B8024 and 8025 High Speed Mode

[Protec]

Gents,

Looking and trying to learn the E38 I've noticed that after a dyno tune my High Speed Mode RPM Enter {B8024} was left at 500

My High Speed Mode RPM Exit {B8025} was left at 400


These were initially set at 4000 and 3900 respectfully.


Can anyone advise on if these should go back to the higher values and if so what their intended purpose is?


Thanks in advance,


John

[Dieselman]

If I can remember correctly these are the settings for when the ECM uses the MAF readings for all airflow measurements. I take it the tune was a MAF only tune and not Speed Density ??

Happy to be corrected if I'm wrong

Ben

[Protec]

Yes, Its MAF only...

Just wondering if there are advantages to decreasing those numbers or they need to be moved back.

Thanks,

John

[Rhino79]

This is very popular on e38's and I have seen it help on transient fueling in the lower rpm cells on some setups.

[joecar]

If the E38 B8024/5 are the same as the LS1B B0120, then setting them to 500/400 disables the VE (i.e runs MAF only).

[Protec]

I would imagine then that these tables are probably disabled to dial in the MAF and might not have been set back.

Looks like I've been running MAF without the VE tables.. In any event it ran great, but I'll try setting them back to stock and see how the engine reacts.

Thanks,

John-

[Taz]

Hello John,

Do you know what tuning software your tuner used ? The reason I ask, is with EFILive tuning both the VVE and the MAF is reasonably straight forward. Not so with other tuning softwares. Some tuners will tune strictly MAF only (never tuning the VVE).

So, perhaps your tuner calibrated both the VVE and MAF tables, and simply omitted to return the MAF to high speed function. Or, perhaps the VVE was never tuned. Just be careful if you make any changes to the tune. Would recommend a WBO in place as a precaution.


Regards,
Taz

[Protec]

Thanks Taz... Looks like they are going more MAF based than VE...

This will give me a chance to learn and work with the VE tables to see which work better or if using them combined is the way to go.

Best,

john