Longacre 4-Pad Scales, Proper Use Options

[KeithO]

A friend loaned me his Longacre 4-pad scale system last evening. This evening after work I need to weigh my car in preparation for my CMC dyno pulls tomorrow (I need to know if/how much hp/tq to pull out of the motor). I planned on weighing the car in my 2-car garage but it has a very gentle slope towards the absolute center to allow runoff to go down the drain. This means that even if I center the car over the drain, the location of the 4 pads may not be perfectly level. As a backup, I took a level out to my rear, omni-stone patio. While it is level, there is some uneveness in some of the stones and it will not likely allow the pads to fully distribute the weight across the base of the pads.

Question:
1) Is this small amount of slope in my garage enough to be concerned about? I want to esnure that I don't damage the scales and I am looking for a reasonably accurate weight.
2) Would I risk damaging the pads if I used them on my omnistone patio given that they may not sit flat against the surface?

Anyone with knowledge/experience with the scales can feel free to chime in on my questions or give helpful hints. I need an accurate weight and the system did not come with instructions...

Thanks.

[rmackintosh]

ANY variation in slope is gonna make the corner weighting function of the scales mute.....if you are looking to just get a weight....then no problem.

I WOULD NOT put them on UNEVEN ground as this could damage the scales if they don't sit flat and you put a heavy car on them...

If ACCURATE corner weignts are what you are after, you will have to get a good long level, and figure out someway to shim the pads level

[KeithO]

Excellent. This is what I was curious about. I am not interested in corner weighting yet because I am not able to set the ride height to the target settings yet. 3rd gen wheels bang the rear quarter panels (0mm offset) and I haven't been able to drive the car in anger with the current setting.

I just need a weight.

Thanks!

[zlexiss]

If you just need weight, you won't need a perfectly level pad, but still needs to be pretty level.

For weighing our missiles (about the weight of an F-body (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif) ) we have pretty thick rubber pads we put under the load cells to absorb loading shocks as the missile is set down, and also to prevent damage from the floor. If you're worried about the surface, try tracking something down.

[1LEThumper]

Depends on the scale setup you are using. Some of them have their own frame work with adjustible pads, others are just the 4 scales themselves and you have to shim them. If you have a frame work type then level the front one then the rear one then to each other....both fore and aft and side to side. You need to make sure what ever it sits on it is solid and firm so that it doesn't affect the scale readings.

Also you need to make sure that the car is aligned before you scale it. Make sure the front tires are both pointed forwards, make sure all tire pressures are set the same and unhook the sway bars. Other than that its up to you as far as fuel in the tank and if you are in the car or not...it should be scaled with you in it however.

[35th_Anniversary...]

unhook the sway bars.

unhook the sway bars?

please explain - curious

I know several people with scales and want to cornerweight my car (z06 - not the SS)

[RedHardSupra]

unhooking the sways is so the corners aren't 'connected' and aren't 'transferring' any weight from one side to the other. with them, each corner gets to sag individually without affecting any neighbouring saggage (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif)

wasn't there a big 'to hook or unhook' sort of thread on here about it few weeks ago? or was that c-c? they had much better explanations, i'm just trying make this into an executive summary infortainment.

[KeithO]

Just to follow up -

I weighed my car in my garage. See sig for results. Based on previous weights that I trust and changes that I have made to the car over the winter, I think I got an accurate reading... Now I just need to get some hp out of the damn car.

[1LEThumper]

Yes you are correct you un do the sway bars so you don't get any side to side effects going on and so that you can adjust the end links once its done.

The alignment and tire pressures are done for the same reading. Wanna have some fun if your bored and have some time...put the car on it and change tire pressures and watch the scale readings.

[Louis]

Antoine is 100% correct. Sways hooked up will add upwards of 30-40#s of mis-reading.

I have a Longacre 4 scale setup, with the scale pads and the scale carrying cart for sale. If any of you are interested, let me know.

[35th_Anniversary...]

I have a Longacre 4 scale setup, with the scale pads and the scale carrying cart for sale. If any of you are interested, let me know.

How much do you want?

[Louis]

This stuff is used, but well taken care of. To get the same stuff through Longacre, you would have 4500+ in it.

3000$ USD, and Ill deliver it to lime rock the 4th of july.