Holley EFI High Altitude MAP scaling?

[Hoopty]

So a few months ago I scrapped my plans for my turbo Foxbody and picked up a Holley Sniper tuned SN95 with a 347. Now that it's back on the road I am getting the tune dialed in (mostly through the learning feature), but came across an issue with the ignition and fuel tables and the MAP readings at my altittude (~6,000 ASL). My first datalog of a 2-3-4 WOT pull shows that the baro pressure at my altitude is only about 80 kPa, so the fuel and spark tables aren't referencing the correct cells. Thus I am sitting in the cruise portion of the map while WOT. This leaves me at 34* timing, and a fuel target of 14.3. I did not hear any pinging or seem to have any detonation, so this leads me to believe I have some power left on the table if I can get the MAP scaled correctly.

So that leads me to my questions...for the base spark tables, do I need to scale the map itself or the MAP axis down to where the car will be operating? I feel that if I leave the MAP axis 0-105 kPA, I am losing some fidelity in the map, since about 15-20% of it wont be used at any point.

I have attached the tune I am working off of, a screenshot of the datalog (cant post the log file type here) and if no one has the Holley software to view, a screen shot of the base timing table and the cells that were referenced during the pull. Let me know if anyone needs more info. Thanks

 

[Hoopty]

Well looks like I figured it out. I ended up highlighting the MAP scale and hit ctrl+down to move the whole thing and the map scale is now 20-87. Now the engine transitions through the spark table correctly.

 

[a91what]

Well looks like I figured it out. I ended up highlighting the MAP scale and hit ctrl+down to move the whole thing and the map scale is now 20-87. Now the engine transitions through the spark table correctly.

That is not a correct way to deal with the issue, cant you use %baro or barometric offset?

 

[Hoopty]

That is not a correct way to deal with the issue, cant you use %baro or barometric offset?

I do not have the Super Sniper, so I do not believe there is a way to add an offset to the MAP sensor out side of the scales on the tables. I have looked around and I can add a VE offset to the fue flowl, and a few others but nothing just to the map value. Can you elaborate on why this is not the correct way? I will keep poking around and call Holley on Monday if need be.

If there is no sensor offset, would you recommend "sliding" the spark advance tables down so I meet the values I'm looking for at the ~80 kPa I'm seeing, while leaving the rest of the table up to 105 kPa with a reduced timing values?

Thanks for the help!

 

[a91what]

with most ecu you can use the initial map reading to set the "100" kpa reference. so as the pressure drop at increased altitudes the table is referenced as normal

 

[Hoopty]

with most ecu you can use the initial map reading to set the "100" kpa reference. so as the pressure drop at increased altitudes the table is referenced as normal

There is no easily apparent way to do that. I'll give holley a ring on Monday and see what they say. This is the most basic EFI setup they have, so I wouldn't be surprised if it's limited in settings.

 

[Hoopty]

The only way to add any sort of offset is to right click the MAP scale on the spark table and type in a positive or negative offset, which then just changes the numbers the same as what I did.

 

[Hoopty]

Spoke to Holley today and they told me that scaling the MAP axis on the spark and fuel tables is the correct way to do it with my setup. There is no offset. Just a limit of their base Sniper set up I guess. Just have to keep in mind when traveling to higher or lower altitudes, and maybe have maps scaled to different pressures if needed. It's just a cruiser and won't be doing any major travel.