Lone Starr (Ivan)

I was following me Jetta yesterday in my TT and simply could not keep up. Ali powered onto an on ramp and I couldn't catch her.

The only differences between the AWP engine in my Jetta and whatver my TT has is VVT. Different gearings in the tranny can affect it of course, but I know where the power is in my TT.

The good news is that the TT got through the lease-end inspection this morning unscathed and I will receive my deposit back in full. Like, Duh.

evan

I think John S. and rasTTa have posted recently about this... <passes the buck>

hoTTub

Also, from what I have heard/read, the VVT is for emissions but I could be wrong.

joe@vwvortex

conclusion is that it really only works during startup for emissions purposes and helps with initial low end torque - but does very little for overall performance. The biggest difference in the ATC and AWP engine is the turbo and compression ratio. Turbo in the AWP is a k03/k04 hybrid and the compression is slightly lower although not as low as the 225TT. The gearing is also significantly different with the TT having much lower gearing in 1-4.

Lone Starr (Ivan)

that is gives more low end and high end torque with the turbo picking up torque chores in the middle of the RPM range. I was hoping to flesh out this explanation since as I understand Toyota and Hondas VVT it only gives more torque high up.

Lone Starr (Ivan)

Man I am so defeated by the search engine on the Vortex. Thanks Joe, I'll keep looking there.

btitus

I don't find any references to 1.8T VVT on the Audi site. Neither the TT nor the A4 engine spec includes mention of variable valve timing.

They do, however, note having VVT on the V6 and V8 engines.

This is not to say that it doesn't exist, but I'm curious as to how VVT would be "added" to the 1.8T. Seems like adding such a system is not insignificant... as I understand it, you vary the cam timing by changing the timing belt geometry -- thru idler positioning? That sounds pretty tricky, especially as an 'add-on.'

I figure I must be missing something -- can someone explain VVT and the 1.8T?

Lone Starr (Ivan)

It seems upon further research it is Variable CAM timing. From the 1.8T forum at VWVortex.

Lone Starr (Ivan)

I have no more info or I'd share it. Someone offered pics and I intend to take them up on it.

john s

People on VWVortex have sent me their logs, done strictly for emissions. Default position is power position. When cam advance on it gives early intake valve opening letting exhaust gas to travel up intake port then back down intake port, removing fuel film on intake valve head and some off port wall. Early closure increases volumetric efficiency at low to moderate speeds but ECU will switch back to power position so you can't see this the way the have it programmed on the new VWs.<ul><li><a href="http://forums.vwvortex.com/zerothread?id=279826">VWVortex link</a></li></ul>