How to: Under $15 Gurney Lip

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May 25, 2008 | 01:50 PM

Smike

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From: somewhere testing various tires, brakes, and suspensions.

How to: Under $15 Gurney Lip

First off thanks to Otter for helping out.

What is a Gurney Lip? Let me quote Mitsubishi here:

Quote:

Originally Posted by Mitsubishi

"The gurney flap creates 14kg (30.8 lbs) more down force at speeds above 180km (112 mph)."

This is OE on the SE and I believe the 06 MRs had them stock. This was also a dealer option in some cases. Whichever the case maybe, I am interested in better aero. These are not new to motorsports. They have been around for about 40 years.

Why would I need this? Well if you are a track runner then this can give you some extra downforce when above 112 mph. Best shown here:

Quote:

Picture the trailing edge of the wing cross-section, with the Gurney pointing upwards and the airflow moving from left to right (above). At the trailing edge, the airflow immediately beneath the wing rolls into a small anti-clockwise vortex behind the Gurney. Immediately above this, a second small vortex, rotating in the opposite direction, is formed by the airflow traveling above the wing as it passes over the gurney's lip. together these two vortices form a small separation bubble - a rotating mass of air removed from the main flow - which is somewhat taller overall than the gurney itself.

http://www.allamericanracers.com/gurney_flap.html

Ok, so I now have sold you on one. You are probaby thinking to yourself - "cool, and how much is this going to cost me?"

Cost at the dealer? About $80 bucks. Aftermarket? About $50.

Let me breakdown my costs (NOTE: this will make 2, yes 2 of these lips! So get a friend

):

Home Depot - door section, vinyl trim molding, 10ft section: $2.49
Auto Store - 3M Body two-sided tape: $6.99
Auto Store - Body colored paint (in my case - black): $6.99
Auto Store - High temp clear coat (opt): $6.99

So lets recap...2.49+6.99+6.99+6.99 = $23.46, divided by 2 = $11.73 ea. If you already have the black paint (and clear) $9.48 or $4.74 ea.

How to:
--Cut vinyl down to the length of the wing.
--Paint to the color of your car
--Clear coat (optional)
--Let dry for a few hours (give the paint lots of time to cure)
--Apply 3M tape
--Stick to car

Results:

Cheers and happy racing!

MG

May 4, 2009 | 05:41 PM

Bster13

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From: Norwalk, CT

Was there any noticeable difference is rear end down force at speed when you did this mod? Did the rear feel more settled? Do you think you lost any speed down the straights? (i.e. too much drag?)

May 4, 2009 | 07:05 PM

Smike

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From: somewhere testing various tires, brakes, and suspensions.

Car did feel more settled at speed. Be it true aero or butt dynamics. I don't think the drag has been effected in a large part. Have no GPS data to show for it though.