Engineering is awesome: Doing Lat G vs Tire vs Camber test for credit, need help.

[Bimmerman325i]

Hey all,

My senior lab group for Mech E at CU has been tasked with designing and carrying out an experiment. Naturally, it involves cars. We are going to be testing camber vs lateral G vs tires, either brand or preferably width. We'll be using my M3 to collect data, but if anyone else wants to come watch, that's chill. We will be setting up a skidpad (probably 200ft diameter) and measuring time at max grip.

We are going to be testing the M3 at maximum speed around the skidpad before slip occurs, and testing camber angle vs tire width vs lateral G. We plan on either using three different tires, or far preferably, a set of 235, 245, and 255/40/17 Dunlop Star Specs. I've got the 245s, I'm getting a set of 235s, but I don't have any 255s as of yet. We hope to get good data on how much lateral G a given tire width at a given camber angle gives.

Does anyone know of a wide open parking lot that we could partly take over for a half day/full day, with a parking lot manager/building owner who is ok with cars going around a skidpad at high speed? We have to do this by the book, and we'll be there for hours, so being legal is critical. I know of a few spots, but if anyone has input/connections, I'd greatly appreciate it!

Also, if anyone has a 5x120 255/40/17 Dunlop Star Specs mounted on 17x9s that we could borrow for the test (you'd get our data in return, and beer/w/e) I'd be very grateful.

Thanks guys! Please, any feedback you have on our test or methodology, let me know!

[iamsam]

what class is this for?

[Bimmerman325i]

Senior Lab

[iamsam]

Measurements Lab? Senior Design? Mechanical Engineering Lab? Elective?

[Bimmerman325i]

.....senior lab. That is the class. I think its called mech e lab officially, but its sr lab.

[KennyT]

There are a lot of things you are missing on this test, or haven't mentioned in the post. Are you going to change camber on only the front tires? Are the tires all going to be shaved for best grip? Are you going to be taking temperatures, tire deflection, tire pressures? Are you going to measure times for left and right handed runs?

I've done tire testing for formula sae and our procedure read like this:
Pressurize all tires in shade, check temps on inside/middle/outside in 3 places to make sure starting temps are equal, mount on vehicle. Run 3 sets of two laps each direction to warm up tires, run 1 timed lap each direction, and check temps on the outside tires. Check pressure on all 4 tires, then check tire wear front to rear.

This is repeated until the data from two runs is rather close, then camber is changed (we started at 0 static and went to -4 static).

I may be missing things, but this was done last June.

[Bimmerman325i]

There are a lot of things you are missing on this test, or haven't mentioned in the post. Are you going to change camber on only the front tires? Are the tires all going to be shaved for best grip? Are you going to be taking temperatures, tire deflection, tire pressures? Are you going to measure times for left and right handed runs?

I've done tire testing for formula sae and our procedure read like this:
Pressurize all tires in shade, check temps on inside/middle/outside in 3 places to make sure starting temps are equal, mount on vehicle. Run 3 sets of two laps each direction to warm up tires, run 1 timed lap each direction, and check temps on the outside tires. Check pressure on all 4 tires, then check tire wear front to rear.

This is repeated until the data from two runs is rather close, then camber is changed (we started at 0 static and went to -4 static).

I may be missing things, but this was done last June.

Thanks for the feedback. I did tire and suspension tests for fsae as well, what school did you go to? We are still in the brainstorming process, and are trying to keep the scope as small as we can. If i was doing this like fsae, itd be too complicated, we are going to keep as much constant and low cost as possible.

[iamsam]

Im still thinking of a place to do it... You would have to probably rent a place, I am sure you can't legally set up a skid pad area for free.

[KennyT]

Thanks for the feedback. I did tire and suspension tests for fsae as well, what school did you go to? We are still in the brainstorming process, and are trying to keep the scope as small as we can. If i was doing this like fsae, itd be too complicated, we are going to keep as much constant and low cost as possible.

I go all out. I'm at MTU. I was originally thinking this was a senior design deal, where you have a budget etc to do your research with.

[CorvallisBMW]

This is so cool. PLEASE post up some results when you're done, I'm sure many of us here would like to see some graphs of camber vs grip

[monkeytaco]

A. This sounds awesome and fun and even useful.

B. I have no ideas for parking lots you could use all day.

C. Tell me when it is happening and I can do some video. That would be fun.

[pengajim]

as for your question about location...I went to CU but it's been awhile since I've lived in Boulder. I good idea would be to contact the local SCCA Solo organizer and ask what property they use for autox. They could hopefully put you in touch with the property owner and you can go from there. Or you could ask the SCCA if you could share the space they use during an autox event, if the lot is big enough to hold their course and your skidpad. Their season should be starting shortly and the timing might work out.

Another idea i have is to contact whoever runs/owns what's left of the old Denver airport (Stapleton). There should be a lot of concrete for you to use there...if it's still there.

Good luck and post your results please!

[sleepingbeauty]

parking lot up on 28th and iris where the pleasure shop and drivers license place is. You can def fool around in there, its not so crowded, just have to mark off the pot holes and loose gravel…

I have toyo proxies on 17x7.5...

[blefevre]

1. Yes, contact SCCA and get the deal on dicks sporting goods place they always go to.

2. Can I attach the G-meter to my car and do a skidpad test?

3. Lets HD Hero this right at the tires to make your presentation awesome.

4. Who's teaching it this year?

[Bimmerman325i]

1. Yes, contact SCCA and get the deal on dicks sporting goods place they always go to.

Will do, but I'm pretty sure the SCCA/BMWCCA pays to use the lot.

2. Can I attach the G-meter to my car and do a skidpad test?

I don't see why not

3. Lets HD Hero this right at the tires to make your presentation awesome.

Hell yes! I was thinking of in car, out of car, and a couple left/right cameras would be sick. It's a poster presentation, but I fully intent on making a video and youtube-ing/having laptop set up next to the poster.

4. Who's teaching it this year?

Carmen Pacheco. I don't know if she was sr lab prof last sem, but she did measurements then.