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Old 06-26-2017, 01:13 AM   #876
yamahaSHO
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Normal and insignificant, especially in fuel trims.
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Old 08-18-2017, 02:26 PM   #877
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just made a new MBC that accepts 1/4" tubing. Not sure if i'll use it but at least ill have it on the shelf in case i want to test. Current set up is working ok but i get a little wave i cant seem to tune out. My car naturally wants to spike hard as soon as it full spools if anything is inline between the compressor and the ewg. Only thing working so far is to tee the lower port bleed style and pressurize the top port to build boost

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Old 11-27-2017, 02:05 AM   #878
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Guys - I've been reading this thread as time allows. I am currently on pg. 35.

Tonight I went ahead and hooked up my Grimmspeed MBC in parallel with my GS EBCS.

Throughout this post I see debate on whether or not to hook up the intake port of the EBCS to the intake tube OR cap them both.

The theory behind capping the intake ports (one on the EBCS and one on the intake) made perfect sense to me. It still does, but in my case it didn't work best.

I am tuned by a 'protuner' so maps are locked. I am sure I can get adjustments made to the tune because my tuner is well, awesome. However the entire point of getting the MBC in the first place was to limit overboosting in colder weather without touching anything else in the map. Ok - so maybe I am bit of a control freak too.

Here's the data- it doesn't lie. Back to back runs. Same time, same road, etc etc....

Based on this data is there any reason to make the WOT WGDC adjustments?Will it spool faster? '

One last thing - without the intake line hooked up I simply hit my target boost no matter how tight I set the MBC. However, look at how long it took to make the target! FWIW my target is 24.5 however I think my tuner built in the extra 2 psi of boost as we road tuned after the dyno and I've been at 26.5 since dyno day.




Thanks to Ride500 and the others who have contributed data throughout this thread. It was a huge help in not only accomplishing my goal, but also in understanding how the entire boost control system works.
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Old 03-20-2018, 01:09 PM   #879
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Based on my install (GS EBCS and Hallman Pro RX MBC & GS EWG )

Port 1 on the GS EBCS must be capped to achieve the desired result (MBC to cap max). If you don't cap port 1 then boost pressure will bleed to the inlet port and not make it to the wastegate. Note: Must cap inlet as well !!!

Additionally you must adjust WGDC to 100% in the areas you want max boost to be controlled by the MBC.

With this set up, I have eliminated the EWG pulsing sound during spool and at max boost areas and achieve rock solid boost that never exceeds my target and I have the safety provided by the EBCS & ECU control




Quote:
Originally Posted by PDXREALTOR View Post
Guys - I've been reading this thread as time allows. I am currently on pg. 35.

Tonight I went ahead and hooked up my Grimmspeed MBC in parallel with my GS EBCS.

Throughout this post I see debate on whether or not to hook up the intake port of the EBCS to the intake tube OR cap them both.

The theory behind capping the intake ports (one on the EBCS and one on the intake) made perfect sense to me. It still does, but in my case it didn't work best.

I am tuned by a 'protuner' so maps are locked. I am sure I can get adjustments made to the tune because my tuner is well, awesome. However the entire point of getting the MBC in the first place was to limit overboosting in colder weather without touching anything else in the map. Ok - so maybe I am bit of a control freak too.

Here's the data- it doesn't lie. Back to back runs. Same time, same road, etc etc....

Based on this data is there any reason to make the WOT WGDC adjustments?Will it spool faster? '

One last thing - without the intake line hooked up I simply hit my target boost no matter how tight I set the MBC. However, look at how long it took to make the target! FWIW my target is 24.5 however I think my tuner built in the extra 2 psi of boost as we road tuned after the dyno and I've been at 26.5 since dyno day.




Thanks to Ride500 and the others who have contributed data throughout this thread. It was a huge help in not only accomplishing my goal, but also in understanding how the entire boost control system works.

Last edited by TurboQueef; 03-20-2018 at 07:16 PM. Reason: Clairification
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Old 03-21-2018, 02:21 PM   #880
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Quote:
Originally Posted by TurboQueef View Post
Based on my install (GS EBCS and Hallman Pro RX MBC & GS EWG )

Port 1 on the GS EBCS must be capped to achieve the desired result (MBC to cap max). If you don't cap port 1 then boost pressure will bleed to the inlet port and not make it to the wastegate. Note: Must cap inlet as well !!!

Additionally you must adjust WGDC to 100% in the areas you want max boost to be controlled by the MBC.

With this set up, I have eliminated the EWG pulsing sound during spool and at max boost areas and achieve rock solid boost that never exceeds my target and I have the safety provided by the EBCS & ECU control
I came to the same conclusion, and am setup the same way.

I also set max boost in the last two requested torque columns to higher than mbc target.

I do have .0.5 psi more boost in 4th and 5th than I do in 3rd. But, that aside, ya..... Rock solid.

I am having some limiting on spool up on third gear pulls, 2500 rpm start Wot, that shows up in the boost and torque curves on road dyno.

This appeared after going full 3" intake from filter to turbo, which gave me 1/2 lb more boost on spool up.

Is it possible the third (back from Wot) requested torque column, 20psi, is somehow getting in the way?
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Old 03-21-2018, 08:32 PM   #881
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What tuning software are you using? I am using Cobb and have used RomRaider/ECU Flash. In he software I use, boost control is managed through wastegate duty cycles, boost targets/limits and turbo dynamic tables. Requested torque in my software is expressed in N-m at a specific RPM by accelerator position.

I am running a modified VF39 turbo so I don't hold max boost (22psi) past 5200 RPM... I let it droop to 16psi by redline.





Quote:
Originally Posted by PDXREALTOR View Post
I came to the same conclusion, and am setup the same way.

I also set max boost in the last two requested torque columns to higher than mbc target.

I do have .0.5 psi more boost in 4th and 5th than I do in 3rd. But, that aside, ya..... Rock solid.

I am having some limiting on spool up on third gear pulls, 2500 rpm start Wot, that shows up in the boost and torque curves on road dyno.

This appeared after going full 3" intake from filter to turbo, which gave me 1/2 lb more boost on spool up.

Is it possible the third (back from Wot) requested torque column, 20psi, is somehow getting in the way?
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Old 07-04-2018, 01:41 PM   #882
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Has anyone tried running a hybrid setup with the AEM tru boost gauge/controller? It's a 3 Port Mac valve but controlled by the gauge itself instead of the ecu.
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Old 07-04-2018, 08:12 PM   #883
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I have not, but I just got the innovate psb-1. It has boost and afr cut, and velvet mode (spring pressure) but no no other boost control.
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Old 07-06-2018, 12:36 AM   #884
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So after doing more research, it appears that since the only way to set target boost with the tru boost controller is via spring pressure and duty cycle, with one setting each across the board, that I canNOT use this in a hybrid setup.

To do so I would need to be able to set wgdc to 100% with full or close to full throtttle. Is this correct? Is there any other way to configure it I'm not seeing?

What if you set the EBC to a target boost slightly under your true target to keep ptfb in check and the manual boost controller to your WOT boost target?

Or could you set the ebc above target boost with spring pressure and duty cycles you know would be too high and let the manual bc cap it, pretty much like you do anyways? My concern with that would be the negative affects of too high a duty cycle in the lower revs/throttle positions assuming there are negatives?

This is on an 02' bugeye wrx and stock or slightly (like 1 or 2 psi) higher boost to avoid ptfb and to hold boost to redline a little better.
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Old 07-09-2018, 03:08 AM   #885
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I don't see why it wouldn't work. You'll have two boost controllers working in parallel. Actual boost is determined by whichever one commands the least boost. Same as with those of us that are using MBCs with the ECU.

But what are you trying to achieve? What's the role of the Tru Boost in your setup?

With the stock ECU, I think of it as an MBC without the PTFB stuff, because the ECU tells the EBCS to reduce boost at part throttle. So the MBC determines my boost at WOT, and the ECU takes over at part throttle.

Does the Tru Boost reduce WGDC when at part throttle? If not, I'd scrap it and use the ECU.

Quote:
Or could you set the ebc above target boost with spring pressure and duty cycles you know would be too high and let the manual bc cap it, pretty much like you do anyways? My concern with that would be the negative affects of too high a duty cycle in the lower revs/throttle positions assuming there are negatives?
My ECU is targeting higher boost than the MBC will allow, so that part is the same. But with the ECU, WGDC ramps down to zero at part throttle and low RPM.

I doubt there are negatives to having high WGDC at low RPM/throttle - the BCS might get warm because it will be constantly powered, but probably not hot enough to matter. But I wouldn't know for sure, because I've never tried it.

ECU+MBC works well enough that I wouldn't bother adding anything else unless I had a clear goal in mind that isn't possible with the ECU+MBC. Is there something that you want from the Tru Boost that isn't possible with the ECU?
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Old 07-09-2018, 04:35 AM   #886
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My goals are what i mentioned at the end of my last post though not very clearly so i will edit that here....

This is on an 02' bugeye wrx and I WANT TO RUN slightly (like 1 or 2 psi) higher boost AND avoid ptfb, WHILE HOLDING boost to redline a little better.[/quote]

As well as because I'm a cheap bastard and thought since I already have a mbc and an ebcs that came with the tru boost, that I could "tune" in a little more boost until I can get a tactrix and a real tune.

Basically my way of getting an ebcs working on my car, to lessen ptfb, and the mbc, to cap max boost, without having to adjust the ecu, since right now I have no way to do so and shouldn't yet if truth be known (have more to learn and still on stock catted up and downpipes for another week or 2)


I plan on getting an etune or using an open source tune like testes1010's soon just as a good base to start with and adjusting slightly from there as I'm far from ready for doing it all myself.

I was under the impression that the 02' ecu's are fairly safe for something like this as long as I don't go crazy with it? eg: fueling will compensate enough for the small increase in max boost and higher up in the revs boost.

I mainly bought the tru boost for the gauge and ebcs that comes with it and because I got a good deal on it, then after reading more about the hybrid setups, thought it might work.

What is too much boost for closed loop/stoichiometric fueling and is that the only problem with ptfb?

Sorry if I'm a little all over the place with my thoughts as they don't sound as smart after writing it out...derp
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Old 07-10-2018, 02:00 AM   #887
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You seem to be mixing up a few concepts that are really best considered independently...

On Subarus, PTFB doesn't cause AFR issues at all. Fueling is based on the MAF sensor, so the ECU is capable of adding the right amount of fuel for whatever airflow there is. PTFB will not cause your car to run lean.

I'm not sure about the 16-bit cars but with 32-bit you can tune them to switch from closed-loop to open-loop at whatever AFR you want. My car is set up to switch to open loop as soon as the target AFR drops below 14.65. That keeps my data logs simple. It might cost a little bit of fuel economy, but if I'm driving for fuel economy I'm not leaving the 14.70 region of the fuel table anyhow.

And if you're in boost, you're way outside of the closed-loop areas of the fuel table.

I don't know how common this is, but with my MBC setup, I still get some boost taper at high RPM. Like 22 peak to 20 at redline or something like that. I could get less taper with ECU+BCS only, by ramping up WGDC at higher RPM, but that's near the bottom of my to-do list.
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Old 07-10-2018, 02:06 AM   #888
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I get boost taper with my hybrid setup as well. I peak at 28 and hold for 1k rpms, drop to ~ 25 @ 7k.

From what I've read PTFB is hard on the turbo and, some find it just plain annoying to drive. Others seem to get used to it and not mind it.

The larger the turbo the less of a problem PTFB is, from what I've read.
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Old 07-10-2018, 01:15 PM   #889
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I always thought that was the problem with PTFB, lean condition because still in closed loop at partial throttle.

What's the big deal then, just the surge of power??? Please I don't want that lol.

The taper I'm talking about from the stock solenoid is going from 14 psi peak to like 8 at redline. With the mbc I have now it peaks the same and holds closer to high 12's which I'm happy with.

So, let me see if I'm understanding this.

Since the stock, unmodified ecu in my car, (02 wrx with 16-bit ecu) controls fueling by the MAF sensor, then at a certain m/g's sec the ecu says no more 14.7:1 now target 11.1:1 or whatever and then it changes to open loop and a richer a/f?

If so then when does it start not adding enough fuel?

As soon as I have a little more boost then stock and therefore no fuel tables for that high of MAF reading

OR

Does fueling just learn until idc's are 100 or more %, until it eventually hits fuel cut or leans out from lack of being able to supply fuel?

And if that's right wouldn't the stock 02 sensor be fairly accurate or at least accurate enough to determine when you start getting toward the lean side?

Also, if that is correct does anyone know the target a/f during open loop on the stock A4SGA00C ROM? I always hear the sensor doesn't read below 11.1:1 but is it safe to assume that is Rich enough, if that's where it's at?

I haven't been able to find a copy of the stock ROM and can't get mine read with my vagcom cable so until I get a tactrix I really don't know what it even looks like.

If someone could email me a copy of a stock 16-bit ROM just so I can look and learn it would be greatly appreciated. [email protected]

I'm sorry if this is too far off topic or I'm asking too many dumb questions. Hopefully this will help someone considering the hybrid setup to understand what or how they are affecting fueling with a hybrid or manual boost control setup on a stock ecu and/or the places to make the fueling changes if they're writing their own.

I know I appreciate you two taking your time to help and everyone else that's contributed to this thread as well! Thank you!
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Old 07-10-2018, 02:23 PM   #890
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Quote:
Originally Posted by Crispy 1 View Post
Quote:
I always thought that was the problem with PTFB, lean condition because still in closed loop at partial throttle.

What's the big deal then, just the surge of power??? Please I don't want that lol.
I'm not sure on the lean part. It makes sense, but you could tune that out I suppose. I always read about the extra wear and tear on the turbo, and extra heat.

Quote:
The taper I'm talking about from the stock solenoid is going from 14 psi peak to like 8 at redline. With the mbc I have now it peaks the same and holds closer to high 12's which I'm happy with.
This is probably because your ECU is tapering the boost, where as your MBC just cracks open at a certain PSI, no less.
Quote:
So, let me see if I'm understanding this.

Since the stock, unmodified ecu in my car, (02 wrx with 16-bit ecu) controls fueling by the MAF sensor, then at a certain m/g's sec the ecu says no more 14.7:1 now target 11.1:1 or whatever and then it changes to open loop and a richer a/f?
That sounds right -though, I've only played with my 2017 32 bit ecu.
Quote:
If so then when does it start not adding enough fuel?

As soon as I have a little more boost then stock and therefore no fuel tables for that high of MAF reading

OR

Does fueling just learn until idc's are 100 or more %, until it eventually hits fuel cut or leans out from lack of being able to supply fuel?
The closed loop to open loop transition can be adjusted but it's a different process for different year cars. Fuel 'learns' (closed loop) until the calibration file tells the car to go to open loop, at which point you can enter in what ever fueling you want at any given rpm/load cell. So, if your boost comes on part throttle at 3k rpms and a 1.4 load and you're getting lean knock you'd want to add fuel to that cell then possibly smooth things out around that cell. You also need to think about timing. You could be hitting PTFB in a rpm/load cell that has timing values for lower load cruise vs. onset of boost.

Google image search some pictures for open loop fueling map if you're not familiar with how they look. It may help you understand this a bit better.


Quote:
And if that's right wouldn't the stock 02 sensor be fairly accurate or at least accurate enough to determine when you start getting toward the lean side?
From my reading the stock O2 is not accurate enough to do anything but help the car determine closed loop fueling. Could be wrong on that. Hell, I could be wrong on a lot of this as I'm new to EFI tuning. But, E for effort



Quote:
I'm sorry if this is too far off topic or I'm asking too many dumb questions. Hopefully this will help someone considering the hybrid setup to understand what or how they are affecting fueling with a hybrid or manual boost control setup on a stock ecu and/or the places to make the fueling changes if they're writing their own.
IME going from a dialed in EBCS to hybrid boost nothing needed to be tweaked in terms of fueling or timing. However, I left my already tuned boost and WGDC tables alone except the last two columns which I pegged at 100% WGDC and shot the boost target a couple psi higher than what I target with my MBC.

I think what you really need is access to your tables. Then, make the changes per the instructions in this thread and you will have a nice hybrid setup.

I know I appreciate you two taking your time to help and everyone else that's contributed to this thread as well! Thank you!

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Old 07-10-2018, 02:28 PM   #891
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That's the least of my concerns! I mean if my 160,000 mile turbo goes bad $100 fixes that. If I blow my motor from running 15 psi at 2,000 rpm and 1/3 throttle because I didn't do something to prevent it, that's proven to work, I'm gonna be pissed, and it's gonna be 100 X's more inconvenient!
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Old 07-10-2018, 02:48 PM   #892
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Quote:
Originally Posted by Crispy 1 View Post
That's the least of my concerns! I mean if my 160,000 mile turbo goes bad $100 fixes that. If I blow my motor from running 15 psi at 2,000 rpm and 1/3 throttle because I didn't do something to prevent it, that's proven to work, I'm gonna be pissed, and it's gonna be 100 X's more inconvenient!
Hopefully someone more experienced will chime in. I personally wouldn't do any modding without a way to monitor the system, mainly knock events.
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Old 07-10-2018, 03:25 PM   #893
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I agree. I have btSsm running almost 100% of the time my car is. If you don't know about it, it's an Android app that is faster and in my opinion way better at monitoring and logging that an AP is. It cost $15 and I paid about $13 for a vagcom cable to run it from my obdII port. They also sell a btSsm specific Bluetooth one for $80-100 that is just as fast if not faster then the wired version and can read CANbus cars as well.
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Old 07-10-2018, 03:34 PM   #894
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I agree. I have btSsm running almost 100% of the time my car is. If you don't know about it, it's an Android app that is faster and in my opinion way better at monitoring and logging that an AP is. It cost $15 and I paid about $13 for a vagcom cable to run it from my obdII port. They also sell a btSsm specific Bluetooth one for $80-100 that is just as fast if not faster then the wired version and can read CANbus cars as well.
Nice - I Have a 10" tablet over my OEM screen. Does that monitor system have knock data?

I've not done much real time tuning because it's hard to watch the knock on the laptop vs. the AP. But, I just realized I could add the laptop screen to my tablet via a USB -C to HDMI connector. I know they have OBD2 splitters so, one could log more than one device I think.
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Old 07-11-2018, 12:06 AM   #895
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Nice - I Have a 10" tablet over my OEM screen. Does that monitor system have knock data?

I've not done much real time tuning because it's hard to watch the knock on the laptop vs. the AP. But, I just realized I could add the laptop screen to my tablet via a USB -C to HDMI connector. I know they have OBD2 splitters so, one could log more than one device I think.
Or you could get this and an otg cable and plug it dielrectly into your tablet.

Don't you have a 2017 sti? As far as I know the support only goes up to 2014 but for the money I would get it anyways and hassle them to get new cars very much up.
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Old 07-11-2018, 01:17 AM   #896
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Quote:
Originally Posted by PDXREALTOR View Post
From what I've read PTFB is hard on the turbo and, some find it just plain annoying to drive. Others seem to get used to it and not mind it.

The larger the turbo the less of a problem PTFB is, from what I've read.
It's just kind of annoying. With the GT3076R that I have, it rarely happens below 3k-4k, so it's no big deal most of the time, but if I try to accelerate gently past 4k, I end up modulating the throttle a lot to keep it smooth. No big deal but the car drives much better without it. With the stock turbo I'm sure it would be more annoying because it would build boost at cruising RPM.

It can't possibly be any harder on the turbo than just flooring it, and much less so really because when it happened I'd just lift off to keep boost down around wastegate level (10psi).
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Old 07-11-2018, 01:26 AM   #897
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A couple of fuel table examples:
https://imgur.com/a/32QslfC
https://imgur.com/96epZ2G

With the 32-bit cars, the OL/CL transition happens when the fuel table commands an AFR richer than some threshold. I set the threshold to about 14.69 or something, so I get CL in cruise (where all the cells are 14.7) and OL everywhere else. It just keeps things simple.

I think 16-bit cars work the same way but I haven't looked at a 16-bit ROM in years.

I have a laptop under the cargo floor of my wagon, and a touch-screen in the middle of the dash. And a switch in the dash so I can put the ECU into reflash mode without futzing with the connectors in the passenger footwell.
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Old 07-11-2018, 02:13 AM   #898
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Thanks NSFW!

I guess what I meant about never seeing a ROM was the different parts of the ROM that affect the fuel map.

How do you tell where it goes to open loop by those 2 maps or can you not? I assume it's near where it gets richer then 14.6?

If you get PTFB and don't lift and continue to build boost will it still not go lean?
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Old 07-11-2018, 03:53 AM   #899
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I forgot to mention that I've also zero'd out the OL/CL delays, but yeah... once that's been done, you'll be in CL when the fuel cable calls for anything leaner than the threshold, and in OL when the fuel table calls for anything richer.

Here's the table where you pick the AFR to switch at:

https://imgur.com/a/r2qYYkf

If you get PTFB and don't lift, you just go faster.

The ECU calculates fuel delivery by looking at how much air the engine is pulling it (as indicated by the MAF sensor) and then looking at what the target AFR is (as indicated by the fuel table) and then doing some arithmetic. Notice that the throttle pedal angle is not part of that process at all. It really doesn't care where the throttle is, it just needs to know how fast the air is flowing into the engine. If you have a bunch of boost, you have a bunch of airflow, so it adds a bunch of fuel.

Suppose the MAF sensor says 100 g/s of air and the fuel table calls for 12:1 AFR. So you need 1 gram of fuel per 12 grams of air, so 100/12 = 8 grams per second of fuel. If the injectors flow 500 g/minute that's 60 g/second. So it needs 8/60 = 13% of the injector's total flow capacity, so that's the injector duty cycle. Throw in some math to account for RPM (I'm getting lazy...) and you get the injector pulse width in milliseconds. So for each intake stroke the ECU opens the injectors for that many milliseconds. Throttle pedal angle and manifold pressure aren't required for any of that.

There are also some compensations involved, for ECT, AIT, MAP, etc, but those are relatively small. They're mostly just corrections to deal with circumstances where the reality inside the engine doesn't quite match what the arithmetic predicts.

There are ECUs out there - not for any turbo Subarus, as far as I know - that calculate fueling based on RPM and throttle opening. The fuel table looks sort of like ours but the X axis is throttle angle instead of load. It's called "alpha-N" fueling (alpha = throttle angle, N = RPM). That approach can work reasonably well for naturally aspirated cars, but it will go lean with PTFB, and I suspect that might be where the PTFB = lean = kaboom theory came from. It's a non-issue for everybody here though. Subaru has been using MAF sensors in their turbo cars since at least 2002.

You might find some old posts here talking about going lean with PTFB, from people who don't really understand what's going on. I don't doubt that people have actually watched their engines run lean while they were having PTFB, but that'd just be coincidence, not cause-and-effect. The real problem was either bad MAF scaling, or fuel injectors that aren't big enough for whatever boost they were running. Fix those and the AFR will stay right on target during PTFB. Or don't fix those, just fix PTFB, and they'd just run lean again at full throttle instead.

Last edited by NSFW; 07-11-2018 at 04:08 AM.
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Old 07-11-2018, 05:27 AM   #900
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I still don't see how it can't be lean at times.

Say for example you can now make 5psi more with your mbc at a lower load and rpm then you ever could before. Your untuned fuel table calls for 14.7:1 in that area but you need more fuel don't you?

Is there a rule of any kind at what boost level combined with load, rpm, or whatever that you need to be richer than 11.5:1 or even richer? Is it something I shouldn't worry about unless I'm getting FBK?

Also if fuel cut is 17 psi does that mean even though it was never meant to go above 13.5 psi that I have fuel tables that go up to 17 psi? Or however much load that would be?
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