Bringing them back from DISC - Verus rear diffuser

[Dialcaliper]

I don’t but it’s super easy. Just remove the rear bumper cover and use a flapper to sand off the plastic from the back until the honeycomb is open. There’s pics in my build page. It’s way easier than the grill. View attachment 65205

How does the lower bumper seem structurally after you sanded out the grille? Does it still hold its shape well, or does it feel flimsy?

 

[Woods247]

How does the lower bumper seem structurally after you sanded out the grille? Does it still hold its shape well, or does it feel flimsy?

Mine is actually better since packed air isn’t pulling at the lower two plastic tabs. Multiple runs over 130mph and zero issues.

 

[Woods247]

Does this really help much? Looks super cool and I'm wanting to do it soon! @Woods247 said higher top speeds. Could you explain more if it's effectiveness?

Air gets packed behind the bumper cover at high track speeds. Actually it’s probably effective at any speed over 45mph. I definitely saw a speed increase by a few mph at the top of 5th gear on track at Road Atlanta. After adding the Verus diffuser (to my already opened rear bumper) I saw no gains anywhere. Others may experience different results but in my real-world tests it showed no gains. The car needs a flat floor and maybe a tiny flap to kick the air over the rear torsion beam and sway bar to make a rear diffuser effective. I’m surprised Verus didn’t account for the OEM floor, rear beam and swaybar in their computer models.

 

[BadShot]

Does this really help much? Looks super cool and I'm wanting to do it soon! @Woods247 said higher top speeds. Could you explain more if its effectiveness?

Ok, now I can say it’s a net positive because I can see my shiny Mountune.

 

[arlisscm]

Plan on opening up the rear grill on my ST as well to reduce parachuting (car basically feels like I hit a wall at ~135mph on the straights). Already did the front grill years ago for DHM FMIC, so I know the joys of sanding/melting the plastic.

However, since my ST is ~90% track duty now, I am contemplating just removing the whole rear valance. Sure, it may look funny and I would lose a few mounting points and some structure, but maybe it would be a wash with cutting a lot of air packing/drag.

Thoughts?

 

[BadShot]

I believe it's a reasonably reversible thing to do, might be worth doing a study with it removed vs being gutted. Report back if you do either or both!

 

[arlisscm]

I believe it's a reasonably reversible thing to do, might be worth doing a study with it removed vs being gutted. Report back if you do either or both!

Yeah, from what I have seen it looks like the rear valance attaches to the bumper cover with the same or similar tab style as the front grill does, which was a bit fiddly, but doable. I'll probably pop the valance out and see how floppy the bumper cover is without it, if its too bad I'll sand the grill and put the valance back on. If the bumper stays fairly rigid, could probably use the tabs for the valance as pickup points for a block off panel to keep air from packing up into the bumper. Either way I'm also tossing in a TB rear crash bar while I'm in there.

 

[BadShot]

Yeah, from what I have seen it looks like the rear valance attaches to the bumper cover with the same or similar tab style as the front grill does, which was a bit fiddly, but doable. I'll probably pop the valance out and see how floppy the bumper cover is without it, if its too bad I'll sand the grill and put the valance back on. If the bumper stays fairly rigid, could probably use the tabs for the valance as pickup points for a block off panel to keep air from packing up into the bumper. Either way I'm also tossing in a TB rear crash bar while I'm in there.

I'm tempted to swap my rear bumper because I can see the rust on it, but I did crash testing for Ford for a decade and am skeptical of aftermarket bumpers. There's a LOOOOOT of R&D into the factory stuff.

 

[arlisscm]

I'm tempted to swap my rear bumper because I can see the rust on it, but I did crash testing for Ford for a decade and am skeptical of aftermarket bumpers. There's a LOOOOOT of R&D into the factory stuff.

Understandable. For me, now that my ST almost never sees the street, I'm not overly concerned with getting rear-ended, plus it'll shave a few pounds.