Drag/Acceleration Mods to improve ¼ mile times and unofficial track thread

[Tonkabob]

Isn't it bad to change maps back and forth?
The ECU needs time to readapt.

Its not really a map change just a little boost. Everything else is the same.

 

[Terry@BMS]

View attachment 30566
I have an excel version but can't upload that but here is the csv. Run 7 was the +3 with timing pull.
Also seems the jb4 only does whole boost numbers. Aka 2.5 is 2.
This track has a hill and a turn so runs about .15 slow.

I can only open the original CSV file anyway. On boost you can set tenth of a psi resolution and appears you have.

The timing drops around timestamp 1070 appear to be a torque limiter of some sort. Does it do that consistently when doing runs at say +3psi? I'm not sure what the mechanism would be to trigger it. The higher the boost setting on the JB4 side the less likely hitting a torque limiter should be.

On the launch this is a standard "launch mode"? Do you have a similar log using the burnout switch? Make sure you load the windows JB4 software to view logs on the computer at home as the app while useful on the road makes it harder to spot trends in.

 

[xot1]

I can only open the original CSV file anyway. On boost you can set tenth of a psi resolution and appears you have.

The timing drops around timestamp 1070 appear to be a torque limiter of some sort. Does it do that consistently when doing runs at say +3psi? I'm not sure what the mechanism would be to trigger it. The higher the boost setting on the JB4 side the less likely hitting a torque limiter should be.

On the launch this is a standard "launch mode"? Do you have a similar log using the burnout switch? Make sure you load the windows JB4 software to view logs on the computer at home as the app while useful on the road makes it harder to spot trends in.

View attachment 30567

Terry,
How come his boost doesnt drop around shifts?
Its almost a flat line.

 

[Tonkabob]

Terry,
How come his boost doesnt drop around shifts?
Its almost a flat line.

Ecu tune with a little extra jb4 boost.

 

[Terry@BMS]

Terry,
How come his boost doesnt drop around shifts?
Its almost a flat line.

The level of boost taper is largely set by the flash target and WGDC tables.

 

[Tonkabob]

I can only open the original CSV file anyway. On boost you can set tenth of a psi resolution and appears you have.

The timing drops around timestamp 1070 appear to be a torque limiter of some sort. Does it do that consistently when doing runs at say +3psi? I'm not sure what the mechanism would be to trigger it. The higher the boost setting on the JB4 side the less likely hitting a torque limiter should be.

On the launch this is a standard "launch mode"? Do you have a similar log using the burnout switch? Make sure you load the windows JB4 software to view logs on the computer at home as the app while useful on the road makes it harder to spot trends in.

View attachment 30567

I only did one run at +3. John has been fighting with this limit at 21-22 psi, but at least we know it isn't a boost limit now.
All launches were normal LC asits more consistent to compare the tunes. With LC i get full throttle at 12 mph and limp snip i dont get full throttle until 20 mph. I'll get you a limp snip, beast mode -5, and maybe a regular beast mode launch log.

To run jb4 software on windows do i need an android emulator? Wasn't sure if that was old but couldnt find the Windows software.

 

[Terry@BMS]

Windows software is posted here: N54Tech.com - International Turbo Racing Discussion - View Single Post - JB4 laptop connection directions

Just email yourself logs and open it in the software for more advanced analysis later. Software is designed to be really quick and easy for analysis.

If trap speed isn't improving much as you slightly increase boost, then your experience is similar to mine. Power peaks out around 18psi and while you can push boost up to 22psi (I have on the dyno) you won't make that much additional power.

I think the two keys for you will be getting full brake boost launching to work and then using the IAT function to keep timing up on warmer days at the track.

 

[Tonkabob]

Windows software is posted here: N54Tech.com - International Turbo Racing Discussion - View Single Post - JB4 laptop connection directions

Just email yourself logs and open it in the software for more advanced analysis later. Software is designed to be really quick and easy for analysis.

If trap speed isn't improving much as you slightly increase boost, then your experience is similar to mine. Power peaks out around 18psi and while you can push boost up to 22psi (I have on the dyno) you won't make that much additional power.

I think the two keys for you will be getting full brake boost launching to work and then using the IAT function to keep timing up on warmer days at the track.

I got some trap and et gain going from 18 to 20 psi. (.06-.07 and about .2 or .3 mph)
I've never seen timing drop even at 145 iat so more looking to keep boost up when iats drop below 100. Might see this at the track in October if it doesn't rain out.

 

[Kato_the_kia_stinger]

I'm just curious how @Kato_the_kia_stinger put down his numbers. 11.599 @ 118.77, 7.464 @93.86, 1.614
Was this just a lucky run where everything hooked up, or does he (or anyone else) have a repeatable, reliable method? I'll have to try @Tonkabob method and see how it goes. crazy numbers here:

Drag/Acceleration - The Official 1/4 mile track thread.​

I’ve gotten similar results over several runs on different days. Two different tracks.

 

[Tonkabob]

@Terry@BMS I tried the beast mode -5 launch but doesn't look like the boost by gear worked. I was on map 6 with no other boost changes and the log shows target = 0. Looks like boost by gear wont fire if map 6 is empty?
First run in the log was map 0 limp snip 3.99 0-60, 1.89 60 foot, 7.77 1/8th at 92.84.
Second run was beast mode and shit just blew up fast. Attempted half pedal to 2800 then let go and floor it. Got a little spin but almost immediately timing cut, throttle cut and blow off all with in 1 second. ECU PSI hit 25.5 and jb4 says boost was 23.5. That was worse than usual getting the trifecta of boost limiting methods, but I suspect the throttle cut I get on other attempts could be overboost. Need to look at some old logs.

Limp snip - map 0


Beast mode map 6 - explosion of badness:


I needed to start logging manually since I was not doing a full throttle launch but did not. So the log starts at 12 MPH during the explosion.

 

[Terry@BMS]

ECU_PSI is the boost sent back to the DME. I can see it's higher than actual but may need to tweak it a bit. Next set 1st gear to 8psi, start the logging manually, and grab another log.

 

[Tonkabob]

ECU_PSI is the boost sent back to the DME. I can see it's higher than actual but may need to tweak it a bit. Next set 1st gear to 8psi, start the logging manually, and grab another log.

Do I need some non 0 values in Map 6? I added no boost in map 6 and it didn't pick up my -5 in 1st gear so suspect it will not pick up the -8 either.

 

[Terry@BMS]

Do I need some non 0 values in Map 6? I added no boost in map 6 and it didn't pick up my -5 in 1st gear so suspect it will not pick up the -8 either.

Target doesn't display negative values but it picked up the -5psi.. It's easily viewable in log looking at ECU_PSI vs. actual.

 

[Tonkabob]

Target doesn't display negative values but it picked up the -5psi.. It's easily viewable in log looking at ECU_PSI vs. actual.

Yes I see that. This ECU is odd, there must be another boost signal to the ECU. In the -5 PSI case the ECU saw fake 21 PSI, 14 actual PSI and cuts timing.
When we hide boost (+3 PSI) the ECU sees fake 17 PSI, 20.3 actual and still cuts timing.

 

[Terry@BMS]

Around 115 the ECU saw 25psi+ (we cap the reading in the log on that signal at 25.5psi so presumable more), with 23psi actual boost. It might be that if we let ECU_PSI get too high it triggers a cut out or fault.

Probably the basic problem we're dealing with here is the set point on your flash at the launch is around 20psi vs. around 14psi for factory flash cars, blowing off the tires, and we need to find a way do dynamically reduce that target just in that situation to allow it to launch cleanly. To do that we need to better understand what effect some of these signal changes have on your car. We can see on your map0 launch mode run boost gets up to 21psi off the line on its own so there is extra WGDC stuffed in there to hit that. In a perfect world we'd have EWG control setup and just dynamically lower wastegate dutycycle but we don't have that set on the Stinger JB4 end.

Need more data though so do as requested in the last post.

 

[Tonkabob]

Around 115 the ECU saw 25psi+ (we cap the reading in the log on that signal at 25.5psi so presumable more), with 23psi actual boost. It might be that if we let ECU_PSI get too high it triggers a cut out or fault.

Probably the basic problem we're dealing with here is the set point on your flash at the launch is around 20psi vs. around 14psi for factory flash cars, blowing off the tires, and we need to find a way do dynamically reduce that target just in that situation to allow it to launch cleanly. To do that we need to better understand what effect some of these signal changes have on your car. We can see on your map0 launch mode run boost gets up to 21psi off the line on its own so there is extra WGDC stuffed in there to hit that. In a perfect world we'd have EWG control setup and just dynamically lower wastegate dutycycle but we don't have that set on the Stinger JB4 end.

Need more data though so do as requested in the last post.

In logs from 9-1 (+3 PSI run #7) I had the timing pull at 17 ECU PSI, 20.3 actual. The car deals with high boost by first a #1 a big timing drop across all cylinders, #2 Throttle Cut, #3 Blow off. If the boost ramps slow you may only see #1 but the if it happens fast or you keep pushing it (timming drop is not a great boost reducer) you get #2 which is super effective so you rarely see #3 unless it happens fast or the throttle cuts are too short. low octane can also cut throttle but first goes rich, then cuts timing and then cuts throttle.

We'll see about more beast mode snip testing. I've been trying to lay off the snip. Seems super hard on the car and even shifting back into park gives a large bang reminding me the car is confused and not happy about being snipped. (You also can't unsnip with out restarting which also puts the car in park with a bang).

 

[Terry@BMS]

The car deals with high boost by first a #1 a big timing drop across all cylinders, #2 Throttle Cut, #3 Blow off.

I can see why you might think that but it's not exactly correct.

Timing is indexed on load (boost). The higher the boost the lower timing is mapped and timing will go down as boost goes up based on it's indexed mapping. Boost is governed primarily by a PID WGDC system with throttle integrated as a backstop. When boost goes over target PID aside the other response is proportional throttle closure. If you get enough throttle closure the difference between TMAP boost (psi in JB4 log) and manifold boost (psi2 in JB4 log) will be greater than the pressure holding the diverters closed and they will blow open. The diverter vacuum line also runs through a solenoid (unless you bypass it) allowing the ECU the option to open it more quickly when letting off the gas at higher RPM to better limit surging and the blow off noise.

Timing is generally reduced to limit toque not boost, for example when you're shifting timing is reduced momentarily and trans line pressure momentarily increased. That is the same behavior you're feeling now in park with the brake wire cut. The car would normally not increase line pressure when shifting in to drive at a stop to avoid that thud but with the cut it doesn't know your foot is on the brake.

On your timing drop as I said I think that is a torque limiter in the flash that needs to be raised. You'll need to do more runs like that to see if it's a trend or an outlier. Torque limiter interactions are normally really aggressive as we see in your log. In a perfect world we'd have boost set point and torque set point in the Stinger JB4 logs like we do on other models. I just haven't found a logging source for those yet to figure out how to log them.

You can see the basic operation in place in your other launch log. The launch boost target normally is around 0psi. Since throttle boost is is greater than 0psi the throttle closes proportionally so that manifold boost maintains the 0psi target. You'll note there is no timing reduction during this despite boost being so far over target throttle is closed to 40%. Timing is right where you'd expect it to be mapped for ~0psi.

 

[Thorne]

I agree, As the adult in the room who uses both products and tunes, I've already shared the TQ limit stuff with John, One thing we notice is RWD guys don't bang off the TQ limiter they blow there tires off. As I shared on FB the current value my car sees for example is 1000nm, Were going to up that some and back off the power ramping some to ftry and find a safe sweet spot... I am not keen on blowing up the diff..

One thing I am planning to test once I have time is using boost by gear to pull out say 10psi and see if I can log a good launch with it not exceed 1000nm.


If anyone lives in the bay and owns a airstrip or large piece of land and wnats to let me test 60's and 0-60s I'll pay ..

 

[Thorne]

My question is Terry, Do you know of any case of someone using more then 22psi? I don't care if its meth cpi what ever. Were all fighting the same limiter, and we know for a fact i can't be a direct boost value because my car only see 16psi in its basemap and even with racegas and octane booster my car was un happy around 21psi.

So in a effort to make us all faster I'm willing to share knowledge, and if you have Wishes for more chagnes to make a awesome back end flash let me know. We all want whats best for the community and right now and for the forseable future the best setup

Tork Tune (17 base / Peak timing for more) 5 degrees tiiming on shift
JB4 running map6
Intake of your choice
Muffler delete
METH

But as far as I'm aware were all stuck at 22psi

 

[Tonkabob]

I can see why you might think that but it's not exactly correct.

Timing is indexed on load (boost). The higher the boost the lower timing is mapped and timing will go down as boost goes up based on it's indexed mapping. Boost is governed primarily by a PID WGDC system with throttle integrated as a backstop. When boost goes over target PID aside the other response is proportional throttle closure. If you get enough throttle closure the difference between TMAP boost (psi in JB4 log) and manifold boost (psi2 in JB4 log) will be greater than the pressure holding the diverters closed and they will blow open. The diverter vacuum line also runs through a solenoid (unless you bypass it) allowing the ECU the option to open it more quickly when letting off the gas at higher RPM to better limit surging and the blow off noise.

Timing is generally reduced to limit toque not boost, for example when you're shifting timing is reduced momentarily and trans line pressure momentarily increased. That is the same behavior you're feeling now in park with the brake wire cut. The car would normally not increase line pressure when shifting in to drive at a stop to avoid that thud but with the cut it doesn't know your foot is on the brake.

On your timing drop as I said I think that is a torque limiter in the flash that needs to be raised. You'll need to do more runs like that to see if it's a trend or an outlier. Torque limiter interactions are normally really aggressive as we see in your log. In a perfect world we'd have boost set point and torque set point in the Stinger JB4 logs like we do on other models. I just haven't found a logging source for those yet to figure out how to log them.

You can see the basic operation in place in your other launch log. The launch boost target normally is around 0psi. Since throttle boost is is greater than 0psi the throttle closes proportionally so that manifold boost maintains the 0psi target. You'll note there is no timing reduction during this despite boost being so far over target throttle is closed to 40%. Timing is right where you'd expect it to be mapped for ~0psi.

View attachment 30626

Good explanation. I can see the more extreme throttle closure causes the blow off.
I'll grab a -9 psi log to see if there is a chance. Its called beast mode for a reason, i don't think it can be tamed with this tune.