Quote:
Originally Posted by kach22i
I suspect that the MR-2 is like the Boxster in that the side intakes feed the engine oxygen. This means the rear deck louvers are for radiant heat release after shutdown.
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Yes, and no. The Boxster simply has its engine hanging out underneath, and the heat dissipates from under the car. The side intakes feed the engine, and a little bit of cooling air perhaps, but they only flow a minimal amount of air.
The MR2 Spyder has two large side intakes feeding the engine bay directly, allowing venting out the top of the engine lid and through a hole in the bumper, as well as underneath the car (which is an aero mess at the rear).
The car I am eyeing has a 2ZZ swap not using the stock intake tube, which should free up some of the flow of air from the driver side intake to the vents.
The vents in the engine lid are primarily useful for venting heat while stationary, as there is a drip tray blocking most of the would-be airflow. I think I will get the VIS V line lid, as that has bigger venting holes that are louvered to prevent water from dripping onto the exhaust pipes. Or maybe I'll get the OEM style one and put louvers over it myself.
I've thought very hard about whether it would be possible to give the car a quasi-fastback by attaching stuff to the trunk lid, but because the lid is so wide and the hinge is placed where it is, I threw that idea away.
My aero checklist for this car is:
-Hardtop
-Add long spoiler to the tail to get it closer to hitting the template, the biggest one is I think the Duraflex Type W, which also happens to be one of the cheaper ones.
-Strip frunk out, add front chassis brace and use that as an attachment point for a piece of coroplast to serve as a smooth floor. The car has no underbody to speak of at the front, all the guts are exposed
-Throw out stock radiator duct, do a custom one in coroplast
-Make a rubber? grille block that's radiused and gradually increases the opening to the radiator's cross section
-Make a simple aluminum diffuser for the back, with strakes to partially seal off the vortices from the wheels. This is extremely effective on a Lotus with a flat belly, hopefully it does something.
-I will add chassis bracing to the bottom of the car, I may wrap it in PVC sheeting since it's so easy to do, even if it probably won't do much.
-Slightly fatter tires on the back to raise the rear of the car, also brings the speedometer error down and lowers rpm on the freeway.
-Manual adjust, long oval racing mirrors. This can probably drop the drag from the stock mirrors by more than 1/2.
-Lithium ion battery to allow some air to vent internally from left side vent to the rear of the car efficiently.
-Attempt to test airflow through the passenger side vent. I suspect the way the engine bay is doesn't allow much air to get through, so it would be good to block the vent off a little.
I think with all of those together, this car could be fairly aerodynamic while not looking too crazy (attracts cops :/). I would try fairings behind the rear wheels, except there are a ton of bumper screws there and I probably want to keep access to them simple and easy.