Power Enrichment Question

[sgod1100]

I will always err on the side of engaging PE earlier than needed rather than later. As engine load (cylinder airmass) increases, so does cylinder temperatures during the compression stroke. The increased heat increases the chance of detonation.

So in my opinion, engaging PE early keeps the temps at bay from the get go. Which is better than delaying PE, which allows temps to increase only trying to cool them down after it is already hot. So if you want to delay PE, then perhaps you should do as GM does and think about keeping Burst Knock on.

I don't think anyone is here is overly concerned with MPG or emissions (at least to the extent that the OEMs are forced to)...so what is the advantage of staving off PE?

--

The table is not available since it is a physical characterization of the geometry of the throttle body. If you were to mess with that, it would throw off the ECM's entire understanding of torque management and idle control. The way you influence these factors are primarily through these scalar values:

• [ECM] 2154 - Idle ETC Area Scalar
• [ECM] 2173 - Idle Effective Area Max

If you ever do decide to upgrade to a larger throttle body, the new Nick Williams 103mm (and also the Katech 103mm which is made by Nick Williams) has been designed to work with the OEM values here (at least if your Gen4 originally came with a gold blade TB). This cuts down on the tuning and quirkiness of a large TB. You will find many posts in here with people struggling to get their NW 102 TB to act right...and lots of good insight from GHuggins on how to tune it.

For me, keeping PE low (i.e. 70-80 kpa) made my part throttle performance feel very lethargic. If I was just accelerating normally from a stop light and went above that PE switch point the car just felt "heavy" in my opinion. Especially since my PE fuel is set to 11.8:1 (afr) which is extremely rich when you are only at 70ish kpa.

[poulina]

For me, keeping PE low (i.e. 70-80 kpa) made my part throttle performance feel very lethargic. If I was just accelerating normally from a stop light and went above that PE switch point the car just felt "heavy" in my opinion. Especially since my PE fuel is set to 11.8:1 (afr) which is extremely rich when you are only at 70ish kpa.

fwiw I have a small turbo/quick spooling setup and I have PE coming in at 95kpa and 5% throttle....

[edcmat-l1]

For me, keeping PE low (i.e. 70-80 kpa) made my part throttle performance feel very lethargic. If I was just accelerating normally from a stop light and went above that PE switch point the car just felt "heavy" in my opinion. Especially since my PE fuel is set to 11.8:1 (afr) which is extremely rich when you are only at 70ish kpa.

I'd look at your timing in the area of concern. That shouldn't be rich enough to lose enough power to make it feel sluggish. There's not a ton of power loss or gain from roughly 11:1 to 13:1 in pretty much anything LS. A few HP maybe but it should be nearly unnoticeable.

[sgod1100]

I'd look at your timing in the area of concern. That shouldn't be rich enough to lose enough power to make it feel sluggish. There's not a ton of power loss or gain from roughly 11:1 to 13:1 in pretty much anything LS. A few HP maybe but it should be nearly unnoticeable.

I'll double check that, but I'm pretty sure my timing isn't ridiculously low in those areas. have to wait until the weather gets nice though....the joys of living in northern IL...smh.

[Allen Vos]

I will always err on the side of engaging PE earlier than needed rather than later. As engine load (cylinder airmass) increases, so does cylinder temperatures during the compression stroke. The increased heat increases the chance of detonation.

So in my opinion, engaging PE early keeps the temps at bay from the get go. Which is better than delaying PE, which allows temps to increase only trying to cool them down after it is already hot. So if you want to delay PE, then perhaps you should do as GM does and think about keeping Burst Knock on.

I don't think anyone is here is overly concerned with MPG or emissions (at least to the extent that the OEMs are forced to)...so what is the advantage of staving off PE?

--

The table is not available since it is a physical characterization of the geometry of the throttle body. If you were to mess with that, it would throw off the ECM's entire understanding of torque management and idle control. The way you influence these factors are primarily through these scalar values:

• [ECM] 2154 - Idle ETC Area Scalar
• [ECM] 2173 - Idle Effective Area Max

If you ever do decide to upgrade to a larger throttle body, the new Nick Williams 103mm (and also the Katech 103mm which is made by Nick Williams) has been designed to work with the OEM values here (at least if your Gen4 originally came with a gold blade TB). This cuts down on the tuning and quirkiness of a large TB. You will find many posts in here with people struggling to get their NW 102 TB to act right...and lots of good insight from GHuggins on how to tune it.

I guess what's going through my mind right now is how much will I need to change PE with the new camshaft.

I can just leave the values stock for now and tweak them once I start driving the car, but one would think with a camshaft that does not start making any power until 3000 RPM the PE would need to be set for a little bit higher RPM as compared to the stock camshaft.

I am only basing this off tuning my old mustang where if the equivalent to PE came on to early it would cause a bog or a flat spot.

Maybe the LS engines are different in that way but in principle I'm sure they are close.

Its something I will need to experiment with.

I'm glad I posted this though as now I understand how the entire PE system works.

Thanks so much guys.

[07GTS]

For me, keeping PE low (i.e. 70-80 kpa) made my part throttle performance feel very lethargic. If I was just accelerating normally from a stop light and went above that PE switch point the car just felt "heavy" in my opinion. Especially since my PE fuel is set to 11.8:1 (afr) which is extremely rich when you are only at 70ish kpa.

what i do is setup PE as if i were n/a so a leaner mid 12's mix for the first 70-102kpa then i use BE above that and i brake it into sections or adding more fuel so 5psi dosnt have heaps like 20psi would need, that one reason i dont like just PE for boost as if u enter boost at 3000rpm u could be 5psi or 20psi and u have to fuel it for 20psi so this is where if u can use the 2bar OS to get the BE so u can control boost fuel based on MAP

[edcmat-l1]

what i do is setup PE as if i were n/a so a leaner mid 12's mix for the first 70-102kpa then i use BE above that and i brake it into sections or adding more fuel so 5psi dosnt have heaps like 20psi would need, that one reason i dont like just PE for boost as if u enter boost at 3000rpm u could be 5psi or 20psi and u have to fuel it for 20psi so this is where if u can use the 2bar OS to get the BE so u can control boost fuel based on MAP

This is what I do with turbo or centri blowers. But I make the PE by RPM the same as the BE. The PD blowers get all the PE right away.

[edcmat-l1]

Allow me to correct you kind sir.....

I am interested in lots of tables in the interest of learning what they do.

How do you think people learn? Is there a problem with wanting to know how things work and why they do the things they do?

I'm sure you didn't know everything when you first started out at this.


Sometimes we need to try things out and make mistakes along the way to learn.

These posts will be valuable information to people like myself that are learning.

Seems kind of dumb to me to only understand 1 or 2 things that are important in the PE area and not put an effort in to understand everything else around it.

I'm pretty sure by what I have read PE denfinletly needs some changes after a cam swap, so why not try to understand everything?

It funny when I went to trade school to be come a mechanic some 20 plus years ago they taught us every little piddly little detail of how things work which is invaluable to being able to diagnose and figure things out.


That is how I learned and how I will continue to learn things.

I can appreciate the thirst for knowledge. I went to tech school 40 years ago and actually taught tech school in 99-2000. One of the things I remember about the students that wanted to know everything about everything is they tended to lose the fundamentals quickly. It really is better to learn how to assemble engines before you start worrying about degreeing camshafts.

Your original thread was about an idle oscillation and you were trying to fix it with tables that shouldn't be modified, based on what you read. The whole time 1 of your primary 3 tables was completely janked up. This is what I'm talking about. Nail the basics first. Get one good base file, with minimal changes first. See where you're at. Hell you aren't even driving the car yet. Most of the tuning needs to be done under load.

[sgod1100]

what i do is setup PE as if i were n/a so a leaner mid 12's mix for the first 70-102kpa then i use BE above that and i brake it into sections or adding more fuel so 5psi dosnt have heaps like 20psi would need, that one reason i dont like just PE for boost as if u enter boost at 3000rpm u could be 5psi or 20psi and u have to fuel it for 20psi so this is where if u can use the 2bar OS to get the BE so u can control boost fuel based on MAP

With my car having a roots blower the boost will be pretty consistent throughout the whole rpm range. My cal doesn't have BE so I'm limited to just using PE. I'm pretty sure I can get BE if I get rid of VVE and go with a normal VE table (some type of patch that I haven't really looked into).

[Allen Vos]

I can appreciate the thirst for knowledge. I went to tech school 40 years ago and actually taught tech school in 99-2000. One of the things I remember about the students that wanted to know everything about everything is they tended to lose the fundamentals quickly. It really is better to learn how to assemble engines before you start worrying about degreeing camshafts.

Your original thread was about an idle oscillation and you were trying to fix it with tables that shouldn't be modified, based on what you read. The whole time 1 of your primary 3 tables was completely janked up. This is what I'm talking about. Nail the basics first. Get one good base file, with minimal changes first. See where you're at. Hell you aren't even driving the car yet. Most of the tuning needs to be done under load.

I understand what you are saying. However getting back to my original thread of the tables I changed that I didn't need to......

If you remember I had 3 different people including yourself telling me 3 different things, so that makes it very confusing to know what the correct way to do things is.

Not to mention most of the reputable you tube guys for tuning had all indicated to change these tables as well

So I did the next best thing and tried everything to find out what worked best. As it turns out, you were the most correct one in that situation.

As a person who is learning what is a guy supposed to do? I don't know who's right or who's wrong. This is why we try things.


Let me be crystal clear here.......

Just because I am asking questions about PE, that does not mean I am making any changes.

This is prolly the third time I have said this. I want to learn and understand things before I dive in to make any changes.

This is why I ask a zillion questions.

As it stands I have not touched PE and I'm also fully aware that I cant tune PE until as you said I drive the car.

I am using my time in this dreadful Canadian winter wisely that way when the car comes out in a couple months I will have a very good understanding of how things work and what to change and what not to change.

I might be a newbie on HP TUNERS but I have tuned cars on other platforms successfully .

Granted I don't know as much as all you guys on here about HP TUNERS but I will get there.

[07GTS]

With my car having a roots blower the boost will be pretty consistent throughout the whole rpm range. My cal doesn't have BE so I'm limited to just using PE. I'm pretty sure I can get BE if I get rid of VVE and go with a normal VE table (some type of patch that I haven't really looked into).

personally id rather the proper VE and the other little perks, but either way works the same in the end

[Guy With A Chevy]

I understand what you are saying. However getting back to my original thread of the tables I changed that I didn't need to......

If you remember I had 3 different people including yourself telling me 3 different things, so that makes it very confusing to know what the correct way to do things is.

Not to mention most of the reputable you tube guys for tuning had all indicated to change these tables as well

So I did the next best thing and tried everything to find out what worked best. As it turns out, you were the most correct one in that situation.

As a person who is learning what is a guy supposed to do? I don't know who's right or who's wrong. This is why we try things.


Let me be crystal clear here.......

Just because I am asking questions about PE, that does not mean I am making any changes.

This is prolly the third time I have said this. I want to learn and understand things before I dive in to make any changes.

This is why I ask a zillion questions.

As it stands I have not touched PE and I'm also fully aware that I cant tune PE until as you said I drive the car.

I am using my time in this dreadful Canadian winter wisely that way when the car comes out in a couple months I will have a very good understanding of how things work and what to change and what not to change.

I might be a newbie on HP TUNERS but I have tuned cars on other platforms successfully .

Granted I don't know as much as all you guys on here about HP TUNERS but I will get there.

Just slow down Man you got it. Just a couple more months and you can finally get everyone's vote. Personally stop hunting for approval and just have fun with it man. You seem like a great reader you definitely get an A+ for participation

[sgod1100]

personally id rather the proper VE and the other little perks, but either way works the same in the end

Honestly I was wanting to do it, but I was paranoid I was going to brick the ECU. I'm not familiar at all with the "patches" that hptuners offers.

[Allen Vos]

Just slow down Man you got it. Just a couple more months and you can finally get everyone's vote. Personally stop hunting for approval and just have fun with it man. You seem like a great reader you definitely get an A+ for participation

Approval? lol Its the internet man. What I am looking for is a crystal clear explanation on procedures. Not approval.

There's a difference.

[gtstorey]

What I am looking for is a crystal clear explanation on procedures

That's the real problem. There is a lot of this that isn't crystal clear to any but a few, and explaining it to a beginner isn't possible within the scope of reasonable time and effort on a forum (and for free). Some of this you just have to take on faith from the experts until you have time and experience to figure out for yourself. I've been reading everything that has came through the GM Gen 3 and Gen 4 forums over about the last 3 years in an attempt to learn as much as I can.

[Allen Vos]

That's the real problem. There is a lot of this that isn't crystal clear to any but a few, and explaining it to a beginner isn't possible within the scope of reasonable time and effort on a forum (and for free). Some of this you just have to take on faith from the experts until you have time and experience to figure out for yourself. I've been reading everything that has came through the GM Gen 3 and Gen 4 forums over about the last 3 years in an attempt to learn as much as I can.

I get where your coming from and I do understand that to some degree. Being an automotive technician I am very thorough in my work and I leave no stone unturned as far as trying to understand things.

So a part of me knows I can overthink things in that respect.

I also learn better using the hands on approach and that's just who I am. This is why all the videos and you tube channels I follow are great and you can actually watch someone else do things and learn that way. But you cant learn everything on You Tube lol

And Yes I ask a zillion and one questions but I think that's how we all learn things.

I'm sure there are other people following along that are learning a great deal from these posts as well.

[JayRolla]

Honestly I was wanting to do it, but I was paranoid I was going to brick the ECU. I'm not familiar at all with the "patches" that hptuners offers.

It's not too sketchy. You just apply the patch in the OS for 2bar. It's like updating the BIOS on a computer. Make sure the battery is fully charged on the laptop and car, don't power either off and flash away. I'm in IT and I'm working on a crucial server that needs a BIOS firmware patch because of a vulnerability. But to get that patch I have to go in order and its 8 years out of date. Its like 15 bios flashes and 18 idrac I have to do one at a time. If this goes down shit hits the fan and I do get a little scared each time, LOL.

[07GTS]

Honestly I was wanting to do it, but I was paranoid I was going to brick the ECU. I'm not familiar at all with the "patches" that hptuners offers.

when u apply the patch u then save the new file to then flash in this will be your new base, i think u write entire the first flash then just calibration as normal after that, check the map sensor settings and make same as yours, then u can inverse the VE table and copy over your vve to it should be close but if the shape is there and its off just move whole VE to correct it then check and adjust as per usual (change all 3 ve when u adjust it) the VE will go out to 255kpa u can keep the <100kpa close then gap the >100kp wider if u need to, also if ur using lower thermostat u can adjust fan temps lower also, maf will be there as normal may have extended range, and u will have BE it works as expected which ever is richer PE or BE it will favor