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-   -   So, we cornerweighted the car (https://www.rx7club.com/race-car-tech-103/so-we-cornerweighted-car-134295/)

Silkworm 11-19-02 11:50 PM

So, we cornerweighted the car
 
Overall weight 2459, 1/4" tank of gas, all fluids, race ready setup, no driver

With driver, 2771 (Ok, yes, I'm a lard ass! ;)) That puts me 90lbs over minimum weight, and if my dieting works out, I should be good to go (I doubt I'm ever going to be below 220 weight wise)

First pass, eyeballed the setup, too low in the front, no driver:

LF 618 RF 659
LR 618 RR 564

LF/RR 1182, 48%
RF/LR 1277, 51.9%
F 1277 51.9%
R 1182 48.0%


With driver

LF 736 RF 669
LR 734 RR 635

LF/RR 1371 49.4%
RF/LR 1403 50.5%
F 1406 50.6%
R 1369 49.3%


2nd Pass, raised LF 3/8", RF 1/4" (3 full turns, 2 full turns)

With driver
LF 739 RF 664
LR 732 RR 637

LF/RR 1375 49.6%
RF/LR 1396 50.3%
F 1403 50.6%
R 1368 49.3%


Final Pass, raised LF 1/8" (total of 1/2" from baseline)

With driver
LF 743 RF 659
LR 726 RR 646

LF/RR 1389 50.0%
RF/LR 1385 49.9%
F 1402 50.5%
R 1371 49.4%

So there you go :)

PaulC

artowar2 11-20-02 01:56 AM

Damn, give or take a few turkey sandwiches and you'll be spot-on :)

Mazderati 11-20-02 07:54 AM


Originally posted by artowar2
Damn, give or take a few turkey sandwiches and you'll be spot-on :)
Heh. Ham sammiches.

KiyoKix 11-20-02 08:52 AM

Ha...sammiches :p:

220...pretty big guy, nice to see the big guys showing some love to the 7 too :D. I'm just a little guy (150...maybe 155 soaking wet).

Samps 11-20-02 10:07 AM

It will be interesting to see if this improves your lap times. And do you need to have the car aligned after you mess with the corner heights?

CarmonColvin 11-20-02 10:12 AM

You got your cross weights as perfect as you can get them.

I will have to go in the other direction when setting up my ITS car next year. I only weigh around 155 lbs (in race trim). In a properly setup ITS car I will need to have some weight in the passenger floor board to be legal.

Here is one thing I suggest you try the next time you have access to corner scales. After setting up your weights as perfect as you can see what they are at different angles of steering input. You will be amazed at how big of a difference 1 turn of the steering wheel will make on your corner weights if you are running a bunch of caster. But then at that point you have to comprimise between proper corner weights and the camber gain you get from the caster with steering input.

Mazderati 11-20-02 10:22 AM

Would you not want an equal weight distribution over all four corners? I ask this because I noticed that you have more weight on the left side of the car. Obviously this is due to you being in it, but what is the reasoning behind not compensating for this added weight and having something closer to a perfect 692.75 lbs. over each corner?

Also, what does the term "cross weight" refer to?

Thanks.

Kyle

Silkworm 11-20-02 12:18 PM

Samps,

We checked to see the alignment changed significantly, and it hadn't with the small changes we made. Yes, it will be very interesting to see if handling balance changes now, our inital setup was significantly biased, but I didn't really notice that much, so I'm very eager to see if it changes.

Carmon,

Yeah, I'll play with that as well. I'm running 6* pos caster, so the changes will probably be very significant.. I can get the scales pretty much any time I need them, but I need to build some ramps for his scales so my buddy isn't having to lug them to my place every time I want to check my weights.. I'll check again after swapping in 500/350 springs and resetting my alignment (I need more than -2.5* camber up front for sure)

Mazderati..

Well, in a perfect world where I could legally remove and add weight whereever I wanted, then I would try to balance it out. However, the rules won't let me :) I've removed everythign I can remove, I've put in everything I'm required to add, so short of adding weight to balance the car (and going even farther over the weight minimums), there's not much left I can do.

PaulC


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