Virtual VE starting point for new build

[g8zimm]

Hey Guys,

I have been reading for the past 2 days straight and give up So I am asking the smart folks here...

I am helping a buddy with a rebuilt 5.3, he removed the DOD and added a mild truck CAM (for a 2007 Avalanche). He just needs to get it safely to a place to have it tuned but they are a ways away... I understand how to shut off the DOD and set the Idle up a bit.

I also understand I should add more fuel to not have a lean condition due to the CAM. Most of what I read is about multiplying the VE table by 1.15. I just want to make sure it works the same with the Virtual VE Editor on the Gen 4? It looks different than most tutorials I have found?!?!?

So... Multiply by 1.15 on the Virtual VE and Multiply the MAF by 1.03. Is that safe, or am i not understanding this?

Thanks a ton for all the info that is here...
-Scott

[Lakegoat]

If it's a mild truck cam, adding 1.03 to the MAF, should get you going. Don't fool with the VVE, let the tuner do that. Don't drive over 2000 rpm or so. I would pull about 3 degrees of timing out of the high octane table just to be safe. You may have to add a little to the Base Running Airflow to get it to idle with the cam. Be sure and make a copy of the base tune before you modify it.

[g8zimm]

If it's a mild truck cam, adding 1.03 to the MAF, should get you going. Don't fool with the VVE, let the tuner do that. Don't drive over 2000 rpm or so. I would pull about 3 degrees of timing out of the high octane table just to be safe. You may have to add a little to the Base Running Airflow to get it to idle with the cam. Be sure and make a copy of the base tune before you modify it.

Excellent... Thanks a TON for the reassurance!

-Scott

[g8zimm]

One more question if you have time to answer... I got it running and it seems pretty good... The idle is still just a little rough, how much is adding a "little" to the Base Running Airflow? I multiplied the entire "Airflow Final Minimum" table in the Base Running Airflow section by 1.03. I am not sure I changed it enough to have an impact at only 3%. The delta at 600rpm is .16 g/s and .23 g/s at 800rpm?!?!?

Thanks again!

[Lakegoat]

What is your idle timing? You may need to add a couple of degrees and set the idle to 750 rpm until you get it tuned. On the Base airflow, if it is 5.** stock, add 1.** to that to make it 6.**g/s, in the lower rpm area, 600-to 1000 rpm areas. And see how that works. Keep track of the changes in case you need to go back.

[g8zimm]

Thanks on the Base Airflow, I will up that tomorrow... And thanks for the advice, I have been making changes one at a time and creating a new file every change.

On the idle timing I am a bit confused on that. Is that in the table that is in Spark->Advance->Main Spark Advance (High and Low Octane)? Or the Spark->Advance->Idle Spark Advance->Base? I would think it is the later, if it is, the Idle Spark Advance in the 600-800rpm range is 16 degrees. In the Main Spark Advance it is 30 to 43 between 600-800rpm on the low octane and 2 degrees higher on the high octane (32-45).

So you are thinking besides a little more fuel, I could add timing in what I assume is the Idle Spark Advance Base?

Thanks again for the help, it actually runs fairly well, minus a small random miss every now and again. I think he is going to have it tuned in a couple of weeks by a pro, but again, it seems pretty decent.

[johnny_boii]

Idle Spark Advance Base!