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-   -   Crapcan/Lemons corner weighting (https://www.miataturbo.net/race-prep-75/crapcan-lemons-corner-weighting-92531/)

cordycord 03-17-2017 11:50 AM

Crapcan/Lemons corner weighting
 
Someone talk me out of this bad, bad idea....x 4

660lbs LCD AC Digital Floor Bench Scale Postal Platform Shipping 300KG Weigh | eBay

pdexta 03-17-2017 12:22 PM

I like the idea, it seems like it would work. Worst case scenario you're out $40. If you do it please let us know how it goes.

MrJon 03-17-2017 12:30 PM

When I was looking for my corner scales, I kept looking on ebay, racing junk, craigslist, etc. I found a set of longacre scales, I paid about $500. The big "problem" with them is that the internal battery is kaput, so it won't store values, and it has to be plugged in. But other than that they are in great shape, and work perfectly. If you look around for a bit you can find decent deals on used ones.

A quick search on racing junk revealed this for the old school baller ...

Scales for Sale in EASTPOINTE, MI | RacingJunk Classifieds

Scaxx 03-17-2017 01:50 PM

Huh, for 40 I feel like it's hard to go wrong. Even if they're within 10lb they'd be a good deal.

Bronson M 03-17-2017 03:01 PM

Just tried ordering 4 and the seller has this restricted to a single scale every 10 days......Why I have no idea. Must think someone is going to resell them or something.

Edit:The seller just pulled the ad down, so we'll see if I get ripped off on the one scale that I ordered

aidandj 03-17-2017 04:21 PM

@soviet

soviet 03-17-2017 05:51 PM

I'm building crapcan scales myself. Aidan linked to those 300kg ones, but our crap cans are not well balanced so I can totally see 300+ kg on one corner.

So I decided on 400kg load cells instead. So far I ordered and received one, and going to be building plates soon to test it out. If it works, I'll order 3 more load cells.

Load cell - High-precision strain gauge load cell electronic scale sensor 400kg?150x44x33? | eBay
HX711 amplifier boards -
And one arduino. I think I can get away with a regular arduino. If not, an arduino mega

For bases, one of the guy has some 3/4"steel plate laying around. That will be the bottom, cut in 12x12". The top will be 1/4" 6x6" steeland 1/2" 12x12" birch


https://lh3.googleusercontent.com/-Y...2017-03-01.png

cordycord 03-17-2017 08:36 PM

I keep looking at the 300Kg Ebay vendors and the low prices all have ZERO sales history. Not good. I've got anytime access 50' away from my shop to real scales that give cross-weights, but thought something like this might be worth getting for the price. This was what made me check out Ebay:

https://nasaspeed.news/tech/suspensi...t-on-a-budget/

Alternative 03-18-2017 07:23 AM

These scales are back up for $10 being sold by users with 0 reviews.

There are more legit legit sellers selling $40 scales shipped.

pdexta 03-18-2017 09:19 AM


Originally Posted by Alternative (Post 1399466)
These scales are back up for $10 being sold by users with 0 reviews.

There are more legit legit sellers selling $40 scales shipped.

I found scales with the exact same pictures and specs on Amazon selling for $54.

nbfather 03-21-2017 11:49 AM


Originally Posted by soviet (Post 1399388)
I'm building crapcan scales myself. Aidan linked to those 300kg ones, but our crap cans are not well balanced so I can totally see 300+ kg on one corner.

So I decided on 400kg load cells instead. So far I ordered and received one, and going to be building plates soon to test it out. If it works, I'll order 3 more load cells.

Load cell - High-precision strain gauge load cell electronic scale sensor 400kg?150x44x33? eBay
HX711 amplifier boards - https://www.amazon.com/gp/product/B010FG9RXO

And one arduino. I think I can get away with a regular arduino. If not, an arduino mega

For bases, one of the guy has some 3/4"steel plate laying around. That will be the bottom, cut in 12x12". The top will be 1/4" 6x6" steeland 1/2" 12x12" birch


https://lh3.googleusercontent.com/-Y...2017-03-01.png

I have been thinking about this for a while.
Getting the Arduino work...that would be sick!

I was wondering if jacking up a Miata and then lowering it on the scale load/bind the suspension and cause haywire readings??
If so, perhaps connecting left and right scales (shorter piece) or front and back with a plank or something stiffer, then adding a turn plate per corner?

Either way subscribing!

Jamie

OGRacing 03-21-2017 12:14 PM


Originally Posted by cordycord (Post 1399308)


something sounds better than nothing. 660lbs doesn't sound like enough. if it scaled out perfectly 50/50 you can only do a 2400 lbs car. i know on my car I've seen 700lbs+ on a corner. I've also seen formula cars scaled on bathroom scales, so it can work.

Alternative 03-24-2017 08:19 PM


Originally Posted by nbfather (Post 1400165)
I have been thinking about this for a while.
Getting the Arduino work...that would be sick!

I was wondering if jacking up a Miata and then lowering it on the scale load/bind the suspension and cause haywire readings??
If so, perhaps connecting left and right scales (shorter piece) or front and back with a plank or something stiffer, then adding a turn plate per corner?

Either way subscribing!

Jamie

Super cheap way to get past this is using a pair of floor tiles or hardboard with grease between them. Not elegant but cheap.

hi_im_sean 09-11-2017 07:45 PM

did anyone ever try these?

current link
4X 660LBS 300KG LCD Digital Floor Platform Scale Bench Postal Shipping Weight W

Bronson M 10-21-2017 09:42 PM

https://cimg5.ibsrv.net/gimg/www.mia...be0c64bded.jpg
So I purchased 4 of the 40$ scales and built a set of ramps out of composite decking boards I had laying around.

​​​​​​https://cimg5.ibsrv.net/gimg/www.mia...63883525fe.jpg

The concerns about exceeding their capacity are valid, there first time I rolled the car onto the scales I had two corners maxed out. The reason I did was because I had an unreal amount of wedge in the car.
​​​​​​
Once I made one round of adjustment and got the corners closer together I was just under the max weight of 660lbs. Considering what my total weight is and Interpolating I was able to figure out my starting corner weights.
L. R
490 738. F
725 431. R
That works out to a wedge of 38.6% or 542 lbs. This was staggering to me considering the ride heights were equal side to side within a 1/4"

I was able to finish up with cross weights within .5% which is 15lbs.

L. R
626. 629. F
563. 551. R

Total weight: 2369
F/R balance: 53%

Honestly this is the best 160$ I've ever spent on the chassis. I knew it was possible to get the cross weights messed up and not drastically affect ride height but I had no idea it could have been that bad. The car was handling odd being loose as hell in right handers and pushing in left handers, very excited to see how well it does at the next event.

​​​​​​It's going to be a crap shoot if your car will weight too much for these scales, to put it into perspective I have no power steering or a/c but a heavy cast turbo manifold and of course a turbo. The interior is stripped except for the dash and carpet under the race seats, it also has a roll bar. With full accessories and full interior with a turbo these scales might not work. I have plans to double them up with a board to bridge them in order to weight heavier cars.

Edit: Wanted to add these weights are without me in it, about 90% of the time I'll have someone else in the car with me so it won't affect the cross weights all that much. It'll be out with just a driver but considering I've been within a 1/2 second of FTD with this horrid setup I think it'll be well within the margin of my uncalibrated ass.


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