vtraudt

Aside from the cam chain tensioner (with solenoid/actuator), does the camshaft (which? Intake or Exhaust, or both) have to be changed also? If so, what is the physical difference between VVT and non-VVT cams?

Since the AEB ECU does not have a provision (newer engines with Bosch 7.1 can be tuned to control the cam), is it feasible to grab an RPM signal and use (via relay) to 'manually' activate the VVT solenoid/actuator?

Has anybody done (links to write ups?) the VVT conversion (any 1.8T engine)?

Ditto AEB?

tofast2belast

there is no difference in the cams, they are interchangeable. its not like the honda vtec. the vvt simply adjusts cam timing on intake.

vtraudt

So all it takes is
- replace the AEB (non VVT) cam chain tensioner/adjuster with an VVT one (by the way: do the ones from the 2.7T (and 2.8 V6 30V fit?
- use cams as is
- wire up the adjuster
- "create" (rpm, ECU) a signal to turn the adjuster on/off

vtraudt

Can someone confirm you conclusion?

tofast2belast

Don't think you can use the vvt from the 2.8 since they are side dependent. And here's another link

http://www.audizine.com/forum/showth...for-an-058-AEB

Prospeeder

Ok the adjuster doesn't just go full on full off, it uses pulse width modulation to control how much oil pressure goes to the solenoid to adjust cam timing through a whole range. If you go through measuring blocks its not cam adjuster on or off, its a percentage of duty cycle. Not just on and off like a honda. Its got a huge variance the logic system uses to optimize cam timing for RPM and load. And The intake cam IS different!! If you put vvt cam on a non vvt engine it will be so freakin gutless from a stop trust me I did it and they ARE different part numbers. Get a ECU and harness, intake cam and vvt solenoid from a 01 AWM A4 engine and just swap the ECU and harness. 2001 cars will have IMO so you will need the imo removed from the ecu.

vtraudt

The 2.7T engines I logged all show 'On-Off' behavior (20 degrees).
Would be surprised if the 1.8T are different?

BTW: How IS the angle change accomplished? Solenoid to allow oil into the cam chain tensioner and pushing the tensioner out?

Prospeeder

Exactly, it can pulse the solenoid a high speed allowing more or less oil in to make the tensioner extend or retract a certain amount for the desired valve timing.

tofast2belast

The cams are not different. The vvt in our car only affects cam timing angle not duration or lift. It's not like the honda vtec systems.

When using vvt on not vvt head must also swap the cam position sensor wheel as this is a 4 window vs 2 window.

If you want I'll show you how the 2 cams are the same.

Prospeeder

They are not the same cam. 6 months ago i swapped a 02 beetle 1.8T vvt head onto a 98 Passat 1.8 AEB. The thing was so awful slow it was hideous. Found the intake cams DID have different numbers, i swapped the intake cam back from the old wrecked AEB head and all was well. Exhaust is the same. Intake is not. Only reason I even realized it was the cam was because on Audizine its been discussed before the cams are different.