Jeep 4.0 I6 tuning for blower

[kpalm]

I've got an I6 4.0 2006 Jeep Wrangler with a supercharger on it. Bigger injectors, going to be wiring in a 2-bar MAP sensor today. I've never tuned before, and plan to find someone with some experience to get a base tune, but have some questions.

My main two concerns will be adjusting the AFR and the ignition. I'm running Beta 2.25 to allow compatibility with my VCM.

What tables/parameters are used to do this?

Airflow I have VE tables, Fuel I have FA Power Enrich tables; as these are the only RPM based tables I find related to AFR, are one of them the correct one to modify? If not, do I need a separate programmable MAP sensor to allow RPM based AFR adjustments?

For spark it looks like the PT Base and WOT Base will be where I change the spark advance, correct?

Thanks for any help.

[Team208Motorsports]

The best thing you can do is scale the tune in half to accommodate your 2 bar map, that way you can get proper fuel and spark once in boost. Yeah it will give half the resolution but at least you will have proper control. How much boost do you plan on running?

[kpalm]

The best thing you can do is scale the tune in half to accommodate your 2 bar map, that way you can get proper fuel and spark once in boost. Yeah it will give half the resolution but at least you will have proper control. How much boost do you plan on running?

So that would be cutting the MAP Sensor Linear value in half as well as the Volumetric Efficiency tables? According to the blower mfg I should be at 7.5-8 PSI max boost.

Here's my stock tune if it helps at all:
stocktune.hpt

[kpalm]

So, from what I see I've got the three inputs for MAP sensor settings. I'll probably be going GM 2-bar, so using tables from the internet I can calculate that it's 40.38 kPa per volt, which will be my linear offset, and the graph gave an intercept of 2.38kPa so that will be my first Sensor offset, what is the second MAP sensor offset, the voltage that in my case is defaulted to 0.10V?

Next I'd update the volumetric efficiency tables of the airflow, I assume the reason I need to cut in half is because my VCM (or maybe just it's OS?) is set up for 100kPa max at the MAP, correct? And this will also be my adjustment table for fuel ratio under boost?

And then when I moved to ignition, 100kPa would actually represent 14.7psi boost? That makes me think I'm going about this wrong, and instead of halfing my VE I'd actually want to calculate it to when the blower is maxed out at 8psi the VE table is outputting 100kPa, losing less resolution in other adjustments as I'd never reach the upper half bar of the 2-bar sensor.

Am I understanding everything correctly or way off on any of these assumptions. I apologize if any of these seem like noob questions, just started looking into tuning today and apparently it's not as easy to learn as I had hoped.

[B00STJUNKY]

No, don't "half" your table as you're explaining it. You need to actually adjust the load range of the table by clicking on the load units label (to the left of the graph), and from there you'll find a table that defines your range and breakpoints.

[kpalm]

No, don't "half" your table as you're explaining it. You need to actually adjust the load range of the table by clicking on the load units label (to the left of the graph), and from there you'll find a table that defines your range and breakpoints.

I can see that it will let me do that in the spark tables, is that where you're referring to? The VE tables only have ratio numbers, "pressure ratio axis" with a ratio and a scale. The spark table it's in kBar so it's easy enough to remap the axis to my new values.

I tried to schedule an appointment with the only dyno in my city, but he's very secretive and won't tell me anything about what he's going to do or has done afterwards, he wants it to be a mysterious black box to me. I'd prefer to understand it as best as possible, so I'm looking to borrow a trailer so I can bring my Jeep down to Sacramento for a more helpful tuner to get a base.

From my understanding, the general idea will be map my new MAP sensor, probably GM 2 bar, and my new fuel injectors (30lb Ford), then somehow command a 1.0 lambda. I saw instructions on how to do this for GM, but it looks like I'm missing options they used to do this. With commanded open-loop 1.0 lambda I'd datalog the wideband and use the delta to modify the VE tables at different points in the table, and interpolate between values I've calculated. Does this sound about correct for the process of getting the AFR correct?

I still need to figure out how the ignition part works but I know that's better left to someone with a Dyno and more experience so I don't blow it up.

[B00STJUNKY]

The VE map uses Pressure Ratio, that is correct. To extend that range, you would do the same thing, click on the load axis label, and modify both the range and configure the breakpoints to your liking. My suggestion would be to leave yourself a good amount of low load resolution, and cut back on the high load resolution. In other words, of the 17 rows available in the VE map, I would suggest using at least 10, if not 12 of those rows for load ranges between 0 and 1.0. Reason for this is that VE airflow curves can change pretty rapidly in the high vacuum sections of the airflow map, but as you near 1.0 and higher, the curves are a bit slower to change, and therefore you don't need as much resolution.

Keep in mind that, just because you are using a 2 bar sensor, doesn't necessarily mean that your maximum Pressure Ratio should only be 2, also. Pressure Ratio is calculated off of atmospheric pressure at your elevation. So, for example, where I live (at 4500 ft elevation) my typical absolute atmospheric pressure is 12.5 psi. If I were using a 2 bar sensor and wanted to max that sensor out at my elevation, I would have to consider that the Pressure Ratio would be greater than 2.0 in order to reach 200 kpa, considering I'm starting with only 85 kpa atmospheric pressure.

200 / 85 kpa = 2.35

So, if I wanted to max a 2 bar sensor out at my elevation and given my atmospheric pressure, I would want to make sure I set the maximum Pressure Ratio value to at least 2.35. But generally, I like to leave some head room so that, in the event I go even higher in elevation and lose even more atmospheric pressure, I still have some range to fall back on if I need to fine tune it at that elevation.

I don't think too many people will ever travel anywhere that has less than 75 kpa of atmosphere, unless you're running Pike's Peak. But, as a general rule of thumb (for myself), I use 70 kpa as the base for determining my maximum Pressure Ratio range.

[B00STJUNKY]

As far as setting Lambda, you can do that in the Fuel tab under the "Stoich" section where you should see 3 tables. FA Stoich, FA Stoich Even, and FA Stoich Odd. The odd/even is for if you (for some odd reason) wanted to command a different stoich value for odd or even numbered cylinders.

Note that the values found in these tables are not listed as Lambda. Rather, they are the ratio of fuel to air (the inverse of air to fuel). So, for a 14.7:1 AFR, your FAR (Fuel to Air Ratio) would simply be 1/14.7 = 0.0680.

There is no simple switch in the software to disable closed loop, so generally what folks do is set the Coolant Temp enable threshold (found in the | Fuel | Open & Closed Loop | section) to a temperature that you won't ever reach during normal operation. After doing so, make sure to reset the trims in the PCM either with a scan tool that is able to reset trims, or by disconnecting the negative battery terminal for a bit. If you skip this step, even though the Closed Loop trims will no longer make adjustments in real time, the Long Term trims that are already stored in the PCM will still be applied.

[kpalm]

The VE map uses Pressure Ratio, that is correct. To extend that range, you would do the same thing, click on the load axis label, and modify both the range and configure the breakpoints to your liking. My suggestion would be to leave yourself a good amount of low load resolution, and cut back on the high load resolution. In other words, of the 17 rows available in the VE map, I would suggest using at least 10, if not 12 of those rows for load ranges between 0 and 1.0. Reason for this is that VE airflow curves can change pretty rapidly in the high vacuum sections of the airflow map, but as you near 1.0 and higher, the curves are a bit slower to change, and therefore you don't need as much resolution.

Keep in mind that, just because you are using a 2 bar sensor, doesn't necessarily mean that your maximum Pressure Ratio should only be 2, also. Pressure Ratio is calculated off of atmospheric pressure at your elevation. So, for example, where I live (at 4500 ft elevation) my typical absolute atmospheric pressure is 12.5 psi. If I were using a 2 bar sensor and wanted to max that sensor out at my elevation, I would have to consider that the Pressure Ratio would be greater than 2.0 in order to reach 200 kpa, considering I'm starting with only 85 kpa atmospheric pressure.

200 / 85 kpa = 2.35

So, if I wanted to max a 2 bar sensor out at my elevation and given my atmospheric pressure, I would want to make sure I set the maximum Pressure Ratio value to at least 2.35. But generally, I like to leave some head room so that, in the event I go even higher in elevation and lose even more atmospheric pressure, I still have some range to fall back on if I need to fine tune it at that elevation.

I don't think too many people will ever travel anywhere that has less than 75 kpa of atmosphere, unless you're running Pike's Peak. But, as a general rule of thumb (for myself), I use 70 kpa as the base for determining my maximum Pressure Ratio range.

So using 70kpa, 200kpa map / 70 kpa gives max pressure ratio of 2.85, I'm at 4500' but drive up to 7000' somewhat regularly. So adjusting the VE axes as you recommended gives me something like shown in the attached screenshot, does that look about right?

I saw a tuner today who told me the 2bar sensor won't work since there's no OS for the 2 bar for me ECM, and he recommended putting the stock sensor back on the throttle body pre-blower (roots-style charger), but if I'm understanding your methodology correctly it makes up for not being able to actually reference 200 kPa in my ECM, does that sound right? The guy I saw was definitely more experienced with subarus, this jeep/dodge stuff seems to be pretty unusual.

Where can I find/buy the Ford injector data without paying $300 for a DVD? I'm happy to pay for whatever I need to get my damn Jeep running, but the only source people seem to reference for injector data would be more cost effective if I planned on tuning lots of different vehicles, not just my one jeep. I'd rather pay $300 for a base map than a DVD at this point in time.

KPTune.hptScreenshot 2015-05-13 16.06.07.png