Best IROC Wing

[jpachard]

I'm in the market for an IROC wing and wanted to know what people have found to be the best one out there. I have looked at TRG, Rennspeed and GT-racing. Any comments ore are there any others I should consider? I'm leaning towards the Rennspeed or GT since they are period correct. The TRG one does not have the secondary vent on the tray.

Cheers, James

[Bill Verburg]

You are loking for the extended tail like this one right? One piece?


Unless you have a use for the second vent it just creates more drag

[jpachard]

Yes, that's the wing I'm looking for. I'm going to be converting my car to an IROC body replica.

Interesting point about the drag. I knew it would create some but how much is another question.

Bill, Do you have any data on this wing?

James

[Bill Verburg]

Do you have any data on this wing?

Yes, I think so, somewhere, I'll have o look.

The same wing(sans extra slot) was used on the Carrera 3.0RS in race trim

[Bill Verburg]

@152mph w/ the small whale
C^Lf = 0.01 5kg(11lb)
C^Lr = 0.025 13kg(28.5lb)

also a@152mph but in race trim lowered w/ big whale, wider wheels and tires
C^Lf = 0.094 47kg(103#)
C^Lr = 0.073 38kg(83lb)




It's interesting to note that the smaller stock whale w/ rubber lip didn't have the second opening unless fitted to an AC equipped car, but the bigger race tail always had the second opening.

It wasn't for the trans cooler as that was in the left front fender.

[jpachard]

Awesome, Thanks Bill. Where did you get the data from? What front spoiler was used? Thanks again for the help.

James

[Bill Verburg]

Where did you get the data from? What front spoiler was used?

Both Fr&#232re and Starkey had the same data, I assume they got it from an origianal source, likely factory documentation.

The front spoiler was the same as the Carrera 3.0RS

[jpachard]

Bill, That's the front bumper I was planning on using too. Do you have any other pictures of IROC cars? I'm looking for some from the side so I can get the correct decals. From what I have seen the #12 IROC car was the only black one made. My car is black so I'm trying to get it as close as possible. Please e-mail me at jachard at skipbarber dot com if you have any info.

Thanks!

James

[bill romero]

james,
i may be picking one up this weekend. i think it's the same as pictured. i will take some pictures and post them to make sure.
-bill

[Bill Verburg]

Do you have any other pictures of IROC cars?

Just the stock stuff that is everywhere on the net.

The red above is the best right side, here is a good front and left




and twins at LRP


i'll look in some archived cds for more

[jpachard]

Originally posted by Bill Verburg
@152mph w/ the small whale
C^Lf = 0.01 5kg(11lb)
C^Lr = 0.025 13kg(28.5lb)

also a@152mph but in race trim lowered w/ big whale, wider wheels and tires
C^Lf = 0.094 47kg(103#)
C^Lr = 0.073 38kg(83lb)

So, If I understand the numbers above, the race car is actually worse. Or, are these numbers actually downforce?

James

[euro911sc]

JAMES JAMES JAMES!!!

Why are you going to IROC that great car? I mean IROC'n mine is easy cause it is causmetically ugly as ***** and needs a complete strip down, but you have a pristine auto... Or did you hit some armco and not tell me

-Michael

[donstevens]

Those Iroc acars are beautiful.

Despite having an engineering degree, I don't understand the aerdynamic graphs above. How does a duck tail actually lower front axle lift? My reasoning is that down force at the rear would cause the rear to squat on the springs and actually lift the front end higher due to a fulcrum effect.

Can anyone explain it to me?

Don

[Bill Verburg]

So, If I understand the numbers above, the race car is actually worse. Or, are these numbers actually downforce?

Yes, the #s are worse. But aero is a tricky thing, the wide deep dish wheels and tires on the race car are terrible in aero terms, little things like a few degrees of rake, side skirt profile and placement, glass placement and position, seams, mirrors etc. have a huge influence on lift and drag #s.

For comparison
H series Carrera w/ rubber chin dam and original short street whale tale
C_d = 0.414
C_Lf = 0.010 +5kg(+11#@152mph)
C_Lr = 0.025 +13k(+28.5#@152mph)

**note this is a Carrera body considerably narrower than the IROC turbo sized body ans has a commensurately smaller aero cross section

[Bill Verburg]

How does a duck tail actually lower front axle lift?

None of these #s are independent of the others

For ease of discussion the areas are broken up into
above or below
front/middle/rear
sides

each affects the others, so that a proper analysis involves differential equations and then wind-tunnel substantiation followed by track testing.

The fact that total drag is generally decreased w/ the appedage type spoilers used on these cars also affects the lift #s

Here is a comparison from the ss that Rex Walter did on the #S
for an F series '73 Carrera 2.7

Car	                         Cd    Sref m^2   Drag Kg   CL front   CL rear  V KPH    V M/sec             q	        L Front Kg      L Rear Kg  Cdi Induced Drag  Drag due to Lift  % of total drag 

"911 F series Carrera RS

W/front RS and ducktail"	0.397	1.6853	193.5615672	0.07	0.084	245	68.05555556	289.3019775	34.12924359	40.95509231	0.007549037	3.680613308	1.901520721



"911 F series Carrera RS

W/front RS and normal lid"	0.409	1.6853	199.4122947	0.064	0.29	245	68.05555556	289.3019775	31.20387986	141.3925806	0.039889322	19.44846253	9.75289039

[jpachard]

Originally posted by euro911sc
JAMES JAMES JAMES!!!

Why are you going to IROC that great car? I mean IROC'n mine is easy cause it is causmetically ugly as ***** and needs a complete strip down, but you have a pristine auto... Or did you hit some armco and not tell me

-Michael

No Hits Mike! Just need to get a wider track and be able to lower the car more. By putting on the widebody, I'll keep the same tire sizes but have more room to lower the car. The more I have been studying, the more it makes sense to increase the track even though I loose a bit on aero(wider flares).

PS. shoot me an e-mail...we need to see if we can meet up at PRI!

[RSBob]

AIR COOL
AIR KUHL
LUFTKUHL
AIR N OIL
AIR PWR (turbo)
AIRFORCE (TURBO)
AIRBOXER
AIRCNTRL

[bigrubberjeep]

Interesting thread, most of the narrow body guys flam on me for having a widebody, they talk about drag and I talk about track, I think the pro's out weigh the cons, but then again, I'm biased.

In any event I love the IROC look also, my car is also black and I will be doign much of the same repication as you, here is a nice picture I found and I think you could use for reference also.



White it my second favorite color, good luck on your conversion, make sure to keep us posted

[jpahemi]

Bi Rubber:
Did you shoot this in the UK?
j.p.

[bigrubberjeep]

j.p. no, I just saved it from a previous post.