Air Flow Question

[6kipps]

I added a CPE TMIC about a year ago and have been incrementally tweaking my hybrid load tuning maps to try and take advantage of the less restrictive design. One aspect that continues to baffle me is why I cannot seem to get much additional air flow moving through the system. With the stock TMIC, I would max out at around 220 g/s and now I'm seeing a max of around 240 g/s at WOT. My understanding is that the KO4 should flow close to 400 g/s without any restrictions, so I would expect something less than that. I've looked at similar setups of other members and their logs and have seen close to 300 g/s.

I've gone back several times into the Noob tuning guide and the forum here to look for some tips. I've checked for leaks, even though the engine doesn't seem to exhibit any of the common symptoms, and haven't discovered any.


Attached is the most recent log:
2.27L datalog1.csv


Looking through the tables, I'm thinking the solution is somewhere in the boost, VVT, fueling (AFR), or WG dynamics tables.

If I've reached a limitation with my current configuration, I can accept that, but I want to make sure before I throw in the towel and shift focus to refining other areas.

Appreciate any help or feedback.

[yangliu]

your engine knock as hell in the logs, did you notice that?

[MSMS3]

Originally Posted by yangliu your engine knock as hell in the logs, did you notice that?

And wastgate is maxed out as well. Not a good tune.

[Vansquish]

To be fair, in order to hold much above 15psi near redline on the K04 with at least one stock catalyst, you do kind of need to run close to maxed out WGDC.

That said, in order to run the relatively mild boost that the OP is running on whatever tune this is, his car definitely shouldn't be knocking so consistently. Moreover, it looks like the OP has tuned around this issue, as the AFRs during the knocking portion of the pull are actually pretty good for a non-knocking pull. Clearly, this is not a well-designed tune.

[Fstrnyou]

Where in the actual f*** did you see/hear the K04 “should” flow 400 g/s? That’s comical.

In the South Carolina heat, i was running about 18-20psi on the K04. WGDC maxed out on the top end and boost was falling off slightly. I believe my g/s at the time were 260-280ish maybe. If I recall correctly the mods were 3.5” intake and 2nd cat delete.

[6kipps]

All, thanks for the feedback so far - still learning to tune and taking it slowly. A couple responses:
1) KR is out of whack. It's on my list to attack in the ignition tables. I had tried smoothing some of the values and believe the interpolation may have contributed to the problem. To date, I have not deliberately tried to tune around the KR problem. It's only been within the last two iterations that things have gotten wonky.

2) My target WG is 80%, with the WG duty error limiter set to +15/-100, which accounts for the 95%ish WG recorded in the logs. My targeted/allowable boost is 19psi and load target is 2.2 at WOT from 3000rpm to redline. If the ECU is working to meet the targeted load, it should adjust: WG (within limits) to increase airflow (boost), fuel, timing, etc to try and meet the target correct?

3) I stand corrected on the KO4 flow rate. I went back to where I thought I saw it (Noob guide pg26) and only found the 300g/s number. Happy to accept the black eye here.

Back to ATR...

[yangliu]

Originally Posted by 6kipps All, thanks for the feedback so far - still learning to tune and taking it slowly. A couple responses: 1) KR is out of whack. It's on my list to attack in the ignition tables. I had tried smoothing some of the values and believe the interpolation may have contributed to the problem. To date, I have not deliberately tried to tune around the KR problem. It's only been within the last two iterations that things have gotten wonky. 2) My target WG is 80%, with the WG duty error limiter set to +15/-100, which accounts for the 95%ish WG recorded in the logs. My targeted/allowable boost is 19psi and load target is 2.2 at WOT from 3000rpm to redline. If the ECU is working to meet the targeted load, it should adjust: WG (within limits) to increase airflow (boost), fuel, timing, etc to try and meet the target correct? 3) I stand corrected on the KO4 flow rate. I went back to where I thought I saw it (Noob guide pg26) and only found the 300g/s number. Happy to accept the black eye here. Back to ATR...

Start from cobb stage2 ots map and turn down wdgc for testing. Then fine tune your maf
Then check if you get serious kr when wot. If no major kr then you can jump to stage3 ots map with your previous tuned maf and wdgc.
Then check kr under wot again. If everything fine then tune up boost then ignition.

[Vansquish]

Originally Posted by yangliu Start from cobb stage2 ots map and turn down wdgc for testing. Then fine tune your maf Then check if you get serious kr when wot. If no major kr then you can jump to stage3 ots map with your previous tuned maf and wdgc. Then check kr under wot again. If everything fine then tune up boost then ignition.

But...why would you do that? If you've already been messing around with values for ignition, WGDC, boost, MAF etc, why in the hell would you go and duplicate that effort in a stage 3 map that puts you back in the wrong direction?

Seriously, this is one of the most questionable pieces of tuning advice I've seen in a long time. Incremental change is the name of the game. Change a parameter, test it, verify that it's working, then change the next parameter, test/verify and wash, rinse, repeat.

There is absolutely no reason to switch to different OTS maps once you've started to fuck around with the values in one of those maps because of the way your car is built and runs.

[Jeff23spl]

400g/s with a k04...if you see it, the tune and the maf is wrong lol.

Below 0f, the best i got with larger intake, catless and meth was about 280 at 19-20psi choking to 17 up top...

[BuddySpeed3]

Originally Posted by 6kipps I added a CPE TMIC about a year ago and have been incrementally tweaking my hybrid load tuning maps to try and take advantage of the less restrictive design. One aspect that continues to baffle me is why I cannot seem to get much additional air flow moving through the system. With the stock TMIC, I would max out at around 220 g/s and now I'm seeing a max of around 240 g/s at WOT. My understanding is that the KO4 should flow close to 400 g/s without any restrictions, so I would expect something less than that. I've looked at similar setups of other members and their logs and have seen close to 300 g/s.

Even with all the higher flowing bolt ons, the k04 is still going to be the bottle neck of the system. In regards to grams per second, this is highly dependent on your Open Loop MAF calibration, and doesn't necessarily indicate a true measurement of how much air is flowing through the engine. If you are targeting a leaner AFR vs a more rich AFR, the tune with the rich AFR will show a higher G/S value in the datalogs.

When it comes to Hybrid tuning, I like to keep it simple. Dial in boost and fuel first, apply load caps, then tweak timing.

[Fstrnyou]

I'm not sure I follow your g/s vs AFR train of thought.

How does a rich tune also read higher airflow?

[Jeff23spl]

Originally Posted by Fstrnyou I'm not sure I follow your g/s vs AFR train of thought. How does a rich tune also read higher airflow?

I was going to ask also...

I think he look at it backwards, not necessary about the real flow of the engine with rich or lean but about the ecm reaction with an higher maf reading for the same flow????...If your maf cal is overdone, you get rich and the opposite get leaner....
In my head, a rich engine will give less output power and probably less real air flow than a lean one closer to the knock limit....but our maf could easily be cheated

And if you cheat the maf to read 400gs for 250 real gs: (i'm not sure of my calcul but you would get something like 1.6 time more fuel for the same flow with a resulting afr below 7

For the op case, i would assume the maf cal is close to factory like many on k04 tunes...?

[yangliu]

Originally Posted by Vansquish But...why would you do that? If you've already been messing around with values for ignition, WGDC, boost, MAF etc, why in the hell would you go and duplicate that effort in a stage 3 map that puts you back in the wrong direction? Seriously, this is one of the most questionable pieces of tuning advice I've seen in a long time. Incremental change is the name of the game. Change a parameter, test it, verify that it's working, then change the next parameter, test/verify and wash, rinse, repeat. There is absolutely no reason to switch to different OTS maps once you've started to fuck around with the values in one of those maps because of the way your car is built and runs.

I mean stage2 is for dial in your maf, boost and check engine health/hpfp pressure/fuel quality with stage2 (lower) ignition timing for safety. No need to tweak the stage2 then jump to stage3 with your own maf, boost setting and start tweaking from stage3. It is not double work just for safety.

[6kipps]

All, much appreciate the lively discussion. Some more background info on how I got to the point I'm at now:
1) After purchasing my AP in 2014, I downloaded the COBB OTS map and hated how the car behaved. So, I downloaded ATR and created an initial map per the Noob tuning guide, to include MAF calibrations.
2) Since then, as I have added mods, I have progressively tweaked the maps based on the tuning guide and posts I found on the forum. After each new map, I usually took 3-4 datalogs, analyzed them to see if the car was performing as desired, and then tweaked again. I'm on overall map #44 right now (hybrid #17 ).
3) The most recent foray was intended to see what effect any changes I made in VVT and ignition tables would have and see how broad a torque and hp curve I could achieve. I noticed that I was having a bit of a challenge attaining what I believed to be reasonable peak sustained loads of 2.1 through the power curve of the motor. Hence the current discussion.
4) In general, I enjoy the way the car performs and have the driveability where I like it. I'm interested in reaching the safe/reasonable operating boundaries, particularly as the car ages and builds up the miles. I'm not really interested in joining the ZZB club.

I am concerned about the excessive KR, which has only materialized recently, so my plan is to go back to the last known good map with good datalogs, take some more logs to validate, and then start tweaking again. Is there value in recalibrating the MAF? IF so, is there a good rule of thumb for periodically revisiting the cal process? Appreciate your thoughts on my intended vector.

[Vansquish]

Originally Posted by yangliu I mean stage2 is for dial in your maf, boost and check engine health/hpfp pressure/fuel quality with stage2 (lower) ignition timing for safety. No need to tweak the stage2 then jump to stage3 with your own maf, boost setting and start tweaking from stage3. It is not double work just for safety.

Again, I can't recommend your approach.

If you take a stage 2 map and start modifying boost, ignition, MAF calibrations, and so forth, then you have already basically made a "stage 3" map. There is no reason to take the modifications you have painstakingly made in one map and transfer them to another map.

If anything, it would make a hell of a lot more sense to take parameters from the stage 3 map (e.g. VVT tables, or something) and plug them into the map you have already been modifying. There's less of a chance of transferring an error or forgetting to make a change from one map to another this way.

[yangliu]

Originally Posted by Vansquish Again, I can't recommend your approach. If you take a stage 2 map and start modifying boost, ignition, MAF calibrations, and so forth, then you have already basically made a "stage 3" map. There is no reason to take the modifications you have painstakingly made in one map and transfer them to another map. If anything, it would make a hell of a lot more sense to take parameters from the stage 3 map (e.g. VVT tables, or something) and plug them into the map you have already been modifying. There's less of a chance of transferring an error or forgetting to make a change from one map to another this way.

Can’t agree, if start from stage3, for safety reason you have to pull the timing for first couple of runs to see if you got shit fuel, false knock, etc. then raise timing a little by a little. For stage2, the timing is not aggressive and it is better for testing your car than stage3. For boost, both stage2 and stage3 you have to lower wdgc first. For others, most parameters are same between stage2 and 3, like vvt, both stage2 and stage3 are same.

[Vansquish]

Originally Posted by yangliu Can’t agree, if start from stage3, for safety reason you have to pull the timing for first couple of runs to see if you got shit fuel, false knock, etc. then raise timing a little by a little. For stage2, the timing is not aggressive and it is better for testing your car than stage3. For boost, both stage2 and stage3 you have to lower wdgc first. For others, most parameters are same between stage2 and 3, like vvt, both stage2 and stage3 are same.

You clearly didn't understand what I wrote.

If you start modifying a stage 2 map, then you should continue modifying the stage 2 map. You could even, as I suggested above, add parameters from a stage 3 map (such as VVT tables, more aggressive wgdc, etc) to the stage 2 map that had already been modified to meet your car's needs.

There is a lower chance of porting an error from one map to the next if you continually and incrementally modify a single base map rather than switching to something else mid-steam.

In point of fact, it would be safest to start with a stage 0 safe tune as the base map and modify from there.

[Fstrnyou]

I started with the stock tune. I NEVER loaded an OTS tune.

[Pu Manchu]

Originally Posted by yangliu Can’t agree, if start from stage3, for safety reason you have to pull the timing for first couple of runs to see if you got shit fuel, false knock, etc. then raise timing a little by a little. For stage2, the timing is not aggressive and it is better for testing your car than stage3. For boost, both stage2 and stage3 you have to lower wdgc first. For others, most parameters are same between stage2 and 3, like vvt, both stage2 and stage3 are same.

I think your logic contradicts itself, because your style would benefit from just starting with the stage0 since you're neutering the tune anyway.

[Pu Manchu]

I had a suspicion, so I decided to take a look at cobb's OTS maps again.

on the USDM MS6 v2.50 93 octane stage2/3 maps, all the tables in the Ignition Tables folder are the same except the stage3 will subtract less timing at high BAT/ECT.

therefore, in this example, any timing you would take out of this stage3 tune to make it safe, you would equally have to take out of a stage2 tune.

[Vansquish]

Originally Posted by Pu Manchu I had a suspicion, so I decided to take a look at cobb's OTS maps again. on the USDM MS6 v2.50 93 octane stage2/3 maps, all the tables in the Ignition Tables folder are the same except the stage3 will subtract less timing at high BAT/ECT. therefore, in this example, any timing you would take out of this stage3 tune to make it safe, you would equally have to take out of a stage2 tune.

And this is part of why I recommended tuning a single map incrementally, rather than trying to port a bunch of changes that you've made to one map into a completely different map. You might not notice that all (or most) of the values in the second map are the same as they are in the first map.

Honestly, I seriously can't buy into what @yangliu; is selling. It just doesn't make sense, and it's far easier to introduce errors into a map when you make a bunch of changes together rather than a single change at a time.

[Fstrnyou]

Starting from stock tune, I think I'm on revision 150-something. Haha. Small change, get a log, small change, get a log, small change get a log, oops...go back to last tune.

[Vansquish]

I'm on revision 144, but that's a bit misleading, as I switched from the K04 to the BNRS3 and re-started the count a few years ago. I also have a few maps from Hypnotic Tuning that Rob put together for me. Funny thing is, I like my own maps better (except for his accelerator pedal to throttle mapping).

I also tend to make two maps for each minor change (a low boost map and a high boost map), and a third for each major engine breathing-system change (Valet mode).

[BuddySpeed3]

Originally Posted by Fstrnyou I'm not sure I follow your g/s vs AFR train of thought. How does a rich tune also read higher airflow?

If tuning on the same size intake, targeting a rich AFR will read higher airflow in the logs because we are telling the ECU that there is MORE air entering the engine so that the ECU delivers MORE fuel. We don't have direct access to controlling injector pulse width's and can only modify the AFR using the MAF table's. The datalogs only display the g/s values that we input into the MAF curve.

Calculated load will also increase or decrease depending on whether a rich or lean AFR curve is targeted, since it's greatly dependent on airflow values in the MAF curve.

[Fstrnyou]

You modify AFRs in the fuel tables.
You modify airflow in the MAF tables.
Once the MAF is calibrated, you should never touch it again and you can target different AFRs using the fuel tables...which will not affect airflow readings.

[BuddySpeed3]

Originally Posted by Fstrnyou You modify AFRs in the fuel tables. You modify airflow in the MAF tables. Once the MAF is calibrated, you should never touch it again and you can target different AFRs using the fuel tables...which will not affect airflow readings.

The AFR values in the Fuel Tables are what the ECU will try and target. Just like how the ECU modulates the WGDC to meet Boost Targets, the ECU also makes corrections to fueling in Open Loop if the MAF curve on it's own doesn't achieve the targeted AFR. These are the Open Loop Fuel Trims that we cannot log. The correction percentage is higher on the Gen 2's from what I've read.

So in order to truely determine what AFR will be achieved when dialing in the MAF curve, these Open Loop Fuel Trims need to be disabled. This is done by setting the load values in the Closed Loop Load Limit Tables A, B, and C to the same values in the Closed Loop Max Load Tables. This will prevent the ECU from making fueling corrections at WOT so that an accurate MAF Curve can be dialed in. Once the MAF curve is complete, just re-enable the OL Fuel Trims by setting the Closed Loop Load Limit Table values out of reach to 5.00 load for slight corrections that may be required based on several factors

[Fstrnyou]

After posting, I began to figure that was direction you were trying to go.

When you say RICH or LEAN, you mean in respect to AFR targets...which would imply the MAF cal is wrong...which means the measured airflow is wrong.

[BuddySpeed3]

Originally Posted by Fstrnyou After posting, I began to figure that was direction you were trying to go. When you say RICH or LEAN, you mean in respect to AFR targets...which would imply the MAF cal is wrong...which means the measured airflow is wrong.

If you do a MAF cal that achieves an 11.5 AFR, and you change the AFR targets to 12.0 in the fuel tables, the ECU will still be looking up an 11.5 MAF cal. In this case the ECU is able to achieve a 12.0 AFR by trimming fuel at WOT, and as mentioned above these fuel trims need to be disabled in order to dial in a MAf cal that actually hits your desired AFR on its own. If not, the ECU will always be correcting the AFR because the MAF cal doesn't match up to the values in fuel tables. I remember reading that these Open Loop fuel trims are learnt over time, sort of like the LTFT's. So it may take several WOT pulls before the ECU can consistently hit a 12.0 AFR on a MAF curve that achieves an 11.5 AFR.

[Fstrnyou]

I do WOT MAFcals immediately after a reflash. No stored trimming.

There still seems to be a miscommunication. Once you have the MAF table calibrated, you're done. Changing the target AFR does not require changing the MAF tables to achieve the new target.
The ECU receives MAF volts and looks up the airflow in the MAF table, it also recieves an RPM signal, air temp signal, and probably a few others to calculate Load. From there, the ECU takes Load and RPM to look up the target AFR in the fueling tables and the ECU decides what the injection timing needs to be to achieve the target AFR, then applies fuel trims.
Again, the ECU decides the proper fueling to achieve the target AFR based on the inputs. If you are having to redo a MAFcal to achieve your new AFR target, then your original MAFcal wasn't correct to begin with.

[BuddySpeed3]

Originally Posted by Fstrnyou I do WOT MAFcals immediately after a reflash. No stored trimming. There still seems to be a miscommunication. Once you have the MAF table calibrated, you're done. Changing the target AFR does not require changing the MAF tables to achieve the new target. The ECU receives MAF volts and looks up the airflow in the MAF table, it also recieves an RPM signal, air temp signal, and probably a few others to calculate Load. From there, the ECU takes Load and RPM to look up the target AFR in the fueling tables and the ECU decides what the injection timing needs to be to achieve the target AFR, then applies fuel trims. Again, the ECU decides the proper fueling to achieve the target AFR based on the inputs. If you are having to redo a MAFcal to achieve your new AFR target, then your original MAFcal wasn't correct to begin with.

All good dude Here's an example of what I've experienced when tuning. If I upgrade to a larger intake but keep the original MAF cal for a smaller intake, the LTFT's will be very positive in closed loop, and the AFR will be lean in open loop. With the OL fuel trims disabled, the ECU will not add fuel to meet the AFR targets in the fuel tables. This allows me to dial in the MAF curve without intervention from the ECU. The ECU disregards the AFR targets in the fuel tables with the OL fuel trims disabled. Once the AFR curve in my logs is where I want it to be after several MAF calibrations, I re-enable the OL fuel trims, and the amount of fueling correction the ECU needs to make is minimal when it looks up the AFR targets in the fuel tables.

Here is where I read this info: Closed loop load limit

[Jeff23spl]

BuddySpeed3 your example is a bit different but interesting.

We all agree that AFR is fuel ratio against air flow ?
But i think the ECM absolutely need to use a commanded AFR to figure out the base fuel to send. How the ecm could use air flow alone ?

If you turn off the fuel trim, the injector duty must continue to change if you change the afr target without changing the maf curve....Or the table isn't working ????

If we forget about all the fine details:
120g/s with 12:1 target would call for 10g of fuel and then, fuel trim correct it until it can read 12:1 on the o2.
If you change the afr target for 10:1 with the same air flow reading: the base calcul would then output something like 12g of fuel instead
If you try to increase both your maf cal from 120g/s to 144g/s for the same volts and also changing 10:1 would theoretically send 14.4g of fuel (2 times de change) while fuel trim would need to reduce it because the o2 would be reading too rich ?

I never tested the above but it seem to be fine for me. I'm i missing something ?

[Fstrnyou]

I only do a MAFcal once. If I want to command a different AFR, I change it in the AFR tables and move on.

If I change my intake, then that's a whole other thing. And once the MAF is recalibrated, I'll never touch it again...unless I change intakes again.

[BuddySpeed3]

Originally Posted by Jeff23spl BuddySpeed3 your example is a bit different but interesting. We all agree that AFR is fuel ratio against air flow ? But i think the ECM absolutely need to use a commanded AFR to figure out the base fuel to send. How the ecm could use air flow alone ? If you turn off the fuel trim, the injector duty must continue to change if you change the afr target without changing the maf curve....Or the table isn't working ???? If we forget about all the fine details: 120g/s with 12:1 target would call for 10g of fuel and then, fuel trim correct it until it can read 12:1 on the o2. If you change the afr target for 10:1 with the same air flow reading: the base calcul would then output something like 12g of fuel instead If you try to increase both your maf cal from 120g/s to 144g/s for the same volts and also changing 10:1 would theoretically send 14.4g of fuel (2 times de change) while fuel trim would need to reduce it because the o2 would be reading too rich ? I never tested the above but it seem to be fine for me. I'm i missing something ?

Originally Posted by Fstrnyou I only do a MAFcal once. If I want to command a different AFR, I change it in the AFR tables and move on. If I change my intake, then that's a whole other thing. And once the MAF is recalibrated, I'll never touch it again...unless I change intakes again.

I see what you guys are saying and it makes complete sense

What I'm finding interesting is HOW the ECU achieves a given AFR at WOT with OL fuel trims disabled.

For example, If I lean out my entire MAF curve and disable my OL fuel trims, the engine will run lean. Without the OL fuel trims active, all the ECU has is a G/S lookup value at a given MAF voltage.

Now if we applied that same leaned out MAF curve to a smaller intake, the AFR would be more RICH.

It's quite possible that there is a base calculation that the ECU uses to determine injector pulse width based only on the G/S lookup values.

All I know is that with the OL fuel trims disabled, increasing the G/S values in my MAF curve causes the AFR to be more rich, and vise versa

[Fstrnyou]

That's what the MAFcal is all about. Getting the lookup values correct so no trimming is necessary.

[Jeff23spl]

Originally Posted by BuddySpeed3 What I'm finding interesting is HOW the ECU achieves a given AFR at WOT with OL fuel trims disabled. For example, If I lean out my entire MAF curve and disable my OL fuel trims, the engine will run lean. Without the OL fuel trims active, all the ECU has is a G/S lookup value at a given MAF voltage. Now if we applied that same leaned out MAF curve to a smaller intake, the AFR would be more RICH.

All that is normal and expected, if you don't have the closed loop o2 signal to compensate, the ECM will use the air flow picked up from the table corresponding to the maf voltage and then divided it by the target AFR to know the fuel amount to send to injectors.

reducing your intake size give more voltage (Higher air speed in the pipe) for the same real flow
So the ecm think there is more air coming in and put more fuel without the o2 feedback to correct it....

But all that doesn't mean the ecm isn't using AFR target if you disable the closed loop feedback....It just mean everything in the ecm is very sensitive to the maf cal. you make....

[BuddySpeed3]

Originally Posted by Jeff23spl All that is normal and expected, if you don't have the closed loop o2 signal to compensate, the ECM will use the air flow picked up from the table corresponding to the maf voltage and then divided it by the target AFR to know the fuel amount to send to injectors. reducing your intake size give more voltage (Higher air speed in the pipe) for the same real flow So the ecm think there is more air coming in and put more fuel without the o2 feedback to correct it.... But all that doesn't mean the ecm isn't using AFR target if you disable the closed loop feedback....It just mean everything in the ecm is very sensitive to the maf cal. you make....

I'm not sure if the ECU disregards the fuel tables entirely with the OL fuel trims disabled. But based on my own experiences, when I installed my Corksport 3.5" intake, I copied and pasted the MAF cal on their website for this intake into my MAF table's. I noticed that the LTFT's in closed loop were more negative, which was to be expected. The values in the fuel tables were set to 11.4 AFR, and I had OL fuel trims disabled.

I decided to take my first WOT log and to my surprise, I was seeing a 12.0 AFR. The ECU was not correcting at all to try and achieve the 11.4 AFR target in the fuel tables.

This is why I always dial in the OL MAF calibration with OL fuel trims disabled, and then re-enable them once my desired AFR is being achieved.