Well, if there is any improvement, it isn't much.
I still can't let go of the idea that they must do at least something good at low loads. A lot of trouble has gone into designing tuned intakes over the years on various vehicles, so seems reasonable there should be some level of benefit from higher velocity air creating that slightly improved VE at low RPM. Even on our non-tuned inlets....
So I left the flaps stock below idle. Closed from idle to 1400, then ramping open to 1800 RPM. (This RPM zone is used in a light load gentle acceleration for me, or light load low speed cruise. As soon as there is any real load, I keep the RPM up above ~2000 RPM to ensure adequate oil film stiffness) They will however go full open anytime the IQ is more than 30, as for me this is firmly in the acceleration range, so the boost is up and I'm thinking less restriction is better.
The other thoughts were that I don't want them stationary and potentially seizing. Also wanted to minimise continuous movement to reduce wear. Stock maps have the swirl flaps almost always moving. So now for me they move if I am in a gentle acceleration, or traveling at low speeds with light loads, but varying RPM. Full open on the fwy so no cycling as the speed changes there.
If you are a true optimist, then you might say there is a teeny tiny slight improvement in economy, but I've only done 2000 k's since the change. No long trips since doing it, mostly just across town, around local streets, or down to the boat. I've gone up to 265/65/17 AT's for the last 9,000k's too. The next time I head down to work will be a better indicator to see what full open does. Long freeway runs there.
Current Swirl Flap commands
or in 3D
