rodneyr

I should be receiving my RS Wing soon for my car I was looking for some general guidelines for setting the Wing angle 4-8 degree shims for Lime Rock Park and Watkins Glen. I am sure their are many variables and trial and error can help. I figure at LRP the Wing would mostly help in the down hill and maybe in the up hill and west bend. I am mainly concerned when the track is dry because when the track is wet the car is typically parked -- yes I am a wimp.

I do have the cup front splitter and the car is lowered with the stock suspension. I will be installing a few items such as TRG rear toe, Motor Mounts.

amaist

4 degrees is where it's at with the RS wing. My datalogger showed a 3 km/h difference at the end of a long straight compared to 8 degrees. I am not sure all 3 km/h are explained away by the wing. I could have been driving better, too, at that point. Other people with the same wing also concluded that 4 degrees is best. There may be too much drag at 8 degrees as the angle gets too steep.

997gt3north

- i would say there is no way to answer this unless you are a real pro because (assuming you're not) more wing will definitely plant the rear end more and this may give you the "confidence" to take the uphill esses faster at the glen than you other wise would and this alone could make up for the added drag going into the busstop - since you mentioned the glen, you know what mean, that transition at the top of the hill as you get faster and faster sure gets the mind thinking - i would just think it would have to be true that less wing is faster at the glen

- now Mosport is different for sure (spoke with a few race tems about it) - if you have the skills #2 and especially #4 can be taken much faster with aero and will more than offset the loss on the back straight

38D

Wing angle will depend on the track, conditions & driver (and setup, and and and). There is no one answer.

rodneyr

Both great points. I can start with 4 degrees and use that as a base line against my previous laps using my Traqmate. Yes, I am Not close to a pro. I do like the idea of more Wing at the Glen going up the esses even if I am am few mph slower at the top end. I would rather say for example carry 5 mph into turn 2 all the way up to the bus stop because that will make up for my top end speed.

I am guessing the Wing is easy to put on and take off. However, I would be worried that I would drop it, scratch it, or the car.

mark kibort

There is not as much drag as people think! a wing, like the GT3wing (i have one) can produce near 170lbs of downforce in the rear at a moderate angle of near 7 degrees at 100mph. This might not be the real angle, as the true angle of attack of the wing is a little bit of a moving target, with it changing as the air flow comes off the roof line. (it might be more along the lines of 14 degrees depending on the car and the speed)

with most air foils, in their most efficient range of angle, they have near a 10:1 lift to drag ratio. So, if the wing is producing a 170lbs of down force, thats near 17 lbs of drag. if you are in 4th gear near 100mph, that might be effectively only at a cost of about 5ft-lbs of torque at the engine (reduced by a factor of 3 based on the gear reduction, where in 3rd, it would be even less) Anway, its very difficult to see the wing costing any real speed down a straight . Usually, the fact that you have a wing will allow you to come into, through and out of a corner faster, and that would easily give you more speed down the following straightaway.

as far as the effect of 5ft-lbs of torque, i can remember phil McClure, a Vet driver in the speed GT world challenge series. when they put on their restrictor, loosing near 20hp, they only saw 1mph difference down the main straight at sears point vs testing the day prior.

I still have yet to produce a time equal in my car at sears point, to the time ive run without the wing. However, the car is much more tame in some of the high speed sections where the car was a little loose. At Laguna, ive produced some faster times, but the track has changed. It also has developed a medium speed push that i fixed with a splitter. I am very confident that i could run the same time without the wing, but it might not be as comfortable and predictable.

With the pictures below, i have the wing set at near 0, as at 5 degrees the car had a very nasty push. but remember, that 0 degrees mated with the downwash off the roof line, is near 9 degrees effectively.

attached also is a lift drag curve for an airfoil very close to the one on the GT3cup
you can see the lift /drag ratio on the far left y axix, shown by the desending curve on the graph going down with wing angle
as the angle goes up, so does the lift, but the drag as well. Its a little blurry, but you can get a real good idea of what is happening with the changes in wing angle.

Mark

38D

You can go flat from T1 to the busstop in pretty much any Porsche even without a wing (assuming stock engines and decent tires). It's what really separates people at the Glen. In a track prep'd street GT3 it should be a no-brainer.

LVDell

Rodney, I run the RS wing on my GT3 and have experimented with both the 4 and 8 shims and the 8's work better for me. I lose maybe 1-2mph at VIR on the back and front straights but I run a FASTER lap since my **** is much more planted. It makes a BIG difference climbing the high speed uphill esses and it did NOT affect my straight line speed leading to the esses. I still enter at the same speed but can exit FASTER at the top.

ps. I use Traqmate data to verify EVERYTHING.

mark kibort

re-check your telemetry since you have it. A wing will alow for greater entrance, and exit speed of a turn, and that should result in greater straight line speed as you are seeing on a couple of the straights. The drag produced by an increased setting is less than equivilant to 1ft-lb of torque at the engine. the wing vs no wing, might do this, but just a setting change of a few degrees doesnt create enough drag to hurt most straights. However, at 160mph, vs the example 100mph drag of 17lbs (or 5ft-lbs at the the engine) suddenly goes to 43lbs and, with less of a gear ratio, like equivilant to near 20ftlbs on the engine. Im sure that certainly can effect top end speed at the end of a long straight, maybe even offsetting the inceased exit speed of the turn prior.

mk

LVDell

Not sure I follow Mark. My back straight speed is a mph or two different (slower with the 8) but my exit at oak tree is the same and the wing angle is not helping through oak tree.

as far as the esses I think I said the same thing you did as I enter at the same speed (didn't lose anything) but I exit FASTER since I can stay on the throttle more through the esses.

Hoosier_Daddy

True ... but more specifically, someone's exit speed from T1, then flat to the busstop, is what really separates the people and I think you are a little more adept at that than the majority.

I think most people would prefer the added confidence the wing adds in having the added bite at the rear of the car and see similar results to what LVDell has seen, faster lap times with a wing. (At the higher levels only) I believe drag on the straights is secondary to grip in PCA type DE days from the white group up until we get to the really experienced folks.

rodneyr

All good points. I am really looking for added confidence. For example, I went from the stock rims to Volk T37's and I got a few tenth's slower at LRP. On paper that does not make any sense because I probably removed 5lbs of unsprung weight from each corner. So, at my level confidence is everything especially with a powerful GT3.

Colin, I don't have the skill, ***** or confidence to go flat out from T1 at the Glen (maybe in a Spec Miata), but not with the GT3 with or without the Wing. I typically am not full out until T3, but as stated that what separates the boys from the men.

997gt3north

- Can someone tell me what speed a street 997gt3 would hit at the 5 brake marker at the bustop if one went wot with good exit speed from turn number 1

- i ask because i'm not quite there yet (and not sure i want to try it incase it goes wrong) but during my last visit this was my typical run:

1) obviously exit #1 as fast as possible (think i was doing well here as i would often gain ground on fast cars here)
2) wot with 3rd until #2
3) short shift into 4th and deliberately pause not hurry the situation
4) slowly feed the throttle all the way up the hill
5) just before crest f the hill where it flattens out put the fot to the floor
6) after trackout shift up to 5th

- at the 5th brake marker speed is 150mph

If you have the skills and the bank account if it goes wrong, if you stay wot in 3rd until the top of the esses and then shift to 4th in the transition is 158mph or so at the 5/6th brake market the limit for a 3150# street gt3 running MPSCs?


thanks


Paul