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Old 11-25-2008, 10:52 PM   #6 (permalink)
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Join Date: Nov 2008
Location: Central Iowa / Memphis TN
Posts: 28

Fiero SE - '87 Pontiac Fiero SE
90 day: 30.17 mpg (US)

EXP SC - '87 Ford Escort EXP SC
Last 3: 36.75 mpg (US)
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I live in the Des Moines area.

zemmo, If you do a full belly pan make sure that you leave an area to vent radiator heat. The best aero mod would be to seal the bottom and carefully vent your hood. Too large of a hole and you will create too much turbulence. Another thing to consider with hood vents is hot radiator air will now be directed past the cabin air intake port and make your car a hotter place to sit. One of my friends with a hood vent said that it is even worse with the sunroof open.

With the Fiero's propensity to catch fire I would recommend keeping the cat and exhaust pipe open as well. The last thing you want to do is provide a place for oil to pool anywhere near the exhaust system.

Once the undertrays have been installed, I thought about removing the middle section of the under-nose air dam. [I would keep the portions outside of the blue rectangle pictured above]. Since the air dam is a functional part of the cooling system bringing air up from below into the radiator, I would add a wing under the nose in front of the radiator to feed it and provide downforce. It would also allow more air to flow under the new, smoother, bottom of the car so that it can more easily recombine with air moving over the top of the car.

I believe the net difference would be an increase in downforce and a lower total drag. I am going to have to get some instrumentation to figure out what difference it makes as far as drag goes. I'll have to wait for a 30+ mph wind day to see if it makes a difference regarding crosswind stability.

Another thing that I think might help would be a small strip along the back side of the trunk lid where it curves down to trip the air and make it separate more cleanly. It would also prevent air from back-flowing from under the car onto the decklid.

Last edited by EXPIOWA; 11-25-2008 at 11:09 PM.. Reason: Added content
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