"Hi Enrico,

You will find my comment on how to put some dump/pop-off valves on a 1993 Ghibli without ABS (the later Ghiblis were fitted with dump valves as standard). Hope it will be of interest to other Ghibli owners.

How to fit dump valves on a 1993 Ghibli without ABS.

First of all, I would like to thanks Jonny Corcutt in The Netherlands, for his knowledge, which helped me a lot.

The Kit The Kit is from Forge in the UK. (www.forgemotorsport.com)

Jonny was the first to ask for such a kit, so it wasn’t difficult for me to get another one.

The Dump Valve Kit consists of: 2 dumps valves (in the picture the valves are already fixed to the chrome metal tubing), 2 chrome metal tubes (same length anddiameter as the standard tubes), 2 T plastic items, a small pipe of approximately 1 metre in length, and a variety of springs: 2 green springs, 2 yellow, 2 blue (which are already installed on the valves) and 2 red.

As you understand, the green are very flexible, and on the other hand the red are hard.

1) How to fit the kit (Part 1).

Before explaining this point, we must bear in mind, that there are two types of plenum cover on the Ghibli without ABS. The first one seems to be on the later one (1992?) As you can see there are 3 pipes coming in the plenum Cover.

On the earlier Ghibli without ABS, it's slightly different (1992?): Indeed as you can see there is a blanked-off port on the centre of the plenum chamber.

To fix the valves, it’s quiet simple. Replace the old metallic item ( by the Forge Kit), and make sure that there is a link between the valves and the plenum chamber. So the first thing I did was to find a pipe connection to fit into the blank port.

Not so hard to find because I've got a plenum chamber from the earlier Ghibli:

So the next step was to fit this pipe connection into the blank port to form a link with the new dump valves.

Then the engine looked like this:

But despite all my efforts, the valves were definitely closed which proved that they weren't working properly(????). Indeed the valves should be open when the engine is running.

So my only solution was to disconnect the small vacuum tube from the top of the new dump valves, at idle (with the engine running) you should feel a vacuum, this is used to open the main piston in the dump valve body (alloy part) viewed through the holes in the side of the dump valve.

But there were no vacuum.

So I looked at the blank port and, the HOLE was CLOSED at the end even if you can fit the item from the other plenum (?????).

No way, I didn’t want to drill any new holes in the plenum.

2) How to fit the kit (Part 2).

So there was a second T-piece (three-way union) in the kit, and I used it to connect the vacuum pipe and the fuel pressure regulator to the plenum chamber.

Here are the different steps:

More important the second T-piece:

Now that the connection between the dump valves and the plenum chamber is complete, it's time to start the engine and: "Victory! The valves are working at idle!!

And finally, more Ghibli engines fitted with dump valves/pop-off valves