Yes, if the MAF tube is smaller you may need to raise the MAX and Vice Versa. Turn LTFT on and use the fuel trims to dial in the MAF, if you know the size difference you can work out the percentage area difference and scale the MAF to get you in the ballpark. You can also make a Math channel to check your work by calculating the airflow difference between MAF and VE, in a steady state they should be the same so the Dynair calc is not bouncing from MAF to VE.Originally Posted by cmitchell17
Do you think its better to tune the MAF through trims (just long term? or long term + short term?) or through the wideband? I am also just running one wideband and it is in the turbo downpipe about 3 or so feet from the turbo outlet.
I have done about 10 maybe 15 iterations of MAF tuning so far with the wideband and it looks like I am within about 3% error vs the wideband although I have seen a spike to about 7% or so for whatever reason, but I am also probably pushing my injectors. I see duty cycle sometimes at around 110-115%. So I put in some 93 octane to mix a little with the E85 already in there which dropped the alcohol percentage down to around 40-50%, but for some reason my duty cycle went higher on my injectors, so I have pretty much lost all faith in the duty cycle PID calculation. I think I remember the DC calc having issues on GEN V stuff as well.
I still need to figure out why it will only make about 2-3 psi of boost. I swear I hear the BOV opening up and letting boost out when I roll down the windows and roll into the throttle about 50% and let boost come up slowly and all of the sudden I hear hissing from where my BOV is mounted. I heard this same sound before and after I switched to the heaver spring and properly tapped a vacuum line to run from the brake booster line to the BOV it seemed like it fixed it, but now its back I guess.
https://1drv.ms/u/s!AkCUE89IhD0Ng-gR...2zhng?e=6sz527
White Truck Turbo (LS9 Stock Timing) ECM TCM FICM.hpt
Also one thing I have been meaning to ask but keep forgetting, is there any chance we could ever utilize the build in supercharger/turbo functions and tables? The OS on the E38 I have in my truck looks like it only has a supercharger section, but I have seen supercharger and turbocharger sections.
It would be really nice to have a stock level of control and drivability, but as always with that kind of stuff you would probably open up 50 million more issues and unknown to trial and error through in order to get it right.
as far as im aware if it dosnt come out with a supercharger or turbo then those tables dont work, there are many tables like that are added but simply do nothing in the e38 as there are so many OS it covers
If you verify your bov is working via a pressure pump and it's opening when it's supposed to then just keep in mind turbo's spoil off of heat - in other words injection and ignition timingYour too retarded on injection and too advanced on ignition...
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Is turning desoot off beneficial? I know this is completely off topic from the OP lol
Desoot is kinda like the PE timers - it leans out under power to heat the chamber and burn off soot or carbon build up. Problem is people put blowers or other power adders on plus add in timing and all of a sudden you have a leaning out time bomb, so yes - good idea to deactivate it. Another thing the OE does for helping to keep carbon burnt off is they add in some timing at high load, low rpms then keep the converters locked up here so the engine will purposely spark knock - to chisel the carbon off so to speak - good idea to check converter settings too.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
I think there is something wrong with my MAP output. I am using the GM 3-bar sensor (12592525) with a 312.5 kPa scale factor and -11.25 kPa offset. I feel like the airmass calculation is scaled wrong or something. Looking at my logs at medium throttle I can see APC go up to over 0.9 grams and thats when boost is at about -1 to -.5 psi so before any boost I am at 0.9 grams of airmass which makes no sense. Before the turbo when my truck was 100% stock, the most airmass it would see was about 0.75 grams.
The wastegate I have supposedly has a 7 psi spring in it, I would also assume I have about probably 1 psi of pressure drop through my 3in intercooler and charge piping. So I am thinking maybe the MAP sensor has the wrong offset? Maybe when I only see 2-3 psi at WOT, maybe it is actually 7 psi because my scale is wrong. I guess I can try to put in the supposedly 13 psi wastegate spring and see what happens.
Also as GHuggins suggested, I should be able to unscrew my IAT sensor in my charge pipe and put my leak down tester in it and see what pressure the BOV is opening at. Although in theory, it should never open no matter how high I go because I have the BOV top barb port hooked up to the brake booster line, so any pressure I put to the charge pipe should be the same pressure that gets routed to the barb nipple on top of the BOV. I guess I would at least have to plug the pipe coming from the compressor output or else it would just leak through the compressor wheel out the compressor inlet and also probably going to leak through a cylinder that's at valve overlap as well. From my understanding of how the BOV works, you hook the top barb port up to behind the throttle blade, that way during WOT the barb port on top of the BOV sees the same pressure as what's in the pipe (minus a small drop through the throttle blade) so that helps in stay closed, then when the throttle blade closes, a vacuum gets built up which the BOV sees from the barb port which creates a very unbalanced force and allows it to open faster. I think the spring in the BOV is there just to ensure that it remains closed because of the slight pressure drop through the throttle body. My BOV came with 2 springs and I switched it from the lighter to the heavier one already and there was no difference I don't think.
What type of wastegate setup are you running?
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
A turbosmart 40mm with a 7 psi spring installed and a Tial Q 50mm BOV with the 18 psi spring installed. I have a cheap Chineseium turbo T4 manifold, crossover, and downpipe, and the wastegate flange is mounted on the crossover pipe on the bottom passenger side so its close to the downpipe. I have one of those braided flex exhaust tubes screwed into the wastegate that goes to the downpipe.
Also the fact that my transmission is shifting way harder now makes me think things are scaled up. In theory if a wrong scaling did occur I basically just dialed in my VVE and MAF to the wrong scale, it still should run a stoich correctly, but of course things like torque reference would be effected.
Last edited by cmitchell17; 02-21-2022 at 01:13 PM.
So I leak tested my charge pipes and intercooler again today. I found a small leak (which I already really knew it was leaking) where I tried to braze my MAF and IAT sensor bungs to the charge pipe (I am using the low temperature braze and it is very difficult to get the intercooler pipe hot enough to melt the braze rod but not melt the bung). So I ended up just covering them up with RTV silicone and now it holds pressure although it seemed like it was trying to pop out the silicone somewhere. I double checked the BOV again and there is no smoke so I just can't find any leaks around it.
Took a test drive and it appears no difference in boost. But I noticed my barometric pressure PID reads 15.2 psi. So I went and compared my cal to a ZR1 cal just to double check my MAP sensor factor and offset again, but then noticed ECM 4112 and 4113 were different. So I started thinking and trying to remember if the barometric pressure sensor was built into the MAP sensor on these, but I feel like it wouldn't be just from looking at the sensor I don't see how it could be done. So I looked in the service manual but apparently only the 6.0 hybrid atkinson cycle engine came with a baro sensor separately and it is mounted on the airbox where they used to put those filter minder indicators for the air filter change. So I guess maybe the baro is built into the MAP sensor on these, but I have no idea why only the hybrid 6.0 engine would have a separate baro sensor? Given how complex those were maybe it makes sense I don't know.
I would go and put the baro values from a ZR1 cal (since I am running the 12592525 LS9 sensor) in my tune and try it out, but I just discovered a nice inch or so hairline crack around the diameter of the oil cooler inlet hose of my radiator. So now I have to try to find a new radiator or order one (I think I am definitely going 100% GM/AC Delco/Stock just from hearing about all the budget radiators cracking). I am also like 90% sure the crack was caused by me. I have been trying to fix a leak at my turbo oil feed adapter that I put on the oil cooler on the oil pan by the filter. Finally get that fixed after finding bad o-rings in them and putting some extra RTV for backup. In the process of fixing it I had the oil cooler hose block/mount thing off hanging and I had it wedged and kind of pried out of the way. I think this put too much stress on it so now I've got a crack, so let this be a warning to anyone reading, be very careful when bending the oil cooler lines if they are connected to the radiator, they are fragile given that they are connected to a long line (lever arm) and the radiator is made of assuming some glass re-enforced nylon that's already probably relatively brittle. So lesson learned, take the lines off the radiator inlet side first before doing anything with them.
Anyway, I am not convinced this baro setting will fix my situation, but it seems logical that it will. If I am about 1 psi off (my logs indicate baro is 15.1 and elevation here is about 900 or so feet and about 14.1 psi baro), then this would explain why when slowly building boost I still see a slight vacuum in the manifold but then have higher airmass than I did 100% stock with no turbo just because I am not seeing the correct boost value. So many other things seem off, like my fuel economy gauge is still reading E85 like mileage even when I went back to E10, and my injector DC% calculation is still showing it hitting 90-100% after I switch back to E10 as well from 70% alcohol. I am using the HPT built in math parameter to log DC, and it apparently only looks at the pulse width. I am still trying to figure out if it is even possible to have a bad scale and still run a stoich, but that is what's happening. I guess the ECM doesn't care as stoich is stoich, obviously its going to throw all output calculations (reported torque etc.) out of whack.
As a non-tuning related question, in everyone's putting forced induction on non forced induction engines experience, how much of a boost leak does it take to start to mess things up? I would guess I could determine a leak rate from the compressor map, but then determining the flow rate of a leak (that you can barely find in the first place) is rather difficult.
Last edited by cmitchell17; 02-23-2022 at 12:12 AM.
I always use the LTFT + STFT for dialing in the closed loop settings as ultimately they are the sensors the car will be running off. you can ditch the LTFT but its nice to have if the trims are a ways off. Use the Wideband for OL mixtues.
You really want 85% maximum injector duty, Id be getting larger injectors, if your fuel system is not boost reference that is a good way to get more from the injectors.
Thanks, I think I will go back and redo VVE and MAF in the non PE regions with the narrowband feedback hopefully it's more stable.
So I have the L9H flex fuel version of the 6.2 truck engine which supposedly has the same FPCMs as the LSA LS9 stuff with some differences, at least I think there seems to be a lot of misinformation and lack of confirmed info on these, since most people mod the cheaper GEN III 4.8/5.3 stuff. I think a lot of people use the stock L9H in tank fuel pump as an upgrade though.
Looking at the FPCM cal it looks like there is a lot of things that could be tried, but most probably have no effect as I don't think the truck flex fuel pumps have the same capabilities as the LSA/LS9 stuff. I have heard people swaping LSA/CTSV FPCMs in the trucks a upgrades, but not sure if the BCM/ECM would complain about a VIN mismatch or anything, don't think so since the GMT900s thankfully I don't think they care about that stuff unless there is a ECM/BCM mismatch of course since I think BCM handles security, or of course radio theftlock as well. But it makes me wonder why I can't just full flash my FPCM to a CTSV OS, but I guess there's probably a large chance of bricking.
I would think I can at least raise the max DC from 90% to 100% but can't find anyone who has really done it and reported improvement. I have heard though you have to add a boost a pump after the FPCM since apparently somehow the FPCM can see the higher voltage and lower it back down.
I say this because I think the stock 6.2 flex fuel system has a lot of potential, and I find with fuel system mods there is a lot of unknown and hacking it seems, which I feel makes the system vulnerable to failing and leaving you stranded.
And how can you get more from the system being boost referenced? I mean I understand it would let you command more pressure based off boost to achieve the same net pressure of the fuel inside the intake manifold, but I don't get what's stopping you from just running more pressure regardless? I guess you would need a physical pressure regulator added to the system anyway to do this, which it would be nice if we could use the already built in functionality in the FPCM to control boost referenced fuel pressure.
I think with a pressure increase, to the supposed pressure the LSA/LS9 runs, I think that can give me significantly more injector flow and room, and time to save up for ridiculously highly priced injectors haha.
Last edited by cmitchell17; 02-25-2022 at 12:48 PM.
Log the pump duty, its a closed loop system so if the duty is 100% its max, the DC tables are a feed forward. You get more from being boost referenced provided the pump can deliver at higher pressure as the pressure differential between the rail and manifold is lower, in a dead head system the boost pressure is effectively the same as drop in fuel pressure as the boost pressure is opposing the rail pressure. To do a boost referenced system you need to block the in tank pressure regulator/relief and fit a higher capacity pump/pumps. If you use multiple pump s the FSCM can control one pump but not two, you can activate a second pump under boost and the FSCM will still attempt to maintain the desired pressure. There are a few ways to tackle this.
You should take a moment to think about this... You have boost on a bone stock engine. That means you have a camshaft that's phasing and an ethanol learn algorithm that is dancing around wildly. You're using fuel trim data to wrap all of that nonsense back into your calibrations. Can't do that... Get a flex fuel sensor or disable it and stick to one fuel...no negotiating that, its absolutely necessary. For the cam phase angle, lock out the tables or otherwise use a filter to capture what's what in terms of airflow. And the clunking...apply the air calc mode patch like I mentioned earlier. I'm looking right at it in your file.
So yes, I had zeroed out VVT tables while tuning VVE. And I am back to straight pump 93, but I am maxing out knock retard and even getting knock at coast down and idle. I have everything as far as knock and knock retard all stock. I tried boostane and other mmt octane boosters but they did nothing, I don't really think they do anything though.
I also tried all the patches with the same results, I think you might be looking at an older version of the file.
However i completely overlooked I still had my passenger side pcv open to atmosphere and the driver's side hooked up stock with just a check valve so it basically a giant vacuum leak. So for now I plugged the manifold pcv port and vented both sides. So that may explain a little bit of the high airmass but it was about 10-20% rich after I ran MAF only open loop. But haven't had a chance to really test it out yet.
I don't really want to run the pcv system vented mainly for the smell. But not sure what else I can do since vented to atmosphere on the passenger side and stock with a check valve on the driver's side is going to allow unmetered air through unless I go back to running speed density and deal with the quirks.
Last edited by cmitchell17; 03-12-2022 at 03:48 PM.
So there DC is maxing out at about 92% and modifying the open loop DC tables didn't have any effect, and neither did rasing all the other DC limits to 100% in the ECM tables as well.
Can't I also try to get the FPCM to boost the pump voltage? Maybe with this table?
Capture.JPG
I just don't know why there aren't any units on the row axis.
It's also really weird why the column axis references intake air temperature, not sure what IAT has anything to do with fuel pump voltage and control.
You zeroed out those tables to calibrate VVE fueling..? And then it was finished? What do you think happens when you reenable it and you've only adjusted for the camshaft straight up? I don't really understand what you're adjusting for anyway if the engine is stock. You could just copy the original 105kpa row into everything higher MAP than that and be 95% the way there. And regardless of the fuel type you have in it, disable the flex algorithm. If there's leanness and the learn is active, it WILL be attributed to ethanol...
Yes I agree, I put my VVE back to stock in the 100 kPa row and down. And I was thinking the change in VE with cam phasing would act the same way as it did stock so I only changed the VVE at 0 VVT angle and left all the rest stock. And sorry I tend to do too many things at once.
I go back and tune VVE in only the boost regions with flex fuel disabled and all the patches applied. Thanks for the help.
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