Turbulators?

[mcrews]

there are sewing siccors that cut like that.......my mom had some yrs ago.

[gijoe985]

So is that just paper glued on there?

[ChazInMT]

Whether they bought it or made it, it is a gross misapplication of the concept. This tabulator tape is made to help aid the flight surfaces on Gliders. They are meant for laminar flow situations and have no business being anywhere on a car which is in a completely turbulent flow aero state.

This would be like going to the beach before a hurricane strikes and putting 20 softball sized stones in the surf zone, then declaring your portion of the beach will be protected from the oncoming 15 foot waves, the stones will break up the flow.

[Ladogaboy]

I just wanted to correct something of a misstatement made earlier. The vortex generators are not, necessarily, designed to work only with the rear airfoil on the EVO. By decreasing the flow separation across the rear window, vortex generators allow more "clean" air to hit the airfoil (allowing the airfoil to more effectively produce downforce). Even if the airfoil weren't there, the car would benefit from the reduction in flow separation.

[ChazInMT]

Originally Posted by Ladogaboy

I just wanted to correct something of a misstatement made earlier. The vortex generators are not, necessarily, designed to work only with the rear airfoil on the EVO. By decreasing the flow separation across the rear window, vortex generators allow more "clean" air to hit the airfoil (allowing the airfoil to more effectively produce downforce). Even if the airfoil weren't there, the car would benefit from the reduction in flow separation.

I'd like to correct the misstatement about the misstatement being a misstatement. The vortex generators (VG's) were indeed placed to make the airfoil more effective, and it is highly unlikely they would provide an iota of benefit in reducing total drag on the car. Very little to no valid information has ever been put up about VG's being beneficial. How do you even know there is a reduction in flow separation?

Everything written about vortex generators has been anecdotal. You're welcome to do some A-B-A testing and let us all look at the results and see what benefit there is. Don’t just come in here guessing that they’ll improve things because it seems to make sense what the people who want to sell you VG’s are saying.

Also, flow separation or attachment is not the magic bullet that automatically gives you better aerodynamic efficiency. Keeping flow attached on a lousy shape will probably actually hurt you. The other thing to bear in mind, is that interactions of the air flowing in from the sides and top over the various shaped automobiles is very complex. Slight changes could have dramatic results by creating larger vortices than those created prior to any change. Slight changes will rarely result in improvements on any modern vehicle due to the advances in aerodynamics that automakers have achieved. Obvious exceptions to this are grill blocks (I think auto makers have to design the cooling system to be driven up-hill, in Death Valley, fully loaded, going full throttle), mirror deletes, and major changes to a cars aerodesign to make it more closely match the aero template.

[Ladogaboy]

Originally Posted by ChazInMT

I'd like to correct the misstatement about the misstatement being a misstatement. The vortex generators (VG's) were indeed placed to make the airfoil more effective, and it is highly unlikely they would provide an iota of benefit in reducing total drag on the car. Very little to no valid information has ever been put up about VG's being beneficial. How do you even know there is a reduction in flow separation?

Everything written about vortex generators has been anecdotal. You're welcome to do some A-B-A testing and let us all look at the results and see what benefit there is. Don’t just come in here guessing that they’ll improve things because it seems to make sense what the people who want to sell you VG’s are saying.

Also, flow separation or attachment is not the magic bullet that automatically gives you better aerodynamic efficiency. Keeping flow attached on a lousy shape will probably actually hurt you. The other thing to bear in mind, is that interactions of the air flowing in from the sides and top over the various shaped automobiles is very complex. Slight changes could have dramatic results by creating larger vortices than those created prior to any change. Slight changes will rarely result in improvements on any modern vehicle due to the advances in aerodynamics that automakers have achieved. Obvious exceptions to this are grill blocks (I think auto makers have to design the cooling system to be driven up-hill, in Death Valley, fully loaded, going full throttle), mirror deletes, and major changes to a cars aerodesign to make it more closely match the aero template.

I, personally, do not have a wind tunnel with which to test the vortex generators; however, Mitsubishi does, and their techs have done extensive testing and analysis. The Evo is a purpose designed platform, and while it is true that low drag is not necessarily the focus of their designs, they were accounting for it. If, through their wind tunnel testing, they found that the vortex generators created a 1% reduction in Cd, I believe them.

[ChazInMT]

So a team of engineers with a windtunnel were able to eek out 1%......I rest my case. Thanks for helping me make my point.

[Ladogaboy]

Originally Posted by ChazInMT

So a team of engineers with a windtunnel were able to eek out 1%......I rest my case. Thanks for helping me make my point.

Now you're just being combative, but if that's what makes you feel better about yourself.

Also, to be fair, the number is closer to 2% (~1.8%). Given that their main focus was not reducing drag, the fact that it has that effect regardless does have interesting implications. Especially for DIYers who have cars of similar designs. If people find this to be a simple way of stabilizing the rear of their cars at freeway speeds while also reducing drag (even if only by a small amount). I know that does not agree with your expert opinion on the matter, but most people value real-world results over expert opinions.

I can understand your obvious concern about companies that market these products of dubious value, but Mitsubishi did not design this as a separate product or gimmick. It was purpose-built and included with the vehicles for sale. They didn't make any extra money on it, and given the nature of the car, it was done as much if not more for performance than for aesthetics.

[Arragonis]

Go and visit the Unicorns on this one, they are getting lonely.