Under bonnet - removing bulkhead/scuttle panel access covers

[Tom109]

SO, I opened this up on mine just to have a look at how the recirc damper was working. here's what I observed.

1. at rest, the recirc damper is about 70% closed, but not sealed.
2. at ignition, it does not seal or unseal all the way but remains in its rest state.
3. when you activate recirc, it closes
4. when you open it, it opens all the way.

after that , it works as expected, either open or closed.

Another observation, with the recirc damper fully open and air on high, the airflow through that vent is clearly restricted by the fairings. There is significant suction on the fairing from the blower fan, meaning that the small grill at the bottom of the windshield is not enough airflow for the HVAC fan. I wonder how many cooling issues could be corrected by providing a way to get more air to that AC intake duct?

Thank you posting this. This pressure drop could affect many performance values. And we now know why there is a blast of cold air in Winter.

I will try pushing the recirculating button tomorrow morning before I switch the heat on.

 

[abakker]

I made one more modification this afternoon. (But did not photograph it as I did it).

On my grenadier, I would frequently get a whistling noise at highway speed when recirc was on. I diagnosed this as blow by air when the recirc damper was closed.

What I did was take a piece of a plastic mesh filter - kind of the texture of a scotch brite pad- that was used in a vacuum cleaner, and cut it to fit over the grate in the attached picture. This is under the hood, and seems to prevent as much pressure from hitting the damper. (Or maybe prevents wind whistling in that grate)

In any case, it works and seems to make things a bit quieter even when the recirc is off.