Variable valve timing with Turbots.

Good evening.

Was thinking earlier about the 24v VW engines with turbos attached, and some of the things I've read posted by JNLRacing.

I'm not sure how easy it is to get cams for the 24 valve engines, but I started wondering if the vvt could be used to adjust the overlap to help the performance or adjust the behaviour of the engine in a different way to how it normally works?

For example, you could adjust the overlap throughout the rev range, perhaps giving more overlap at lower revs to help get the turbo spooling, then reduce the overlap to make the most of the extra air?

Or after looking at some of the functionality of the DTA perhaps depending on how hard the go pedal is shoved it could adjust the timing of the cams.

Maybe all rubbish ideas, but just wondered what would be possible.

Not rubbish ideas at all Tom, Dave and I were discussing this exact topic the other day.

I think the key is seeing how it works in standard for and seeing what information something like the DTA can actually use.

Kev I'm sure will have some idea.

I seem to remember reading a VW Driver tech article on one of the VW VVT engines where the timing was altered by oil pressure as the revs rose, quite a simple mechanical device, not sure if that's how the V6's work though, would be interested to find out more.

The 24v has an adjustable guide between the two cam sprockets, that I believe moves up and down to adjust the overlap. A simple PWM output should manage to control that.

Schimmel do some 264 cams for the 24V and Schrick do a set of 268s.

I don't think the VVT in 1.8 and 24V applications is for performance reasons, but rather to improve cylinder filling efficiency for emissions, but that could work well for turbos. I need to study how the timing works and what events / parameters trigger it. I did learn on Karl's engine that it has twin cam position sensors, so if you're going standalone, the VVT won't work as the software isn't written for twin sensors. You could just one of them for sequential fuelling though.

^^^ yep the factory vvt to my understanding is to improve economy at motorway cruising etc.... Although theoretically a stepper motor to regulate oil pressure and a map to control it would do the job. The key is to work out what variables in the table controlling the stepper motor create what sort of cam overlaps. IMHO not worth the effort for the gains seen.
It make an interesting end of year uni project though.