Street Tuner/Access Tuner Race Discussion Thread

[bugblatterbeast]

I'm not sure if it is boost or fuel cut. around line 130 of the second pull, there's a sudden drop in MAF flow and boost but the AFR is not comensurate with no fuel and turbo dynamics indicates that the ECU is trying to get the boost back up. Can you try decreasing the number of items logged and increasing the logging speed? maybe the BPV is leaking?

 

Ok guys need some analysis of my logs.

 

This morning it was a little colder and I experienced fuel or boost cut... I don't know. I got 1 pull in fine, but the second pull (hotter run) caused the cut. My last log was from gunning it in 2nd, then shifting into 3rd. I experienced some knock there.

 

right-click save-as

First run:

Around 4.1k - 5.2k my DA and timing drop about 2 points.

www.casopolis.com/tuning/032907_3rd_gear.csv

 

Second run:

Hit boost cut but no CEL. P0244 is programmed not to show though...

www.casopolis.com/tuning/032907_3rd_CUT.csv

 

Third 'run':

Shifting from second to third gear in this one. Knock was shown once I hit third gear....

www.casopolis.com/tuning/302907_2nd_3rd_knock.csv

[edmundu]

I'm not sure if it is boost or fuel cut. around line 130 of the second pull, there's a sudden drop in MAF flow and boost but the AFR is not comensurate with no fuel and turbo dynamics indicates that the ECU is trying to get the boost back up. Can you try decreasing the number of items logged and increasing the logging speed? maybe the BPV is leaking?

 

No it's boost/fuel cut. I know what the boost limits are, and they were exceeded for 2 lines of the log, and that is enough to trigger the cel....

 

The denser air, allowed the turbo to crank up easier, so the 2.8-3.2k rpm band needs to taper the wgdc some more. Or using a base flash, we can add more wg compensation.

[edmundu]

Thanks for chiming in Christian! Your input is much appreciated!

[Christian.]

Thanks Christian. Now I'm really confused. I think we are saying essentially the same thing but are referring to different points on the turbo. By turbine inlet pressure I was referring to the pressure before the turbo on the hot side. Based on your comment about the inlet pressure being slightly below the manifold (except at idle) I'm guessing you are talking about the cold side just before the compressor. I agree that the pressure just before the compressor will drop as flow increases and level off as one near choke flow. For the hot side, I was always under the impression that the pressure was around 2x boost at stock flow levels but possibly 2-3x boost when one abuses the turbo Are we talking about different things here?

We are on the same page, I believe that I miss-read your post. Turbine housing + turbine wheel = turbine or exhaust side, compressor housing + compressor wheel = compressor or inlet side of turbo. Taking this into account, excess exhaust gas pressure prior to turbo creates excess heat, when you see this start to get exponential when compared to manifold pressure this is a good time to start to taper boost.

medium rpms, we are making a compromise between intake manifold resonant effects and catching the exhaust scavenging pulse with the right overlap

I am not confident that Subaru has designed any significant intake resonance features into their intake manifold design. I do not see this in any of the calibrations nor in the dyno charts for the various turbo models. This is usually a feature implemented on normally aspirated vehicles. The manufacturer is doing everything it can to help those cars out. The Honda S2000 is a prime example; you can see a small hump in torque at lower RPM on a chassis dyno and the ECU is calibrated to inject significantly more fuel and run less timing around this point. The fuel curve is linear before, during, and after this point which leads you to believe the engine will make more torque here which it does.

 

Take care,

Christian.

[bugblatterbeast]

thanks Christian. It is really nice that you take the time to help us noobs out one of the reasons I have confidence in Cobb products is that you guys are very forthcoming with information and have nothing to hide.

[bugblatterbeast]

No it's boost/fuel cut. I know what the boost limits are, and they were exceeded for 2 lines of the log, and that is enough to trigger the cel....

 

The denser air, allowed the turbo to crank up easier, so the 2.8-3.2k rpm band needs to taper the wgdc some more. Or using a base flash, we can add more wg compensation.

 

I see. Knowing the boost cut value would certainly help:lol:

 

just for my own clarification, does our ECU cut fuel and cue the wastegate when the boost limit is exceeded, or just cue the wastegate. the reason I ask is I'm confused by the logs. I can understand if the wastegate was overridden to drop boost and the setpoint was not moved (hence the turbo dynamics value) but I can't make sense of the AFRs. It looked like the AFR went a little leaner because of the drop in load. I would have expected a much bigger change if the injectors were turned off briefly (or is the O2 sensor slow enough to smooth out the reading?)

[CasopoliS]

thanks Christian. It is really nice that you take the time to help us noobs out one of the reasons I have confidence in Cobb products is that you guys are very forthcoming with information and have nothing to hide.

 

wow if you are a n00b than what am I !?!?! All of this is over my head at this point!!!!

[bugblatterbeast]

wow if you are a n00b than what am I !?!?! All of this is over my head at this point!!!!

 

we are both on the learning curve;) there are many like Christian and Edmundu with far more experience... so in comparison to them we are still noobs. my background is in electronics (mostly RF) and control. the car stuff is a hobby. the funny thing is the math is the same for many different technical subjects so it is matter of learning what things are called and getting practical experience. practical being more important (but more costly to get)

[edmundu]

I see. Knowing the boost cut value would certainly help:lol:

 

just for my own clarification, does our ECU cut fuel and cue the wastegate when the boost limit is exceeded, or just cue the wastegate. the reason I ask is I'm confused by the logs. I can understand if the wastegate was overridden to drop boost and the setpoint was not moved (hence the turbo dynamics value) but I can't make sense of the AFRs. It looked like the AFR went a little leaner because of the drop in load. I would have expected a much bigger change if the injectors were turned off briefly (or is the O2 sensor slow enough to smooth out the reading?)

 

 

Oh the ECU does indeed cut fuel! If you have ever run into it, it is not subtle. It jars/bucks the car. Now, thanks to Christian, I know that the ECU doesn't spit out info to the log anywhere near as fast as it makes decisions for the engine. So many times you will not see it in the log, particularly if you have a lot of params.

 

I have never seen Tip In delta % of higher than 6-7%, yet the table does go to 31.3%, and if you don't have the right fueling adjustments, you can feel it, but not see it....

[Christian.]

you guys are very forthcoming with information and have nothing to hide.

Except for that rash that keeps coming back on my... j/k

 

No problem, we are here for you guys. I will come back to this thread if you have any more questions or concerns about the StreetTUNER software. We have another StreetTUNER thread in our forums specifically for the LGT. You are welcome to post there as well. If this thread gets too large we can start another so people do not have to read through the whole thing to get to the information that is currently being addressed.

 

Take care,

Christian.

[BlackGT]

^ I am for now. If you read over Cobbs tuning progression steps thats one of the last things.

 

Are you on Stock injectors?

 

If you are having spooling issues with a VF39, never go bigger

 

Nope, no spooling issues, I have yet to get it fired up, waiting for one more piece to get the engine back together.

 

I have 650cc injectors, and a good fuel pump. Gives me a little headroom.

[CasopoliS]

What is turbo dynamics telling me here? As you can tell, this log is not good... taking it easy on the car. I might even go back a map.

 

right-click save-as

http://www.casopolis.com/tuning/TUNER_070329171802.csv

[rc0032]

Turbo dynamics is a calculation used when tuning WGDC. It tells you how far off from your target boost you are. So if target is 16 and you are at 15 it will read a few hundred points. If target is 16 and you hit 17 it will show a few hundred negative.

 

In an ideal condition you want it to be zero (you are hitting target boost). a 100 points in dynamics could be missing boost by as little as .09lbs. Don't worry if its not zero just more work to do

 

If their a particular line you are concerned with?

[Christian.]

To be more specific, the value Turbo Dynamics on the LGT is actually a pressure Delta measurement. Turbo Dynamics is the Delta (or difference between) your Boost Targets value and the measured manifold absolute pressure (boost), as measured by the stock MAP sensor. The measurement is in millimeters of mercury (mm/Hg):

1 Bar = ~750 mm/HG

1 Bar = ~14.5 PSIa

1 PSIa = ~51.72 mm/HG

 

I will include some text from our Tuning Guide which should be helpful.

 

If your datalogged turbo dynamics value is a negative value then your ECU will remove wastegate duty cycles to hit your boost targets because the engine is over-boosting; the pressure measured at your intake manifold is higher than what is dictated in the Boost Targets table for the given RPM and TPS values. If your boost is surging up and down or then your boost control is searching because it is grossly overshooting its target. If your datalog shows a negative value for turbo dynamics then the ECU will use the additional authority in the negative portion of the Turbo Dynamics tables to lower WGDC until the target boost is achieved.

If your datalogged turbo dynamics value is positive value then your ECU will add wastegate duty cycles to hit your boost targets because the engine is under-boosting; the pressure measured at your intake manifold is lower than what is dictated in the Boost Targets table for the given RPM and TPS values. If your boost is lower than what is dictated in your Boost Targets table then you will need to increase your WGDC for the given RPM and TPS values. If your datalog shows a positive value for turbo dynamics then the ECU will use the additional authority in the positive portion of the Turbo Dynamics tables to increase WGDC until the target boosts are achieved.

If you are increasing or holding wastegate duty cycles steady and boost is dropping then you have most likely reached the threshold of the mechanical efficiency of the turbo or your exhaust gas back pressure prior to the turbo is too high and is forcing the wastegate valve to open.

If you are having a small boost spike you may need to decrease the WGDC percentage a few hundred RPM prior to the overboosting event to allow the exhaust energy to be realeased past the turbine wheel.

 

NOTE: With porting a wastegate, you are trying and make the wastegate valve function potentially work better which means that your turbo is going to lower boost super fast when the wastegate door/valve opens or not run as much boost as it was engineered to. If you make your wastegate react quicker then boost will be very difficult to stabilize and reach peak #s at an earlier RPM. If you make the wastegate flow better, then the exhaust energy your turbo needs to make and maintain boost will have less opportunity to flow across the turbine wheel. Generally speaking, air/pressure/exhaust gases will always flow along the path of least resistance. Not bashing, just trying to give you a different perspective.

I hope this helps.

Take care,

Christian.

[rc0032]

Ya what he said

turbo dynamics then the ECU will use the additional authority in the negative portion of the Turbo Dynamics tables to lower WGDC until the target boost is achieved.

I agree with you here but you also limit the amount of freedom with the WGDC table high and low (should be within 10 points of each other). If you are over boosting you can only bring WGDC down to the low value on the table. If the low value still has you at too high of a PSI there is nothing you can do to bring them down further and reduce boost. This is why you set your boost limits to be just a few points higher than your targets. For me I have the limits set 1.5lbs higher than my targets.

Same goes for high if you are not reaching boost and still at the top of the WGDC limits you cant go higher.

Also you need to take into account the outside air temperature. There are a few basemap tables (WGDC Air Temp Comp A, B, WGDC Bara. Comp A, B), that take this into account. I don’t fully understand how these work but they are a multiplier of sort that takes into account the air temperature and reduces WGDC to help prevent over boosting in the extreme cold or heat.

Christian can you explain these more? For my purposes I have just left them alone. Also thank you for repeatedly visiting this thread!!

[CasopoliS]

Does someone with ST have what they feel is a good intake calibration table for the K&N typhoon?

 

Right now 5.0v = 355 g/s for me and 4.3v = 209 g/s just to give you some points. Edmundu said I should tune my MAF so that my fuel table looks more logical. I am pretty sure my tuner was just going to tweak fuel to get a good AFR, but the MAF should really be tuned so my fuel table makes more sense.

 

Any tips on tuning MAF for a new intake? The idea is to correlate output from the sensor to flowrate as accurately as possible.... but how does one figure this out?

 

I am starting to learn a lot here. This is fun. My next move is a WB. Any suggestions on a WB for ST (I don't need a gauge). *search n00b*

[rc0032]

I like the LM1 WB Cobb has a .dll for it, its $190 shipped w/o a gauge. rao makes fun of it because it comes with a reset button

 

As for the Intake, sorry no table, but its not that hard to do (even easier on a dyno!!)

 

But here is how to do it. If you make or find a good table let me know. There is a local OH guy looking for one. If you don't, we will probably make him one next week sometime and can send it to you.

 

How to do it:

 

2nd – Fine tune your Intake Calibration table. This table is used to tell your ECU the mass of air that is entering your engine so that you can properly calculate the mass of the fuel it needs to inject into the motor to get the air/fuel value dictated in the Primary Fuel table or by the closed loop control, 1 Lambda. Under closed loop conditions the ECU is always going to try and hit 1 Lambda or 14.7:1 A/F, which is an air mass of 14.7 to every 1 fuel mass.

 

Start the vehicle, let it idle, and come to temperature...it may not perfectly idle, but just deal with it until it comes to temperature, 180-190 F. Use the dashboard to pull up your A/F Trim Immed., A/F Trim Learned, MAF Voltage, and Coolant Temp. After the vehicle has come to temperature, re-set the ECU (you will be prompted to turn the vehicle off then back on). Start the motor again, and then watch your MAF voltage and A/F trims. You want the combination of your A/F trims to be as close to 0 as possible. EX = If your A/F Trim Immed. is +5% and A/F Trim Learned is 0, then simply look up the MAF Voltage, which should be close to 1.2-1.28 volts at idle, on the Intake Calibration table and adjust the grams/sec value for that voltage up (+) until your combined fuel trims are 0 or close to zero. These adjustments can be made very easily by looking at the combined % correction of the A/F Trim Immed. & A/F Trim Learned. If that total is +6% then you can highlight the Intake Calibration cell for that particular MAF voltage and hit the “M” key, you will then be prompted to enter a floating point value. The correct value for this particular situation would be 1.06; this adjustment will now tell your ECU for that particular MAF voltage you now have a 6% greater MASS of air entering the motor so 6% more mass of fuel should be injected. After this adjustment is made you’re A/F Trims should be close to zero. (If that total is -6% then you can highlight the Intake Calibration cell for that particular MAF voltage and hit the “M” key, you will then be prompted to enter a floating point value. The correct value for this particular situation would be 0.94; this adjustment will now tell your ECU for that particular MAF voltage you now have 6% less MASS of air entering the motor so 6% less mass of fuel should be injected, bringing your fuel trims close to zero.) I would shoot for a A/F Trim Learned value of +/- 5% max. You may have to re-set your ECU throughout this process to remove any learned trims. To re-set your ECU while live tuning, close down any tracing or dashboard, then you can go to the “ECU” drop down menu and select the Reset ECU option. You will be prompted to turn your vehicle fully of and back on again. When you do

this, you should notice that your DAM (Dynamic Advance Multiplier) will be set back to the default value. Make sense?

 

Do this along the Intake Calibration table up to 2.6 volts or so ON A LOAD-BASED CHASSIS DYNO at

part-throttle. Be sure to run the vehicle with the A/C on as well to make sure your calibrations are consistent. If you have a properly designed intake system the Intake Calibrations should look very similar to your stock Intake Calibration graph under the table data. Be sure to keep your throttle movement as steady as possible during this process. Rapid movements of the throttle will employ adjustments from the Tip-in Enrichment table and may skew your fuel trims.

 

Your trim values will always adjust back and forth (+/-); let them, that is what they are supposed to do. Do not beat yourself up trying to get them at exactly 0...it is impossible (temperature, weather, gasoline, etc. changes will not keep anything constant while you are tuning).

 

If you are seeing plateaus, spikes, dips, or flat spots in the graph for the Intake Calibration table then you

know something is wrong...replace the intake system with a properly designed one.

 

NOTE: Changing the Intake Calibration table will change your calculated load output. If all other variables remain constant, the less airflow you calibrate in the ECU for a given MAF voltage; the less engine load will be calculated.

[Christian.]

Any tips on tuning MAF for a new intake?

Funny you ask...our AccessTUNER Calibration & Tuning Guide for Subarus has recently been updated to v1.08 and it now includes more graphics, updated information on fuel injector table settings, and more tuning tips for DBW applications. This tuning guide goes over specific steps for tuning your Intake Calibration table. Please read through this document and let me know what you think.

 

rclark0032 was super fast on this one...thanks.

 

Take care,

Christian.

[edmundu]

Funny you ask...our AccessTUNER Calibration & Tuning Guide for Subarus has recently been updated to v1.08 and it now includes more graphics, updated information on fuel injector table settings, and more tuning tips for DBW applications. This tuning guide goes over specific steps for tuning your Intake Calibration table. Please read through this document and let me know what you think.

 

rclark0032 was super fast on this one...thanks.

 

Take care,

Christian.

 

 

So when is Cobb going to update the ST software to allow us to adjust the tables needed for a full injector tune like FIBET, and Coolant Temp compensation/Cold Start? It is mentioned in the guide, but we cannot get to it. Asking a Protuner to do so, when we have no affiliation with one won't work, unless we pay them, which we shouldn't have to...

[rc0032]

^ Not sure what tables it will have but... http://www.cobbforums.com/forums/showpost.php?p=448723&postcount=80

[CasopoliS]

by 'combined they = 0' do they mean:

learned = 3% then immed = -3% ?? or do they mean both values should be the same?

[rc0032]

The sum of the values should be zero.

[CasopoliS]

The sum of the values should be zero.

 

ok got it. I assume on the dyno you just hold the throttle at 1 spot the best you can and use live tracing to see what value its using. Then adjust that value until you get the desired result (values summing to zero).

[rc0032]

After doing the initial tune parked. Since I did mine on the street im not sure about a dyno but that’s what I would assume. So I would log then try to drive around slow street holding it as consistent as possible then look at the logs and sort by the MAF value. The MAF values you are looking at are partial throttle and you don’t need a lot of speed.

I did this a few times and the logs were all over the place so I got it close and said F it. I figure I can go back and fine tune it later

[Christian.]

Yes, I have the luxury of a chassis dyno. Although, I usually tune the Intake Calibration in the highest gear, 5th in your case. We have the ability to do this in a safe environment and we highly suggest you perform the intake calibration tuning on a load-based chassis dyno. If you tune the intake calibration table in lower gears you will see more variance in your fuel trims and this can be frustrating. I suggest you provide as stable of an environment for tuning this table...which I have found to be the tallest gear.

 

Take care,

Christian.