VE tuning questions/problems

[darkhorizon]

Obviously enough,the maf overrides the map sensor stuff, so trying to tune VE with the maf in is impossible.

When in "ve mode", you are going to be using a whole different setup of stuff, and "ltft" revert to a bit of a different situation.

While research into "maf failure mode" aka VE only mode, is fairly limited, I can say that there are issues with it.

First off, LTFT's are never going to be "disabled" in open loop, with or without oxygen sensors. There is a hidden table that adds and subtracts to LTFT using IAT, and possibly something else such as egr functions, IAC adders/subtractions, even things like decel enleanment, and accel enrichment could show up, all coming from hidden tables, or at least hidden to HPT (I and others have many many more tables than what is accessible in HPT).

So in short, you can NOT use LTFT's for any function in VE mode, other than using them as a metric to accurately adjust the VE table in spots you need. So in your tuning, you would be hashing LTFT, commanded afr, and actual afr vs the VE table, instead of just command / actual afr. It is fairly uncharted territory, so you will need to do a bit of trial and error.. But I would suggest that you run without any o2 sensors in hopes of making it as easy as possible.

[thebeewantsboost]

maybe you should get another 5 maf sensors haha
i had no idea hptuners was gonna be so lacking for the v6 cars.
i'm really starting to question what the point of tuning is... im sure every tank of gas im going to get will have different amounts of ethanol in it, so its not smart to run in open loop all the time... but in closed loop using trims, my stock 02's are going to change my work.

[darkhorizon]

maybe you should get another 5 maf sensors haha
i had no idea hptuners was gonna be so lacking for the v6 cars.
i'm really starting to question what the point of tuning is... im sure every tank of gas im going to get will have different amounts of ethanol in it, so its not smart to run in open loop all the time... but in closed loop using trims, my stock 02's are going to change my work.

In theory, you could run o2 sensors in VE mode, it should work ok.

[Perforator]

i had no idea hptuners was gonna be so lacking for the v6 cars.

It's not HP, it's GM.

[murphinator]

could you possible set up the ITB's to all draw from a sealed cold air supply thats fed by an inlet with a maf in it ?

[thebeewantsboost]

In theory, you could run o2 sensors in VE mode, it should work ok.

i understand that, but it's also been discussed that by tuning, then running a tune with 02 sensors. its gonna learn fuel trims according to the stock narrowband.( the more i think about it, i don't know how bad of a thing that is.)

[thebeewantsboost]

It's not HP, it's GM.

100% on that?

[darkhorizon]

i understand that, but it's also been discussed that by tuning, then running a tune with 02 sensors. its gonna learn fuel trims according to the stock narrowband.( the more i think about it, i don't know how bad of a thing that is.)

The issue with o2 sensors in a VE only tune would be a strange one..

Like I said, there would be some interesting things going on across the board, and it would be a very bad idea to use LTFT to tune anything with, as I know for a fact that it is a "random" number in VE mode.

[LETZRIDE]

could you possible set up the ITB's to all draw from a sealed cold air supply thats fed by an inlet with a maf in it ?

I could, but then that defeats the purpose of ITBs, as the sealed piece feeding it now acts/becomes the intake manifold.

The reason why ITB's are so great is because none of the cylinders have to fight for air, where as in a manifold the cylinders are drawing air from what is present at any one time in an enclosed box.

I know from the research I did, I read that for the Ls1's running ITB's they saw a 65 rwhp over the fast 90 intakes, but when they placed a cover over the ITB's and ran it to a filter, they got about the same power and the Fast 90 manifold.

The only other thing I was thinking of, is I would have to find a Maf that is small enough to go into a 42mm throttle body, and run it into 1, but then multiply the MAF table by 6...I dont even know if that would work...but EVEN if I did that, I wouldnt have the same amount of air flowing into each cylinder now because I have a sensor sticking in one, and not in the other 5 lol.

I actually still need to see where I can put the IAT sensor, or if I will really need it...that is really my only remaining issue in the design, everything else has been addressed...

[murphinator]

if the car is a race car/toy more than a street car how about alpha n like Greg Banish references in his books ?

[Perforator]

100% on that?

GM decided to use the MAF sensor instead of the VE table.

[darkhorizon]

I actually still need to see where I can put the IAT sensor, or if I will really need it...that is really my only remaining issue in the design, everything else has been addressed...

The "maf sensor on 1" idea would never ever work..

The IAT sensor is required, and would need to go somewhere... I wouldn't get too carried away with its placement. You just need to get a good idea of the air temperature of the air coming into your motor.

[thebeewantsboost]

GM decided to use the MAF sensor instead of the VE table.

im sure this is true. but we are lacking open loop tuning tables and IFR tables. and whatever feature it is that allows people to adjust there narrowband 02's to corroborate with their wideband. However After Rereading Russ K's Maf tuning thread. he says that if when going back into closed loop the ltfts are off its more than likely a bad wideband.

[darkhorizon]

im sure this is true. but we are lacking open loop tuning tables and IFR tables. and whatever feature it is that allows people to adjust there narrowband 02's to corroborate with their wideband. However After Rereading Russ K's Maf tuning thread. he says that if when going back into closed loop the ltfts are off its more than likely a bad wideband.

Eh, we have open loop tuning tables, and IFR tables... what else do you want?

Although I do remember that HPT might not have the open loop air mass table.... Either way it is not that critical of a table, I have yet to even mod it.

There are a few OSID's that us DHP guys have access to O2 sensor / LTFT settings, such as swing counts, min/max swing values, etc.

[LETZRIDE]

if the car is a race car/toy more than a street car how about alpha n like Greg Banish references in his books ?

the car is a street car that is daily driven EVERYWHERE lol...Im driving it in the snow right now, I use it all year round (I dont have the money/storage room for another vehicle...mainly storage space though)

I am not familiar with Greg Banish's books? Do you have the titles, I may just look into his stuff just to see what he says...

The IAT sensor is required, and would need to go somewhere... I wouldn't get too carried away with its placement. You just need to get a good idea of the air temperature of the air coming into your motor.

I was thinking of maybe putting it beside the air horns (even though it would not measure the air going into the motor) it should be able to get the temperature of the air entering no? I mean, I think this way because air is being circulated into the engine bay when you drive, and since the air stacks are going to be drawing from whatever air is in the engine bay, I am going to assume it should be more or less the same temperature as what is going in the motor... when you are idle, the motor would be sucking stale air from in the engine bay, which would be hot air...and the IAT sensor should still reflect that. I dont think that the air in the stream of the air horn is going to be much hotter/cooler then the air right beside the air horn at any 1 given time....

[murphinator]

I am not familiar with Greg Banish's books? Do you have the titles, I may just look into his stuff just to see what he says....

http://www.amazon.com/Greg-Banish/e/B001JOVJT2

[darkhorizon]

If I remember right (this is drawing on 2+ year old memories here), the PCM adds or subtracts 1 LTFT per 10 degrees off of like 35C. Obviously the hotter the more subtracts, the colder the more it adds. You are going to want it somewhere that is fairly consistent with whatever air is going into the motor if you want the best possible situation.

[thebeewantsboost]

what open loop tables do we have? i'm not really worried about ifr tables atleast at the moment, but i know we dont have as many ifr tables as other vehicles.

[LETZRIDE]

we got the MAF and VE tables for open loop...chose which one you want to use lol.

I dont know anything about LTFT, or how to use them...Ive honestly just been using error% of the VE table, copy and pasting by % 1/2...and you know what? My part throttle AFR is VERY close...I dialed them in a little better tonight...I am within 2%...this is slowly getting better, but its hard to see many changes when you are multiplying by like 1.xx %

I have my stoich set to 14.4, and cruising I am sitting right at 14.4ish to 15.2ish...constant...which is actually beautiful, and more or less where I want it (even though its not 14.4) as this will give me awesome gas milage I think.

I got two 20 minute drives in tonight at part throttle, and I was steady 2-5% on 95% of my cells...it was very light throttle though because of the snow on the road.

WOT is also getting very close, it just needs a tad more working over, but this will have to wait until the roads clear up a little.

I've been driving around with this VE tune in for about a week now (tweaking it as I have to drive to places) but I mean, it has been pretty damn consistent.

I'll see if I can post a scan or so tommorrow, but I am pretty happy with where I am sitting.

I've had to cheat to get my desired afr at WOT...I want 12.5 at WOT after 4000rpm...so instead of commanding 12.5, I have to command 12.0, and this is because I am at the maximum 200% on the 100kpa cells...by commanding 12.0, I get the 12.5...I didnt want to do it this way...but so be it if it works...

[thebeewantsboost]

"There seems to be allot of methods to tune the AFR on the V6 cars. Since these cars don't yet have an open loop table like the V8's and the V6 (4.3) trucks, the commanded AFR while in open loop is all over the place when not in PE. In PE the commanded AFR will be were you set it." Russ K
this is what i was getting at. i'm glad you've found something that worked.