N/A tuning 20V, VVIS, something diffirent.

[tjts1]

Does the car you did the modification to happen to have a trip computer to give you real time fuel economy? I would be curious if its move efficient with just the long or both long/short intake turned on. I could see having VVIS setup with a switch in the dash. Both runners open for FE, and just the long runner open for power at low RPM.

[razorx]

Very nice work! I wonder why Volvo chose to configure the system in the way they did?

I am still wondering.

What is the normal state of the VVIS valve? If it's normally in the closed position, I suppose one could test the low-speed improvement by simply unplugging the actuator?

The best description is the official Volvo one, in my first post.
Very short description:
Always both channels open, except when below 4100rpm AND more than 80% throttle opening.
When you accelerate the original system will only give you wat you need with more than 80% throttle, and to late.

Did you happen to log air-fuel ratio for the runs you posted earlier? Does the stock ecu correct automatically for changes in the changes in volumetric efficiency?

In some earlier tests we logged the AFR. It is still round the 14,7.
The stock ecu ccan handle this. A very important question b.t.w..

I believe I tested my idea by unplugging the connector.
Not 100% sure.

[razorx]

Does the car you did the modification to happen to have a trip computer to give you real time fuel economy? I would be curious if its move efficient with just the long or both long/short intake turned on. I could see having VVIS setup with a switch in the dash. Both runners open for FE, and just the long runner open for power at low RPM.

The modified car has a trip computer.
With quiet driving the economy improves a little bit.

If you enjoy the system, the economy worsenes.
The switch I only used for testing purposes.
0 means Volvo system
1 means my system, which opens de schort duct automatically above 4100rpm.

[RobTheModd]

*cough cough* when can we get our hands on this.
as i have a 96 850 GLT id love to try it out. providing its not going to damage the car lol.

[matthew1]

Razorx,

Please continue to use this website as your bullhorn regarding your research and product.



I do not consider this advertising at all. On the contrary, this is super information for N/A owners.

Please continue to update us about your research, and your plans to make this a product.

[tjts1]

+1
I really enjoyed reading about your project and learned a lot.

[razorx]

Sorry for the delay, yust soldering some circuit boards.

@Matthew: Thank you, I yust sent you a PM to be sure.

Well, after a year of serious testing, with multipe engine versions. MT/AT LPG/Gasoline, AFR e.t.c. I can only say it is a ready and well tested product.

If somebody is interested, please feel free to send me a PM.

At the Dutch Volvo 850 forum, http://www.volvo850forum.nl another person has started a very interesting topic about low budged tuning.

This is not as easy as my mod and involves some craftsmanship.
(Manifold matching). Lot of work b.t.w., but interesting.
I will inform you when there are the first results.

Kind regards,
Y.

[razorx]

Good morning,

mck1 has helped me a lot working on the manual. I dared to change a few things.

Please read it well, my native language is not English:
http://www.paerl.it/volvo/vvis%20manual%20eng.pdf

Is this clear enough?
Kind regards,
Yits.

[beewerks]

A very good writeup! The grammer could be tweaked a bit, but it can still be understood. So how long till we can get our paws on one of these babies!?

[razorx]

They are available.
So anyone interested, please pm for more information.
Kind regards, Yits.