I am toying around on paper with ideas for classes/series and with my limited knowledge of aerodynamics have a couple of questions.

Assuming a DC2 chassis in EP, setup for max track allowed with max slicks to fit on the required 15"x7" wheels, I would definitely have to flare my front and rear fenders. Would a Box flare or round flare be more suitable? Would a minimal flare blended in to the fender be better than widening the the whole fender?

Thanks

Victor Penner

 

I haven't a clue, but looking at most curernt EP cars, the entire fender is flared.

 

For a sec I thought "rase" was a typo. Those are some nice photos, thanks. That white 2nd gen RX7 looks like a show car!

 

Thanks for the pics CM!

The bumper on the 2nd gen does not look even close to legal from my take on the rules.

Victor Penner

 

To me, the added frontal area of the flares seems like it would negate any gain you get by running a wide track. Especially given that you're running 7" rims like so many of us IT/HC guys do. If it were me I'd leave it with rolled, not flared, fenders.

Mere speculation though. I'm no aero expert.

 

7" wheels maybe, but cantilevered slicks stick out at least 1.25" on either side of a wheel like that, plus the extra track would be worth it. Straightaway speed is important but I have a feeling the ITR will need to make the most of its handling to be able to stay in front of a Miata through the twisty bits.

 

Victor,

I would implore you, whatever you do, to preserve the elegant lines of the original front fender / hood...you know that muscular bulge that's kind of like a clearance blister for the tires. It's one of my favorite visual features on the car - the rest of which still holds up pretty good 10 years later to these eyes.

Scott, just had to say it...btw, don't worry so much about the back...run Goodyear 23X9X15's in front and Toyo RA1's in 205 in the rear...JDM to the Max!!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">Victor,

I would implore you, whatever you do, to preserve the elegant lines of the original front fender / hood...you know that muscular bulge that's kind of like a clearance blister for the tires. It's one of my favorite visual features on the car - the rest of which still holds up pretty good 10 years later to these eyes.

Scott, just had to say it...btw, don't worry so much about the back...run Goodyear 23X9X15's in front and Toyo RA1's in 205 in the rear...JDM to the Max!!!!</TD></TR></TABLE>

Well, I just ordered a set of fiberglass Z3 fenders so it will look original...for a bmw!

Victor Penner

 

Contact Yasu at ATS USA. He has some experience with flaring fenders and replacing front and rear fenders with alternative materials (fiberglass) on a DC2.

Great guy...great product

 

I would think primary determinant of drag is frontal area and of course Cd. When you look at the car from the front and enclose the body in an imaginary silhouette, you want to keep the area inside the silhouette to a minimum. So don't flare any more than you have to. As for flaring fenders, I once spoke to a circle track guy showing off his car during an open house visit at the NRC wind tunnel. I asked him what they actually could do to improve the car in the wind tunnel since they had so many rules and couldn't change much. He told one of the most interesting things they had found in testing was the position of the fender panel behind the rear wheel. They have turnbuckles at wheel center height to move the body in and out around the tire, and this had a tremendous effect on drag. So to lower Cd, I would say blend and don't bulge! And bring your car to Ottawa and I'll go watch you figure it out in the wind tunnel. Those Honda engineers from Ohio brought their class winning Acura TL here to test, so I am sure a Honda would fit in there.

I just watched some show (Ultimate - Best Racing Cars) where they showed the Cobra at Le Mans in the early 60's I think. They managed to do well for one year but said those bulging fenders just made too much drag and they couldn't keep up with the blended cars. So they came back the year after with the Daytona Coupe and won. All smooth and not bulgy.

 

I wonder if my accountant will let me write off "wind tunnel testing" on my business taxes? Maybe I will have a bill made out for "Consulting by Claude" .

Victor Penner

 

Joo don't need Wind Tunnels...or some guy named Claude...

Joo just ned to think like Air!

Scott, who has an uncanny natural ability to think like Air...I can also think like ARRRRRR...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RR98ITR &raquo;</TD></TR><TR><TD CLASS="quote">Scott, who has an uncanny natural ability to think like Air...</TD></TR></TABLE>

Such a great setup. A little too easy, though.

&lt;--- makes a career out of the movement of air...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Victor Penner &raquo;</TD></TR><TR><TD CLASS="quote">I wonder if my accountant will let me write off "wind tunnel testing" on my business taxes? Maybe I will have a bill made out for "Consulting by Claude" .

Victor Penner

</TD></TR></TABLE>

Victor, you know what to ask your wife for Xmas: A 10 minute joy ride in here. Cheap on gas too, you can run with an empty tank.



It has just been upgraded for ground based beings.

"For surface vehicle testing, a floor boundary layer suction system that can be manipulated to simulate the Earth's surface wind mean velocity distribution and turbulence profile was recently added. A new PXI-based data acquisition and control system has also been installed. "

All your questions will be answered.

http://iar-ira.nrc-cnrc.gc.ca/aero_6a.html

It has a 9000 HP motor. I think that is in WHP, as in Wind Horse Power. Not quite as much as some gents I know, but impressive nonethless!