PDA

View Full Version : B8024 Set to 10



Highlander
August 10th, 2009, 04:05 PM
Just wondering...

Haven't tried this, but... Wouldn't it be easier to tune a cam if we only tuned the MAF portion? Just like the LT1 days?

Just wondering about this...

Thanks

swingtan
August 10th, 2009, 05:44 PM
I guess it's a question of how much influence the VVE has below this value. I'm not sure if any one has actually tested for the effects of of the VVE below the value in B8024, or maybe there are a few and no one is talking about it.....


I do know that getting the VVE close and reverting back to a MAF retains the "SD" feeling in the car. In fact that's how I'm running ATM, OL-MAF. I haven't revisited the VVE for a while so maybe I should see what the effects of altering B8024 are.....

Simon.

Highlander
August 10th, 2009, 05:54 PM
The purpose was to "disable" VVE altogether.

GAMEOVER
August 11th, 2009, 07:44 AM
I guess it's a question of how much influence the VVE has below this value. I'm not sure if any one has actually tested for the effects of of the VVE below the value in B8024, or maybe there are a few and no one is talking about it.....


I do know that getting the VVE close and reverting back to a MAF retains the "SD" feeling in the car. In fact that's how I'm running ATM, OL-MAF. I haven't revisited the VVE for a while so maybe I should see what the effects of altering B8024 are.....

Simon.

I've been wanting to try OL-MAF in my truck but I didnt want to lose that SD feeling either...I really like the way it runs in SD! I can't remember where my MAF is anyways...:D For OL-MAF... Do I just re-enable the MAF, dial it in using my WB02 and that would be it? If I set B8024 to 10, that would disable the VVE? Or?

swingtan
August 11th, 2009, 09:32 AM
The purpose was to "disable" VVE altogether.

Yes, I got that. But I wondered if the VVE still provided some important feed back at the lower RPM's. I was thinking about why GM set the trigger point at 4,000 RPM in the first place. Was it so that below 4,000 RPM, the engine could still run after a MAF failure, but it would not run over 4,000 RPM? Or maybe there was some other drive-ability issue that the VVE helped the MAF along with?


I've been wanting to try OL-MAF in my truck but I didnt want to lose that SD feeling either...I really like the way it runs in SD! I can't remember where my MAF is anyways...:D For OL-MAF... Do I just re-enable the MAF, dial it in using my WB02 and that would be it? If I set B8024 to 10, that would disable the VVE? Or?

Basically, yes. Re-enable the MAF and dial it in. In the E38 controller, there are a few parameters that rely on the MAF air flow readings. Without the MAF, these tables would work off the "0" airflow cells, which is not the greatest idea for a daily driver. You can calculate a pseudo MAF airflow figure, but it is not as responsive as the MAF and often lags the MAF reading on transients.

At the moment I'm very happy with the MAF and think it's the way to go with the E38, but we'll leave that for another thread....

Simon.

Highlander
August 11th, 2009, 06:30 PM
Yes, I got that. But I wondered if the VVE still provided some important feed back at the lower RPM's. I was thinking about why GM set the trigger point at 4,000 RPM in the first place. Was it so that below 4,000 RPM, the engine could still run after a MAF failure, but it would not run over 4,000 RPM? Or maybe there was some other drive-ability issue that the VVE helped the MAF along with?



Basically, yes. Re-enable the MAF and dial it in. In the E38 controller, there are a few parameters that rely on the MAF air flow readings. Without the MAF, these tables would work off the "0" airflow cells, which is not the greatest idea for a daily driver. You can calculate a pseudo MAF airflow figure, but it is not as responsive as the MAF and often lags the MAF reading on transients.

At the moment I'm very happy with the MAF and think it's the way to go with the E38, but we'll leave that for another thread....

Simon.

Fueling is more consistent at low "speeds" in a SD arrangement. Thing is that if there is turbulent flow, the reading is not going to be good. It's not the same thing to have a VE table that "corresponds" to your base fueling as something that is really measured and corrected. It is much faster/precise to get the reading from a correct table than to have a sensor measure the flow and/or immediately correct through the O2. Car is/should be more responsive and or less prone to miss/surge. But... it is much more time consuming to dial in the VE table than it is to dial in the MAF table.