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I have a new short block in the car. The tune is coming along really well. As part of that I’ve been modifying AE, basically taking fuel out. The pedal feels crisper and more responsive, But curious to know what others do to determine that AE is correct,
i get no bog, and as I decreased pumpshot, the car SOTP accelerated stronger etc. But what tells u that its ON?
The first thing is to ensure your ramp-in on your fuel table is sufficient - IE the low MAP, low RPM areas that the ECU will sweep through with you mash on the throttle.
AE is to "fix" lean out that can't be accommodated in the beginning of that area in the fuel table without compromising cruise mixtures.
Once you are sure you have the fuel table where you want it, you add or subtract AE till you get rid of any bog on tip-in. You can data-log with a wideband, or tune it on the dyno..... it's not an exact science. It's like tuning a carb. Back it off till it stumbles, then turn it up till it goes away and then give it an extra quarter turn of enrichment.
On the dyno I want to see the fuel mixture dive right down to my target ratio at WOT and stick there - flat-lined out to redline.
GD
Last edited by GeneralDisorder; Mar 6, 2020 at 06:23 PM.
I know your engine is different, but my only reference point is my Miniram...
My experience is that it seems to like a very quick shot of significant AE at tip in, and then taper off pretty quickly. I'm actually not surprised you're finding that taking out some AE helps.
While the Miniram definitely liked the $DA3 LT1 AE settings as a baseline starting point over the 8D ANHT settings, the LT1 settings are a little on the rich side it seems. Since leaning it out a little resulted in improved tip in and acceleration. When it comes to AE, more is definitely not always better.
I've also found that the quality of the AE tip in seems to "set the tone" for how the engine follows through on further acceleration. When the AE is right, the engine seems to keep accelerating stronger. If its not right, it feels like the engine lags and never quite recovers.
But like GD said, keep going leaner until you feel it start to lose power or bog, and then richen it back up. The old addage applies... give the engine what it wants.
So true ULTIM8Z. Of course the best way to do this is on a dyno. Have done this before and u r correct that the right amount of AE leads the AFR to the level requested when the PE table takes over for the commanded AFR. Haven’t gotten there yet, so I wanted to share my SOTP observations w others to see if I was headed on the right track.
As an update, I am now revisiting my tune which came from when I was having issue w the old bloc re: knock etc
Aside from changes to the VE which is pretty close at this point, I’m having a look at some other parameters that I had massaged in order to make the previous motor behave. So I’m finding things to change or change back to what would be more stock settings than previous, ie reducing AE pumpshot etc.
More news on my AE front... not sure if it'll help you...
Did a deep dive through Tunerpro on AE and found a few parameters (which don't exist in Tunercat) that actually made my throttle noticeably more crisp... and that's saying something because anyone who would have driven the car before would have said it was already perfect.
AE MAP, RPM lag filter coefficient (Used to Lag Filter RPM/12.5 before using it for AE-MAP calculations. saved to 0x013D for later use. Factory Default = 0.039) => I zeroed this out.
AE TPS, Min 12.5ms TPS change threshold (The minimum 12.5ms change in TPS to enable or continue AE-TPS Factory Default = 3.13% TPS) => I set this to 0.4%.
AE TPS, Min 6.25ms TPS change to Invoke if NOT in AE-TPS (The amount of 6.25ms TPS% change needed to INVOKE AE-TPS if not currently in AE-TPS. Decrease this value to invoke AE-TPS sooner on throttle tip-in. Factory Default = 1.17% TPS). => I also set this to 0.4%.
The changes as you can see are minimal... 1.17% to 0.4% 3.13% to 0.4%... You'd think that such little throttle movement wouldn't amount to much...
And I'm not sure if I'm interpreting TP's explanations properly, but seat of the pants feel is telling me that the AE is now coming as soon as I even breathe on the throttle. Where this is helping is on the very-light throttle take off, where before I would notice just the infinitessimally small hesitation (enough to bother someone **** about it like me).
Again, the Miniram (from my experience) seems to like a lot of initial AE very quickly to overcome that tip-in, but as soon as you're past that point, the AE can drop off pretty substantially (relative to GM's factory calibration) and pick up some additional performance.
Again, I know you have a different engine and I'm not sure what AE parameters you have to play with, but maybe this might spur some thought.
I’m going to give these a try. Altho the LT-5 of course is different than a MiniRam SBC, it is an SD motor. I have found that my time tuning my old Xfire is directly relatable to the LT5. On my most recent cal, I again backed off on the AE settings I had w the previous motor. There’s no bog and no hesitation at all. In fact, its too easy to spin the michelin PSS 345x19s in back. It seems as if the motor reacts to the slightest movement of the accelerator. And that acceleration rate increases in direct relation to how deep u go into the pedal.
AE TPS, Min 12.5ms TPS change threshold (The minimum 12.5ms change in TPS to enable or continue AE-TPS Factory Default = 3.13% TPS) => I set this to 0.4%
This one could give you issues with a big cam IIRC.
From my experience, the MAP AE is also enabled from this setting. With my somewhat lumpy idle I was seeing AE with each pulse of the engine.
While it ran ok like this, It was fogging my fueling of the tables because of the extra fuel.
I'm researching my tip in lean spot right now to remove some initial knock retard that occurs as I stomp on the throttle.
Can you provide the actual address of those items you commented on?
There is a difference in terminology from TunerCat to TP definitions and I want to be sure what the actual item is.
I'm looking for strictly TPS increase in AE as my MAP increase seems to be doing the job properly except for the "stomp" response.
TIA,
Jp
Ps, to be clear, I'm questioning if this parameter is actually a differential TPS% or a straight TPS% value.
I'm thinking it is NOT a differential but the minimum level indicating you are using the go pedal.
I know Tunercat (as well as TP) has the table for delta-MAP enable threshold vs TPS (with different settable thresholds for various TPS% ranges). If this parameter affects delta-MAP, would that compete with this other table?
To answer your question about address, as near as I can tell (given I'm a hex ignoramous) it seems like TP is saying the address is 0x538?
0x538 is the correct one you referenced.
That is the minimum "Change" threshold to enable or continue AE. (Not the off-idle enable I was thinking of)
I run an HSR which also needs a healthy shot (unless you were referring to Dom's LT-5) Hopefully this is helping you as well.
For AE-TPS i was looking at table 0x543-553 " named "6.25ms TPS change factor (for pump shot)"
It appears to be backwards as the values in my table get smaller with larger TPS difference. Seems like there should be more pump shot if a bigger TPS% differential (Wondering if the Table X axis inverted?)
This is investigation for now, Governor just put us on lockdown so won't be out beating on it as much.
Jp
I think that table is counterintuitive, but it is correct.
TP says " Increasing the values in this Table will result in an increase in AE-TPS PW."
Yet, counter intuitively, the larger delta-TPS changes have smaller AE values. I have played around with that table and with my WB, it seems like it's true, that smaller values will produce smaller AE shots of fuel.
If you're having a tip-in issue, maybe try reducing the value in this table...
AE TPS, Min 6.25ms TPS change to Invoke if NOT in AE-TPS (The amount of 6.25ms TPS% change needed to INVOKE AE-TPS if not currently in AE-TPS. Decrease this value to invoke AE-TPS sooner on throttle tip-in. Factory Default = 1.17% TPS).
Here's the values I am using now. if you will note the LT-5 cal does not use AE-TPS adjustments except to address MAP changes, just AE-MAP. Nothing discreet based on TPS movement.
These are current value and the compare bin provides the stock values.
As some here know, I've spent a lot of time looking at the $8d AE code and have posted several related blurbs. Based on that, this thread causes me to dump some things that may be helpful (or maybe not). Most of the discussion seems to center around AE-TPS with one comment about AE-MAP. Accordingly, will primarily deal with AE-TPS. It is the asynchronous (only as required) PW. AE-MAP PW is more complicated than AE-TPS PW (if that can be possible), so will leave that for another time unless there is a desire to address it.
Before addressing AE-TPS, let's address viewing Calibration items in TCat or TPro. Regardless of which program is being used, the available Calibration information is solely based upon the XDF being used. If the XDF doesn't include a given Calibration item, you won't see it. To my knowledge, the TPro-compatible S_AUJP v6 XDF is the most complete available. It includes and describes almost every $8d Calibration item. Many thanks to JP86SS for the initial work!
All comments below are related to $8d in S_AUJP v6, but other OBDI masks are likely similar.
The rules for AE-TPS are:
To put the DRPs above in perspective, at 2400 RPM there will be 1 DRP every 6.25ms (160 DRPs per second), 2 DRPs every 6.25ms at 4800 (320 DRPs per second), etc. So things happen very quickly and AE-TPS will not remain active for very long. It's really like a carbureted engine pump shot of fuel with pedal depression. It's instantaneous and then disappears.
Regarding Calibration items mentioned in the above posts:
0x57D-AE MAP, RPM lag filter coefficient (Used to Lag Filter RPM/12.5 before using it for AE-MAP calculations. saved to 0x013D for later use. Factory Default = 0.039) => I zeroed this out.
Zeroing this will have little if any effect on AE-MAP PW because the factor is so small. In lag filtering, the smaller the factor the closer the filtered value is to the old value (here RPM).
0x52E-AE TPS, Min 6.25ms TPS change to Invoke if NOT in AE-TPS (The amount of 6.25ms TPS% change needed to INVOKE AE-TPS if not currently in AE-TPS. Decrease this value to invoke AE-TPS sooner on throttle tip-in. Factory Default = 1.17% TPS). => I also set this to 0.4%.
Looking at the rules above, lowering this from 3.13% TPS to 0.4% TPS is a HUGE percentage decrease. It means that AE-TPS will be invoked with barely any change in TPS%. This applies whether idling and accelerating or moving and accelerating, so it's not surprising an immediate impact is noticed.
0x538-AE TPS, Min 12.5ms TPS change threshold (The minimum 12.5ms change in TPS to enable or continue AE-TPS Factory Default = 3.13% TPS) => I set this to 0.4%.
Again looking at the rules above, this change has a potentially adverse effect. A TPS% change > 0.4% causes the index into the the 0x53B Table to be set = 3, bypassing possible use of the largest value in the Table's element #1.
The following addresses additional details of AE-TPS:
AE-TPS PW is a function of the calculated BPW required to run the engine and the 6.25ms TPS% change. The following are used to factor the BPW and TPS% change to arrive at AE-TPS PW:
0x534 - AE-TPS, Base Pulse Width Multiplier (0.125). Results in 1/8 of the calculated BPW.
0x535 - AE-TPS, 6.25ms TPS Change Multiplier Factor (0.125). Results in 1/8 of the 6.25ms TPS change (A 6.25ms TPS% change >50% does not further increase AE-TPS PW).
0x543-553 Table - AE-TPS, 6.25ms TPS Change Factor (for Pump Shot). Used to factor twice the above 0x535-factored 6.25ms TPS change.
JP - This should explain what you noticed. The table is not accessed with a true TPS difference, but with a significantly smaller factored value based on 0x535.
.After several more calculations using the above factored BPW and TPS% change values, a preliminary AE-TPS PW is determined.
One has to be on another planet to come up with these bizarre calculations!
But that's not all. After the above calculations, the resulting AE-TPS PW is next factored based on coolant temperature. The lower the temperature, the greater the resulting AE-TPS PW.
After the above, the 0x53B=AE-TPS, Factor for Pulse Width Calculation (Pump Shot) Table is used. It's this value along with the 6.25ms TPS% change that determines the magnitude of AE-TPS PW. Beginning with the largest value of this 8 level table (element #1), each element is successively accessed every 6.25ms. After 8 accesses (50ms), the 8th element continues to be used until AE-TPS is deactivated. The first element is the maximum available value and provides the largest possible AE-TPS PW. The remaining 7 values are significantly less resulting in a very small AE-TPS PW which may not be used if < 0.854ms (0x3EF). Also, AE-TPS PW cannot exceed 5.5ms (0x532).
Simulating the AE-TPS code provided the following results:
Either this helps to explain things, your head hurts, or both.
Elky
Last edited by 84Elky; Mar 25, 2020 at 02:06 PM.
Reason: Change in red text and new AE-TPS PW Table
Thx 84Elky, this is turning into a great discussion on AE, which wasn’t my original intent but most welcome and appreciated.
84Elky, your comment here was of interest
”Looking at the rules above, lowering this from 3.13% TPS to 0.4% TPS is a HUGE percentage decrease. It means that AE-TPS will be invoked with barely any change in TPS%. This applies whether idling and accelerating or moving and accelerating, so it's not surprising an immediate impact is noticed.”.
With the LT-5, MAP is the primary way of regulating the amount of AE, altho TPS is used as a modifier for MAP. With my Xfire using EBL, IIRC, I had tables for both TPS Delta and MAP Delta. Its not clear to me why no TPSDelta is used for the LT-5. Perhaps due to 4V DOHC breathing?
But in any case, even very small changes in MAP invoke AE including 0. And so w lumpier cams, MAP can vary +-2kPa or more. I can only surmise that AE is constantly invoked even at a steady idle.
Thoughts?
So given that AE is a function of VE, what AE should u start to tune with? And then once u have honed in on an accurate VE table, do changes to the AE begin to affect VE which then leads to changes in the VE? So is this a continual feedback loop?
IIRC RBob once told me quite a while back that AE can also be incorporated into the VE table. I’m fuzzy on this and could be completely wrong.
On the $8D code, there's a flag you can un-set, which decouples AE from the INT/BLM. "Reset INT when AE active". It's set from the factory, and my guess is it's for emissions.
Yes, with that function active, it did it in fact end up in a feedback loop that I struggled with for a few years before I stumbled across that flag. It was a game changer once I unchecked that box. The TPI's may be ok with it, but with an extremely-AE-sensitive manifold like the Miniram, it can drive you bonkers trying to get the AE where you need it while the ECM essentially keeps fighting against you.
Not sure if the LT5 code has something similar. But if so, I would definitely recommend unchecking that box.
On the $8D code, there's a flag you can un-set, which decouples AE from the INT/BLM. "Reset INT when AE active". It's set from the factory, and my guess is it's for emissions.
Yes, with that function active, it did it in fact end up in a feedback loop that I struggled with for a few years before I stumbled across that flag. It was a game changer once I unchecked that box. The TPI's may be ok with it, but with an extremely-AE-sensitive manifold like the Miniram, it can drive you bonkers trying to get the AE where you need it while the ECM essentially keeps fighting against you.
Not sure if the LT5 code has something similar. But if so, I would definitely recommend unchecking that box.
ULTM8Z-Not meaning to quibble here, but in the factory AUJP bin, the referenced bit default is "NOT set" (0x018 b1=0). It is also not set in S_AUJP. The reasoning appears to be to not affect the INT and BLM if in CL so they report the effect of the additional AE fuel. It would be in this NOT set condition that the ECM IS "fighting against you" so to speak if in CL because fuel is being adjusted based on INT and BLM changes.
When the bit is set, INT is forced to =128, which means the BLM does not change, so no effect on fueling other than the AE. In OL, setting of the bit is a "don't care" because it is only checked if in CL.
Is it possible you meant to say you have the bit SET?
ULTM8Z-Not meaning to quibble here, but in the factory AUJP bin, the referenced bit default is "NOT set" (0x018 b1=0). It is also not set in S_AUJP. The reasoning appears to be to not affect the INT and BLM if in CL so they report the effect of the additional AE fuel. It would be in this NOT set condition that the ECM IS "fighting against you" so to speak if in CL because fuel is being adjusted based on INT and BLM changes.
When the bit is set, INT is forced to =128, which means the BLM does not change, so no effect on fueling other than the AE. In OL, setting of the bit is a "don't care" because it is only checked if in CL.
Is it possible you meant to say you have the bit SET?
Nope, you're quibble is valid! I did have it backward... lol
So given that AE is a function of VE, what AE should u start to tune with? And then once u have honed in on an accurate VE table, do changes to the AE begin to affect VE which then leads to changes in the VE? So is this a continual feedback loop?
IIRC RBob once told me quite a while back that AE can also be incorporated into the VE table. I’m fuzzy on this and could be completely wrong.
A few thoughts:
Perhaps RBob could respond to why $D0 does not have AE-TPS and only AE-MAP. I'd like to know.
Where AE-TPS is used, it's asynchronous (only as needed). Has nothing to do with the synchronous fuel calculated to run the engine. AE-MAP on the other hand is added to the synchronous fuel requirement. Both accomplish the same thing but based on different inputs--they provide fuel in addition to the base requirement to run the engine. AE-TPS is generally large instantaneously and immediately disappears. AE-MAP once added, is decayed out at a calculated rate over time.
Not sure how AE-MAP could be incorporated into VE. Seems AE-MAP PW would only be added if a recent change in MAP kPa exceeded a threshold. If in the VE table, it would be there all the time.
Nope, you're quibble is valid! I did have it backward... lol
Good catch.
In fact, IIRC it was RBob that suggested setting that bit in the $D0 code for just the reason 84 Elky has described. So I have been doing my tuning with that bit set, and right now the tune is pretty darn close. My biggest issue is warm restart with motor shutting down once I am assuming the crank fuel has dissipated. So I need to bump Start Up fueling or increase the time before motor goes closed loop at warm temps.
In fact, IIRC it was RBob that suggested setting that bit in the $D0 code for just the reason 84 Elky has described. So I have been doing my tuning with that bit set, and right now the tune is pretty darn close. My biggest issue is warm restart with motor shutting down once I am assuming the crank fuel has dissipated. So I need to bump Start Up fueling or increase the time before motor goes closed loop at warm temps.
Dominic: What xdf are you using? Was it provided with the EBL? I can find none publically available for correction: $D0 that have that bit or any of the items you've posted. Would really like to peer into $0d unless the xdf is proprietary.
Last edited by 84Elky; Mar 27, 2020 at 03:52 PM.
Reason: mask correction
I thought perhaps u may have gotten my response to your message. Not using EBL for the LT-5. Its stock ECM W $D0A Mask which could be found, I think, on TPro.net or GMECM. RBob is also familiar w it.
I do have a more fully documented .xdf than is available on the web.
The C/L Reset is Option Word 3 Bit 1 at 0x 1A for the $D0A mask, same addy for $D0
Last edited by Dominic Sorresso; Mar 27, 2020 at 04:20 PM.
I thought perhaps u may have gotten my response to your message. Not using EBL for the LT-5. Its stock ECM W $D0A Mask which could be found, I think, on TPro.net or GMECM. RBob is also familiar w it.
I do have a more fully documented .xdf than is available on the web.
The C/L Reset is Option Word 3 Bit 1 at 0x 1A for the $D0A mask, same addy for $D0
Apologies. Misread the PM.
But color me stupid. I've googled and searched the net for 2+ hours now (among ZR1Specialists, LS1Tech, ZR1net, CorvetteForum, TunerPro, gearhead-efi). I see your footprints on several. I have found all manner of $D0 BINs. Not a problem. But a $D0/$D0A XDF specifically for the '92 LT5 with the degree of detail you are seeing I cannot find. In fact, there is all manner of web discussion about just that issue. So, if you or anyone has a link to such a file, I sure would appreciate it. Otherwise, I remain in the dark.
If u indicate the parameters ur looking for, I can send u an .xdf w those outlined. The $D0A is probably the one u want. The “A” versions for each MY are the ones most prevalent and there is little difference between the early and latter versions of each .xdf.
Well just to revive this thread. I have been chasing knock these last several months which reared its ugly head. Turned out to be a combination of issues necessitating the need for new coil packs, a couple of replaced injectors, and installation of new plugs w a .035” gap rather than a .045”.
The coil packs were MSD 8224s w 13 years on them. The casings were cracked on 3 of the 4 coil packs and the carbon tracking was obvious on one of them. I checked resistance on injectors and found that I had 2 secondaries that were basically not firing or firing improperly. Finally, I was using NGK BKR6E-11 w a .045” gap. I was experiencing knock even after having replaced the injectors and coil packs. Finally decided to go back to BKR6Es using a .035” gap, and voila knock is gone and I’m now tuning to see where I can advance the timing where I was retarding it earlier.
So now I’m left w getting the BLMs in line and fine tuning the AE. The one issue I am having w AE is w small MAP changes or where MAP is not changing hardly at all but I am holding rpms at about 3000 for a bit. After a few seconds of that, I’ll get a miss. If I begin depressing the accelerator a bit further it will cease and continue accelerating. Rereading some of the discussions on AE, I am wondering if it as much a matter of the DURATION for AE as it it is the AMOUNT of AE. So I’ve been looking at the lag filters.
I always thought AE duration was in the few-millisecond range... in which case it would have ended long before you got up to that RPM.
Also, (at least in 8D) the AE delta MAP requires a certain delta-MAP threshold to be crossed before delta-MAP AE activates. So if your light-throttle RPM increase doesn't generate a sufficient delta-MAP event, AE won't have a reason to re-activate after the initial tip in on the throttle.
Maybe it's just a normal operating fuel issue? Do you have a WB O2? If so, what's the reported AFR when the missing occurs?
I don't have a chance to look at my WB gauge and haven't datalogged it yet. Waiting to get to dyno for that. Here's most of the factors in the $D0A Mask re: AE The values are compared to stock.
Not sure I fully understand all of the $D0A AE parameters (my frame of reference is only $8D). So I'm probably not being that much help here... lol..
But your delta-MAP requirement to trigger AE is <1kPa. That's pretty sensitive. You may be getting some delta-MAP AE in there just by virtue of minor MAP changes despite steady throttle.
Is all of your AE triggered solely off of delta-MAP? No delta-TPS AE parameters? On $8D, some of it is triggered by delta-TPS w/o any regard to MAP or delta-MAP.
Looks like on yours, TPS only comes into play to trigger the delta-MAP AE.
Any rate, if you're holding the throttle perfectly steady on the way up to higher RPM, then unless you're MAP is varying by >.94 kPa, you shouldn't be getting any further AE then when you did the initial throttle tip in. That said, on $8D, there's a table on how quickly the delta-MAP AE decays (it's a function of time, but I think it's plotted against injector reference pulses or something?). Anything table like that in $D0A? I'm not sure what your decay factor is that you're showing there or how it works.
Without WB or datalogging data, it's hard to know what's going on. My gut says it's not an AE though from what you're describing.
Pretty much the AE on an LT-5 is MAP controlled. Not much that TPS is involved with. You can hold accelerator steady and still get AE on the basis of slight MAP variations. DOHC sucks in a LOT of air. Then add to that a motor that has plenum and heads ported w some more aggressive cams and headers, motor pretty much operates with high airflow. The stock values for the calibration don’t really deal w that very well. Some items need to react more quickly, like AE, while others like Prop Gain and IAC need to be reduced.
Just the slightest additional pressure on accelerator elicits a change. There’s no bog or seeming “dead spot” before it gathers itself up and goes. It just does.
Going to try just a smidge more AE in the 0-5kPa delta area see if that does it.
Update: I like the way the AE is working. Motor feels very responsive. Like u have a rod connecting the accelerator to the throttle.
After looking at latest datalog, I believe my issue is w PE not AE. But motor feels really strong.
As I posted above, I believe my issue may be w PE at a pretty specific RPM. There is a table in the LT-5 definitions for commanding AFR when in PE. Reviewing the logs, I’m in PE, according to the TPS%, when I experience this momentary “miss”. My suspicion is that when in already in PE mode and giving the accelerator a small nudge, I may be loading up the motor, which clears itself out quickly but produces a slight “miss” like a puff puff. The logs show no knock during that event. That’s one indication to me that its not running lean at that point. Plus, it appears that this type of “miss” is reduced or eliminated when I reduce the AE, particularly at the small increments of MAP delta. Once past that point, it pulls like a freight train.
The LT-5 calibrations, regardless of year, has 2 PE tables. One adds fuel based on CTS, the other based on RPM once in PE. When it enters PE is based on TPS%. In the stock calibrations, the PE v RPM is zeroed out. Only the CTS table has a value of -18.25% for the range of CTS C*. My tables have values for both, so I suspect I may be getting BOTH barrels of PE when I enter it right at around 3k rpm.
Going to try zeroing the RPM table as is stock and see what happens.
One thing I noticed on my tuning is that AE delta MAP is very easily over done. I dragged over all of the LT1 DA3 tables given the similiarty between the LT1 manifold and the Miniram. And it worked "well". But I found that leaning out the tables AE delta-MAP (mainly for higher delta-MAPs) as well as the AE delta-MAP vs coolant actually produced crisper throttle response... particularly as you say when you're already into the throttle a little.
There is an $8D also a table for delta-MAP AE multiplier vs TPS%. Basically it's divided up into (IIRC) 5 TPS% ranges. It has nothing to do with delta-TPS. Rather for a given TPS% of where you're at on the throttle at any given moment (say within 0-12% TPS, or 13% to 25%, etc), you can increase or decrease the final delta-MAP AE delivered.
Looking at it another way, for the same delta-MAP value (say a delta-MAP event of 40kPa), the engine may like more fuel during an off idle tip-in with 40kPa delta-MAP as opposed to say if you're starting at 60% throttle and going wide open from there producing that same 40kPa delta-MAP event. So that table allows you to fine tune that aspect. Not sure if your LT5 code has anything like that.
The LT-5 cal has the same table and no AE table for TPS%. I have adjusted it however based on my review of the logs, I can see I am in PE mode when my “hiccup” happens right at around 3krpm. And the hiccup doesn’t produce any knock which is one reason I believe its too much fuel rather than not enough.
Last edited by Dominic Sorresso; Jul 15, 2020 at 11:55 AM.
Follow on w AE. For the most part, tuning on this LT-5 is very close (famous last words right?!). I have one nit to deal with. While driving to Michigan over the Labor Day holiday, I had cruise control set. At one point I wanted to increase speed and used the Resume button to try bumping up mph. When I did that I noticed a stumbling And slight bucking until motor got somewhat beyond 2200rpm. I’ve repeated this during subsequent logging sessions and noticed my WB gauge showing 10:1 AFR at throttle tip in. It increased over time but still remained a bit on the rich side. So I am trying to accelerate from 75-83 mph in 6th gear from about 1700 to 1900+ rpm. I’ve tried adjusting the AE MAP table but w a small improvement. May need to adjust lag filters and duration.
Follow on w AE. For the most part, tuning on this LT-5 is very close (famous last words right?!). I have one nit to deal with. While driving to Michigan over the Labor Day holiday, I had cruise control set. At one point I wanted to increase speed and used the Resume button to try bumping up mph. When I did that I noticed a stumbling And slight bucking until motor got somewhat beyond 2200rpm. I’ve repeated this during subsequent logging sessions and noticed my WB gauge showing 10:1 AFR at throttle tip in. It increased over time but still remained a bit on the rich side. So I am trying to accelerate from 75-83 mph in 6th gear from about 1700 to 1900+ rpm. I’ve tried adjusting the AE MAP table but w a small improvement. May need to adjust lag filters and duration.
Changing a lag filter coefficient (the only way filtering can be affected) is generally not the way to go because the filtered value could be used for other decisions, which would affect something else. For example, a changed coefficient might fix AE but the new filtered MAP value is now being used for table lookups or comparisons to other variables, possibly unrelated to AE.
Changing a lag filter coefficient (the only way filtering can be affected) is generally not the way to go because the filtered value could be used for other decisions, which would affect something else. For example, a changed coefficient might fix AE but the new filtered MAP value is now being used for table lookups or comparisons to other variables, possibly unrelated to AE.
Elky,
I have read several of ur excellent posts both recent and several years back. I’m aware of your thoughts. How would u affect duration? Is it just the PW? I did raise the lag filter on my last drive, albeit just 2 ticks from 10.55% stock to 11.33%. Found I liked and could sense the difference in pedal response and crispness. It leaned out WOT AFR a bit but not enough.
Last edited by Dominic Sorresso; Sep 25, 2020 at 12:02 PM.
currently also working on AE tuning in a SBC with HSR intake but with a EBL, a bit trickier b/c there isnt many post/threads to give a good starting point much like ultm8z did yrs ago with his hybrid lt1 parameters for mid to short runner guys
What I found when starting with the LT1 AE tables...
The Miniram likes a large quick shot of AE as soon as the throttle is even breathed on. While the AE delta MAP is actually less important and can be reduced.
I changed the threshold to invoke TPS AE to 0.39% (in Tunerpro) which is the minimum value allowable. All of the rest of AE delta TPS tables are factory LT1.
However, on the delta-MAP AE side, I actually reduced the coolant factor by 17%.
What I think was happening was the larger and more prompt AE TPS pump shot provided an improvement in initial tip in feel (the first few milliseconds), but once the AE delta-MAP fueling kicked in and combined with the delta-TPS, it was too rich and you could feel a laggy response until the AE delta-MAP decayed out. Mind you, this observation occurs within about a second, but it's noticeable via seat of the pants and the WB O2.
Reducing the AE delta-MAP pump shot still provides the razor sharp initial feel on tip-in, but with a lesser delta-MAP AE fueling, the follow through by the engine transitioning from AE fueling to normal fueling is much more crisp and linear.
My experience w the LT5 would be very much in agreement w that. The factory tables are on the rich side for obvious reasons. Right now, my initial pumpshot gets me to 11:1 when I’d really like to be somewhere ~ 12.8-13. I also need to trim the O/L v kPa fueling for the longer term WOT AFR.
Last edited by Dominic Sorresso; Oct 1, 2020 at 10:53 AM.
My experience w the LT5 would be very much in agreement w that. The factory tables are on the rich side for obvious reasons. Right now, my initial pumpshot gets me to 11:1 when I’d really like to be somewhere ~ 12.8-13. I also need to trim the O/L v kPa fueling for the longer term WOT AFR.
If it's anything like mine, attack the delta-MAP to lean that out. Even with the much richer $DA3 LT1 AE TPS tables (richer than $8D AUJP that is) I'm right at that 13:1 AFR during the AE event and it is spot on in terms of feel.
After having done the Accel module and coil upgrade, I've been re-tuning the AE ever so slightly.
Not sure if this is a function of that upgrade, but along the lines of the Miniram liking less AE delta-MAP than the factory $DA3 LT1/LT4...
What I'm finding is that the farther into the throttle I am when the delta-MAP event occurs, it likes even less delta-MAP AE. That is, for a given throttle position, it likes less delta-MAP AE when starting at higher throttle positions. One thing I love about the $8D is how fine-tuneable the AE is...
So I've been messing with the AE delta-MAP Factor Multiplier vs TPS table.... At 37.5%, I've leaned out by about 5%. At 50% and up, I've leaned out by about 7%. It's certainly a crisper feel to the pedal. Very interesting...
After having done the Accel module and coil upgrade, I've been re-tuning the AE ever so slightly.
Not sure if this is a function of that upgrade, but along the lines of the Miniram liking less AE delta-MAP than the factory $DA3 LT1/LT4...
What I'm finding is that the farther into the throttle I am when the delta-MAP event occurs, it likes even less delta-MAP AE. That is, for a given throttle position, it likes less delta-MAP AE when starting at higher throttle positions. One thing I love about the $8D is how fine-tuneable the AE is...
So I've been messing with the AE delta-MAP Factor Multiplier vs TPS table.... At 37.5%, I've leaned out by about 5%. At 50% and up, I've leaned out by about 7%. It's certainly a crisper feel to the pedal. Very interesting...
Yep, same result here. The initial pedal movement requires a bit more pump shot than is needed to support accelerator as it progresses towards WOT. In the case of the LT-5, the 5-10% Delta MAP changes seems critical.
