Ear buffeting and relief vent noise/flutter after alucab and seat delete

[Teqsand]

So I am having some problems with my hardtop 2023 JTR after a few modifications. I have done the following:

• alucab contour canopy
• 60% goose gear seat delete.

My main problem right now is I am having some pretty intense ear buffeting with all the windows up. Driving on the highway, or honestly above 30mph, I get rapid pressure changes in my ears that uncomfortable and buffeting like when a single window is down. I can also hear my rear right pressure relief vent flapping and making noise like it never used it (confirmed visually looking through the speaker clasp). It seems to go away a bit when I open the rear bed window. What I fear is the alucab has changed the pressure behind the cab in a way that is messing with the pressure vents window of operation. The flapping closed is annoying but whatever, but the pressure changes and buffeting causing my ear problems is too much.

I am at a bit of a loss for what to try to fix this, its so uncomfortable to drive right now and I am preparing for a cross country trip. I have ordered some hothead headliners just for cabin noise reduction, but the pressure buffeting and vent fluttering when driving is getting to be too much. Does anyone have any things I could try or advice? I cant find anyone else with these problems which makes me feel a little crazy.

I have a DIY seat delete and a non RSI cap (damn near same) and don't have that noise issue.....

Off the top of my head, it the cardboard on top worked, why not get a peice sheetmetal and place it between the bed and the cap horizontally between the cab and the bed.... makes a small inconspicuous wind deflector just above the vents

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[BourbonRunner]

I have a DIY seat delete and a non RSI cap (damn near same) and don't have that noise issue.....

Off the top of my head, it the cardboard on top worked, why not get a peice sheetmetal and place it between the bed and the cap horizontally between the cab and the bed.... makes a small inconspicuous wind deflector just above the vents

I would think the platform rack you have is disturbing enough of the a slip stream over the cabin to prevent the issue OP is having.

That being said, what cap is that?

 

[Teqsand]

I would think the platform rack you have is disturbing enough of the a slip stream over the cabin to prevent the issue OP is having.

That being said, what cap is that?

Good theory, but I just installed that rack about 3 days ago. Lol.....

Its the Chinese version, and uses same latches as RSI and its a great top, well made and solid

 

[BourbonRunner]

Good theory, but I just installed that rack about 3 days ago. Lol.....

Its the Chinese version, and uses same latches as RSI and its a great top, well made and solid

I stand corrected!

Probably has something to do with whatever variance between the AluCab and the Chinesium's shape is on the leading edge then.

 

[Apothum]

For now I have some insulation installed and it seems to have fixed the flapping and reduced the cabin buffeting. Still might look into a simple gutter fairing to try and really fix the problem and give me .25 mpg back.

 

[nanook12]

That will collect road grit and grind it into your paint finish. I wouldn’t leave it there for long.

 

[Teqsand]

I stand corrected!

Probably has something to do with whatever variance between the AluCab and the Chinesium's shape is on the leading edge then.

Possibly

 

[smlobx]

This is what I’m working with

As I said last night I have the earlier version of the canopy and it looks like I have about the same gap as the OP without any buffeting. I do leave the crossbars on all the time but I don’t know if that comes into play.

 

[NotSo Bright White]

For now I have some insulation installed and it seems to have fixed the flapping and reduced the cabin buffeting. Still might look into a simple gutter fairing to try and really fix the problem and give me .25 mpg back.

If you were closer, I would sell you my spare gutter roof rack cheap as I had to buy a complete set. Hope you figure it out.

 

[Apothum]

Possibly

As I said last night I have the earlier version of the canopy and it looks like I have about the same gap as the OP without any buffeting. I do leave the crossbars on all the time but I don’t know if that comes into play.

Might be the seat delete combo and tinnitus ridden ears. I’ll try some sound foam covering the rear wall too.

 

[Lunentucker]

As I said last night I have the earlier version of the canopy and it looks like I have about the same gap as the OP without any buffeting. I do leave the crossbars on all the time but I don’t know if that comes into play.

That crossbar probably does cause enough negative pressure up there to move the air slightly differently. That could be a relatively cheap fix.

 

[Rocksalt]

Might be the seat delete combo and tinnitus ridden ears. I’ll try some sound foam covering the rear wall too.

I doubt the rear seat delete has anything to do with it

 

[Escape.idiocracy]

I doubt the rear seat delete has anything to do with it

I agree- I bet it is the air pressure difference being caused by the gap/air interference with this particular canopy.

OP- the vent pops out…. Maybe look at modifying the top edge (on the side between the cab and the bed…) possibly even some more of the insulation foam you have- just isolate it to the vent. Could also look at adding poly foam at the vents to see if this will make a difference…. Don’t want to block them completely…. But maybe slowing the air down will make a difference.

the noodle/insulation is changing the air flow and pressure going between the cab and bed… gotta replicate this down at the vent.

 

[Apothum]

I agree- I bet it is the air pressure difference being caused by the gap/air interference with this particular canopy.

OP- the vent pops out…. Maybe look at modifying the top edge (on the side between the cab and the bed…) possibly even some more of the insulation foam you have- just isolate it to the vent. Could also look at adding poly foam at the vents to see if this will make a difference…. Don’t want to block them completely…. But maybe slowing the air down will make a difference.

the noodle/insulation is changing the air flow and pressure going between the cab and bed… gotta replicate this down at the vent.

I did also confirm that I can stop the flapping noise and somewhat stop the ear pressure (not totally sure) by placing several towels and a 2 inch thick piece of foam pressed up against the back of the cab where the seat once was. So the theory of slowing down the air has some merit.

I have removed the noodle after more thinking about the paint damage. I’ve ordered an alu cab low profile cross bar/rack and a rhino fairing which should extend forward and complete cover the gap. I hope this works and offers a more permanent solution.

Longer term I’ll be removing that flimsy plastic rear wall and replacing it with something like the goose gear rear plate and maybe putting some dynamat on the back wall and acoustic foam on the goose plate.

 

[mx5red]

I doubt the rear seat delete has anything to do with it

The bed cap is causing the buffeting. The rear cabin vents are the entry point for the air. I think it's easier to block those vents to stop the buffeting than to fab something to the roof.
You don't want to put a sheet of metal/plastic on top of the roof because there is a small amount of movement of the cab relative to the bed, so anything mounted to the bed rack that's also stuck to the cab will rub the paint off the top of the cab. OP If you want to buy a rack and deflector to put up top then go for it, if you want a cheaper option then block the vents.

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