Resetting Baro Correction Maximum

[KenK]

Is there a way to set the Baro Correction Maximum Value??

I need more control.

KenK

[Moody]

Not sure if the details of your vehicle. But I recently switched SD fueling to %Baro on a vehicle that changes elevation frequently in one drive cycle (using a separate baro sensor) and it worked flawlessly with the same SD fuel table.

Would this be an option for yours?

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[Moody]

I adjusted the baro curve slightly but honestly don't think needed to, looking back.....

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[KenK]

Moody:
Thanks for your input.

In my case, the engine is in an Off Road car.

MS2 System:
The MS2 system is currently running on the SD technique.
I do have a separate pressure for BARO.
The MS system is using sequential injection with one injector for each cylinder.
I am using four (4) 48mm throttle bodies, one for each cylinder. Since the motor is a "Boxer" design, the throttle bodies are designed as pairs (two pairs are mounted on the engine).
The MAP signal is a composite average of all four cylinders.
The ignition system is NOT controlled by the MS2 system. I am using a centrifical advance distributor with a single coil.

Engine Details:
The motor I am working with is an air cooled VW motor that has been stroked and bored to 2331cc.
The exhaust system is an open Tri-Mil system with a 2” diameter stinger about 18” long. The cam I am using (Engle 120) is running about 293 degrees of duration.
The compression ratio used is about 11.8 to 1.

The motor starts to come on at about 2200 RPM and the torque starts to fall off at about 5000RPM. Due to dilution issues, the AFR reading below about 1800 or 1900 RPM is pretty unreliable unless the engine is loaded pretty heavily or I run an extension pipe on it. As such, I do most testing in the 2500 to 4000 RPM range.


VE Table:
The VE table I am currently using has a range of 40 kpa to 100kpa. Would this be appropriate for %Baro??

Other than making the changes to the "Engine and Sequential Settings" screen, What other changes do you have to make??

Again, Thanks for your input.

KenK

[KenK]

Converted to %Baro yesterday. Testing still in progress

See link below
http://www.msextra.com/forums/viewtopic ... 34&t=63844

KenK

[Matt Cramer]

Is there a way to set the Baro Correction Maximum Value??

I need more control.

KenK

If you're on the current firmware, set the correction values under Calibrate MAP / Baro to zero and use the barometric correction curve. You can flatten out the curve below (or above) a specific point.

[KenK]

Matt:

I am running the new version of the firmware and the Baro/Correction numbers are set to zero.

The software limits you to 120% as a maximum Baro correction. In my case, going from sea level to 6500 feet above sea level (ASL) was going to take a significantly larger multiplier than 120%. That is why I was asking about being able to change the range of allowable multiplier.

I have changed the calculation from SD to %Baro. When I did this, I set the Baro correction curve at 95 across the board. That will give me a little more room but I am hoping that the %Baro calc will work better for me. At this time, I pretty much have the tune ready to go at least a sea level. On the first weekend of Sept. I plan to go to a location where I can go from about 2000 feet ASL to over 8500 feet ASL. By the end of the weekend, I will know of converting to %Baro will do the trick.

I am hopeful.

Ken

[pit_celica]

In my understanding, your engine will require less fuel at higher altitude (lower baro). So, the maximum limit of 120% for the BaroCorrection shouldn't be a problem here.

Sam

[suberimakuri]

Hi Sam, friends if you're running percent baro or SD. Typically will need more if SD (same with an).

[KenK]

Well, I am happy to report that % Baro worked for me!!

As I stated back on August 11, I converted my system from pure SD to % Baro. I set the baseline elevation correction to 95 from sea level to 10,000 feet ASL. The 95 baseline was used to give me a little more room on the elevation correction table. The conversion to %Baro in my case did require significant rework of the VE table. I had to lean out the engine pretty much across the board at higher loads.

I did make the trip to the desert during the Labor Day weekend. In my case, that was from August 31 through September 4. The weather was HOT all weekend with late and evening afternoon thunder showers. The temperatures ranged from a low in the high 70 degree range to as high as 110 degrees F. Humidity was also high (80% or higher). The base elevation was about 1800 feet ASL and we went as high as 7600 feet ASL.

I am happy to report that the engine ran great at all altitudes. The engine may have leaned out a bit the the higher elevations but not enough to be of any real concern for my application. At this time I do not plan to make any changes to the elevation correction table.

I will do a little more work on the tune at low loads to improve fuel economy but other than that, I am pretty happy with the results.

Elevation problem solved.

Ken