GTM Performance Engineering Stage 1 Turn key Supercharger kit In house Installation.

Originally Posted by Jordo!

I don't get it. Is it that their reflash device can not edit the VVEL maps, or just no one knows what they're doing? They should be able to nail this within 4-6 hrs of systematic changes to the maps provided they have full control over VVEL...

As someone else said, too much valve overlap will blow the boost right out before enough cylinder pressure builds. At least you don't have to deal with the built in restriction of a turbo...

Once they get the rough fuel and spark advance map sorted, they just need to run successive dynos manipulating valve and lift. Overlay the dynos to find where power is gained vs lost, while noting boost levels (note that more boost doesn't always mean more power either).

My educated guess is that you need less overlap in the low and midrange and probably don't even need to mess much with lift until the boost really starts to build (centrifigul's build boost late, so this means few changes until later in the rev range).

If it needs changes early on, it might actually be flowing less air if the manifold design was altered from stock, so it might need a little less lift and a little more duration until higher RPM's when boost starts to seriously build -- again, just a guess).

I'm really sorry you are having a tough time with this -- I hope they figure out what they are doing soon -- good luck!