Opps, wait, change that 4 to a 2. My bad.

this has WAY too many assumptions in it to be accurate.... Dan, what was the MAF reading at that point in the datalog?

using MAF, engine speed, and known cylinder displacement, you can calculate a LOT more accurate VE value than assuming it. none of the factory 3800s can manage above a ~80% VE without a blower due to intake and exhaust restrictions(mostly the heads). and FWIW, at idle you'll see around a 40% VE.

Oh so were doing it wrong?

basing the VE of a 3800 on a modern DOHC engine is a bad idea, WAY different animals. and assuming VE has a constant relation to throttle position is also a bad idea, a good example here is 25% throttle, at 1600 RPM, you may see ~75% VE, but at 3200 RPM, you may see only 50%, but 50% throttle at 1600 RPM may only be 77%(a 2% gain) VE, while 50% throttle at 3200 may be 75%(a 25% gain)...

those are realistic numbers BTW, verified on my wife'* LH0.

this is an equation i came up with a while ago to determine VE based on MAF readings:


((2*X)/((Y/60)*3.791))*100


X is MAF reading in grams/sec and Y is engine speed in RPM.

The thing is i am just guessing because i have no way of reading it, i do not have a scanner that will read my computer.

well, Dan does...

any other L36/L67 owners care to chime in with data as well?

At 1600 RPM I have about 4200 hz on the MAF. However I have a ported throttle body, so that'* going to change it. As stated, there'* a lot of factors involved.

what does 4200 Hz translate to in grams/sec, assuming fuel trims are close to perfect at that frequency?

and you'll give OP the benefit of more info: modded motors

also, the 3.791 in the equation? that represents engine displacement, in case there was any confusion about it.

Says here, 2.27 lbs per min at 4200 hz

great... that'* ~17.16 grams/sec....

so ((2*17.16)/((1600/60)*3.791))*100

which is roughly 33.95% VE when at ~7% throttle and ~1600RPM