Behind the rear tires

[Floordford]

Ive noticed that behind the rear tires of alot of cars there is no inner fender molding. Im speaking of the area where a mud flap would go. It could have a parachute effect. Not sure if its best to leave it alone or make adjustment. I dont see too many threads on it. I was wondering if anyone had done anything with that area.

[NeilBlanchard]

I think the tapered fairing behind the wheels is called a strake. I have them on my xA, and I believe that they help. The Prius has small strakes.

[lunarhighway]

i believe Floordford is refering to the lack of something inside the rear fender rather than a boattail, wich few cars have. my car too has an inner rear fenders that do not extend down to the edge of the bumper.

my rear fender liner is metal and so it makes sense from a weight saving perspective to not have it run down all the way down. however i'm also wondering on it's aerodynamic propperties, intended or not.
especially since i have build a rear undertray and to avoide dirt and water gettin on top of the tray i had to construct my own inner fender extention to close the gap. the transition is somewhat rounded but i'm wondering if this construction is a local drag contributor compared to stock.

[California98Civic]

Originally Posted by Floordford

Ive noticed that behind the rear tires of alot of cars there is no inner fender molding. Im speaking of the area where a mud flap would go. It could have a parachute effect. Not sure if its best to leave it alone or make adjustment. I dont see too many threads on it. I was wondering if anyone had done anything with that area.

You mean inside the wheel well? Sorta above the mud flap and behind the tire but inside the well? The result is that the bumper becomes maybe a "parachute"? If so, I noticed the same when I removed my stock rear mudflaps. So I cut off the mudflap section and reinstalled the upper part of the assembly that went inside the wheel well. But it made me aware of the rear bumper as a 'chute. I figured a rear short belly pan would be useful. Have not gotten around to it yet. This is what you are referring to, yeah?

[Bill in Houston]

Noticed this on my Element, plus that the whole wheel well in general was larger than it needed to be. I made fender liners out of coroplast. They go all the way from the front of the arch to the rear. They tied into my rear undertray. Undertray eventually got ripped off, but I still have the fender liners.

[Floordford]

Originally Posted by California98Civic

You mean inside the wheel well? Sorta above the mud flap and behind the tire but inside the well? The result is that the bumper becomes maybe a "parachute"?

Bingo. It seems like it could be very messy for air flow.

[California98Civic]

Originally Posted by Floordford

Bingo. It seems like it could be very messy for air flow.

Try a rear undertray or belly pan. Have you searched them on this site?

[Floordford]

Originally Posted by California98Civic

Try a rear undertray or belly pan. Have you searched them on this site?

Well i was really wanting to see if anyone had done specific testing in that area. Mostly to see what designs of aero channeling (i guess) works best in that area. Extending an inner fender might cause the parachuting effect. But it may not. I don't know. Thats why im putting it out there