# 1.8t with variable valve timing



## simongti (Dec 24, 2001)

My buddy says that his audi 1.8t has some sort of variable valve timing. I have never heard anything like this or seen it. Iam just curious if any 1.8t motor has anything remotely close to this.


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## traian (Jan 18, 2001)

*Re: 1.8t with variable valve timing (simongti)*

I think AWW and AWP motors have VVT on one of the camshafts (I think the intake cam, but I'm not sure).


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## memnuts (Mar 23, 2000)

*Re: 1.8t with variable valve timing (simongti)*

Also keep in mind that only the Audi's have continuously variable valve timing. As proved by me running data block on my friends 2001 A4. Mean while the Volkswagens cam timing is only active during warm up running. Good old VAG logic mystifying again.


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## Kei78 (Oct 8, 2001)

*Re: 1.8t with variable valve timing (simongti)*

hmmm i think your talking about variable CAM timing...


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## john s (Nov 14, 2000)

*Re: Volkswagens cam timing is only active during warm up running (memnuts)*

Here's where they're coming from:
"Strategies to Improve Cold Start, Warm-up and Transient Operation by Means of Variable Valve Timing" by Prof. Dr.-Ing.Stefan Pischinger, Chair for Internal Combustion Engines,
RWTH Aachen, and Dr.-Ing.Wolfgang Salber (lecturer), FEV-Motorentechnik GmbH, Aachen:
Variable valve timing not only results in a significant reduction of fuel consumption but also in a further optimization of cold start, warm-up and transient operation. In contrast to the conventional throttled engine, an optimized control of load and in-cylinder gas movement is achieved from the start of the first cycle. With the control strategy "Late Intake Valve Opening", the HC-start-emissions can be reduced by approximately 60 %. Compared to a conventional start the particulate emissions can be further reduced with a throttled engine by adapting the cylinder load during starting. Because of a smaller wall-applied fuel film the control strategy "Late Intake Valve Opening" improves the transient idling after starting. It was demonstrated that excellent smoothness and variable valve timing, thanks to the low emissions generated during starting, constitutes an essential method for meeting more stringent emission standards in the future. Very good lean-mixture driveability at low operating temperatures can be achieved with late inlet-valve-open timing in the early phase of the compression stroke. A late exhaust-valve-open timing during the exhaust stroke results in good exhaust gas afterburning and thus in significantly higher exhaust gas temperatures and lower HC-emissions. With conventional camshaft-driven engines, the intake pressures influence the wall-applied fuel film during transient operation, which in the case of negative load changes cannot be compensated for by modifying injection parameters. With variable valve timing, the negative load change can be improved significantly by means of a sudden backflow of exhaust gas with high momentum into the intake port.


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## soundzero (Aug 17, 2001)

*Re: 1.8t with variable valve timing (simongti)*

quote:[HR][/HR]My buddy says that his audi 1.8t has some sort of variable valve timing. I have never heard anything like this or seen it. Iam just curious if any 1.8t motor has anything remotely close to this.[HR][/HR]​Noone really answered your question yet I see.
AWP 1.8t engine for VWs also have VVT. You can confirm this through VW dealership service people.


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## MRP2001GTi (Oct 6, 2000)

*Re: 1.8t with variable valve timing (soundzero)*

VW has VCT but its not used for additional power. Audis use the same feature for added power. From what I understand anyway.


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## Seanathan (May 1, 2002)

*Re: 1.8t with variable valve timing (soundzero)*

The AWP'S have VVT, Variable Valve Timing, not VCT, Variable Cam Timing. VVT is similiar to Toyota VVTI technology and Honda's notorious V-TEC. Except like said, its not really used in VW's for power. We have enough torque already. Don't listen to what everyone else says. Believe me and Soundzero. We know. It's in the Bentley Manuals, and many posts.


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## AZGolf (Jun 6, 2000)

*Re: 1.8t with variable valve timing (Seanathan`)*

quote:[HR][/HR]The AWP'S have VVT, Variable Valve Timing, not VCT, Variable Cam Timing. VVT is similiar to Toyota VVTI technology and Honda's notorious V-TEC. Except like said, its not really used in VW's for power. We have enough torque already. Don't listen to what everyone else says. Believe me and Soundzero. We know. It's in the Bentley Manuals, and many posts.







[HR][/HR]​BZZZZZZT! No sir! Pull your valve cover off and look at the cams. Only one lobe per valve actuator. Compare that to a VTEC cam or Toyota VVTL-i cam which actually has two SEPARATE cam profiles on the camshafts. None of the 1.8T's have multiple camshaft profiles.


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## magtI.8t (May 14, 2002)

*Re: 1.8t with variable valve timing (AZGolf)*

I think he said VCT is VTec / VVTi ? porbably a typo for 
VVT is similiar to Toyota VVTI technology 
should be 
VCT is similiar to Toyota VVTI technology


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## John A (Feb 19, 2001)

*Re: 1.8t with variable valve timing (Seanathan`)*

quote:[HR][/HR]The AWP'S have VVT, Variable Valve Timing, not VCT, Variable Cam Timing. VVT is similiar to Toyota VVTI technology and Honda's notorious V-TEC. Except like said, its not really used in VW's for power. We have enough torque already. Don't listen to what everyone else says. Believe me and Soundzero. We know. It's in the Bentley Manuals, and many posts[HR][/HR]​um... no... i've got here my copy of the bosch motronic book from bentley...








there is no variable valve timing on any current 1.8t vw engines -- it is indeed variable cam timing -- and like it was said a few times above, it's only used during warm-up for emissions control. 
http://****************.com/smile/emthup.gif


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## MRP2001GTi (Oct 6, 2000)

*Re: 1.8t with variable valve timing (Seanathan`)*

quote:[HR][/HR]The AWP'S have VVT, Variable Valve Timing, not VCT, Variable Cam Timing. VVT is similiar to Toyota VVTI technology and Honda's notorious V-TEC. Except like said, its not really used in VW's for power. We have enough torque already. Don't listen to what everyone else says. Believe me and Soundzero. We know. It's in the Bentley Manuals, and many posts.







[HR][/HR]​I think your wrong but then again I was wrong once so I could be mistaken. Makes a lot of sense huh? Anyway as far as I know the AWW and AWP has VCT and the way it works is very simple. There is a servo motor that adjust where the slack is located between the intake and exhaust cams giving the intake cam a little plus or minus on the retard or advance. You could call it VVT because in a way it is. But its the intake cam that your primarily retarding or advancing. Now I think Toyota has VVTL which retards and advances timing and changes the amount of lift. Anyway its not like we get any power from it so its nothing but a waste of breath to mention if your talking performance.


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## Miljan (Dec 29, 2001)

*Re: 1.8t with variable valve timing (MRP2001GTi)*

Hope this will contribute to the ongoing discussion.
This is an scanned document from Erwin (european version of bentley manuals).
engine codes:
AGU=AWD
AUM=AWW
AUQ=AWP

http://80.62.251.114/doc/enginedata.tif 


[Modified by Miljan, 4:14 PM 8-2-2002]


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## Hapa TT (Feb 24, 2002)

*Re: 1.8t with variable valve timing (AZGolf)*

quote:[HR][/HR]BZZZZZZT! No sir! Pull your valve cover off and look at the cams. Only one lobe per valve actuator. Compare that to a VTEC cam or Toyota VVTL-i cam which actually has two SEPARATE cam profiles on the camshafts. None of the 1.8T's have multiple camshaft profiles.[HR][/HR]​vtec isnt _continuously_ variable, meaning it has a low and high-rpm mode, thus that is evident with the cams. someone mentioned continuous VCT or VVT, and im not really sure how that is achieved (I don't think my car has it) but probably quite mechanically different from vtec, I imagine.


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## BoxCar (Jan 11, 2002)

*Re: 1.8t with variable valve timing (AZGolf)*

If the cams drive the valves and the cams are variablely timed doesn't it follow that the valves are variably timed as well?


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## john s (Nov 14, 2000)

*Re: There is a servo motor... (MRP2001GTi)*

Nope, just a solenoid, oil pressure moves the tensioner. You get 2 positions, power (default) and torque. About 24° difference.


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## smd3 (Aug 5, 2001)

*Re: 1.8t with variable valve timing (simongti)*

I didn't read the whole thread, so this may be repeat. UKAUSSI found that AWW/AWP VCT only works during cold start for emmissions reasons. The new 170hp Audi 1.8t uses it all the time I guess, as well as a couple other changes to make it ULEV.
EDIT:
Ok, now I've had a chance to read the thread entirely, and yes I repeated, but I guess I'm just backup everyone up on this one.
who needs variable valve timing anyway. It's really only useful in those high strung, low torque motors. Our cars develop torque low, and hold it pretty damn well for the average driver. Hardcore enthusiasts will most likely upgrade the turbo which will bring the power higher in the RPM band. VVT would just be one more hassle to deal with, we don't need it.


[Modified by smd3, 4:22 PM 8-2-2002]


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