Volvo 242 CG height for Kevin

As promised we actually did the CG height calculations on the Volvo...only a month later than promised...try to think of it as a JVAB time estimate For general reference it's measured by weighing the front and rear of the car as one end is lifted (forklift in this case) and the change in front to rear weight distribution allows you to calculate the CG location vertically. To minimize the variables the suspension was blocked solid at ride height by welding a set of junk struts on the front and replacing the rear shocks with solid tube replacements. It still wasn't as consistent as I would have liked but it's still better than guessing.

Special thanks to Al for his carpentry skills on the scale supports:


Lift, Measure, Weigh, Repeat:


And the results:

Holy shit! How is that car so light?
Last time I weighed mine it was 2760!
(That was on a truck scale, before the cage...)

That orange is completely awesome!

Honestly though, with that car appearing to weigh ~400# less than my car, I'm not sure how valid the data is, but it does provide a good place to start.

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Monika Hawkinson
Seattle, WA

How about a simple profile drawing for the aged and conceptually challenged?

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

john vanlandingham Wrote:
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> How about a simple profile drawing for the aged and conceptually challenged?
>

Tim,

I'd like to see a sketch too, please. (But won't admit to the reasons John gave.)

Rich Smith

Kevin,

Even if the scale wasn't calibrated accuratly, I don't think it should affect the CG calculation. It's the relative difference that should matter.

But, what do you think of the methodology?

Rich Smith


PS: Tim, thanks for posting. Stuff like this is great!







Edited 2 time(s). Last edit at 07/01/2008 03:40AM by Rich Smith.

Sofa King Wrote:
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> Holy shit! How is that car so light?
> Last time I weighed mine it was 2760!
> (That was on a truck scale, before the cage...)

Cage is probably the big one.

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Grant Hughes

Don't want to gloat, but with Tim's kustom trailing arms, its even two pounds lighter!

wink wink


yep, I was suprised it was so light too. no spare tire, no cage of course, pretty much nothin' but a seat and a instrument cluster hanging from bailing wire.I've scaped it quite a bit and cut out a few big chunks of metal that weren't doing anything. Its a '76, and I think the earlier cars were lighter, It has a skinny little drive shaft(for now). I did get a tubular header that dropped like 50 lb. over the stock iron. Anyway it will be plenty heavy with Alberto Gordo at the wheel...

-Al

Attached are two images from Fred Puhn's book, "How To Make Your Car Handle".

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Self-righteous douche canoe

hoche Wrote:
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> Attached are two images from Fred Puhn's book,
> "How To Make Your Car Handle".

Thanks, you beat me to it...I don't have a scanner at home. I pulled the equations from Milliken "Race Car and Vehicle Dynamics" Section 18.2-Wheel Loads where it is a special case equation and part of calculating the sprung mass, etc, etc. They all work the same though.

Tim

Yeah, a simpler version is also in Staniforth's "Race and Rallycar Sourcebook", and I think I remember seeing it in one of Carroll Smith's books.

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Self-righteous douche canoe

Jeepers, my golf weighs 2400lbs and I thought it was fat!

Carl S Wrote:
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> Jeepers, my golf weighs 2400lbs and I thought it
> was fat!

beginning to see why I push these 240s and Xratties?
Let me point out 2300 SOHC with turbo so more torue than the VW will EVER make by 50%, only a bit heavier.

Which do you think ought to be quicker?

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Hey Tim,
Is that you in the picture?

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Monika Hawkinson
Seattle, WA

Sofa King Wrote:
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> Hey Tim,
> Is that you in the picture?
>

nope that's master carpenter "Alberto Gordo" aka Al Kun.