I would guess that none of the LLY beta testers can answer but maybe Ross can. I see a few LLY booststicks for sale in the For Sale section. Is the thought that with EFI we LLY guys will not need the boost stick at all?

I would guess that none of the LLY beta testers can answer but maybe Ross can. I see a few LLY booststicks for sale in the For Sale section. Is the thought that with EFI we LLY guys will not need the boost stick at all?

That is right, we have all the boost and turbo control tables, including the over/under boost diagnostic limits.
For example, on the std GM tune the ECM is still commanding the turbo vanes to be approx 40% open at around 2000RPM.....what a waste!!.

Cheers,
Ross

For example, on the std GM tune the ECM is still commanding the turbo vanes to be approx 40% open at around 2000RPM.....what a waste!!.

Cheers,
Ross

Ross, could you elaborate on why this is a waste, and what we might change it to, and why? You know, for us rookie tuners :)

That is right, we have all the boost and turbo control tables, including the over/under boost diagnostic limits.
For example, on the std GM tune the ECM is still commanding the turbo vanes to be approx 40% open at around 2000RPM.....what a waste!!.

Cheers,
Ross

What is GM's engineers wasting?
And why?

With the Variable Nozzle Turbo's (VNT) it is possible to change the characteristics of the turbo as you wish, so ideally you want very fast spool up down low (like a small turbo would do) and big boost once things wind up (like a big turbo). With the VNT's you can control the way it spools up down low (which GM would probably have set to ideal anyway), but it is possible for GM to limit the turbo 'efficiency' (might not be the correct term) so that when RPM/boost really starts to build they change the vane pitch which in turn limits what boost the turbo could achieve.

So as the RPM's climb they can open the vanes so the turbo just won't create the sort of boost as though they were closed.

Our beta testers have all weekend to play around with these new tables, we'll let you know how it goes.

Do a search on this forum for VNT or LLY Turbo, there is plenty of better descriptions on how they operate than what I offered.:o:

Cheers,
Ross

Thanks!

Gm's turbo map is a compromise between performance and emmisions. There is a lot of room for improvement. The VVT is very capable of producing lots of low end boost economically but is not commanded to. But, like everything else it is a balancing act.

Cleaning up the VVT tables is only part of the solution. There is a need for a little logic adjustment too.