SCCA CAM-C Thread

[Dallas J]

Ive been meaning to 3d scan the void below the edges of the trunklid and the bottom od thr trunklid itself along with the hinges to model a 3d printable insert for that void. Haven't gotten around to that yet though

Apparently I didn't save the inner sheetmetal area and don't have the car here to look at, but isn't the trunk stop right there or close? Ahead of that I think the trunk is just going to lift so filling wont help much more than the stop is already doing, right?

Either way, we'll see how it goes. I can always iterate and move things around.

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[webspoke]

Having run a gt500 anderson clone wing on high risers (8") and with a large 1" wicker at speed, I can share the trunk weak points. No reinforcement in my trunk, I did fill the voids in the rubber bumpers btw the tailights after the first day of running. This car hits 140-150 on track regularly, and the wing should be making 300-400lbs of DF. The wing itself is a 12"chord on a curved 67" span.

You can see the marks on the tailights and the crease in the structure from all the load on the outer edge.

The trunk will also dig down into the bumper skin.

If I did it again I would do something like this shortened trim panel on the old GT4 gt350.

 

[Dallas J]

Ooh, thanks for the pics there. That was definitely pushing down with serious force. So looks like some sort of stronger stop is necessary at some point. Or maybe thats what @mavisky was eluding too.

Once my car gets finished at Radium I'll scan that trunk inner edge area too, maybe make something that can fill that void and become a load transfer piece preventing your failure mode.

I cant tell whats going on in the GT4 picture though.

 

[webspoke]

Ooh, thanks for the pics there. That was definitely pushing down with serious force. So looks like some sort of stronger stop is necessary at some point. Or maybe thats what @mavisky was eluding too.

Once my car gets finished at Radium I'll scan that trunk inner edge area too, maybe make something that can fill that void and become a load transfer piece preventing your failure mode.

I cant tell whats going on in the GT4 picture though.

I know a few people that would be interested in an outer brace on the underside.

In the GT4 picture, this panel is about an inch shorter than the street cars, so it can't hit the bumper.

 

[Dallas J]

The bottom brace would normally just have some screws running up to the mount. I wonder if there's room for some adjustable bumpers I could put at the bottom.

Still wouldnt prevent the crack you (webspoke) saw where the trunk meets the center section though. Just thinking about it, the joggle in my uprights may help with that since it would better support the mounts flexing inward.

 

[NightmareMoon]

I did make solid inserts for my main rubber bumpstops. Ill send pics of the uprights later tonight.

 

[NightmareMoon]

More pics of wing mounts, shamelessly inspired by @ajhartman's wings.

I wanted to highlight the reinforced areas under the decklid. A lot of the decklid is a single layer of skin in a box shape. The sides of the decklid are mostly boxes 1 layer thick. In the middle there's some areas where two layers are bonded together (green) next to embossed features which should add strength in 3D (blue). They also kind of line up with the main rubber bumpers, (purple) which you can also reinforce with inserts. You can see where my mounts bolt through at the silver washers (red arrows). There are additional points through the single layer skin around the back edge. Following around the back edge corner should help those single layer spots hold up.

The wings of the decklid are boxed in a way where without filling the gaps between the top and bottom skins, you're stuck bolting through one layer of skin. Just using the single top layer alone will be really easy to bend.

There are little rubber stops on the sides, but the main bumpstops are more central, which is why the Ford racecar above is bending the wings and cracking the taillights.

Here's what it looks like on the top. You can see the brackets are large and match the decklid contours.

Anyway, not saying its perfect, but its been working out so far.

 

[ajhartman]

Yeah I did an install video of our wing kit. How you tie into the trunk, especially with wings that make a lot of downforce is important.

 

[rxryanm]

What do you guys use to pull pedal percentage data from gas and brake? I'm not very feel-oriented with anything I do, so would love to have actual numbers for what my foot's doing.

 

[Biggsy]

What do you guys use to pull pedal percentage data from gas and brake? I'm not very feel-oriented with anything I do, so would love to have actual numbers for what my foot's doing.

What OBD device do you have?

 

[rxryanm]

RTD(+?) I'd buy something else, if needed.

 

[Biggsy]

RTD(+?) I'd buy something else, if needed.

I just ask because sometimes the channel name is different between devices. For throttle it may be TPS or throttle position.

brake pressure is usually derived by doing some maths. I can see it on my data logger but not my tuning device.

 

[kz]

What do you guys use to pull pedal percentage data from gas and brake? I'm not very feel-oriented with anything I do, so would love to have actual numbers for what my foot's doing.

For throttle whatever OBD dongle you have, a lot of people are using OBD Link of some sort, it's a standard PID so can be read with whatever.

For brake you don't have brake pedal percentage since it's a hydraulic system but you can get brake pressure off CAN bus - which is a bit more complicated than just reading PIDs and newer cars require tapping into wiring rather than just using OBD.

I read brake pressure off the same OBD Link using CAN preset in either Race Capture or more recently Solo Storm.

 

[rxryanm]

For throttle whatever OBD dongle you have, a lot of people are using OBD Link of some sort, it's a standard PID so can be read with whatever.

For brake you don't have brake pedal percentage since it's a hydraulic system but you can get brake pressure off CAN bus - which is a bit more complicated than just reading PIDs and newer cars require tapping into wiring rather than just using OBD.

I read brake pressure off the same OBD Link using CAN preset in either Race Capture or more recently Solo Storm.

I'll have to come up to Cincy for one of your events and check your setup out.

 

[kz]

I'll have to come up to Cincy for one of your events and check your setup out.

Anytime - I'd most likely be on every single one of them - I used to run RaceCapture but now it's OBD LInk + RaceBox Mini (awesome little device, superb GPS accuracy compared to just about anything else) + Solostorm on the tablet.

Since my car is 2018, CAN bus can be accessed through OBD port and OBD Link.

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