93 and 94 850 Variable-Geometry Intake Manifold info

[j-dawg]

94 VVIS intake manifold on top, and '95 non-VVIS manifold on bottom

[admin edit: split from 95 to 97 850 manual swap topic, photo added]

93 and 94 850s had a variable-geometry intake manifold with a switching-length intake runner. It switched between two intake runner lengths to account for pulse effects in the intake manifold at different engine speeds.

For more info see http://www.volvoclub.org.uk/tech/850glt ... chinfo.pdf. It's an interesting read. Look at page nine - the variable intake lets you ride the top of that ve curve. It's responsible for the sorta croissant-y shape of the manifold. More discussion on this here VVIS vs. Non-VVIS, Would You Do It? <- I Did.

Volvo evidently decided it wasn't worth the cost and complexity because the system was cut after a few years. I'm surprised your car has that because it's a 95, and i thought the system was discontinued after 94.

[dairyqueen814]

Oh awesome that IS cool.
Yeah its a 95. On the title it says it's a 95 GLT but I'm just about positive it's not. This thing is bare bones stock, no winter package, tan cloth interior, no spoiler etc.
I checked the VIN and it says its a 95. Also that it came off the line right in Sweden maybe that has something to do with it.
Maybe it's just an anomaly


Nick

[Ozark Lee]

I think another reason that Volvo eliminated it was that it had a tendency to get stuck. It wasn't terribly reliable.

...Lee

[matthew1]

Maybe it's just an anomaly

The P80 range anomalies are so interesting to me, this included.

[erikv11]

There is something awry in that link up there, it says "page not found" for me, I suspect it is trying to point to this thread, a good one to link when VVIS questions come up:

https://www.matthewsvolvosite.com/forums ... =5&t=30281

[matthew1]

Thanks Erik. Fixed.

[jblackburn]

Funny they're discontinued - they're right back to using them in many non-turbocharged makes/models today!

[shaker_chi]

I have an early 1994 with the VVIS system. Based on my experience, it does NOT give the car anymore low end torque or power. I replaced my PCV system about 10 years ago and I messed up the vacuum hoses so the I mistakenly disable the VVIS system. Turns out I didn't realize any loss in power, but it did kill my gas mileage. I was used to getting 31 on the highway at 65 MPH and it had gone down to 26. It took me a couple months to figure it out, but that was the only difference I noticed.

[dairyqueen814]

It's going to take a while but Im going to see what I can play around with considering I have the entire engine to mess around with. More of a fun project than a necessity but still interesting!

[se13allmylife]

My U.K. spec '95 850 has the VVIS system and all the info I've seen over here suggests it was only on the 20v models and ran till the OBD2 cars came in , which here I believe was late '95 / early '96.