Success for me today woohoo !!!!!!! I had no rattle sounds like my interior is breaking into piece's up to 75mph with all combos of windows down up partially open safari windows etc.
****ATTENTION****. There are 2 downsides. 1 of which I knew going in.
1. I knew buffeting would increase if I increase restriction to the pressure vents. It took may test drives and combos to get a balance. The buffeting is now like an old friends 2003 Audi A4 when you only roll down 1 rear window. But I prefer having to crack a second wind then the noise this vent was generating.
2. Once we got up to 83mph on the toll road the vent began to flap again but the sound is extremely different. It's subtle and not like before. And I don't drive at those speeds with windows down. Any thing over 65mph they are up or are just cracked open. So my target was 75mph just for margin.
If this sounds good enough for anyone else out there here is the list of my modifications. Pictures attached for parts and steps etc.
1. Make new custom flaps out of silicon mat. The one I got measured 1.3mm even though the add said 1.5mm. They way on average 2 more grams each. You will need to make 10 total in 5 different size. I used the factory flaps to trace the new ones. You will need an exacto knife and a leather hole punch. When installing on the vent frame face the shiny side facing outside of the Grenadier. You will know what I am saying when the mat arrives one side is shiny and kinda tacky and the others is matte. Take your time in reality you only need 10 but in total I ended up cutting out 18 because of my lack of cutting skills. The silicon comes shipped folder. Don't make flaps over the folded section they will not be flat enough for the frame.
2. I used 2 different thickness of the same type of foam I purchased at Joannes. A US retail store of fabric and upholstery if you are outside of the US. 1 inch and 1/2 inch thick.
3. Charcoal filter screen sheet. I only purchased because the foam I could find that was breathable was green. And you could see it through the interior panel slots.
4. You will need the left over silicon for the next step. So make your flaps first.
5. See the template pic attached. It is about 3/4 inch wider then the vent cavity. I ended up trimming it down but this should help not waste material. Trim down for your desired tension in the cavity.
5. The cavity filling order that worked for me. 1.25 inch wide strip to fill the gap between the C pillar of the rear and the vent frame. Make sure there is a lot of tension. This piece is because of how the vent frame is acting like a periscope. The air is bouncing of the back of the cab. Pushing and pulling on the flaps. You will see what I mean when you get the interior paneling off and how the mount bracketry is designed. Then the 1 inch thick foam of the template shape . Pay attention to the metal bracket holes on the sides. The foam needs to restrict these too. Al layer of left over silicon sheet. A layer of silicon sheet. A layer of 1/2 inch foam. And last the charcoal filter so you can't see the green.
Depending on your foam source you may not need this combo. I had to add the silicon sheet. Without it the flaps would till cause a racket. The other foams at the store seemed to restrictive and I cabin pressure vent still needs to operate. Your combo could be different based on the supply's you can source. I confirmed vent operation by closing the small tailgate door and watching the flaps open and close. I noticed that the flaps are no longer audible while opening and closing and doors
. That will be the first confirmation of you combo.
Apologies for the long post but it has been a long week of iteration. But I exceeded my target of 75 and hit 82mph. I have been in email contact with Ineos. They confirmed that there are no plans of a new design so it was time well spent. I really like my Grenadier. I asked if they are interested in my fix and they said yes. Will they come up with there own solution, who knows. While I had the paneling off I added left over dynamat from a previous project since I opted for no carpet. I can tell the difference. If you have any questions I would be happy to answer.
Cheers
Edski
