VE tuning......anybody done it yet?

[guardsman01]

It sounds like the way to go for tuning is the VE route, at least for the V8s....has anybody here been doing it?

If so, what are the results, where did you start, etc.?

Now that I've seen that other people have been doing it, and some method of doing it, I'm going to start playing with mine, and I'll keep you all up to date on how it's going.......if anybody else starts doing it, fill us in....

And, hopefully, some of the V8 guys will come in here, and give us pointers, slaps in the head, etc., to help us along......

So far, I've been leery about playing with too much, as I have to drive my car every day, so the only thing that I've really done so far is:

Tinker with the timing a bit, just adding a couple of degrees at most across the board, then tweaking it from there;

Bump my MAF flow rates to adjust for my MAF screen being gone (I increased them 2.5% (multiply by 1.025) as a ballbark guess, and it has made a noticeable difference in the way the car behaves).

And I adjusted the VE in one spot to help with a stumble when I hit the gas from idle, and that helped it out.

So, again, if you've been doing, or start doing it (and doing it is the in thing, now man), let us know how it goes for you.....John

[Screamn03]

It's working for me. I tweaked my ve and then plugged the MAF back in. Can't complain, this is the best the car has ran so far. I believe the V6 stuff works the same as the V8. Can anyone confirm this?

[guardsman01]

We can change the VE the same as you guys, but there's other stuff that we can't access, although I still have to look at all of the features that are on the 1.5.1 update....

Also, some of the stuff is a bit different, like our IFR, the V8s go in 5kpa intervals, the V6s go in 10kpa intervals, so we can't get the accuracy in fuel control that you can....

Also, how did you do your VE tuning?

I saw a few of the posts on it, but nobody really got in depth in it. I know you unplug the MAF, and then tune from there, but are you using the stock O2s, or using a wideband?

And how are you adjusting the actual VE values? I.e., how much of a change are you making in individual cells, and how many cells are you doing at once, that kind of thing?

And, thanks for coming over

[Missing2]

???

are you all talking about running in speed density mode??

or jsut methods for tuning the VE tables..

if you are interested in running a speed density tune see the thread i made (a few post back in the v6 section) art hanson resently made a pretty informative post..

[guardsman01]

Yeah, I'm not talking about running speed density, but just tuning the VE using VE.

From what they are talking about there, it basically sounds like VE tuning and setting up to run speed density are the same basic process, except for plugging the MAF back in after VE tuning.

So, keep us up on what you're doing. John

[Screamn03]

Also, how did you do your VE tuning?

I saw a few of the posts on it, but nobody really got in depth in it. I know you unplug the MAF, and then tune from there, but are you using the stock O2s, or using a wideband?
I used my stock 02s to update the LTFTs ( ;D that's what they do anyway, I didn't do anything special, just sounds good saying it like that). It's the LTFTs that I used to edit my VE table. This was a "work in progress" over a couple week period because I had to let the LTFTs settle. I'm in the process of getting the new EIO interface so I haven't used my wideband on this car yet (LM1). I also just sorta roughed out the tune so far because I have Mac Midlenth, no cat y, and a catback to go on the car with will throw everything off again.

And how are you adjusting the actual VE values? I.e., how much of a change are you making in individual cells, and how many cells are you doing at once, that kind of thing?

I directly directly input what I see in my LTFT histogram. If it says +5 I subtract 5 from the VE table at the point. If it says -4 then I add 4 to the VE table. I do this within reason and try to make the VE table as smooth as possible. I do it to as many cells that are off all at the same time.

And, thanks for coming over

No problem bro, . I kept getting lost but finally found my way .

[Quick6]

As long as you have your MAFF plugged in and it is functioning properly, the VE table is useless. Why do you think you have to unplug it to see your adjustments make changes??

It is used to verify maff operation only and if the maff fails, then it uses the VE table. Now if you want to run junk speed density mode then by all means get rid of your maff and adjust your VE table tell your hearts content.
Not trying to be rude, sorry if it came accross that way.

[guardsman01]

The VE table isn't useless with the MAF plugged in....the PCM uses the VE table when it senses conditions where it can't or doesn't trust the MAF readings, like when you step on it.

The MAF sensor can't keep up with the airflow changes, so the PCM uses the VE tables.

I understand what you mean though.....

After looking at all of this stuff, I have come up with this (anybody feel free to chime in if I'm wrong somewhere).....by unplugging the MAF sensor, and then tuning the VE tables, you are adjusting the VE tables for your set-up....

The stock tables are based on the stock intake and exhaust, and even that is a ballpark, as each engine will act differently.....

So, you are adjusting for your particular engine, and also any mods that you have done that increase or decrease the amount of air that the cylinders can take in on each stroke.

One thing to consider, is that if you make any intake or exhaust changes after you do VE tuning, you need to redo the tune to adjust for those changes......

Anyhow, the VE tables will now be properly tuned for when the PCM needs to use them.....

Now, that brings us to what needs to be done after plugging the MAF back in......

From what I've seen, everybody has said that the LTFTs will change when the MAF is plugged back in......however, they are then adjusting the VE tables again to compensate, which I am going to say I think is wrong.....

I think at that point, the MAF tables need to be adjusted.....again the MAF sensor frequency tables are ballpark figures......

The actual airflow, and the measured airflow, will be different from sensor to sensor.....then, if you descreen, P&P, etc., you sensor, you are changing the sensor again.....just like the engine...

So, at that point, you need to adjust the MAF sensor tables, to bring them in line with what the MAF is actually flowing AND reading....

Another thing to consider in all of this, is that you aren't tuning the WOT tuning, as you will then be in PE, and in open loop....

That will need to be tuned using a wide band O2.....

Anyhow, the route I'm going to use is unplug the MAF, do some normal driving, and then also do some driving with the car in 2nd gear, so that I can max out the RPM, without having to go into PE....that way I can tune across the entire rpm range......that won't get the PE nailed right in, but it will get it in the ballpark...at least that's the way I figure it.....

I may have a couple of weeks off in the near future, and depending on my money situation at the time, I will do my tuning then........

I'll keep you guys up on what I find out......John

[Screamn03]

John,

You pretty much nailed it.

that won't get the PE nailed right in, but it will get it in the ballpark...at least that's the way I figure it.....

You should be able to set the PE to whatever AFR you want and get that at the tailpipe. If your VE, MAF, and IFR tables are all correct then it "should" happen. If you set the PE to 1.18 then you are commanding a 12.46:1 AFR (14.7/1.18=12.46). This part is really easy if you have all your airflow tables and IFR correct.

From what I've seen, everybody has said that the LTFTs will change when the MAF is plugged back in......however, they are then adjusting the VE tables again to compensate, which I am going to say I think is wrong.....

I think at that point, the MAF tables need to be adjusted.....again the MAF sensor frequency tables are ballpark figures......

I agree with you here also.

You have to remember that anything you do to the motor to help in breath will require a VE adjustment. If you get you MAF dialed in it should stay that way unless you make anychanges on the inductions, such as lids, filters, move the maf, clean the maf, all this affects it because you change the way air flows across the sensor.

-Mike

[Quick6]

You should be able to set the PE to whatever AFR you want and get that at the tailpipe. If you VE and MAF tables are all correct then it "should" happen. If you set the PE to 1.18 then you are commanding a 12.46:1 AFR (14.7/1.18=12.46). This part is really easy if you have all your airflow tables and IFR correct.

Please be careful when posting numbers like this and specify what engine you are referring to

The S/C V6 is a totally different table and numbers. Our base under PE mode is 12.400 and it goes down from there depending on load, which i've seen as low as 10.5:1 on my car!!

You could get a newbie looking at this and if he applied that to his s/c v6 he would be replacing pistons!

[Screamn03]

My bad :-[ .

[guardsman01]

Hey Mike,
On the PE thing, I think that I'm a bit confused, or maybe your tables are set-up different.....

My PE values are in the tables as actual AFR values (13.0, etc.). Then, we have a PE AFR adder, which is input as a negative number (-1.0) to lower the AFR, and as a positive number to raise the AFR, at given points.

So, where you're talking about using a 1.18 being used in reference to the PE, I'm confused.....I just want to make sure that I'm not missing something or misinterpreting something here.....Thanks. John

[Chris@HPTuners]

V6 and V8 code is different, V6 code uses AFR and not "Equivalence Ratio" that the V8's use.

In any case the theory is similar and yes whatever AFR you command you should get at the WBO2.

The basic idea is this.
1. you decide your target AFR based on exhaust temperature, calibration engineers sit on the engine dyno with thermocouples and stuff on the bits that get hot with reasonable timing in the engine and see what AFR they need to maintain a "safe" exhaust temperature. Mostly so you don't heat stress (or melt) the mechanical engine compents. Especially true on s/c and turbo engines. It's nice that the V6 code has a time based PE that you generally setup to get richer as you keep into it longer to keep things cool. Also, this is why things like COT exist - too keep the catalytic converter cool. Interestingly spark retard increases exhaust temperatures and the PCM uses this fact to heat the cats up faster on startup (purposely commanding extra retard).

2. You set your PE table to your target WOT AFR (you just determined via EGT's - or guessed on the safe side)

3. now you get into the process of working with your IFR's and airflow calibrations (MAF/VE/both) to make sure that the AFR you are measuring with the WBO2 is the one you are commanding.

IMHO, airflow calibration is the main culprit when it comes to fueling inacurracies be it MAF or SD based. If you have the MAF connected it's time to start recalibrating it. Personally, i think the big differnce between SD and MAF setups is the flexibility SD gives you in some installs and the better transient fueling response (simple fact the MAP sensor reacts faster than the MAF).

Now everyone can start a debate on what is a safe EGT/time levels and the mechanical engineers on the forum can get hot and sweaty

Chris...

[Black_97_GTP]

EGT of 1400 degrees, 1600 is getting to hot. At least that was the rule of thumb with my DSM.

[S2002S]

I saw a few of the posts on it, but nobody really got in depth in it. I know you unplug the MAF, and then tune from there, but are you using the stock O2s, or using a wideband?
I used my stock 02s to update the LTFTs ( ;D that's what they do anyway, I didn't do anything special, just sounds good saying it like that). It's the LTFTs that I used to edit my VE table. This was a "work in progress" over a couple week period because I had to let the LTFTs settle. I'm in the process of getting the new EIO interface so I haven't used my wideband on this car yet (LM1). I also just sorta roughed out the tune so far because I have Mac Midlenth, no cat y, and a catback to go on the car with will throw everything off again.

I directly directly input what I see in my LTFT histogram. If it says +5 I subtract 5 from the VE table at the point. If it says -4 then I add 4 to the VE table. I do this within reason and try to make the VE table as smooth as possible. I do it to as many cells that are off all at the same time.

No problem bro, . I kept getting lost but finally found my way .

"I directly directly input what I see in my LTFT histogram. If it says +5 I subtract 5 from the VE table at the point. If it says -4 then I add 4 to the VE table. I do this within reason and try to make the VE table as smooth as possible. I do it to as many cells that are off all at the same time."

This seems to be backwards (for a V-8 anyway)....

[Missing2]

"I directly directly input what I see in my LTFT histogram. If it says +5 I subtract 5 from the VE table at the point. If it says -4 then I add 4 to the VE table. I do this within reason and try to make the VE table as smooth as possible. I do it to as many cells that are off all at the same time."

This seems to be backwards (for a V8)....

???

is that actauly an effective/safe method?

[Screamn03]

That is odd, you would think that if you are adding air to the VE table then that extra air would be used in the fuel cal. and more fuel would be added also.

WARNING:V8 user here, I don't know anything about the V6s.

[98A4LS1]

So, if you modify the induction side of things ie air lid and ported TB, it would be better to adjust the MAF Calibration (MAF Airflow vs Frequency) rather than VE? or both if your running a MAF setup?
Thanks

[guardsman01]

98A4LS1, any changes to the induction set-up are going to require modifications to the VE tables....

As for the MAF sensor, a the tables for a stock, untouched sensor will have to be tweaked for the engine, ideally.

Once it is tweaked, unless you physically make changes to the sensor itself, you shouldn't have to do any more adjustments for the MAF tables.

Physical changes would include de-screening, porting and/or polishing, or anything else that changes the airflow over the sensor wires.

Hope that helps.