Installed Yitsbox VVIS Modification

Post by **Ben850** » 01 Nov 2012, 21:48

I was finaly able to install this modification today. I had already done the throttle body mod for the early 850 N/A which was a noticeable improvement in throttle response. But I must say, the "Yitsbox" tied up the loose ends as far as the seemingly confused powerband I was dealing with.
I'm not sure how these engines were originally supposed to run, but I do believe I've got this '93 20V N/A to be about all it can be without blueprinting, and fabricating manifolds, throttle bodies, heads etc...

I ordered the Yitsbox from his ebay listing after a few private messages here on MVS. He was kind enough to find out if I had the Alter 1, or 2 style dash switches. I have Alter 1. It came to around $130. U.S. Shipping time was acceptable from Amsterdam.

I gathered my collection of overkill for the job.

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So what you get in the package is simply the small PC Board/switch with LED on a blank switch plate, Phoenix connector terminals, and two eyelet terminal connectors. The instructions are a single page pdf that is in the ebay listing page.

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This is not a difficult installation. The hardest part is deciding where you want to get through the firewall. I think I was practical and creative with my decision on this. The path of least resistance was what came to mind.
After removing the knee/kick panel under the dash, and the switch blank where the piece would be installed, I looked for a way to get from there to the coil area. This is also close to the vacuum solenoid that needs to be tapped into.
I was able to find a place to drill through the outer fuse box that came out where I wanted to be. One hole through the cowling, and a notch in the rubber grommet on the fusebox harness and I was through and where I wanted to be.

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The fusebox cover sealed the wires, pushing them tightly into the harness grommet. I used Seal-All to close up the small hole in the cowling, needed or not.

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After the cable run was completed, I stripped the switch ends and soldered the terminal connections for the Phoenix plug.

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On the engine compartment side, two wires needed to be spliced into the vacuum solenoid switch, and two wires go to the coil area. One to the coil signal and one to ground.

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I actually soldered all splices and terminal connectors. I like bullet proof.

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After I felt all my connections were good, I buttoned everything up, plugged the switchboard into its Phoenix connector, and pushed the "Yitsbox" into the dash.

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I wanted to add a shot of these cool led work lights that I came across. They are Gyros Magna lights. Just Google that and they can be found, but they are a great help. The magnetic bottom sticks to any ferrous metal surface. ( the yellow light stuck on the torque arm)

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I have only put about 20 miles on it since the installation, but it is a completely new experience. It runs through the gears effortlessly (automatic) whereas it bogged in mid powerband, and upshifted at inappropriate times before. For instance, while ascending a slight grade, it seems to pull right on up without upshift, and very little extra throttle.
The throttle comes on instantaneously, and remains consistent to the amount of "foot" you put into it. I can only imagine this being a positive with respect to mileage.
The only negative to mileage is the amount of "foot" that I find myself wanting to put into it. I have seriously never felt it launch off the line like it does now. I know that is also partially due to the throttle body modification.

In summary, I think it was the most pleasureable outcome to ask for. This was money well spent for the immediate return, and the project itself was not difficult. Actual time working, approximately 2 and a half hours. More time was spent thinking through the routing of the wire, but once it came to me it went fast. And I took Photos.
So if you are dealing with a VVIS equipped setup. I can highly recommend this little box.

Here is the original thread, It has been running for three years.
https://www.matthewsvolvosite.com/forums ... =5&t=24681
Have Fun.

DHLLR27 · Post by **DHLLR27** » 23 Apr 2016, 13:39

Hey, I am super interested in this mod.. Do you know how to get hold of the guy who made it?

Post by **Ben850** » 23 Apr 2016, 19:21

It will not work on a '95. It does not have a VVIS manifold.
Also, I don't think he makes them anymore.

razorx · Post by **razorx** » 27 Apr 2016, 11:29

The chip I used is not being produced anymore.

But it seems that there are still people interested in this "Yitsbox" .

With an amount of 10 to 20 interested people, I can make a new, microcontroller based version.

Post by **matthew1** » 09 May 2016, 10:57

Finally got this in the VRD. Thanks for the reminders ^ guys.

DHLLR27 · Post by **DHLLR27** » 07 Jun 2016, 03:10

@Ben850 At least mine 95 2,5 20V has it, I saw it, when I was doing the PCV System on mine.. before that I didnt even know it existed.

Post by **Ben850** » 10 Jun 2016, 14:57

DHLLR27 wrote:@Ben850 At least mine 95 2,5 20V has it, I saw it, when I was doing the PCV System on mine.. before that I didnt even know it existed.

I see you are in Europe. I have no idea the versions that had come out there over the years.

See if Mr. Yitz can help. It seems he is willing with enough interested parties.

By the way, it is still working well on my '93. I simply leave it switched on full time.

Have Fun.

jantt · Post by **jantt** » 13 Jun 2016, 10:29

Ben850 you have a 93 model and I have a 92 model and it works on yours ?

razorx told me that because I have one of the first 850`s then his switch will not help my car.
I don`t loose power in low rpm. It`s the later models.

Don`t understand that.
If it works on yours then it should work on mine too ?

jantt · Post by **jantt** » 14 Jun 2016, 10:44

I am up for trying and buying.

razorx · Post by **razorx** » 14 Jun 2016, 10:52

The very first 850's had exactly the opposite problem: They lacked power in high revs.

And indeed I am still willing do design a new series. Microcontroller based, because the analog chip I used is not being produced anymore.

Right now we have 3 guys interested:
DHLLR27
Jantt
Triton (volvo850forum.nl)

10 or more interested people will make the production wothwile.

Regards,

Yits.