Fine tuning corner weights

1980SC · 05:27 PM

I'm corner weighting the SC, and have the following (in pounds):

563__521
837__808

Total weight with a full tank of fuel and my butt is 2729 lbs.

Anyone that has done this before have any comments on how the numbers look?

I've got the diagonal weights at 50%, but was hoping to get the fronts a little closer to each other. I autox in stock class, so I can't move any ballast around.

Rob
1980sc

ttweed · ttweed's Garage

GO HERE to Thom's calculator and plug in your numbers.

Looks like you're within 7 lbs. of ideal weight on the corners, so I'd call it close enough and wouldn't mess with it.

TT

1980SC · 05:54 PM

Hey Thanks !

How is that page determining "ideal" weights?

I just made one minor adjustment (it's fun, I can't help it) and got :

556__525
846__799

When I plug those numbers into Tom's page, it says my weights are the ideal weights (within 1 lb). Are they really? I would think a better side to side balance would be more ideal.

Thanks,
Rob
1980sc

masraum · 06-09-2003, 07:47 PM

These cars will have a front to back split and a right to left split, so the weights will be heavier on the left. (I guess RHD would be opposite)

ttweed · ttweed's Garage

Quote:

Originally posted by 1980SC
When I plug those numbers into Tom's page, it says my weights are the ideal weights (within 1 lb). Are they really? I would think a better side to side balance would be more ideal.

Good job! Within 1 lb. is very accurate. You'll probably change more than that just by running your gas tank down.

You'll not get a better side to side balance in a 911 Porsche with the driver's weight in the left seat (or right seat, for your RHD countries) without relocating some heavy things on the chassis somehow.

That's not important to your handling balance, luckily, what you want is for the F/R weight distribution to be the same on the left side as it is on the right. This will insure that the tendency to under/oversteer is the same when turning both ways (given that the rest of your setup is equal side-to-side). Of course for roundy-round racing, it's a whole 'nuther ball game...

TT

Wil Ferch · 06-10-2003, 07:33 AM

Look up posts that I made in addition to Thom and Chuck Mooreland. Went into considerable detail. For "tin-can" cars like ours diagonals being equal is *not* the target ( good for Formula type cars, though). Target should be LF/LR=RF/RR ....or ...LF/RF=LR/RR. Lots to say about this as to "why". See our archived ( lengthy) discussions on this.
---Wil Ferch

masraum · 06-10-2003, 08:03 AM

So Wil, why are the ideal weights closer to equal diagonals than to equal side to side weights?

Side-to-Side
Left 1402 51.43 %
Right 1324 48.57 %

Diagonal Weight
Left Front / Right Rear 1355
Right Front / Left Rear 1371

Since our cars aren't set up like an indy car how are we supposed to get equal weights left to right short of having one side higher than the other?

Chuck Moreland · 06-10-2003, 08:21 AM

Have a look here:
http://www.elephantracing.com/techtopic/cornerbalance.htm

Your numbes look pretty good!

masraum · 08:44 AM

Nevermind, I found the archived thread in question with the big discussion, Quick Corner Balance Question!

Here's another good article
http://www.pelicanparts.com/techarticles/911_alignment_tips/911_alignment_tips.htm

Wil Ferch · 06-10-2003, 09:58 AM

Whew, thanks...i didn't want to go through *that* again

--Wil

1980SC · 06-10-2003, 01:42 PM

Ah, I see now.

My diagonal weights are only slightly different at 50.3% and 49.7%.

But more importantly, both of my front wheels have 39.7% of their side's weight.

Thanks alot !

Rob
1980sc