Is tuning for part throttle boost a problems for the LS engines?

[robertway]

Hey folks,

I have been hanging out on lxforums.com forums lately (don't throw anything at me please) and noticed one of the big issues/concerns for the hemi tuners is tuning for part throttle boost situations in closed loop. It seems that the out of the box ECMs don't have a VE Table that scales beyond atmospheric pressure out of the box so during closed loop when boost comes in the system tries to maintain stoich (14.7 AFR) and things start to heat up apparently. Was wondering how part throttle boost is being tuned for the LS engines, in the "limited" reading I have done about tuning the LS3 it looks like the VE table have a lot more resolution and go well beyond atmospheric pressure. Just wondering if the part throttle boost was a concern in the LS world as much as it seems to be in the hemi world.

In any event, I found this thread an interesting read...

http://www.lxforums.com/board/f286/p...lained-208347/

[ADM PERFORMANCE]

We don't have these problems because we have
MAFS

[robertway]

Originally Posted by ADM PERFORMANCE

We don't have these problems because we have
MAFS

I am assuming then the HEMIs do not and are restricted to using a MAP Sensor and since the default VE Table is only set up to 1.0 (atmospheric pressure) anything over that (part throttle boost) the table commands fuel based on the 1.0 VE Table row which winds up being too little fuel hence the lean part throttle boost condition. Correct me if I am wrong in this assumption.

At the same time, I know some folks do "Speed Density" tuning on forced induction which from what I understand is when the MAF gets disabled either because the tuners wants to disable it or because it has to be disabled since the boost the setup is running exceeds the capacity of the MAF and tuning is done strictly off the MAP Sensor. Are all the HEMIs without MAFs and all tuned "Speed Density"?

Edit: Ok, I think I answered my own question, this thread explains that the HEMIs are Speed Density only: http://www.chargerforums.com/forums/...ght=maf+sensor

[boostedyards86]

hows it going rob? looking at hemi's now?

[robertway]

Originally Posted by boostedyards86

hows it going rob? looking at hemi's now?

Hey, you gotta do what ya gotta do, as much as the ZL1 is a nice ride or even a slightly used CTS-V they are a little too steep for me at this point, the 2011/2012 Dodge Chargers look like a fun family hauler with a lot of potential down the road. I looked at some 2009 G8 GXPs but they didn't really "speak" to me even though I am more familiar with their platform.

By the way, how is my car, I mean your car treating you:-)

[Jon@MagnaCharger]

Originally Posted by robertway

the 2011/2012 Dodge Chargers look like a fun family hauler with a lot of potential down the road

Just a word of warning right now - there is currently no tuning options for the 2011+ Dodge vehicles of any kind. Chrysler has locked the ECU's up tighter than Fort Knox and no one in the entire aftermarket tuning industry has been successful in programming them. If you are looking for one that you will be able to modify right away, makes sure you look at 2010 and older.

[SC2150]

The Mopar is MAP only and Jon is correct, nothing for the 2011 yet and everyone is pulling their hair out trying to break through.

The 2010 and earlier we can tune but not with HP tuners or EFI live so that is frustrating as well. Have a 2010 maggie build we are having difficulty getting tuned correctly.....

[ADM PERFORMANCE]

Originally Posted by Jon@MagnaCharger

Just a word of warning right now - there is currently no tuning options for the 2011+ Dodge vehicles of any kind. Chrysler has locked the ECU's up tighter than Fort Knox and no one in the entire aftermarket tuning industry has been successful in programming them. If you are looking for one that you will be able to modify right away, makes sure you look at 2010 and older.

You can lead a horse to water!

[JANNETTYRACING]

Originally Posted by robertway

I am assuming then the HEMIs do not and are restricted to using a MAP Sensor and since the default VE Table is only set up to 1.0 (atmospheric pressure) anything over that (part throttle boost) the table commands fuel based on the 1.0 VE Table row which winds up being too little fuel hence the lean part throttle boost condition. Correct me if I am wrong in this assumption.

At the same time, I know some folks do "Speed Density" tuning on forced induction which from what I understand is when the MAF gets disabled either because the tuners wants to disable it or because it has to be disabled since the boost the setup is running exceeds the capacity of the MAF and tuning is done strictly off the MAP Sensor. Are all the HEMIs without MAFs and all tuned "Speed Density"?

Edit: Ok, I think I answered my own question, this thread explains that the HEMIs are Speed Density only: http://www.chargerforums.com/forums/...ght=maf+sensor

I have tuned Many boosted Hemis so i have first hand experience with this, and it is real.

With Proper tuning it can be avoided but is tricky, The Computer system is totally different they GM and Ford, and the only one I know of that is Speed Density in Newer Cars.

GM and Fords Do not have this problem.

Ted.

[robertway]

I knew the 2011/2012 computers were locked but was kinda optimistic that they would be cracked within a couple of years when the mod bug really started to hit. Who knows, maybe by then I'll have just decided to rip the 5.7 out and drop a 440 Stroker in the bitch and call it a day :-)

OK, no more HEMI talk, this is a Camaro forum, I'll ask for forgiveness now :-D

[leviticus88]

Originally Posted by JANNETTYRACING

I have tuned Many boosted Hemis so i have first hand experience with this, and it is real.

With Proper tuning it can be avoided but is tricky, The Computer system is totally different they GM and Ford, and the only one I know of that is Speed Density in Newer Cars.

GM and Fords Do not have this problem.

Ted.

One more reason to avoid Mopar...

[JANNETTYRACING]

Originally Posted by leviticus88

One more reason to avoid Mopar...

No Comment

[robertway]

[East Coast Supercharging]

Originally Posted by leviticus88

One more reason to avoid Mopar...

I like this guy already..




just an FYI, I tune many Corvettes and Camaro's in closed loop speed density (no MAF) in certain situations. They run perfect and the owner would not be aware of how it was tuned.

Chrysler's are just Chrysler's so they cant help themselves, they are like the Star trek-"trekys" or "Joe Dirts", people of the automotive world.

(ok I'm not a Mopar fan, but if you are I'm just kidding around. Please do not take offensively)


Doug @ ECS