS% from something like 60-70% in the early RPM up to 20-30% in the higher RPM so there's less chance of a high rpm/non pe situation

On the Target AFR/Commanded PE, some people use a straight across the board PE, and some start fat and taper like you suggested. IMO, it has a lot to do with the weight of the vehicle. The heavier the vehicle, the more it could benefit from being fat down low. Stall size, and manual/auto will play a role too. Lots of variables.

[Intenseblue]

I will be attempting to use lambda. im actually wiring in wideband now. Ive always been familiar with afr, but e10 pump fuel and all its variances put a knot in that.

Regarding PE, if youre correct and ive understood right, then if i nail 100pct throttle at 2800rpm the computer is looking for stoich until i hit 5krpm. I cant grasp that being accurate. However, this seems to be a majority concensus as to how it engages, so im not saying youre wrong. On the flipside, im assuming youre correct and the VE table is doing its own richening progressively. if thats the case, then why do we tune pe at all instead of disabling it and solely use the vve/maf for all rpm and throttle positions?

Im likely overthinking AND missing something. Just trying to have a full grasp on what im doing.

To add to this, if i part throttle tune to 4k rpm to stoich, then wot my entire rpm range, what happens to 4500rpm-5000rpm at say 73pct throttle. Say im tuning sd only, is the ve calcuator making adjustments for those cells or is it a full blown theoretical 14.7 to 12.5 light switch?

Thanks for the response. 2x

[07GTS]

the PE 5000rpm is a delay not a waiting until point, u should set it to zero and change the PE TPS to like 40-50 so it comes in sooner then just WOT its not actual tps its PE TPS which is a bit higher then actual, when ur using the wideband error and ur in PE or not the error is still correct, as the commanded changes the error changes to suit it when the target is lambda 1 or if the PE is lambda .85 all u have to do is get the WB in lambda to equal that commanded and it will be correct

[village_idiot]

Because you do not want the same AFR/EQ at 2500rpm/WOT as you do at 2500rpm/15% or 3000rpm/0% decel

VVE to PE is a full on/off switch type action. You can also adjust your total timing while in PE based on gas/alcohol to add timing on top of your base table while in PE. I set it where I know it will not get into PE while cruising or light driving, and any time the throttle is aggressive, it will be in PE.

You can use math back and fourth to verify AFR/Lambda/PE Ratio.... Example...

14.7 / 12.5 = 1.176 (Stoich divided by Target AFR = PE Ratio)

12.5 / 14.7 = 0.85 (Target AFR divided by Stoich = Lambda)

14.7 * 0.85 = 12.5 ( Stoich times Lambda = Target AFR)

[Intenseblue]

the PE 5000rpm is a delay not a waiting until point, u should set it to zero and change the PE TPS to like 40-50 so it comes in sooner then just WOT its not actual tps its PE TPS which is a bit higher then actual, when ur using the wideband error and ur in PE or not the error is still correct, as the commanded changes the error changes to suit it when the target is lambda 1 or if the PE is lambda .85 all u have to do is get the WB in lambda to equal that commanded and it will be correct

Thanks for the clarity on the afr error taking pe modification into account during a transition. To throw a curveball, what I was envisioning was looking at a table I'd created for ve tuning where I copied the column and row labels of the vve table into a histogram and had the cells populating with lt fuel trim errors. I'd imagined doing the same thing with the wideband and wondering what itd do in the higher kpa cells and higher rpm cells. If it would account then. I have a feeling now this is not the right way to do it wot.

Lastly, with 5000rpm being a delay and NOT a waiting until point, meaning PE can activate before that rpm, then what is it for? Situations where you're holding or maintaining that rpm without being at the throttle position activator? Such as towing, or trans problem?

[Intenseblue]

Because you do not want the same AFR/EQ at 2500rpm/WOT as you do at 2500rpm/15% or 3000rpm/0% decel

VVE to PE is a full on/off switch type action. You can also adjust your total timing while in PE based on gas/alcohol to add timing on top of your base table while in PE. I set it where I know it will not get into PE while cruising or light driving, and any time the throttle is aggressive, it will be in PE.

You can use math back and fourth to verify AFR/Lambda/PE Ratio.... Example...

14.7 / 12.5 = 1.176 (Stoich divided by Target AFR = PE Ratio)

12.5 / 14.7 = 0.85 (Target AFR divided by Stoich = Lambda)

14.7 * 0.85 = 12.5 ( Stoich times Lambda = Target AFR)

Your first paragraph is one of the concerns I was hitting on. If I take a 3500rpm at WOT at a given afr, I'd expect the same rpm at 65-70pct throttle would want a leaner afr. But not stoich. Where is this accounted for in the tune? I think I mentioned earlier wondering if the vve table was guestimating for you during coefficient calculating. But I wasn't sure. I do a LOT of mountain driving.

[Intenseblue]

I feel like an idiot haha. I've totally misunderstood the vve table I think....and my lightbulb has just went off

[07GTS]

VVE or VE or MAF tables represent Lambda 1.0 then all multiplier values for PE or OL EQ startup and taken from those base tables and just multiplied

[village_idiot]

I'm right there with 07GTS... Setting the delay to 0rpm, and setting the TPS to around 60% in the early rpm and tapering down to around 30% in the upper rpm is usually the way I go. Id rather control the PE by TPS and MAP than I would RPM. Speaking of, if your mind wasn't blown enough already... I don't think we've discussed the "Minimum MAP" settings on the PE yet. You can also control it in that manner.

[Intenseblue]

VVE or VE or MAF tables represent Lambda 1.0 then all multiplier values for PE or OL EQ startup and taken from those base tables and just multiplied

So you're saying at higher rpm and higher kpa readings, if I'm underneath my pe tps requirements and pe is NOT active that my pcm would be shooting for a stoich air fuel ratio? This would include 70pct throttle at 4000rpm? Considering my stock tps pct is at 87pct. That's one of the things I'm having an issue graping.

[Intenseblue]

I'm right there with 07GTS... Setting the delay to 0rpm, and setting the TPS to around 60% in the early rpm and tapering down to around 30% in the upper rpm is usually the way I go. Id rather control the PE by TPS and MAP than I would RPM. Speaking of, if your mind wasn't blown enough already... I don't think we've discussed the "Minimum MAP" settings on the PE yet. You can also control it in that manner.

This is th e general direction I'm leaning towards.

[Intenseblue]

I'm right there with 07GTS... Setting the delay to 0rpm, and setting the TPS to around 60% in the early rpm and tapering down to around 30% in the upper rpm is usually the way I go. Id rather control the PE by TPS and MAP than I would RPM. Speaking of, if your mind wasn't blown enough already... I don't think we've discussed the "Minimum MAP" settings on the PE yet. You can also control it in that manner.

This is th e general direction I'm leaning towards.

[village_idiot]

PE TPS SETTINGS.png

This is the sort of taper I was talking about with the TPS. I'll usually set the TPS something like this, RPM Delay to 0, and the Minimum MAP to 60kPa or around there (this can all vary a bit depending on setup)

[07GTS]

So you're saying at higher rpm and higher kpa readings, if I'm underneath my pe tps requirements and pe is NOT active that my pcm would be shooting for a stoich air fuel ratio? This would include 70pct throttle at 4000rpm? Considering my stock tps pct is at 87pct. That's one of the things I'm having an issue graping.

yes u want to be at stoich/closed loop for the majority of driving then once u want power then u set the PE to come in to enrich it when needed, also the PE TPS isnt the same value as actual TPS so your 87% is basically full throttle, if u set the PE TPS to about the 20% that will be about 50% actual so keep that in mind when adjusting it

[Intenseblue]

David, thanks for the pic. I discovered that early yesterday rereading and browsing my editor tables and descriptions.

07GTS, again, thank you as well. I'd actually been curious on that subject because of looking at tables in the throttle body tab where it seems to indicate differences on pedal position vs blade position. I've downloaded a few vette/fbody/g8 etc files to compare theirs to mine and see what the oem was getting away in regards to pe tps and a/f targets.

I'll probably ask 1-3 more minor questions this evening just so I feel confident in what I'm doing.

14.7:1 to straight wot fueling is different than how carburetors work for sure. I always imagined fuel injected setups worked in similar fashion. Learn something new every day. That probably cant be said enough times.

[blindsquirrel]

Well, in a carb, as long as we're talking Holley-type, the power valve open or closed has no effect on idle/part throttle because the PV only adds fuel to what comes out of the boosters, and all the idle/part throttle fuel comes from the idle and transition circuits. If the airspeed isn't high enough to draw from the boosters it doesn't matter if the PV is open or not. However with EFI the idle, part throttle, and WOT mixtures all have to come out of the same injector...

I tend to think of the primary PE enable setting to be the MAP, since that's the best indicator of engine load and if it needs enrichment for power/safety or not, and the TPS/RPM settings as more of a disable or override for those conditions where MAP is high (low vacuum) but PE isn't really needed or desired. Instead of 'above 30% TPS, enable PE' think of it as 'below 30% TPS, disable PE'.