[Msquared]

Originally Posted by 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.

A real race chassis allows much less weight, much more stiffness, an uncompromised suspension, a different driver placement, a rearward engine placement, possibly a transaxle, better mounts for aero parts, and a gazillion other things I can't think of right at the moment. And all that weight you save will be able to come back as ballast, where you can place it very low and near the rear axle line. So you end up with way, way better suspension geometry, a much lower CG, and a ~45/55 (or even more rearward) weight bias. It will also have a race-oriented aftermarket ABS and traction control system, highly adjustable suspension geometry and rates, etc. If you're trying to build the fastest GT car you can - and that's essentially what CAM is - then there's no way you would ever start with a production chassis.

The 2018 factory CAM-C car is still a stock car with a few - very few - mods. Tuning the factory eLSD is ST-class stuff. That car would be right at today's minimum weight with an average male driver. It wasn't extreme in any way, except for the way it ate turbochargers.

A truly built CAM-C car should blow SS away. The angst about the pax index is because nobody really wants to build such a car, even though the rules allow it. It would be like entering CP on RE71RSs and complaining because everybody else is using slicks and going way faster. And just to be very clear, I'm not endorsing the current CAM rules. I think they are ridiculous because they don't reflect the cars that people want to build and enter. Back in the day, I sent in suggestions on how to reimagine the rules to reflect the cars people are actually bringing to national events (production based chassis, truly streetable, etc), but that was ignored. I'm just pointing out what the current rules actually allow, and that the pax index is based more on what could be run rather than what is being run. If anything, the recent rule changes indicate that the powers that be intend to take CAM in an even more wild and non-streetable direction. Have fun with that: I'm enjoying FS.

[joelster]

I do tons of CAM type races. My car is built to SCCA standards just because there is a clear rules set online to follow. But most of the old school CAM guys that I race with would never enter a national SCCA race for a few reasons. Those reasons are, 6 runs spread out over 2 agonizingly long days, plus you get to work the course as an added bonus lol. You'll likely never see a CAMC car walk an FS car or a CAMS car walk an AS car. Unless the Peacheys show up. CAM was intended to get the car show guys with their 69 Camaros out to the track. There's no way to expect those cars to have their original equipment so the rules were left wide open. But anyways, we're headed way off topic now.

[DaveC113]

It's pretty obvious CAM was imagined to get resto-mods, pro-touring and TT guys to autox, but it didn't work, nobody cares, lol. I agree the issue is limited seat time, you have to work, and the time commitment for that 3 min of driving is overall a hard sell for many. Oh well. Now that we know nobody is interested in spending 6-figures to build an autox car, maybe SCCA can just give up on the idea and make CAM into an ST class. Right now it fits nobody. A full-on CAM car as Matt describes probably needs a ~.9 PAX and hardly-modded Camaros and Mustangs that actually show up are getting f'ed at .827. Who are they trying to make happy here?

On topic, the aero rules are supposed to allow the TT cars than never attend a place in CAM, but what a load of BS that is. If one decides to show up XA or XB or whatever would be just fine.

On the aero rules that allow a wing that makes for unbalanced front to rear downforce, I do question that a bit because despite the fact that is true, I won't argue that fact... maybe it's suitable for autox where it wouldn't be for track? Whatever you can do to get more rear grip to allow more throttle is going to make the car faster, that's basically what it comes down to, the fastest runs are always going to be the runs with more throttle if everything else is equal. If wings allow for more throttle, they may work well despite being technically unbalanced?

[joelster]

I'm on the fence regarding the aero imbalance. Yes there may be way more aero in the rear than in front, but typically you can get way more camber up front, and there's more weight up front. My car is always neutral or the ass comes loose. It rarely pushes. If my front is losing grip then the rear is likely to lose grip as well. I do do many non SCCA events with hundreds of other racers. Have a huge one coming up at UMI at the end of the month. We'll get 15-18 runs and we'll get fed every day. No working the course, and we can do track "walks" on a scooter or a moped. The big SCCA events are a tough sell for me.

[Msquared]

Originally Posted by DaveC113

It's pretty obvious CAM was imagined to get resto-mods, pro-touring and TT guys to autox, but it didn't work, nobody cares, lol. I agree the issue is limited seat time, you have to work, and the time commitment for that 3 min of driving is overall a hard sell for many. Oh well. Now that we know nobody is interested in spending 6-figures to build an autox car, maybe SCCA can just give up on the idea and make CAM into an ST class. Right now it fits nobody. A full-on CAM car as Matt describes probably needs a ~.9 PAX and hardly-modded Camaros and Mustangs that actually show up are getting f'ed at .827. Who are they trying to make happy here?

On topic, the aero rules are supposed to allow the TT cars than never attend a place in CAM, but what a load of BS that is. If one decides to show up XA or XB or whatever would be just fine.

That's a pretty succinct way to put all of this, yeah. And I agree. I will say that the CAM Challenges (there are two this year) allow more runs than that over the weekend. But they aren't setting the world on fire with attendance.

On the aero rules that allow a wing that makes for unbalanced front to rear downforce, I do question that a bit because despite the fact that is true, I won't argue that fact... maybe it's suitable for autox where it wouldn't be for track? Whatever you can do to get more rear grip to allow more throttle is going to make the car faster, that's basically what it comes down to, the fastest runs are always going to be the runs with more throttle if everything else is equal. If wings allow for more throttle, they may work well despite being technically unbalanced?

The way I think of it is that the rear-heavy aero lets you set up the car pretty loose for low-speed turns (more toe out, stiffer rear wheel rates) while still allowing more stability at high speed. So the imbalance isn't bad, per se. It's just that we already had the ability to achieve enough imbalance with the previous (and still standing) spoiler rules. The only thing the wing does is allow track-focused cars (TT, like you said) the ability to come enter CAM events using the same wing they use on track, but probably adjusted up to a much higher AoA. You would never want to use a 10"-chord spoiler on track.

So again, I just don't think the wings make anyone significantly faster than the spoilers for autocross use. It's hard to see that, though, because I haven't seen either wings or spoilers fully implemented properly.

[joelster]

Originally Posted by Msquared

That's a pretty succinct way to put all of this, yeah. And I agree. I will say that the CAM Challenges (there are two this year) allow more runs than that over the weekend. But they aren't setting the world on fire with attendance.


The way I think of it is that the rear-heavy aero lets you set up the car pretty loose for low-speed turns (more toe out, stiffer rear wheel rates) while still allowing more stability at high speed. So the imbalance isn't bad, per se. It's just that we already had the ability to achieve enough imbalance with the previous (and still standing) spoiler rules. The only thing the wing does is allow track-focused cars (TT, like you said) the ability to come enter CAM events using the same wing they use on track, but probably adjusted up to a much higher AoA. You would never want to use a 10"-chord spoiler on track.

So again, I just don't think the wings make anyone significantly faster than the spoilers for autocross use. It's hard to see that, though, because I haven't seen either wings or spoilers fully implemented properly.

What would you say is a properly implemented spoiler? There isn't much leeway with them. The old rules were 10" maximum distance from the body line. I "should" be able to test my spoiler setup as well. I'm curious to see how it does compared to the wing at 0-40mph.

[Msquared]

Originally Posted by joelster

What would you say is a properly implemented spoiler? There isn't much leeway with them. The old rules were 10" maximum distance from the body line. I "should" be able to test my spoiler setup as well. I'm curious to see how it does compared to the wing at 0-40mph.

The big mistake I see is that they are not vertical: most are laid back to something less than 90 degrees from horizontal. That's just wasting effectiveness and decklid space. Unlike a wing that works using laminar airflow attached to it, a spoiler works by damming up air and preventing laminar flow. That creates high pressure in front of it, which then acts on the decklid to create downforce. By laying it back, you give up some damming effect. You also give up some decklid area for it to act on since the rules says it has to fit within the silhouette in plan view. The rule of thumb is that the decklid sees higher pressure for an area the width of the spoiler and with length of 2x the spoiler's chord. So a good CAM spoiler wants to see 20" of decklid space in front of it.

Another mistake I've seen a few times or discussed with people is adding a gurney flap to the top edge of the spoiler. That can only create lift, something we obviously want to avoid!

Spoilers are much more effective with good end plates. There's not a peep in the CAM rules about end plates. However, when I still had a C4 and wanted to install a spoiler, I was going to mount it purely using large end plates (like at least 20" long and 10" high) and make it removable for street driving. Before spending time and money fabricating it, I emailed the CAM leadership to verify its legality. Naturally, they said "no end plates." I pointed out the omission of any such statement in the rules. That was four years ago. Do you think they've put any verbiage in the rules handout yet to clarify? Nope.

[joelster]

Did some testing yesterday.

Ran my wing at 4 different main angles. Ran it at 3 degrees, 10 degrees (that's what's the max recommendation), 16 degrees, and a crazy 36 degrees. The second element is 34 degrees higher than the main wing so it's 37 degrees, 44 degrees, 50 degrees, and 70 degrees.

Total surface area of the main wing is 4.51sq/ft and the second element is 1.81 sq/ft for a total of 6.32 sq/ft.

Cliffs notes: 16 degrees crushed them all for autocross work.



At 16 degrees, it hit 100lbs of downforce roughly 15mph sooner than when it was at 3 and 10 degrees. The 36 degree angle was a mess as it barely hit 100lbs of downforce even as I approached 65mph. Approaching 70mph the 3 degree angle started to surpass the 10 degree angle, both were around 139lbs at 70, and at 75mph the 3 degree angle was 161-167lbs while at 10 degrees and 75mph it was 152-163lbs. But at 16 degrees it was at 173-180lbs. I'm guessing that if I ran the test up to 85-90 that the 3 degree angle would have shined and passed the 16 degree angle as well.

I sent the data to a few VERY experienced aerodynamic guys. They told me a few keys things. Most data that's computer generated only shows "clean" air hitting the wing. You'll likely never see clean air hitting your wing during a run. Why? That's because we are typically transitioning the car around the course, it's rarely perfectly straight. Plus we have both windows down, which greatly disrupts the air flowing around the car, and any front aero that you add can have an impact on the rear aero as well. Also, they said that the distance that I have between the 2 elements is likely too big. they said I should tighten that up.

Just a few notes about my setup. It's a digital force gauge with a s-beam load cell in the trunk. The trunk lid is heavily braced, and the load cell can float on 2 rod ends so it doesn't get bound up. YES I'm aware that SOME of the downforce is being felt by the trunk hinges. There's no way for me to fab up something exotic that eliminates that from happening. I am merely interested in the differences in downforce between changing the angles of the wing assembly.

[DaveC113]

Originally Posted by joelster

Did some testing yesterday.

Ran my wing at 4 different main angles. Ran it at 3 degrees, 10 degrees (that's what's the max recommendation), 16 degrees, and a crazy 36 degrees. The second element is 34 degrees higher than the main wing so it's 37 degrees, 44 degrees, 50 degrees, and 70 degrees.

Total surface area of the main wing is 4.51sq/ft and the second element is 1.81 sq/ft for a total of 6.32 sq/ft.

Cliffs notes: 16 degrees crushed them all for autocross work.



At 16 degrees, it hit 100lbs of downforce roughly 15mph sooner than when it was at 3 and 10 degrees. The 36 degree angle was a mess as it barely hit 100lbs of downforce even as I approached 65mph. Approaching 70mph the 3 degree angle started to surpass the 10 degree angle, both were around 139lbs at 70, and at 75mph the 3 degree angle was 161-167lbs while at 10 degrees and 75mph it was 152-163lbs. But at 16 degrees it was at 173-180lbs. I'm guessing that if I ran the test up to 85-90 that the 3 degree angle would have shined and passed the 16 degree angle as well.

I sent the data to a few VERY experienced aerodynamic guys. They told me a few keys things. Most data that's computer generated only shows "clean" air hitting the wing. You'll likely never see clean air hitting your wing during a run. Why? That's because we are typically transitioning the car around the course, it's rarely perfectly straight. Plus we have both windows down, which greatly disrupts the air flowing around the car, and any front aero that you add can have an impact on the rear aero as well. Also, they said that the distance that I have between the 2 elements is likely too big. they said I should tighten that up.

Just a few notes about my setup. It's a digital force gauge with a s-beam load cell in the trunk. The trunk lid is heavily braced, and the load cell can float on 2 rod ends so it doesn't get bound up. YES I'm aware that SOME of the downforce is being felt by the trunk hinges. There's no way for me to fab up something exotic that eliminates that from happening. I am merely interested in the differences in downforce between changing the angles of the wing assembly.

Thanks very much for doing this!

I know it's a bit more than you probably want to do, but it would be interesting to compare this to a SLE spoiler + a larger wicker bill. Mostly because I'm cheap and don't want to buy a wing, lol.

At some point I'll go all in on a wing and splitter. Someday...

[joelster]

Originally Posted by DaveC113

Thanks very much for doing this!

I know it's a bit more than you probably want to do, but it would be interesting to compare this to a SLE spoiler + a larger wicker bill. Mostly because I'm cheap and don't want to buy a wing, lol.

At some point I'll go all in on a wing and splitter. Someday...

I can do a spoiler test as well. Give me some time though lol. The only spoiler test I'll do though is a CAM-C legal one that is 10".

[DaveC113]

Originally Posted by joelster

I can do a spoiler test as well. Give me some time though lol. The only spoiler test I'll do though is a CAM-C legal one that is 10".

Nice! I'm thinking of just adding the ZL1 Addons Wickerbill, it's cheap and I still want to drive my car on the road at times. Don't want to put too much into it as a wing is inevitable the way things have been going.

Agreed the most useful test is vs the largest legal spoiler though.

https://zl1addons.com/products/camar...42283286823083