Predator Setting based on Mods

**The Silver Goat** · 03-21-2009, 05:38 AM

Every mod I've installed is external to the engine. My focus relative to this question are the setting(s) for the slope injection given I've installed catch can and breather filter.

First assumption: the engine is consuming cleaner air therefore the motor requires more gas to ensure or obtain a programmed setting for the a/f ratio of 14.7 to 1.

Second assumption: to improve performance and attain an a/f ratio of 12.5 or 12.8 to 1 one is continually fighting the pcm which attempts to get it back to 14.7 to 1.

I've had her dyno tuned so the settings I have obtain are 12.5 to 12.8 - 1 a/f ratio. But, if I take her on a 4 hour tour at these setting I get a lean code.

Are these two assumptions correct assuming no other changes?

I have specifically stayed away from what the settings are on my slope injection to ensure the answers focus on the logic stated above...

**0rion** · 03-21-2009, 09:05 AM

I think you're looking at it incorrectly. True the computer does try to maintain 14.7:1 in closed loop but when you're commanding 12.8 at WOT you're in open loop so the computer is basically just doing what you told it to do. WOT fueling uses a multiplier to determine fuel based on 14.7:1. To command 12.8:1 your multiplier would be 1.148. 14.7/1.148= 12.80 That's all your pcm knows as it goes to open loop...use the mulitiplier. Now is when your long term trims come into play. If the long term trim in the cell prior to going wot ( open loop) was positive (lean) it will add that percentage to your final fueling calculations at wot. So let's say you were at +5 in the cell prior to wot then the pcm would add that 5% to the final fueling calculations to ensure you don't go lean at wot. If your trims are 0 or negative the pcm adds nothing to the final calculations.
If you're getting lean codes that would be from your cruising or long term trims. The pcm will throw that code once the LTFT's drift too far out of range. I would log your LTFT's and adjust your fueling down in the cruise regions to bring those trims to -3 to 3 percent although I almost always shoot for zero or slightly negative. This is where I'm not sure how diablo adjusts their fueling. The car is running primarily on the maf so the maf table is where the fueling changes should be made....not the injectors.

**The Silver Goat** · 03-22-2009, 03:39 AM

I have to change the setting on the slope to go touring, decreasing the slope (which with a diablo is holding open the injector longer because the company assumes you've changed out to a bigger injector). It does not the capabilities to change MAF tables.

I took her to a local shop in area for a dyno and found out from my neighbor, who use to race a lot, that one of the guys on the team is one of the founding father Diablo. In my discussions with the shop owner he could send file to diablo and they'd write a custom tune.

The shop also has a couple ground cams he developed for ls1's, but the focus was on a 1/4 mile.

I haven't decided how far I want to go with mods and living in Michigan today does not mean you'll have a job tomorrow.

Let me ask this question - isn't 12.8 rich?

**Sarge** · 03-22-2009, 08:14 AM

Not at WOT it isnt.

**The Silver Goat** · 03-23-2009, 01:20 AM

Alright I'm in my 50's and do not understand how the PCM is controlling everything. Use to be back smoke was to rich and knocking meant not enough fuel or the timing was advanced too far...

What is open and closed loop?

I'm trying to get my head around this and understand if I have a vacuum leak somewhere or the mods have required a significant change to the slope on the injectors. I've balanced my LTFT at a-18% which gets me ~-1% to %0.

One item I did not list above was de-screening the MAF which in combination with all above I beleive contributes to the equation.

**0rion** · 03-23-2009, 03:38 AM

Originally Posted by The Silver Goat

Alright I'm in my 50's and do not understand how the PCM is controlling everything. Use to be back smoke was to rich and knocking meant not enough fuel or the timing was advanced too far...

What is open and closed loop?

I'm trying to get my head around this and understand if I have a vacuum leak somewhere or the mods have required a significant change to the slope on the injectors. I've balanced my LTFT at a-18% which gets me ~-1% to %0.

One item I did not list above was de-screening the MAF which in combination with all above I beleive contributes to the equation.

that statement kind of confuses me. Does that mean in the diablo you dropped your trims 18% and that put your LTFT's -1 to 0%?
I'm not against modding the MAF if you get tuned for it but I do believe modding the MAF and not tuning for it can create problems for people. Some will say that they've de-screened their MAF and everything was fine but twice that many have issues after de-screening it. How old is the diablo you have? My understanding is that the newer diablo's have the ability to record data, does yours? The older model I had didn't have that ability. Your best bet is to log some data if you have that option with your diablo and look at your LTFT's in all the cells and see where you're going lean at. If you can export it as a .csv file you can mail it to me and I'll look it over at ibzrg6@aol.com
The O2 sensors "close" the loop. That's pretty much it in a nutshell. Open loop is when the car runs off of the tables without the input from the O2's.
You can still check for vacuum leaks like we did in the old days with carb cleaner. I would imagine you're going to find that MAF to be the culprit though.

**The Silver Goat** · 03-23-2009, 04:39 AM

Sorry about that - by setting my slope injection to -17/18% I've attained LTFT's of -1% to 0% when cruising around town.
The Diablo does not have the ability to retain data - the wife does...on a limited basis. (it's the older version)
I'm going to start by replacing the sleeves on the CAI and go from there as far as searching for leaks.

**Sarge** · 03-23-2009, 04:50 AM

I wonder if we can exchange our Wife V.1 for the newer models in a "group buy" type scenario?

**6.0LiterImportEater** · 03-23-2009, 07:11 AM

That is a problem with the Predator. It really only allows you to adjust at WOT when you go into a "open loop". Your very limited during "regular" driving with this type of tuning.

I have only owned my GOAT for a little over a month so still learning about this beast and the LSX motors. So have a few questions regarding this thread but also a little outside but we are all here to learn so posting here.

Is there any piggyback ECU's available for our ride?

From what I know most "piggybacks" get overwritten with closed looped scenarios if the ECU is "tricky enough". Is this true with ours?

The new AEM FIC is a nice set-up but not sure how it will function with our computer. I am NOT a fan of MAF tuning.....BOO!! With the AEM FIC I would have the ability to switch it to a O2 Wideband Controller. Reading the fuel in your exhaust is much better for tuning and it will allow your computer to compensate from running too lean/rich on the fly quickly. Much better results this way then calculating everything from the amount of air intaked.

Has anybody tried this? This is the route I want to go just the AEM FIC or some other piggyback is really the only "affordable" option. Going to a full standalone AEM ECU will cost approximately $5G's alone and will lose all functionality of the dash and such which I am against.

Let me know your thoughts!!! Thanks!

Boobs?

**6.0LiterImportEater** · 03-23-2009, 07:24 AM

To anybody thats new I am discussing changing from a MAF sensor to a MAP sensor for tuning/engine management (3 bar for N/A or 5 bar for boost).

**The Silver Goat** · 03-23-2009, 02:05 PM

Originally Posted by Sarge

I wonder if we can exchange our Wife V.1 for the newer models in a "group buy" type scenario?

Current version = V.1.50.
I'm suspect of V.2.25, to ditzy...
Maybe V.2.35

**0rion** · 03-23-2009, 03:37 PM

Originally Posted by 6.0LiterImportEater

That is a problem with the Predator. It really only allows you to adjust at WOT when you go into a "open loop". Your very limited during "regular" driving with this type of tuning.

I have only owned my GOAT for a little over a month so still learning about this beast and the LSX motors. So have a few questions regarding this thread but also a little outside but we are all here to learn so posting here.

Is there any piggyback ECU's available for our ride?

From what I know most "piggybacks" get overwritten with closed looped scenarios if the ECU is "tricky enough". Is this true with ours?

The new AEM FIC is a nice set-up but not sure how it will function with our computer. I am NOT a fan of MAF tuning.....BOO!! With the AEM FIC I would have the ability to switch it to a O2 Wideband Controller. Reading the fuel in your exhaust is much better for tuning and it will allow your computer to compensate from running too lean/rich on the fly quickly. Much better results this way then calculating everything from the amount of air intaked.

Has anybody tried this? This is the route I want to go just the AEM FIC or some other piggyback is really the only "affordable" option. Going to a full standalone AEM ECU will cost approximately $5G's alone and will lose all functionality of the dash and such which I am against.

Let me know your thoughts!!! Thanks!

Boobs?

Hptuners offers a nice full editor for our pcm's along with efilive. Both are very capable and will work for 99.9% of the people out there. The LSx pcm is actually very flexible and can be tuned to handle quite a bit of engine. Both software suites allow for wideband logging. You log the wideband input right along with your other pid's.
I've tuned mine with and without the MAF. They both have their bright spots and until you start running boost or a significantly sized cam the MAF can be tuned just fine.

**Quik** · 03-23-2009, 03:51 PM

Originally Posted by 6.0LiterImportEater

To anybody thats new I am discussing changing from a MAF sensor to a MAP sensor for tuning/engine management (3 bar for N/A or 5 bar for boost).

please do more research on these motors. first off these motors use both a map and a maf. 1 bar is NA others are for boost.

the way you speak you come from the import world. anything you know of imports just forget it.

**The Silver Goat** · 03-24-2009, 12:41 AM

Using the Diablo I knew I was bringing a knife to a gun fight - I'm attempting to gain a better understand of the logic of the pcm...

Having had it dyno tuned I've resided myself to forms of driving (using the Diablo). One setting for touring (it bugs the $hit out of me to have the engine light on) and the dyno tune settings if I'm looking to rape the gear box.
Meaning if I leave the dyno tune in it eventually I'll get a lean code.

The difference between the settings on my slope injection is 7% to 8% to attain a LTFT's of -1% to 0%. I can get away with -15% until July...

**Quik** · 03-24-2009, 04:08 AM

Originally Posted by The Silver Goat

Using the Diablo I knew I was bringing a knife to a gun fight - I'm attempting to gain a better understand of the logic of the pcm...

Having had it dyno tuned I've resided myself to forms of driving (using the Diablo). One setting for touring (it bugs the $hit out of me to have the engine light on) and the dyno tune settings if I'm looking to rape the gear box.
Meaning if I leave the dyno tune in it eventually I'll get a lean code.

The difference between the settings on my slope injection is 7% to 8% to attain a LTFT's of -1% to 0%. I can get away with -15% until July...

toss the handheld and get software. your vehicle will be much safter and faster in long run

**6.0LiterImportEater** · 03-24-2009, 04:10 AM

Originally Posted by Quik

please do more research on these motors. first off these motors use both a map and a maf. 1 bar is NA others are for boost.

the way you speak you come from the import world. anything you know of imports just forget it.

Hmmmm......I am doing research there bud! I didn't know that and thanks for letting me know even though you were a huge dick about it!

**6.0LiterImportEater** · 03-24-2009, 04:55 AM

Originally Posted by 0rion

Hptuners offers a nice full editor for our pcm's along with efilive. Both are very capable and will work for 99.9% of the people out there. The LSx pcm is actually very flexible and can be tuned to handle quite a bit of engine. Both software suites allow for wideband logging. You log the wideband input right along with your other pid's.
I've tuned mine with and without the MAF. They both have their bright spots and until you start running boost or a significantly sized cam the MAF can be tuned just fine.

Thanks for the info Orion!

Where can I grab these software suites and all neccesary hardware to connect to the PCM?

**0rion** · 03-24-2009, 05:06 AM

hptuners.com and efilive.com for the tuning suites. Then a wideband is also recommended. I have an LC-1 and LM-1 from innovate motorsports but there are several others out there.

**6.0LiterImportEater** · 03-24-2009, 05:26 AM

Originally Posted by 0rion

hptuners.com and efilive.com for the tuning suites. Then a wideband is also recommended. I have an LC-1 and LM-1 from innovate motorsports but there are several others out there.

Is there any recommendation on what software suite is better? Any feedback? User friendliness?