2012 GT throttle "overshoot" on tip-in phenomenon, Edelbrock supercharger

[WesDuenkel]

Attachment 105454

Try this, Your tune does need quite a bit of dialing in still. I changed your drivers demand and a lot of map settings, torque limits, map limits, and rescaled your tables to ressemble your load as well. Let me know how it acts.

Making some progress. A few things:

1) The driver demand in your tune made the car almost underivable. Way to "responsive." Reverting to the driver demand in the attached tune below is much better.
2) Still had a lot of throttle oscillation, so I reverted to the Edelbrock torque model, and it's much better.
3) I'm still seeing "overshoot" in the data, but it's less perceptible by the seat of the pants. Moderate driving I can still feel the throttle move around, though, which is irritating.

So, making some progress, but still has some work to do to "settle down" the throttle "overshooting."

Here's a log with my latest tune:

Screen Shot 2020-12-06 at 7.20.21 AM.png

Here is the log file:
Edelbrock drivability throttle overshoot 10.hpl

Here is the tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v23.hpt

[aaronson]

Yeah that was my bad I accidentally copied a 2013 gt500 driver demand table and I didn?t mean to. Sometimes the boost bypass on those are sensitive and that causes throttle oscillation as well because the torque rapidly increases. What Lund actually tells people to do is order some nitrous jets and put the jet in the vacuum line that connects to the boost bypass on the supercharger. That restricts the amount of vacuums the bypass will see and allows the transition to boost less aggressive causing throttle oscillation. The reason factory cars like roush don?t have that issue is their ecu strategy is different and the roush engineers and ford engineers specifically hard program something to deal with that issue into the computer. So unfortunately you can?t really do much about it besides minimize it. Like I said in pm. I can write you a more proper base file. The oscillation will most likely still be evident.

[aaronson]

Making some progress. A few things:



1) The driver demand in your tune made the car almost underivable. Way to "responsive." Reverting to the driver demand in the attached tune below is much better.
2) Still had a lot of throttle oscillation, so I reverted to the Edelbrock torque model, and it's much better.
3) I'm still seeing "overshoot" in the data, but it's less perceptible by the seat of the pants. Moderate driving I can still feel the throttle move around, though, which is irritating.

So, making some progress, but still has some work to do to "settle down" the throttle "overshooting."

Here's a log with my latest tune:

Screen Shot 2020-12-06 at 7.20.21 AM.png

Here is the log file:
Edelbrock drivability throttle overshoot 10.hpl

Here is the tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v23.hpt

It does look a lot better though in the log so I?m sure we can keep chugging away to get you squared up.

[murfie]

Yeah that was my bad I accidentally copied a 2013 gt500 driver demand table and I didn?t mean to. Sometimes the boost bypass on those are sensitive and that causes throttle oscillation as well because the torque rapidly increases. What Lund actually tells people to do is order some nitrous jets and put the jet in the vacuum line that connects to the boost bypass on the supercharger. That restricts the amount of vacuums the bypass will see and allows the transition to boost less aggressive causing throttle oscillation. The reason factory cars like roush don?t have that issue is their ecu strategy is different and the roush engineers and ford engineers specifically hard program something to deal with that issue into the computer. So unfortunately you can?t really do much about it besides minimize it. Like I said in pm. I can write you a more proper base file. The oscillation will most likely still be evident.

I think I mentioned pilling the bypass vacuum line back in 2018 for someone's SC surge, as its what Subaru did in their OEM boost controllers. The pill reduces the rate of change of the pressure on the diaphragm, reducing flutter rate in the wastegate. Essentially giving a larger gap between hysteresis(WG reclose) and target boost(WG open).

Appling this to a SC bypass it would be a larger difference between the low vacuum(Bypass closes) and hysteresis(higher vacuum bypass reopen). It opens the window of MAP pressures that the bypass is closed for, but the airflow is not significant enough to produce boost on the engine. Essentially giving you a low vaccum bypass, but having the benefit of remaining closed at lower airflows if the throttle try's to shut a little to reduce any increase in airflow from the bypass closing. You still may need to get your ETC vac/SD/VE lined up with BARO(stock SD and known good TB model usually work well) to stay off the "MAP delta above baro" values and make this work.

Then keep in mind there's a lot of bad, mismatched, out of spec throttle bodies and that can easily lead to blaming the calibration, and you will never fix it in the calibration.

[aaronson]

I think I mentioned pilling the bypass vacuum line back in 2018 for someone's SC surge, as its what Subaru did in their OEM boost controllers. The pill reduces the rate of change of the pressure on the diaphragm, reducing flutter rate in the wastegate. Essentially giving a larger gap between hysteresis(WG reclose) and target boost(WG open).

Appling this to a SC bypass it would be a larger difference between the low vacuum(Bypass closes) and hysteresis(higher vacuum bypass reopen). It opens the window of MAP pressures that the bypass is closed for, but the airflow is not significant enough to produce boost on the engine. Essentially giving you a low vaccum bypass, but having the benefit of remaining closed at lower airflows if the throttle try's to shut a little to reduce any increase in airflow from the bypass closing. You still may need to get your ETC vac/SD/VE lined up with BARO(stock SD and known good TB model usually work well) to stay off the "MAP delta above baro" values and make this work.

Then keep in mind there's a lot of bad, mismatched, out of spec throttle bodies and that can easily lead to blaming the calibration, and you will never fix it in the calibration.

exactly, as I mentioned to him the he does need to dial in his tune more. I corrected some of the most obvious map issues I the calibration. But I very much agree with you. With everything dialed in the oscillation will be almost non existent. And if it still is then pilling it should work.

[aaronson]

Making some progress. A few things:

1) The driver demand in your tune made the car almost underivable. Way to "responsive." Reverting to the driver demand in the attached tune below is much better.
2) Still had a lot of throttle oscillation, so I reverted to the Edelbrock torque model, and it's much better.
3) I'm still seeing "overshoot" in the data, but it's less perceptible by the seat of the pants. Moderate driving I can still feel the throttle move around, though, which is irritating.

So, making some progress, but still has some work to do to "settle down" the throttle "overshooting."

Here's a log with my latest tune:

Screen Shot 2020-12-06 at 7.20.21 AM.png

Here is the log file:
Edelbrock drivability throttle overshoot 10.hpl

Here is the tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v23.hpt

2012_EB2.3_LTH_91-93_basefile.hpt
here's a base file I got bored and built you one

[WesDuenkel]

there's a lot of bad, mismatched, out of spec throttle bodies and that can easily lead to blaming the calibration, and you will never fix it in the calibration.

The Edelbrock supercharger uses the factory GT throttle body, so I assume the throttle body ETC calibration shouldn't be a factor.

[WesDuenkel]

I think I mentioned pilling the bypass vacuum line back in 2018 for someone's SC surge,

It's worth a try as a last resort for the reasons you mentioned. However, I'm dubious if that's the ultimate source of the issue as the the throttle trace in my data logs are *exactly* what the car feels like it's doing: overshooting, reeling it back in, than undershooting on tip-out. When the throttle acts smoothly, torque delivery is smooth.

I would think if the supercharger bypass was the culprit, I'd feel things that weren't reflected in the throttle traces, which I don't. Does that make sense?

[WesDuenkel]

2012_EB2.3_LTH_91-93_basefile.hpt
here's a base file I got bored and built you one

Sorry for the delay. Finally got some time today to run some testing. A couple things regarding the tune you attached (2012_EB2.3_LTH_91-93_basefile)...

1) I assume the intake cam phasing limit table should have -65 degrees, NOT +65 degrees in there?

2) I see you left [ECM] 44351 - MAP Max Delta above BP vs. RPM zeroed out. Should this have a boost curve in it (in inches of Hg?), or is all zeros still OK for a boosted car?

3) Max Aircharge Load is 1.00. Should it be higher, like 1.90?

4) I see that you have Pressure Density Scale "disabled." Why, and what does that do? I haven't seen anyone else change that.

5) Regardless, here is a log with that tune (aside from changing #1 as I assumed it was a type-o):
2012_EB2.3_LTH_91-93_basefile_2_1.hpl


In the mean time, I did a little more tweaking using a mashup of things from the Edelbrock tune and Coyote Cookbook, etc. It runs pretty well, save for a few things

1) Here is that tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v28.hpt

2) Here is the log file:
Edelbrock v28 Drivability_1.hpl

3) I still seem to be having an overshoot on tip-in/undershoot on tip-out situation which also directly corresponds to some very large torque errors.
Screen Shot 2020-12-10 at 7.48.55 PM.pngScreen Shot 2020-12-10 at 7.49.08 PM.png

We're making progress, but the root of the problem still seems to exist.

[aaronson]

Sorry for the delay. Finally got some time today to run some testing. A couple things regarding the tune you attached (2012_EB2.3_LTH_91-93_basefile)...

1) I assume the intake cam phasing limit table should have -65 degrees, NOT +65 degrees in there?

2) I see you left [ECM] 44351 - MAP Max Delta above BP vs. RPM zeroed out. Should this have a boost curve in it (in inches of Hg?), or is all zeros still OK for a boosted car?

3) Max Aircharge Load is 1.00. Should it be higher, like 1.90?

4) I see that you have Pressure Density Scale "disabled." Why, and what does that do? I haven't seen anyone else change that.

5) Regardless, here is a log with that tune (aside from changing #1 as I assumed it was a type-o):
2012_EB2.3_LTH_91-93_basefile_2_1.hpl


In the mean time, I did a little more tweaking using a mashup of things from the Edelbrock tune and Coyote Cookbook, etc. It runs pretty well, save for a few things

1) Here is that tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v28.hpt

2) Here is the log file:
Edelbrock v28 Drivability_1.hpl

3) I still seem to be having an overshoot on tip-in/undershoot on tip-out situation which also directly corresponds to some very large torque errors.
Screen Shot 2020-12-10 at 7.48.55 PM.pngScreen Shot 2020-12-10 at 7.49.08 PM.png

We're making progress, but the root of the problem still seems to exist.

Answer to 1: the -65 values in the ECM 38167: max phasing limit RPM intake cam is actually correct. The intake values are negative and the exhaust values are positive.

Answer to 2: I left that stock because that?s something that needs to be logged and entered. Aka log your map versus rpm with the scanner if possible(definitely a question for more experienced) . It helps to know the boost curve. I personally have left it stock on the centrifugal car I tuned, but I?m not as experienced as murfie. I have looked at a super cobra jet file( one with a 2.9 whipple) and their values are all 30 inHG from 1000 rpm to 6500 rpm. stock. As well their speed density. A better practice is to dial in SD as murfie said.

Answer to 3: It?s not necessary to change this at least in my experience, I know the coyote cookbook says to but a lot of manufacturers tunes leave it at 1(probably not the best practice but works).

Answer to 4: I believe that?s a limiter and the only reason you?re turning it off is so the throttle doesn?t try to shut until you get the surge figured out then you turn it back on.

After all this I believe it?s going to be dialing in your torque tables because I noticed that edelbrock leaves them stock. So you?ll want follow how to do it in the coyote cookbook since you have it. The wording is a little tricky but it makes sense once you do it. Turn off all your mapped points and only use your OP table in the torque table. Set up a histogram in the scanner with your X and Y axis and for the values use indicated engine torque. Then use those values to input into your OP torque model table, rinse, wash repeat. It?s a tedious process but it?s probably the best you can do. You can use the same process for throttle angle error as well.

[aaronson]

Sorry for the delay. Finally got some time today to run some testing. A couple things regarding the tune you attached (2012_EB2.3_LTH_91-93_basefile)...

1) I assume the intake cam phasing limit table should have -65 degrees, NOT +65 degrees in there?

2) I see you left [ECM] 44351 - MAP Max Delta above BP vs. RPM zeroed out. Should this have a boost curve in it (in inches of Hg?), or is all zeros still OK for a boosted car?

3) Max Aircharge Load is 1.00. Should it be higher, like 1.90?

4) I see that you have Pressure Density Scale "disabled." Why, and what does that do? I haven't seen anyone else change that.

5) Regardless, here is a log with that tune (aside from changing #1 as I assumed it was a type-o):
2012_EB2.3_LTH_91-93_basefile_2_1.hpl


In the mean time, I did a little more tweaking using a mashup of things from the Edelbrock tune and Coyote Cookbook, etc. It runs pretty well, save for a few things

1) Here is that tune file:
Wes 2012 Mustang GT Edelbrock Blower Headers No Cats v28.hpt

2) Here is the log file:
Edelbrock v28 Drivability_1.hpl

3) I still seem to be having an overshoot on tip-in/undershoot on tip-out situation which also directly corresponds to some very large torque errors.
Screen Shot 2020-12-10 at 7.48.55 PM.pngScreen Shot 2020-12-10 at 7.49.08 PM.png

We're making progress, but the root of the problem still seems to exist.

Also if you could post a log file if you driving that would be the best instead of just a screen shot, I learned my lesson with that.

[WesDuenkel]

Also if you could post a log file if you driving that would be the best instead of just a screen shot, I learned my lesson with that.

Log files are attached to that post. Do they not show up?

[WesDuenkel]

Answer to 1: the -65 values in the ECM 38167: max phasing limit RPM intake cam is actually correct. The intake values are negative and the exhaust values are positive.

Noted. That's what I figured.

Answer to 2: I left that stock because that?s something that needs to be logged and entered. Aka log your map versus rpm with the scanner if possible(definitely a question for more experienced) . It helps to know the boost curve. I personally have left it stock on the centrifugal car I tuned, but I?m not as experienced as murfie. I have looked at a super cobra jet file( one with a 2.9 whipple) and their values are all 30 inHG from 1000 rpm to 6500 rpm. stock. As well their speed density. A better practice is to dial in SD as murfie said.

Noted. I have a dyno run from 3,000-7,000 RPM where we logged boost. Used that as a basis.

Answer to 3: It?s not necessary to change this at least in my experience, I know the coyote cookbook says to but a lot of manufacturers tunes leave it at 1(probably not the best practice but works).

Edelbrock changed it to 1.90

Answer to 4: I believe that?s a limiter and the only reason you?re turning it off is so the throttle doesn?t try to shut until you get the surge figured out then you turn it back on.

OK, I'll try that out.

After all this I believe it?s going to be dialing in your torque tables because I noticed that edelbrock leaves them stock. So you?ll want follow how to do it in the coyote cookbook since you have it. The wording is a little tricky but it makes sense once you do it. Turn off all your mapped points and only use your OP table in the torque table. Set up a histogram in the scanner with your X and Y axis and for the values use indicated engine torque. Then use those values to input into your OP torque model table, rinse, wash repeat. It?s a tedious process but it?s probably the best you can do. You can use the same process for throttle angle error as well.

The problem is I don't have my personal dyno. I'll see if I can figure that out.

[aaronson]

Log files are attached to that post. Do they not show up?

Yessir they did I say them right after I posted that

[aaronson]

Noted. That's what I figured.



Noted. I have a dyno run from 3,000-7,000 RPM where we logged boost. Used that as a basis.



Edelbrock changed it to 1.90



OK, I'll try that out.



The problem is I don't have my personal dyno. I'll see if I can figure that out.

You can do it on the street because the torque in your tune is crank torque, so your scanner will be very close. Even if you were to use a dyno you would have to multiple the numbers by your parasitic loss.

[murfie]

Your SD is calculating MAP too low for the airflow the MAF is reporting. Put your TB model back to stock. Put your MAF curve back to stock.

No promises this will fix it, but it could.
Copy these quad, slope and offset values in the attached spreadsheet into MP9, MP10, and MP OP. Its ok for them to all be the same. Also in there is values for IPC table for the pressure monitors ECM 44343. Torque model> monitors >IPC> pressure monitors.

QSO.xlsx

If you can remove (SAE) channels and replace them with non SAE channel option that will collect more data. Remove channels that are redundant.
Add scheduled torque and engine brake torque. If you can find it trans throttle position ADC as well. Take another log.

What injectors are these?

What the SD changes do, it makes your Load translate to a more stable MAP. Therfore a more stable ETC vacuum, and path through the TB model.
OLD vs NEW MAP.PNG

This is why I don't rely on HPT SD calculator, and recalculate my own coefficients.

This is stock MP9.

MP9 Stock.jpg

This is just raising the calc. map max.

64inHg MAP Max only.jpg

This is me recalculating the coefficients in excel.

64inHg recalculated.PNG

I think anytime the calculated MAP max is increased all the MPs need to be recalculated.

[murfie]

You can do it on the street because the torque in your tune is crank torque, so your scanner will be very close. Even if you were to use a dyno you would have to multiple the numbers by your parasitic loss.

This is the last row of torque values in a stock DD table from a manual car compared to a stock dyno graph(showing what you are saying). There's about a consistent 45ftlb difference across the RPM range. Driver demand is calculated to the wheel. The automatics operate fully on how much torque they have coming into them and how much they are out putting to meet the drivers request.

DD table to wheel torque.PNG

[aaronson]

This is the last row of torque values in a stock DD table from a manual car compared to a stock dyno graph(showing what you are saying). There's about a consistent 45ftlb difference across the RPM range. Driver demand is calculated to the wheel. The automatics operate fully on how much torque they have coming into them and how much they are out putting to meet the drivers request.

DD table to wheel torque.PNG

Is that just for the driver demand or torque tables as well? And do you think using the scanner for indicated torque then say multiplying by .15 for parasitic loss would be accurate enough? Or is a dyno the only true way to dial DD and torque model in?

[WesDuenkel]

Your SD is calculating MAP too low for the airflow the MAF is reporting. Put your TB model back to stock. Put your MAF curve back to stock.

Done. However, the Edelbrock tune only tweaked the factory MAF values down low. Throttle body model was only slightly modified.

Copy these quad, slope and offset values in the attached spreadsheet into MP9, MP10, and MP OP. Its ok for them to all be the same. Also in there is values for IPC table for the pressure monitors ECM 44343. Torque model> monitors >IPC> pressure monitors.

Done. Thanks.

If you can remove (SAE) channels and replace them with non SAE channel option that will collect more data. Remove channels that are redundant. Add scheduled torque and engine brake torque. If you can find it trans throttle position ADC as well. Take another log.

Good point regarding SAE channels. I noticed they were very "slow."

What injectors are these?

Ford M-9593-LU47. I checked the Edelbrock tune and verified the values are entered as Ford recommends.

What the SD changes do, it makes your Load translate to a more stable MAP. Therfore a more stable ETC vacuum, and path through the TB model.

Understood...mostly. This is all new to me, as this is the first car I'm learning to tune. STEEP learning curve!

This is why I don't rely on HPT SD calculator, and recalculate my own coefficients.

And this is why I GREATLY appreciate the help provided here.

I think anytime the calculated MAP max is increased all the MPs need to be recalculated.

Noted. Are you implying I should change something else in SD besides changing MP 9, 10, and OP as suggested? (Just don't want to miss something).

As a side note: changing the MAP Max parameters under SD > General resulted in a weird behavior: After a heavy load event, the throttle would "stick" closed at light throttle. But after a while (say, 10-15 seconds, or a gear change) it would "time out" and the ETC would return to normal. I have a log of it, but didn't post it as I have bigger fish to fry. I suspect it's related to the Pressure Monitor > MAP Maximum IPC.

Regardless, I'll make these changes and report back. I can't thank you all enough for your invaluable help.

[WesDuenkel]

I also have two questions regarding driver demand and throttle position: apparently pedal position is in AD counts, with a max of 1023

1) If WOT start is 501, and WOT end is 542, is it correct that WOT mode starts at 49% throttle and the driver demand table is completely ignored at > 53% throttle?

2) If that's the case, bottom row of the DD table is for 53% throttle. If the bottom row of the driver demand table reflects dyno torque at 100% throttle, isn't the DD table grossly overestimating available torque (since 542 corresponds to only 53% throttle)?