Rear Wing Removal

Has anyone done any timed track testing with and without the wing? Interested as we are doing some testing in a week or so's time and the crew are keen to try this.

Interested to know if this has been tried and if so with what results.

Thanks, Kel.

Kel, thought the wing was cosmetic at original height ? but at rasied height had benefit, but some drag..would be great for some real world test..personally can't put consistant laps down to help..Bill

Kel,
My guess, with your flat bottom and defuser, the lack of a wing is not likely to be a major source of overseer as it would have been prior (given your aggressive splitter). Only actual testing would tell for sure and if the reduction in weight and drag would show up in lap times. I don't think the wing is optimized for the car originally, but moving it seemed to help at the rear to balance a proper splitter (Tom's car). The use of the wing could allow for some adjustability if it is modified to allow for some angle of attack adjustment. I would tend to want to retain an adjustable wing (not necessarily the original) to allow for adjustment of rear downforce. If a wing ends up slowing you down, I know what you'll do!

I think your car is beyond anything anyone else is running now. We will all be interested in what you discover in testing. As you said, the stop watch is king. If the wing turns out to baggage with the other aero you've done, I think there will be a run on defusers and flat bottoms.

I haven't done the splitter or rear wing move yet and the car has great balance, but I'd like it to stick better. If I can skip the wing move and go straight to the flat bottom and defuser along with the splitter, I'm all for that (assuming I can swing the bucks some day). The cheapest and simplest aero upgrade is to do a splitter and move the wing. Your recent testing gave an indication what the defuser and flat botton can be worth.

Thanks for all the info you've shared and your aggressive innovation. We are dying for some external and in car video of you at work on the track. I got my flu shot so don't get concerned about it going viral.

Mike

Kel,
My guess, with your flat bottom and defuser, the lack of a wing is not likely to be a major source of overseer as it would have been prior (given your aggressive splitter). Only actual testing would tell for sure and if the reduction in weight and drag would show up in lap times. I don't think the wing is optimized for the car originally, but moving it seemed to help at the rear to balance a proper splitter (Tom's car). The use of the wing could allow for some adjustability if it is modified to allow for some angle of attack adjustment. I would tend to want to retain an adjustable wing (not necessarily the original) to allow for adjustment of rear downforce. If a wing ends up slowing you down, I know what you'll do!

I think your car is beyond anything anyone else is running now. We will all be interested in what you discover in testing. As you said, the stop watch is king. If the wing turns out to baggage with the other aero you've done, I think there will be a run on defusers and flat bottoms.

I haven't done the splitter or rear wing move yet and the car has great balance, but I'd like it to stick better. If I can skip the wing move and go straight to the flat bottom and defuser along with the splitter, I'm all for that (assuming I can swing the bucks some day). The cheapest and simplest aero upgrade is to do a splitter and move the wing. Your recent testing gave an indication what the defuser and flat botton can be worth.

Thanks for all the info you've shared and your aggressive innovation. We are dying for some external and in car video of you at work on the track. I got my flu shot so don't get concerned about it going viral.

Mike

We re aligned the car yesterday to suit the 285's Mike so will be track testing at first opportunity that suits the crew. I suspect that the last run we do is likely to be a wingless run just to see what happens. I dont know if you noticed but I am running a Gurney flap on my wing so there may be some additional drag with this in high wing config.

Yup I would love to have some in car footage as well. The honest truth of the matter is that all available budget goes to making the car faster/more reliable and paying for racing. None left over for an in car setup!! The NZ Endurance Series was supposed to be televised so thought we would have some footage to share. Unfortunately the TV side fell through.

Will let you know how it goes if we try removing the wing.

Kel.

Kel, thought the wing was cosmetic at original height ? but at rasied height had benefit, but some drag..would be great for some real world test..personally can't put consistant laps down to help..Bill

Agreed Bill. We still get oversteer on high speed corners though in endurance races with the wing raised up and with a Gurney flap. Hoping that with setup changes we have just made and with the flat bootm/diffuser that the car is more balanced "hot" and with heavy fuel load.

Will let you know what happens timewise if we remove the wing Bill.

Kel.

K
I was wondering if you had any luck with the wing removal. By the way, how much higher is your wing over the standard height?
Also, I was curious to see a picture of your front splitter because I have been trying to fabricate one.
Thanks,
Todd

K
I was wondering if you had any luck with the wing removal. By the way, how much higher is your wing over the standard height?
Also, I was curious to see a picture of your front splitter because I have been trying to fabricate one.
Thanks,
Todd

Todd, cant tell you how much higher than standard as my old mount plates are stores away. The new mount (measured from the top of the trunk lid to the center of the top attachment bolt) is 365mm high.

I chose this height as by our Motorsport regs we are not allowed to run the wing higher than the roofline of the car.

Regards the front splitter, I had posted a bunch of pics of this many moons ago but have since wiped all of the photo's. I will be owrking in the shed this weekend so if you can wait will take some new shots and post those.

Have not tested without wing yet Todd as am waiting for some new rocker covers from the States with spring oilers in them. Supposed to arrive next Monday so hoping to test perhaps next week or the following week. I was also waiting till I had GPS based data logging which I managed to purchase today.

Kel.

Kel,
Thanks for the reply!
The roofline wing height seems to make sense. Almost every other car I see at the tracks have wing heights this level.
Absolutely, next week for some pictures would be awesome.
I am working on my rear diffuser currently also trying to find a little downforce. Where did you find the new wing mounts, or are they custom?
Todd

Kel,
Thanks for the reply!
The roofline wing height seems to make sense. Almost every other car I see at the tracks have wing heights this level.
Absolutely, next week for some pictures would be awesome.
I am working on my rear diffuser currently also trying to find a little downforce. Where did you find the new wing mounts, or are they custom?
Todd

Todd I made my wing mounts up at home. Pretty easy to do using the old parts as templates for the lower portion. Note that most of us have also moved the wing back when we have raised it up.

I used 5mm thick "hard" commecial grade alloy but would also recommend likes of 2024 T3 aircraft alloy if you can get it easily in similar thickness.

I have also added a stay onto the wing uprights on either side within the trunk to assit with eliminating any sideways movement of the wing under load. I have also added a "Gurney Flap" to the trailing edge of the wing to make it more efficient.

The height issue is really just about going as high as you legally can to get into "clean" undisturbed airflow.

Kel.

Wouldn't the wing cause more UNDERSTEER on high speed turns vs oversteer? seems the extra downforce at speed should make it grip better not worse, maybe I am looking at this wrong...

Kel,
The Gurney flap is a great idea, I'd like to see how you incorporated that.

What is your view/experience with varying the angle of attack of the wing? I believe it doesn't take much to have big effects on the air flow over and under the wing surfaces and am wondering if it is effective in tuning aero results or if it is just important to get it at the designed angle and then tune conservatively on the trailing edge Gurney flap. If it is best to stay with the designed angle, how do you determine that position? I doubt that Panoz paid much attention to that with the original mounts.

Jim Hall's Can-Am cars used the idea of drastically changing the angle as an air brake (drag), but I never knew what happened proportionally to the down force or balance. Obviously that was an extreme application of changing angle of attack. Went around high speed corners like it was glued down and still had the straight line speed. Enough to get banned.

Congrats on the GPS system. Those German cars better be checking their mirrors in your next race!

Mike

K
I am nor sure what a Gurney flap is. Maybe you can post pictures of it next week when you have time.
I was also wondering if you knew of a way to get extra air under the hood to the engine?
Would seem to help on hot days or after longer run durations.
T

Wouldn't the wing cause more UNDERSTEER on high speed turns vs oversteer? seems the extra downforce at speed should make it grip better not worse, maybe I am looking at this wrong...

Hi Eric, you are correct that rear wing would help to reduce oversteer by loading the rear tyres more and to much could induce more oversteer.

What we would be testing by removing the rear wing would be the difference between decreasing the drag from having the rear wing fitted (i.e. straightline speed) Vs loss of the additional grip from downforce (cornering speed). There is a balance between these for each track and I have team members really keen to see if we gain more by reducing drag. Naturally I am less keen as I end up wrestling with the car at 125mph when the back end breaks out........:screwy:

Kel.

Increasing rear wing drag/down force will add rear wheel traction, reduce top speed, and relatively unload the front wheels.... or some combination of this. The end result should be a tendancy to increase "push" or understeering.

That being said it usually requires pretty sophisticated data aquisition and driving to define a delta. A GPS that samples at at > 5hz may work depending on software. Look for greater end of straight speeds. Usually most noted at end of straight prior to a high speed corner. If your track is just all "twisty" doubt the Panoz will get fast enough to make much differance.

Very important to try to gather data around the same time with same fuel loads etc. Aero changes on these types of cars are hard to measure accurately.

Kevin

Increasing rear wing drag/down force will add rear wheel traction, reduce top speed, and relatively unload the front wheels.... or some combination of this. The end result should be a tendancy to increase "push" or understeering.

That being said it usually requires pretty sophisticated data aquisition and driving to define a delta. A GPS that samples at at > 5hz may work depending on software. Look for greater end of straight speeds. Usually most noted at end of straight prior to a high speed corner. If your track is just all "twisty" doubt the Panoz will get fast enough to make much differance.

Very important to try to gather data around the same time with same fuel loads etc. Aero changes on these types of cars are hard to measure accurately.

Kevin

Agree Kevin. On the track I am running on regularly our average lap speed is just over 100mph. There are 2 straights that make up approx 50 - 60% of the circuit length, hence looking at the drag Vs grip scenario.

Totally agree on the data logging front. I have just bought a GPS based unit to assist (XT Racing GPX unit). This will give us some capability around analysis. We will not get to scientific though, will look at changes in max speeds but obviously comparative lap times and driver feel will win out.

Kel.

K
I am nor sure what a Gurney flap is. Maybe you can post pictures of it next week when you have time.
I was also wondering if you knew of a way to get extra air under the hood to the engine?
Would seem to help on hot days or after longer run durations.
T

A Gurney Flap is a right angle section added to the top surface of the wing at the training edge per pic of my wing below.

http://i427.photobucket.com/albums/pp355/NZGTRA/IMG_2849.jpg

Improved the efficiency of the wing and is simple to add or remove. Mine is rivetted on and we use it for "trimming" the car. I.e. we run it in the wet for max downforce but not always in the dry.

Regards engine bay airflow I have cut out the dimpled sections of the sides of the bonnet and also put a set of louvres into the bonnet behind the radiator and just in front of the engine (where pressure in the engine bay is highest). Aim of these mods was to increase airflow and decrease pressure. There are a number of other owners who have done these mods as well and there is a lot of info on the site about them in earlier posts.

Kel.

K
I was wondering if you had any luck with the wing removal. By the way, how much higher is your wing over the standard height?
Also, I was curious to see a picture of your front splitter because I have been trying to fabricate one.
Thanks,
Todd

Todd, splitter photo's

I built this 3 or more years ago now. Used commercial alloy. If I was doing it now I would graft on a thicker sectioned splitter with diffusers on the underside. This is a future mod for my car. The aluminium is also on the heavy side but very durable.
http://i427.photobucket.com/albums/pp355/NZGTRA/IMG_2850.jpg

View from behind. As you can see I used a shrinking tool at a local aero restoration workshop to make the curved attaching extrusion for the splitter flat panel.
http://i427.photobucket.com/albums/pp355/NZGTRA/IMG_2851.jpg
I have put a few stiffening members on the splitter flat section to help prevent this buffeting and coming adrift. I have seen this happen before.

Kel.

Kel,
The Gurney flap is a great idea, I'd like to see how you incorporated that.

What is your view/experience with varying the angle of attack of the wing? I believe it doesn't take much to have big effects on the air flow over and under the wing surfaces and am wondering if it is effective in tuning aero results or if it is just important to get it at the designed angle and then tune conservatively on the trailing edge Gurney flap. If it is best to stay with the designed angle, how do you determine that position? I doubt that Panoz paid much attention to that with the original mounts.

Jim Hall's Can-Am cars used the idea of drastically changing the angle as an air brake (drag), but I never knew what happened proportionally to the down force or balance. Obviously that was an extreme application of changing angle of attack. Went around high speed corners like it was glued down and still had the straight line speed. Enough to get banned.

Congrats on the GPS system. Those German cars better be checking their mirrors in your next race!

Mike

Mike, have attached a pic of the GPS fit to whet your appetite.
http://i427.photobucket.com/albums/pp355/NZGTRA/IMG_2852.jpg
Looking forward to mapping my laps Vs my co-driver to see where we can learn from each other.

We have not played around with varying the angle of attack of the wing as there is not much spare material for adding holes in the mount plates. Instead I have fitted the gurney flap (have posted a pic on a response today) so that we can trim the wing and add downforce if desired (normally in the wet).

Yes interesting to see wings that are variable in motion. There are a couple of very advanced gravel rally cars over here that use very large in car adjustable wings. Amazing to watch these bad boys in action and watch the dust off the gravel travel across the wing sections and then see the wake they leave. One of the cars I have seen set up like this was a Mitsubishi Cordia with a mid mounted 6.5 liter alloy Donovan sprintcar type engine, homemade 4 wheel drive system and huge front and rear co-driver adjustable wings. That things was an amazing beast!!

Just to get some USA Vs NZ rivalry going Mike...............I thought the fastest Can-Am cars ever raced in the States were built by one Bruce McLaren :iceslolan, a good old Kiwi boy!

Kel.

Kel,
No doubt that Bruce was the king of Cam-Am. But his dominence was after Jim Hall's Chap's were legislated out of contention. If they hadn't outlawed the moveable wings and sucker fans, Bruce probably would have furthered their development and been right up there. No doubt that the McLaren's were some of the most beautiful closed wheel brutes ever. I've been able to see some run vintage events and they are awesome. Makes for goose bumps.

Mike

Kel,
No doubt that Bruce was the king of Cam-Am. But his dominence was after Jim Hall's Chap's were legislated out of contention. If they hadn't outlawed the moveable wings and sucker fans, Bruce probably would have furthered their development and been right up there. No doubt that the McLaren's were some of the most beautiful closed wheel brutes ever. I've been able to see some run vintage events and they are awesome. Makes for goose bumps.

Mike

Great to see cars like that running all right Mike. We have had a resurgence over here of F5000 racing. Therer are now several meetings a year where up to 20 - 25 F5000's battle it out. These guys are pretty serious with these cars and they are running more hp today than they ever had back in the day. Fantastic to see.

Kel.

K
Thanks for all of the photos, that really helps!
T

Agree Kevin. On the track I am running on regularly our average lap speed is just over 100mph. There are 2 straights that make up approx 50 - 60% of the circuit length, hence looking at the drag Vs grip scenario.

Totally agree on the data logging front. I have just bought a GPS based unit to assist (XT Racing GPX unit). This will give us some capability around analysis. We will not get to scientific though, will look at changes in max speeds but obviously comparative lap times and driver feel will win out.

Kel.

Update on this topic. I drilled an extra set of holes in my wing uprights to provide a higher downforce rear wing adjustment setting.

We did some limited track testing on the low and high downforce settings back to back. There was around a 3pkh top speed difference between the settings (237kph Vs 240kph off data logger) on the back straight of my local track.

As we were there to run a new gearbox in, we had to fit the testing in around this and were not able to do comparative lap times. We learned enough to consider that we would run the low downforce setting at this track but may use the high downforce setting on tighter lower speed tracks.

Kel.

Do you have replacement uprights on the car to move the wing up?

Do you have replacement uprights on the car to move the wing up?

Yes we fitted taller uprights early on in the cars development Brian. The wing is approx at roof height as this is the max within NZ rules. Per previous posts we have also fitted a Gurney Flap so we actually have 3 levels of downforce adjustment on the rear.

This weekend we are running a 4 hour endurance race at a different track that has average speeds more around 130kph (rather than our local tracks 160kph) so we may use full rear downforce hence the new mod.

Not sure I mentioned the new New Zealand pro race class to you Brian. Google "New Zealand V8 Supertourers" and have a read. All cars have Chev factory sealed race 7 litre LS engines and 6 speed sequentials fitted. Have a read and if you are interested I will give you some feedback via PM. They are certainly learning quite a bit on the durability front hence my suggestion to dry sump the LS.

Kel.

W/o mucking up your thread the LS2/3/7s definitely need a dry sump as they revised the oil passages. In the LS3/7 the new intake port shape negatively affected oil drain-back too. The LS1/LS6 fares much better than the others and doesn't need the dry-sump. Not saying it wouldn't benefit from one, but it's not in the plans with the current build.