variable valve timing
AudiWorld Super User
Joined: Mar 2000
Posts: 21,108
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From: Gainesville, FL
Yea, a lot of technology for little hp.....
I'm not trying to start a flame war here, so everybody just sit down. What I am saying is that Audi has invested lots of R&D into VVT and 5 valves per cylinder....and for what? A 2.8 V6 that puts out the same, if not less hp than the competition's V6s. Same goes for the 1.8t 170 engine. All that technology of VVT, DBW, and 5 valves....for only 170hp? Not that impressive until you chip it. BUT, I did hear that the VVT on the 170 1.8t was mostly engineered for low emissions (now certified an ULEV engine).
Junior Member
Joined: Nov 2000
Posts: 767
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The VVT is on the exhaust cam only and only varys phase.
Mostly for emissions remains my guess.
Honda's VTEC uses two seperate cam profiles and allows one to be tuned for high RPM, the other for low. When most people think VVT they think VTEC and high RPM motors.
170hp is not the impressive stat of the 1.8T, the good thing about the 1.8T IMHO is it's totally flat torque curve starting at low RPM. Same goes for the 2.7T.
Hp numbers are one thing, but how the motor drives, torque, is a seperate, more important, issue.
I was not that impressed with the 2.8, but that was mostly based on it's cost. I think the new 3.0 should be better as well.
Honda's VTEC uses two seperate cam profiles and allows one to be tuned for high RPM, the other for low. When most people think VVT they think VTEC and high RPM motors.
170hp is not the impressive stat of the 1.8T, the good thing about the 1.8T IMHO is it's totally flat torque curve starting at low RPM. Same goes for the 2.7T.
Hp numbers are one thing, but how the motor drives, torque, is a seperate, more important, issue.
I was not that impressed with the 2.8, but that was mostly based on it's cost. I think the new 3.0 should be better as well.
New Member
Joined: Apr 2001
Posts: 248
Likes: 0
You're right...
Compared to the 170 hp 1.8 VTEC in my Integra GS-R, Audi's 1.8T is way better... You don't have to push it to 6000 RPM (8200 RMP redline on the GS-R) to get going, and people don't think you are showing off because of all that noise!!
Still, a 8000 RPM redline is nice... ;-)
Still, a 8000 RPM redline is nice... ;-)
Member
Joined: Mar 2000
Posts: 3,348
Likes: 0
No, VVT is on the intake cam.
The exhaust cam is directly connected to the crank via the timing belt so the timing can not be changed. The exhaust cam and intake cam are connected in the rear of the head with a chain. The tensioner on the 01 1.8ts are replaced by an 'adjuster' which moves up and down to vary the relationahip between the 2 cams so the timing of the intake cam can be changed in relation to the exhaust cam.
You're right about it only varies the phase.
You're right about it only varies the phase.
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Junior Member
Joined: Nov 2000
Posts: 767
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From your first post..
The tensioner thing you describe sounds really crappy. Usually the sprocket itself has two parts, allowing the camshaft to twist a few degrees (controlled by oil pressure) within the sprocket.
What you describe, just sounds...bad.
Is there a matching tensioner on the other 1/2 of the chain? Or does it just run the chain loose at times?
What you describe, just sounds...bad.
Is there a matching tensioner on the other 1/2 of the chain? Or does it just run the chain loose at times?