getting my Si slippery

[i_am_socket]

I might have to steal that rubber bumper trick for the back of my roofline. It'll match my packing tape rather well

[dichotomous]

Originally Posted by i_am_socket

I might have to steal that rubber bumper trick for the back of my roofline. It'll match my packing tape rather well

Thats the exact reason I posted it, so others could use it, enjoy, they are pretty cheep too, $3 for 16 bumps
I think they are making a difference already, my current tank is at 320mi and at about 4/5 empty, so its likely around8-9gal used, the light comes on at 10gal used, and thats at the empty mark. I had been getting 280mi to the fuel light, so this should be an awsome tank.

of course I have also been using a different route, premium gas, and cruising at lower speeds and NOT P&Ging where it would bug someone, but using the hills to keep momentum. also, I've been driving 50mph on the interstate till a big boxy truck drove by around 60-65mph and then jumping behind it at a reasonable distance, no closer than other cars would drive to each other while passing faster so I dont call it drafting, I also try to make sure I can see a mirror at all times. oh, dont forget the warm air intake as well, maybe I'll take a shot of that later today

[Daox]

Its my first time looking at this thread. So, I hope you realize that those bumps are probably hurting you if they are even doing anything.

[dichotomous]

Originally Posted by Daox

Its my first time looking at this thread. So, I hope you realize that those bumps are probably hurting you if they are even doing anything.

you dont think they might act as small VG's and keep the airflow "pasted" to the roofline and windows instead of bubbling off into larger turbulance?

[dichotomous]

Originally Posted by NeilBlanchard

Hi,

Have you tried blocking the upper grill, and/or a partial lower grill block? That and if you can manage to get smooth wheel covers would be the biggest benefit, I think.

I am designing a full front aero bumper cover. but I will likely throw some covering over that upper grill because its right there in the flow and such, same with the bottom grill, though I will leave a small triangle under the plate for cooling. thats while I am designing and building (and saving for the material cost) the bumper cover. I want it to look nice and professional, not a backyard job.

[Daox]

VGs do not keep airflow pasted to the roofline. Thats just not what they do. They will induce turbulence (which is bad) to slow the air down and allow it to follow a steeper curve. This, at the very best, increases the pressure on the rear window of a sedan which does help. But, the turbulence induced by the VGs normally offsets any gain.

I have never seen any documentation (from people not trying to sell VGs) that shows that VGs improve mileage. MetroMPG has also done testing that supports this.

[dichotomous]

Originally Posted by Daox

VGs do not keep airflow pasted to the roofline. Thats just not what they do. They will induce turbulence (which is bad) to slow the air down and allow it to follow a steeper curve. This, at the very best, increases the pressure on the rear window of a sedan which does help. But, the turbulence induced by the VGs normally offsets any gain.

I have never seen any documentation (from people not trying to sell VGs) that shows that VGs improve mileage. MetroMPG has also done testing that supports this.

well then, we shall see! ths being the point of putting them on there, I may take them off at some point, but they are behind where the airflow seperates so they should not add much in the way of drag, but they do seem to keep the air on the roof as explained by the dry roof, I'll see how they handle snow.

[basslover911]

You have to place them a tid bit closer on the mirror...

Also take off the ones at the back, thats right VG's are used to stick airflow to things but if the car "ends" then they just cause turbulance...

Also, but some behind the front and rear wheel wells... thats ALWAYS an area of great turbulance unless the fenders are vented- which yours are not and 99% of cars are not...

[Christ]

So what is the purpose of dimpling metal panels to increase aero?

[dichotomous]

Originally Posted by basslover911

You have to place them a tid bit closer on the mirror...

Also take off the ones at the back, thats right VG's are used to stick airflow to things but if the car "ends" then they just cause turbulance...

Also, but some behind the front and rear wheel wells... thats ALWAYS an area of great turbulance unless the fenders are vented- which yours are not and 99% of cars are not...

I'll think of venting the fenders to the rear bumper once I build an undertray, thats a good idea there, thanks.

yeah I know about the mirrors, didnt want to do a ton of them though, so I'm likely to do tape on that area, it would work better for that anyways

I put the rears there to try to keep air attached the rear 1/4's, they taper a bit, maybe not enough to allow seperation though, it was an afterthught. the rear ones on the wing supports are there to try to break the larger vortex that the wing support would make.

my next step is to get some aluminum tape and cut it into zigzag and scalloped bands (kids craft scissors, YAY) and build up a few layers (each one smaller, pyramid style) of this tape about midway on the wing supports, flip the wing and have it come down further, with a few layers of the tape there as well to keep the flow attached beyond 22.5*.