SpecRacer.com

I am trying to use AIM Data
for comparing HP & Torque from different sessions. Thanks

Probably need drag coefficient, too?

Y u p !

For what its worth - I got pretty close to 2150 square inches for the frontal area.
I did that using the 3 view drawings widely available. In sq meters, that is, 1.387 . A CAD rendering results in 1.0741 sq meters or 1664.85 sq inches. Note, the CAD does not include the roll bars, helmet pad, mirrors, etc - only the body (no wheel/tire cross section).

There are drag coast down spreadsheets available on the interweb, or I could send you one. It would be great to get a good set of the data, especially as a baseline for my car. If I did a coastdown test on my car it would be totally "unrepresentative" of a Spec Racer Ford. Shown below with mirrors relocated and minus the rear wing, splitter, or air dam attached. Also unseen, the rear is totally opened up, no parachute, and shortened the deck about 6 inches. Nose is also "bobbed" about 6 inches - required from trailer rash repair.
Cheers - Jim

Thank you.

phantomjock wrote:For what its worth - I got pretty close to 2150 square inches for the frontal area.
I did that using the 3 view drawings widely available. In sq meters, that is, 1.387 . A CAD rendering results in 1.0741 sq meters or 1664.85 sq inches. Note, the CAD does not include the roll bars, helmet pad, mirrors, etc - only the body (no wheel/tire cross section).

There are drag coast down spreadsheets available on the interweb, or I could send you one. It would be great to get a good set of the data, especially as a baseline for my car. If I did a coastdown test on my car it would be totally "unrepresentative" of a Spec Racer Ford. Shown below with mirrors relocated and minus the rear wing, splitter, or air dam attached. Also unseen, the rear is totally opened up, no parachute, and shortened the deck about 6 inches. Nose is also "bobbed" about 6 inches - required from trailer rash repair.
Cheers - Jim

We need to see more pics of this! You have told me but never shown us anything!!!!
Also if those are what was dubbed big honking holes over the wheel arches I would cover em up with louvers. The big holes were only done with the LMP cars to help prevent the yaw induced blow overs and such. aka lots of drag and pressure stuff.

Chris -
Yes, there are louvers, just installed in it that photo.

We had a planned test session to "scope out" all the downforce contributions for various mods, evaluating each in turn. Over 16 configurations and minimum of 5 laps per. That was going to give us; track out, 3 hot laps and then a coast down in. We were configured with 4 independent load cells - (one on each corner) and pressure taps all over and reconfigurable. Even had a spray bottle of green florescent Flo-Viz! But, alas, the plans of mice, men, and race engineers are subject to the vagaries of weather, etc.

As a side note, Coast Down testing is always good for bench racing talk, but in fact, it can be useless unless you can pull out crosswind components. We were going to use one of the tufts mounted (more or less clear of near field flow) on the body as a "vane" of sorts. Then, keeping the speed zones for the coast down from top speed down to 80-90 range you'll improve the fidelity of the results. Aerodynamic drag is more significant in that speed regime and a better chance for good results. The nice thing about data acquisition systems is you can do all the collection on track, and then work the calculations later.

We planned to use the downforce info between major configuration changes to start with the best settings from previous session(s).

Sorry for blathering on there, just real disappointing we didn't get the sessions in. Maybe later.

What engine are you running in SPU?

Much modified Renault--but still under 2.5L and no Turbo/supercharging.

I swapped out the 1.7 for a 2.0L. Then, when doing some cylinder head work, we noted some hairline cracks in the upper face of the block, so went back to the 1.7L block. It now has the 2.0L(+) head, race cam, larger valves, adjustable dephasing cam pulley, and crank trigger pre-mounted [waiting the install of the electronic ignition]. Apparently, the 2.0L head on the 1.7L block was a "common cheat" in earlier days. I'm guessing 110/20+ HP at the wheels, then there are the dual Weber DCOEs sitting on the bench for some added "zip" too.

But alas, the Corvette cries for my attention, and she has been very patient (10 years).

Cheers - Jim

In addition to SPU - it is a fantastic Track Day car,. Very cheap to run with "non-Spec" parts-sourcing."