[joelster]

How many of you guys run CAM in here?

I added a wing this year and have some data on what the optimal angle should be for maximum downforce (drag be damned). I took a ton of flak for my setup, but the car feels fantastic. In the next few weeks, I'll adjust my meter and try to get the most accurate readings possible. Most wing manufacturers test them out to 10 degrees AoA, and say that they stall beyond that angle, and to add a second element. I did some single element testing with a smallish wing (4.5sq/ft) and found that it was making more downforce well beyond what the experts say is the "stall" angle.

[cdrptrks]

Do you have a link to the new rules? I haven't seen them and didn't find anything with a quick Google search.

[joelster]

https://www.scca.com/downloads/59661...rules/download

Basically the rear wing can't go too far above the roof line or back beyond the rear bumper. It can't be wider than the car, and total surface area of it can't exceed 8 sq/ft.

[SCCAForums]

Nice work... any close ups of the wing setup? yeah, you can run something like 10" above Roof line... and 6" max rear of the bumper.

You can also add a front splitter that goes 6" forward max of the front fascia.

I run the 9 lives dual element rear wing, and an MFR front splitter.

Best regards,
Dave

[DaveC113]

I run in CAMC, and imo SCCA totally f'ed folks who built according to last years' rules and the .819 PAX index, considering CAM cars have to be street legal as well. Most people who drive their cars on the street don't want huge wings and splitters on their cars.

Not a lot of people who have Camaro race cars with full aero participate in autox, but TONS of people who have Mustang and Camaro street cars with a few handling mods and alignment mods or even power mods that throw them out of FS run CAM.

Also, PAX is supposed to be determined by actual results and not a theoretical build nobody has actually run.

So thanks for the info on wings, but SCCA sucks for doing this. Last year's .819 PAX was a little soft, but the .827 PAX is ridiculous for a full-weight car with minimal mods. Now I have to raw-time C6Zs and Cayman GTS's in AS in my 3700-lb Camaro? My previously competitive car is no longer even close. SCCA has their heads way far up their asses on this one.

[Msquared]

In general, the experts are right: there's an angle of attack beyond which a wing stalls and makes a lot more drag and loses lift. Every wing and installation is different in what that angle is, of course. It's easy enough to determine if a wing is stalling: just install a bunch of yarn tufts on the underside and see if they are "luffing" or not.

I have yet to see anyone even come close to an optimal wing in CAM so far. However, that doesn't really matter because with the current rule set one can easily make more rear downforce than can be balanced out with the allowed front splitter and dive planes. In fact, I would consider moving the rear wing as far forward as the rules allow to try to distribute as much downforce forward as possible. It would look goofy as hell, but that's a function of the current rule set. I agree that CAM should not allow wings, but that ship has already sailed.

[joelster]

Originally Posted by DaveC113

I run in CAMC, and imo SCCA totally f'ed folks who built according to last years' rules and the .819 PAX index, considering CAM cars have to be street legal as well. Most people who drive their cars on the street don't want huge wings and splitters on their cars.

Not a lot of people who have Camaro race cars with full aero participate in autox, but TONS of people who have Mustang and Camaro street cars with a few handling mods and alignment mods or even power mods that throw them out of FS run CAM.

Also, PAX is supposed to be determined by actual results and not a theoretical build nobody has actually run.

So thanks for the info on wings, but SCCA sucks for doing this. Last year's .819 PAX was a little soft, but the .827 PAX is ridiculous for a full-weight car with minimal mods. Now I have to raw-time C6Zs and Cayman GTS's in AS in my 3700-lb Camaro? My previously competitive car is no longer even close. SCCA has their heads way far up their asses on this one.

100% agree with you here. I'll gladly go back to a spoiler and an .819 pax. Changing the rules to allow wings will not do anything to attendance.

Originally Posted by Msquared

In general, the experts are right: there's an angle of attack beyond which a wing stalls and makes a lot more drag and loses lift. Every wing and installation is different in what that angle is, of course. It's easy enough to determine if a wing is stalling: just install a bunch of yarn tufts on the underside and see if they are "luffing" or not.

I have yet to see anyone even come close to an optimal wing in CAM so far. However, that doesn't really matter because with the current rule set one can easily make more rear downforce than can be balanced out with the allowed front splitter and dive planes. In fact, I would consider moving the rear wing as far forward as the rules allow to try to distribute as much downforce forward as possible. It would look goofy as hell, but that's a function of the current rule set. I agree that CAM should not allow wings, but that ship has already sailed.

Somewhat agree with you. Yes the angles beyond 10 AoA will make the wing stall, but it's still bolted directly to the car, and it still making downforce. It's just making significantly more drag while doing so. There's a sweet spot in there somewhere. I tested at 3 degrees, 16 degrees, and 32 degrees. 16 was the best for my car at 0-40mph.

https://www.youtube.com/shorts/EL_arifKuS4

This was with a single element that is way undersized for CAM. It's roughly 4.xx sq/ft.

I have a new testing setup that won't deflect any of the downforce and "should" give me more accurate readings. Hopefully I'll get some data this weekend.

[Msquared]

Originally Posted by joelster

Somewhat agree with you. Yes the angles beyond 10 AoA will make the wing stall, but it's still bolted directly to the car, and it still making downforce. It's just making significantly more drag while doing so. There's a sweet spot in there somewhere. I tested at 3 degrees, 16 degrees, and 32 degrees. 16 was the best for my car at 0-40mph.

Although it will usually still create some lift, a stalled wing by definition is making less lift (downforce) than it does at its best AoA. Drag is also rising at the same time. I have no doubt your wing is making more lift at 16 deg than at 3 or 32. Maybe it's stalled at 16 and maybe it isn't, but if airflow is no longer attached on the underside, then it will probably make more lift with less drag at some slightly lower AoA. Of course, drag doesn't matter at all for autocross use, but if a wing is stalling then reducing the AoA will create even more lift. Now that you have a very coarse indication that 16 is better than 3 or 32, the next step is to start testing in increments of 1 or 2 degrees on either side of 16 to hone in on the best angle.

I'll gladly go back to a spoiler and an .819 pax.

Going back to a spoiler-only rule and leaving all other rules the same won't change anything about the pax. Rear downforce is not the limiting aspect of CAM aero: front downforce is. A properly implement 10" spoiler is still capable of making more rear downforce than the allowed front aero can balance out. As with rear wings and spoilers, though, I'm not seeing a front splitter design and dive planes that are maximized within the rules.

This is kind of a detour from the thread topic, but the real issue with CAM and pax is that nobody - and I mean nobody - is running a car that's even close to maximizing the full CAM rule set. If you started your CAM build with a production car platform, you already gave up huge opportunities. CAM actually allows a bespoke tube-frame chassis and any suspension one wishes, as long as it retains stock wheelbase for the car it's trying to emulate. You can also put a full carbon fiber body on it, set the engine anywhere in front of the driver, etc. Think along the lines of Mike Dusold's "Camaro." All you have to do is trick your state into licensing it and (maybe) inspecting it. A proper CAM building should require about 500lb of ballast to make minimum weight, it should have a very low CG, and it should have a weight bias of about 40/60. It should not be remotely streetable, even though it must technically be legal to drive on the street. Anything less than that is not a full CAM build.

This is why I got the hell out of CAM: the rules are just plain ridiculous. CAM-S is even worse: you are explicitly allowed to run a kit car replica of a British roadster with a 90" wheelbase and any engine you want at 2500lbs (which done properly still requires ballast), but a 84+ Corvette has to run at 2900lbs because they are believed to have magical powers. why nobody has emulated Kiesel's Sprite but on a 90" wheelbase with an AC Cobra body is beyond me, but you get the idea of how fast and unstreetable a proper CAM-S build should really be. CAM sort of implies that it's about modified production cars that still get driven on the street, but it very much isn't. It is not a class for "hotrodders," and yet those are the only people interested in running in it. The current state of CAM is a hot mess.

[DaveC113]

Originally Posted by Msquared

Going back to a spoiler-only rule and leaving all other rules the same won't change anything about the pax. Rear downforce is not the limiting aspect of CAM aero: front downforce is. A properly implement 10" spoiler is still capable of making more rear downforce than the allowed front aero can balance out. As with rear wings and spoilers, though, I'm not seeing a front splitter design and dive planes that are maximized within the rules.

This is kind of a detour from the thread topic, but the real issue with CAM and pax is that nobody - and I mean nobody - is running a car that's even close to maximizing the full CAM rule set. If you started your CAM build with a production car platform, you already gave up huge opportunities. CAM actually allows a bespoke tube-frame chassis and any suspension one wishes, as long as it retains stock wheelbase for the car it's trying to emulate. You can also put a full carbon fiber body on it, set the engine anywhere in front of the driver, etc. Think along the lines of Mike Dusold's "Camaro." All you have to do is trick your state into licensing it and (maybe) inspecting it. A proper CAM building should require about 500lb of ballast to make minimum weight, it should have a very low CG, and it should have a weight bias of about 40/60. It should not be remotely streetable, even though it must technically be legal to drive on the street. Anything less than that is not a full CAM build.

This is why I got the hell out of CAM: the rules are just plain ridiculous. CAM-S is even worse: you are explicitly allowed to run a kit car replica of a British roadster with a 90" wheelbase and any engine you want at 2500lbs (which done properly still requires ballast), but a 84+ Corvette has to run at 2900lbs because they are believed to have magical powers. why nobody has emulated Kiesel's Sprite but on a 90" wheelbase with an AC Cobra body is beyond me, but you get the idea of how fast and unstreetable a proper CAM-S build should really be. CAM sort of implies that it's about modified production cars that still get driven on the street, but it very much isn't. It is not a class for "hotrodders," and yet those are the only people interested in running in it. The current state of CAM is a hot mess.

Yup, I even looked into how much a used GT4R Camaro costs, unfortunately the answer is about $150k. Half that and I'd be trying to buy one, can't imagine how much fun it would be. Registering one could be tricky, but possible in some places, lol. I'm not that interested in spending a ton on my SS 1LE or compromising it as a street car that much either.

The issue with current rules is there's no ST class that our cars fit into, STU is full of much smaller cars more suitable for autox and a .830 PAX. So anyone with mods past FS is in CAM by default, there's nowhere else to go. CAM-T should theoretically be slightly faster than CAM-C with it's smaller cars and lighter minimum weights. We have 2 Fox body Mustangs with IRS conversions running 315s at ~3000 lbs...

It's really not a huge deal as far as results as nobody is paying me, but it's frustrating to prep a car for one set of rules with a .819 PAX only to have the rules and PAX change so drastically. If I would have known I'd probably have remained in the street classes and have that nice, soft .813 FS PAX, lol.

[joelster]

My point with regards to the PAX was that a CAMC car with a spoiler and .819 is likely more competitive than a CAMC car with a wing and .827 PAX. On a standard 35 second course the SCCA is saying that a wing is worth .339 seconds. I'm not buying it. I'm fairly certain that from 0-40mph a spoiler is producing more downforce than a typical dual element wing setup. We spend most of our time floating around the 25-50mph zone at an autocross. My force gauge was binding up because of the way I had it mounted. I changed the entire mounting setup so it can "float" as the lid gets pushed down. It will be far more accurate for my next round of testing.

This is some interesting data for those that say steep angles don't work. Check out the downforce at 52 degrees at 80mph:

[Msquared]

Originally Posted by joelster

My point with regards to the PAX was that a CAMC car with a spoiler and .819 is likely more competitive than a CAMC car with a wing and .827 PAX. On a standard 35 second course the SCCA is saying that a wing is worth .339 seconds. I'm not buying it.

You're missing my point: the change to allowing wings alone is not why the pax got harder for CAM-C. In fact, didn't the current indeces come out before the CAM rules even changed? I don't think one had much to do with the other. The wing allowance by itself doesn't add anything to the speed of a CAM car because either a wing or the 10" spoiler - done properly - make more downforce than the front aero can balance.

The bottom line on the CAM-C index is that a car built to max out the rule set is a bespoke race car and should be faster than any street class, whereas right now the index is between AS and SS. The fact that nobody has built a true "max effort" CAM-C car so far is the reason it seems too hard of an index. As DaveC113 implied, what most people in CAM-C really wanted to make is a car modded to ST levels. Unfortunately, instead of making a useful ST class for modern pony cars, SCCA has a non-jacketed class that caters to Optima builds and allows nearly anything, including full frame and body changes. That sucks, but the problem is the class structure rather than the index.

I'm fairly certain that from 0-40mph a spoiler is producing more downforce than a typical dual element wing setup.

Both a spoiler and a wing produce downforce as a function of velocity squared, so their downforce scales the same amount as speed builds.

This is some interesting data for those that say steep angles don't work. Check out the downforce at 52 degrees at 80mph:

Nobody said steep angles of attack don't work. What I said was that if you set an AoA such that the wing is stalling, it will produce less downforce than it will if it retains attached and orderly flow on the low-pressure side. I have no idea what wing that is in the data, now how it's mounted, nor even how they are measuring angle of attack; but it does not appear to be stalling at 52 degrees. It's pretty well known that a multi-element wing with well chosen foil sections can run really high AoAs and not stall. That's the whole reason for using multi-element wings, and airplanes do something similar with complex flaps and leading-edge slats. But again, if you increase a wing's AoA and it keeps making more downforce as you do, then by definition you have not caused it to stall.

[joelster]

The only max effort CAMC car that I know of would be that GM test vehicle from few years ago. I only say this because it was able to hit the minimum weight target. That's really the hardest thing to do with CAMC cars. It was that turbo-4 1LE. They got it making really good power, and the F/R balance was excellent. This was before the wing rules. There is one that ran at Bristol as well by John Ward. He had everyone covered by 1.168 seconds on Sat and by .738 on Sun. he was 14th in PAX on Sat, haven't seen the numbers for Sun.

[Msquared]

Originally Posted by joelster

The only max effort CAMC car that I know of would be that GM test vehicle from few years ago. I only say this because it was able to hit the minimum weight target. That's really the hardest thing to do with CAMC cars. It was that turbo-4 1LE. They got it making really good power, and the F/R balance was excellent. This was before the wing rules. There is one that ran at Bristol as well by John Ward. He had everyone covered by 1.168 seconds on Sat and by .738 on Sun. he was 14th in PAX on Sat, haven't seen the numbers for Sun.

This is what I mean when I say that nobody seems to understand what a CAM "max effort" would look like. I was at the 2018 CAM Challenge in Peru and saw that car up close, and I talked to a couple engineers. That was a stock, off-the-shelf 2019 2.0T 1LE with ZLE (I think) wheels and tires, a straight-pipe cat-back, and a tune with anti-lag. That's a lazy ST build at best! Yes, it was fairly light (3270lb as I recall), but it was still above the minimum weight at the time. The fact that this car dominated the season in 2018 is a testament to the disconnect between the CAM rule set and what actually gets entered in the class.

A true edge-of-the-rules CAM build looks like a Sprint Cup car (CAM-C) or a slightly larger version of Kiesel's EM Sprint (CAM-S), but with more wing and on 200tw tires. If you can drive it to the event, fuggedabowdit. The only thing OE on it should be the VIN plate, which is welded to the custom tube frame, and maybe the wiper motors and mirrors so you can pass a state safety inspection.

[joelster]

Minimum weight for CAMC is 3480 with driver. I don't see how a tube chassis will be a help if you can get the car way under that mark with a stock turbo-4 chassis, and then add weight where you want to. Modern chassis' are extremely stiff. The tube chassis would be significantly lighter but if there's a minimum weight to meet and you have to add several hundred pounds then it may be a moot point. That GM car had way more secrets in it, then they let everyone believe. I have 2 friends of mine that were "in the know" regarding the 3 or 4 cars that they had campaigned during that time. They basically had an unlimited budget and were green lit to try anything and everything that they could think of, and a few things made it into the production cars, specifically the eLSD tune that they developed.

When I get my car back out for some more testing I will try smaller increments of wing angle to see what happens. I'm currently waiting on a longer cable for the display. It's a royal pain in the ass to record a video while the display is just out of sight in the back seat area lol. It comes with a 6 foot cable, i'm having them build me a 12 foot cable.