113 replies to this topic

[Speedy]

So you don't want to be stoich with boost but you don't want to enrich. What do you want? What is your concern with going open loop in boost if you are saying you don't want to run closed loop in boost? You are kind of talking in circles here Speedy. ...

J

 

Is it possible with today's tuning to enrich fueling in boost without it seeming like you have no control of the throttle?  That's really what's at issue.  In my experience, once OL or PE was achieved 60% throttle felt like 100%.  That's been a complaint from a lot of boosted folks.  Maybe we're talking past each other here?

 

In an ideal world, for me, as soon as boost is achieved the AFR would enrichen to match, but driver wouldn't even know it happened.

 

To dumb it down, when the driver depresses the accelerator 60% if OL or PE are requested in the tune would it feel like the driver had floored the throttle to achieve this?  If the answer is yes then that is a concern as 60% throttle shouldn't feel like 100%.

 

Make sense?

[345_CHLNGR]

Speed not sure why you say it is a bad thing going into PE at PTB, but as long as it is a smooth transition there is nothing wrong with it at all. If it is tuned this way you can typically handle more timing with small amounts of SKNK without much issue of hurting anything. On the other hand if no PE and running 14.7 a little SKNK and 4 to 5lbs Boost can cause major issues if lugging it around.

 

I have ran mine both ways and I feel it has better drivability with PE during PTB as my timing doesn't have to be backed off.

 

Just my .02

[Speedy]

How can you have PE in closed loop?

How can you have OL and PE in PTB without the car taking off like a rocket when the throttle is barely depressed?

Those are the issues I didn't think had been solved. If they have I'm all for it.

[legmaker]

So you don't want to be stoich with boost but you don't want to enrich. What do you want? What is your concern with going open loop in boost if you are saying you don't want to run closed loop in boost? You are kind of talking in circles here Speedy. ...

J

 

let me ask you this way joel..... because this topic always intrigues me......

 

can the needed fuel enrichment be made in open loop WITHOUT manipulating the PE % so the car is not seeing stoich when in boost in open loop???  in essence, harrison's comments that when his jeep went into boost, the fuel richened up.  i know harrison does not drive his jeep like a total wot asshole all the time to get the closed loop tuning (well.....maybe some of the time).....  so how was he seeing his a/f get fatter in ptb?  

 

btw - this is probably one of the better discussions i have read on this forum lately. 

[ostmike]

Chris, I think you are confusing closed and open loop. Also, keep in mind the fueling control for the RT's and SRT's is different (for the most part).

You can have PE without transitioning into WOT.

Speedy - in the recent tune I sent you I moved the PE to a lower throttle rate change. It should not be too noticeable but as observant as you are you should see a slight difference in when your AF starts to enrichen

[Jerseyboy]

Is it possible with today's tuning to enrich fueling in boost without it seeming like you have no control of the throttle?  That's really what's at issue.  In my experience, once OL or PE was achieved 60% throttle felt like 100%.  That's been a complaint from a lot of boosted folks.  Maybe we're talking past each other here?

 

In an ideal world, for me, as soon as boost is achieved the AFR would enrichen to match, but driver wouldn't even know it happened.

 

To dumb it down, when the driver depresses the accelerator 60% if OL or PE are requested in the tune would it feel like the driver had floored the throttle to achieve this?  If the answer is yes then that is a concern as 60% throttle shouldn't feel like 100%.

 

Make sense?

 

 

let me ask you this way joel..... because this topic always intrigues me......

 

can the needed fuel enrichment be made in open loop WITHOUT manipulating the PE % so the car is not seeing stoich when in boost in open loop???  in essence, harrison's comments that when his jeep went into boost, the fuel richened up.  i know harrison does not drive his jeep like a total wot asshole all the time to get the closed loop tuning (well.....maybe some of the time).....  so how was he seeing his a/f get fatter in ptb?  

 

btw - this is probably one of the better discussions i have read on this forum lately. 

 

Ok, this is the where the problem lies. You are associating going WOT with going open loop. That isn't necessary as the two don't have to be tied together. You can go Open loop any time you want without going WOT. Hell, I even do some race tunes that are Open loop all the time when running leaded gas extensively. That is  actually how Harrison was running at Bradenton.

 

Also, don't confuse running open loop with running rich. I can set open loop fueling wherever I want. Hell, every time your car starts its open loop until the O2 sensors warm up (anywhere from 5-30 seconds depending on temperature).

 

J

[Speedy]

Chris, I think you are confusing closed and open loop. Also, keep in mind the fueling control for the RT's and SRT's is different (for the most part).

You can have PE without transitioning into WOT.

Speedy - in the recent tune I sent you I moved the PE to a lower throttle rate change. It should not be too noticeable but as observant as you are you should see a slight difference in when your AF starts to enrichen

 

Cool beans, will test it out!

 

Ok, this is the where the problem lies. You are associating going WOT with going open loop. That isn't necessary as the two don't have to be tied together. You can go Open loop any time you want without going WOT. Hell, I even do some race tunes that are Open loop all the time when running leaded gas extensively. That is  actually how Harrison was running at Bradenton.

 

Also, don't confuse running open loop with running rich. I can set open loop fueling wherever I want. Hell, every time your car starts its open loop until the O2 sensors warm up (anywhere from 5-30 seconds depending on temperature).

 

J

 

Well, that bring another question then.  If OL fueling can be controlled like that, why even have closed loop at all for FI cars?  Set that joker to OL and tune for 14.7:1 out of boost and 11.8:1 or whatever you want in boost and call it a day?  Does it cause some other side effect or CEL or something?  I didn't realize you could swap to OL and it not affect throttle.

[rick s]

I don't want to go off-track, but this looks like a good place to ask this:

Ford and GM use a MAF sensor instead of a MAP sensor.  From what I understand, using a MAF sensor allows for much more linear tuning in forced induction.

 

Has anyone tried to make an electronic black box, that would allow us to ditch the MAP sensor, install a MAF sensor, and the black box would convert/interpret the signals to the Dodge PCM?

[Speedy]

It's a good question, but would be complicated to implement since so much of the car's driving parameters revolve around the MAP based system.  The 4Runner I spoke of earlier is MAF and it did actually adjust all on it's own when I bolted the supercharger on it up to 7psi.  Above that I needed a little extra with a 7th injector hooked up to the piggy back.  I was pretty impressed it could auto adjust fueling for 7psi, although richer than I wanted at 10.9AFR.

[1FST4DR]

I don't want to go off-track, but this looks like a good place to ask this:

Ford and GM use a MAF sensor instead of a MAP sensor.  From what I understand, using a MAF sensor allows for much more linear tuning in forced induction.

 

Has anyone tried to make an electronic black box, that would allow us to ditch the MAP sensor, install a MAF sensor, and the black box would convert/interpret the signals to the Dodge PCM?

  They use is Mass air flow instead of speed density ..

[toofart]

Cool beans, will test it out!

 

 

Well, that bring another question then.  If OL fueling can be controlled like that, why even have closed loop at all for FI cars?  Set that joker to OL and tune for 14.7:1 out of boost and 11.8:1 or whatever you want in boost and call it a day?  Does it cause some other side effect or CEL or something?  I didn't realize you could swap to OL and it not affect throttle.

Emissions.  The o2 sensor will help keep it at 14.7 whether it's -20 or 100, 0 ft elevation or 5000 ft.

[Jerseyboy]

I don't want to go off-track, but this looks like a good place to ask this:
Ford and GM use a MAF sensor instead of a MAP sensor. From what I understand, using a MAF sensor allows for much more linear tuning in forced induction.

Has anyone tried to make an electronic black box, that would allow us to ditch the MAP sensor, install a MAF sensor, and the black box would convert/interpret the signals to the Dodge PCM?

MAF sensor has nothing to do with it. If you have the VE right it will do the same thing. Think of the MAF as an O2 sensor for air flow. It is a feed forward device though, not a feedback device like the O2 sensors. Ford is actually doing away with the MAF sensors on their future products. Alot of the higher hp GM guys are pulling their MAF sensors as well and going speed density. It's not whether it's MAF or MAP based. It's all about making it all work together properly.

J

[ostmike]

Alot of the higher hp GM guys are pulling their MAF sensors as well and going speed density.

 

 

Joel, you know I respect you but I need to disagree - at least partially, since this is a "pet peeve" of mine (lack of MAF tuning in this platform)

 

I tune quite a few decent HP GM's (1000+ whp) and for the older models where the CAL can't support the higher MAF frequency you are correct - we will do as you are suggesting and switch to a 2 or 3bar OS and tune via SD.

 

However, on the CAL's that can support the MAF frequencies, in 100% of the cases we will swap the MAF cartridge into a larger intake tube and tune via MAF before trying to switch to SD. MAF tuning is a breeze and from a cutomer/performance modification standpoint the MAF tuning allows the customer to swap in components (exhaust, intake), raise or lower boost etc. and (in most cases) no tuning changes required. The MAF also is fantastic at adjusting for ambient temps so the need for a different tune for cold/dry air vs. hot humid air is diminished.

 

Two weeks ago I did a big turbo LS car that we switched from MAF to 3bar SD. It took about 3-4 revisions to get the idle/cruise tuning correct and about 7 dyno pulls/revisions (3 different boost levels with the AMS controller) to get the tune dialed in.

 

Monday I will be tuning a newer turbo GM truck, same HP level (1100+ whp) and this will be MAF only. I am hoping I can nail it in one idle/cruise revision and 3-4 dyno pulls.

 

I guess it's a moot point here....

It sure would be nice to have that option on this platform (or a blended SD/MAF) but that may never happen...

 

Again - no disrespect intended.

I do and will continue to look to you as a resource and a sounding board for ideas with the Gen III Hemi platform.

[Speedy]

The Hell Cat went to MAF correct? Must be a reason there.

[rick s]

So. . .  there's absolutely no way to swap all the GM engine control components/computers into our cars and build a black box to communicate between those computers and the rest of our car?  I'm not suggesting it would be easy, but with the talent available these days, I would think it could be done.

[legmaker]

Ok, this is the where the problem lies. You are associating going WOT with going open loop. That isn't necessary as the two don't have to be tied together. You can go Open loop any time you want without going WOT. Hell, I even do some race tunes that are Open loop all the time when running leaded gas extensively. That is  actually how Harrison was running at Bradenton.

 

Also, don't confuse running open loop with running rich. I can set open loop fueling wherever I want. Hell, every time your car starts its open loop until the O2 sensors warm up (anywhere from 5-30 seconds depending on temperature).

 

J

 

Joel - no....... i think you are mis-understanding my comments.  i am not saying open loop only happens when going wot.  i know for sure that they are not tied together.  i watch my gauges all the time and know what my foot is doing.  i can get my car into open loop without hitting the floor.  my question was can you manipulate fuel enrichment when the car is in closed loop and is seeing boost and 14.7 afr?  this, and only this, is the reason i run a meth system.  with a 17% OD dampner and small pulley on the F1, i can see 5-6 psi and 14.7 afr easily when driving around town.  

 

and yes, i know you have done race tunes where open loop is happening all the time.  you did one for tvrobs car before vmp.....

[Jerseyboy]

Joel, you know I respect you but I need to disagree - at least partially, since this is a "pet peeve" of mine (lack of MAF tuning in this platform)

I tune quite a few decent HP GM's (1000+ whp) and for the older models where the CAL can't support the higher MAF frequency you are correct - we will do as you are suggesting and switch to a 2 or 3bar OS and tune via SD.

However, on the CAL's that can support the MAF frequencies, in 100% of the cases we will swap the MAF cartridge into a larger intake tube and tune via MAF before trying to switch to SD. MAF tuning is a breeze and from a cutomer/performance modification standpoint the MAF tuning allows the customer to swap in components (exhaust, intake), raise or lower boost etc. and (in most cases) no tuning changes required. The MAF also is fantastic at adjusting for ambient temps so the need for a different tune for cold/dry air vs. hot humid air is diminished.

Two weeks ago I did a big turbo LS car that we switched from MAF to 3bar SD. It took about 3-4 revisions to get the idle/cruise tuning correct and about 7 dyno pulls/revisions (3 different boost levels with the AMS controller) to get the tune dialed in.

Monday I will be tuning a newer turbo GM truck, same HP level (1100+ whp) and this will be MAF only. I am hoping I can nail it in one idle/cruise revision and 3-4 dyno pulls.

I guess it's a moot point here....
It sure would be nice to have that option on this platform (or a blended SD/MAF) but that may never happen...

Again - no disrespect intended.
I do and will continue to look to you as a resource and a sounding board for ideas with the Gen III Hemi platform.

I'm well aware of the larger mafs. I worked for Lingenfelter when we came out with the 100 mm MAF for the vettes. Problem with the big MAF is it doesn't read low flows well. Make it closed coupled near the tb and and a big NA cam and watch it freak out due to the overlap. Each system has its benefits and it's drawbacks.

A MAF by itself will not fix speedy's issue of part throttle boost. It would make your job easier but if you don't calibrate the pcm to enrich at the proper time, you will still have the same issue. You still need to calibrate that control system properly for it to work.

J

Joel - no....... i think you are mis-understanding my comments. i am not saying open loop only happens when going wot. i know for sure that they are not tied together. i watch my gauges all the time and know what my foot is doing. i can get my car into open loop without hitting the floor. my question was can you manipulate fuel enrichment when the car is in closed loop and is seeing boost and 14.7 afr? this, and only this, is the reason i run a meth system. with a 17% OD dampner and small pulley on the F1, i can see 5-6 psi and 14.7 afr easily when driving around town.

and yes, i know you have done race tunes where open loop is happening all the time. you did one for tvrobs car before vmp.....

I'm not missing interpreting what you are saying chris. You don't have to go wot to get enrichment but some people believe you will go wot if you go open loop. That's not 100% true.

I can get a vehicle to enrich when in boost without Going wot. Yes. Most of the other well known tuners can as well. That's why Harrison's truck would go richer when he got into any boost level.

J

[lxmodguy]

Just two cents from another guy who tunes gm stuff tune. Like JB already said. A lot of boosted gm apps turn off the maf and go to 2bar/3 bar custom os' s. When you do VE on a gm generally speaking you turn off the maf, build the VE table, and turn it back on. We have a far better platform to tune starting with speed density and easily making 2 and 3 bar changes without complications

[legmaker]

I'm not missing interpreting what you are saying chris. You don't have to go wot to get enrichment but some people believe you will go wot if you go open loop. That's not 100% true.

I can get a vehicle to enrich when in boost without Going wot. Yes. Most of the other well known tuners can as well. That's why Harrison's truck would go richer when he got into any boost level.

J

 

we are kinda going in circle joel.  i clearly understand that wot and OL are not mutually INCLUSIVE.  so what is it that you and other good tuner do to achieve the fuel enrichement?  my understanding is that the pcm must be in open loop, note i am NOT saying wot, to manipulate fuel?  correct or incorrect???  i know you can set things to be in OL all them time if you so choose.  is the manipulation as to what it takes to get into OL how tuners are making ptb fuel increases???  

[345_CHLNGR]

we are kinda going in circle joel.  i clearly understand that wot and OL are not mutually INCLUSIVE.  so what is it that you and other good tuner do to achieve the fuel enrichement?  my understanding is that the pcm must be in open loop, note i am NOT saying wot, to manipulate fuel?  correct or incorrect???  i know you can set things to be in OL all them time if you so choose.  is the manipulation as to what it takes to get into OL how tuners are making ptb fuel increases???  

OL is how they are making ptb fuel enrichment. Remember Closed Loop is trying to keep Engine at 14.7 and a good VE surface can do what is needed to tune a Boosted car. Issues have been like Mike stated earlier were that RT's did not really have a good VE to work with. What it has took was a lot of time for the tuning community to have VE working consistently. You got to remember that there a BUNCH of different CAL ID's on these cars and some of the CAL ID's have good VE Surface but a lot don't. I know my CAL ID # matches what is suppose to be in the car, but is actually a whole different animal inside with a VE that actually works.