[Guest]

This past weekend I had the opportunity to borrow the drive on scale from work (used to weigh Airplanes) and measure corner weights on my 96 Impala. I would say that weight wise mine is typical of most "street" class Imapala SS's. I would say that these figures should be close for a large % of the cars.
Weight wise: HA bars front and rear, extra 23 lbs in trunk/package shelf. misc. odd 10 lbs. scattered in mods.
Car was weighed 4 times with 3 load cells, 4th tire was leveled with board. Averages are listed below (in pounds).
Car was weighed in Auto X set-up. Glove box and console empty, trunk empty (no spare, etc) tire pressures set, seat adjusted accordingly, FULL FUEL and fluids full.

LF: 1183 RF: 1163

LR: 922.33 RR: 943.67

Front Weight: 2346 56%
Rear Weight: 1866 44%
Left Weight: 2105.33 50%
Right Weight: 2106.7 50%
Total Weight: 4212


Same as aboveexcept with driver, helmet and 6 point harness (+230 lbs)

LF: 1283.67 RF: 1180

LR: 995 RR: 983.33

Front Weight: 2463.67 55%
Rear Weight: 1978.33 45%
Left Weight: 2278.67 51%
Right Weight: 2163.33 49%
Total Weight: 4442.0

Observations: 4400+ lbs is a HEAVY race car!
55% of the weight is on the front wheels - aluminum heads and a rear mounted battery would go a long way to evening things out.
It is interesting that right at 75% of the drivers weight is carried on the left side and that 51% of it is on the front wheels.
(My car has stock springs - this would change with different springs)

I hope to get some spring dimensions and some loaded height dimensions to better look at spring and shock changes/alternatives.

 

[Guest]

Very interesting information. I doubt many people have gone through allthat with their cars.

 

[Guest]

Todd,

Nice work!

Would be interesting to see if "relaxing" the sway bars made/makes any difference in the corner weights. I'd also be interested in knowing how changing something as simple as the tire pressure at one corner affects all of the weights.

If you have a chance to scale the car again, also suggest that after the car is set up on the scales, pull the battery and move it to the trunk (temporarily) to see just how much differnce it makes....I know, NOW you tell me!

It also appears that the battery placement in the car has quite an effect on how much the left/right weight differential shows up as it did with the driver in the car. Time for that lightweight drivers seat, or a new diet! Or maybe an aluminum head on just the left side....

Add a lightweight hood to that list of front end mods. There are other things, like lighter wheels and lighter brakes, but since they are unsprung--and class modifiers--they don't figure as directly into the equation.

 

[Guest]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Navy Lifer:

Or maybe an aluminum head on just the left side....

<HR></BLOCKQUOTE>

This cracked me up! Now that would be one unique mod!

Maybe for rac'n we could remove the exhaust on the left side from the cat back? or maybe take the rear door off?

Mike

 

[Guest]

Great info, Todd! And glad to see you over here on the Forum. Folks, Todd KNOWS his stuff about these cars (especially on suspension), he's a good guy to know!

As for your last paragraph : I no longer have any stock front springs. I DO have some stock rear springs lying around (currently NOT on the car). Let me know what numbers you need off of them, and I'll see what I can do.

On a "total weight" comparison : we weighed both my car and Les Brown's car last month on our Napa Valley Wine Cruise at one of the wineries (huge scales for weighing trucks that have grapes on them). Les' car was practically identical on weight to your car (within about 10 lbs if I remember right). My car was about 100 lbs heavier : mostly the Scott Williams trunk kit, 9C1 rubber mat (all HEAVY, and almost all on the rear springs!) and my seats (12-way Bonnys) are about 25-30 lbs heavier (if I remember correctly) as well. This means mine weighs more, but is probably about 54/46 on the F/R distribution (with no one in it).

 

[Guest]

This weight differential with the driver adn other stuff is a good reason (as many know) to top off the fluid in your car and be present and be in the car when doing an alignment. Every little bit helps. Things like the airpump delete, homeplate delete, et.. go a long way. Also, by leaving the spare in would help 50/50 the car out in autoX trim. I have never had any complaints from any officals about leaving it in..(at least in FLA)

Thanks for the work. But like you said The Impala is no Miata by any means

 

[Guest]

...and then there was the one about the spare tire filled with concrete...

 

[Guest]

Todd,

Another thing we want to do in the future is run the same checks on a car with the axle relocated back to see just what effect it has the numbers.

It will be good to have some different springs on hand to play around with, at least for the rear.

 

[Guest]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Marcsmith:
This weight differential with the driver adn other stuff is a good reason (as many know) to top off the fluid in your car and be present and be in the car when doing an alignment.<HR></BLOCKQUOTE>

Is this why my steering wheel is ALWAYS off no matter where I go and how many times I go to have my alignment done?
It's getting pretty frustrating. And now, the alignment is supposedly correct (done by a very competent shop), but I have to apply force in the counter-clockwise direction on the wheel to keep the car going straight... if I don't, the steering wheel straightens itself out, and the car veers to the right. Extremely annoying . Could it be my steering gearbox?

 

[Guest]

Bill, Ed or ??
I will start making a list and maybe we can put together a bunch of parts for me to try?
and record info. I can pretty much borrow it most any weekend? If it's not being used.
Shipping suspension components around could get $$ though.

Ed I could used the following info on the Stock Rear Springs:
Free Height
wire dia.

If someone has a set of stock front spring:
I could use same info.

Thanks in advance.

 

[Guest]

Eric,
It's getting pretty frustrating. And now, the alignment is supposedly correct (done by a very competent shop), but I have to apply force in the counter-clockwise direction on the wheel to keep the car going straight... if I don't, the steering wheel straightens itself out, and the car veers to the right. Extremely annoying . Could it be my steering gearbox?"

It sound to me like you just got another poor alignment. A good shop will know how to compensate for this difference and also if local roads are "crowned" more and be able to get car to drive straight, not pull and not chew up tires!

"ideal" alignments for the street and for the "track" are not necessarily the same.

The best alignments I have gotten are from "OLD Guys" that KNOW HOW to use the equipment. I took my old Malibu to a shop and it wasn't in the computer so they said they could not align it!

Good Luck,

 

[Guest]

Eric,
It's getting pretty frustrating. And now, the alignment is supposedly correct (done by a very competent shop), but I have to apply force in the counter-clockwise direction on the wheel to keep the car going straight... if I don't, the steering wheel straightens itself out, and the car veers to the right. Extremely annoying . Could it be my steering gearbox?"

It sound to me like you just got another poor alignment. A good shop will know how to compensate for this difference and also if local roads are "crowned" more and be able to get car to drive straight, not pull and not chew up tires!

"ideal" alignments for the street and for the "track" are not necessarily the same.

The best alignments I have gotten are from "OLD Guys" that KNOW HOW to use the equipment. I took my old Malibu to a shop and it wasn't in the computer so they said they could not align it!

Good Luck,

 

[Guest]

The guy who did my last alignment was an old guy named "Buster"... I gave him the specs from B-Body.net, and he seemed to know what he was doing. The car has had more than 5 alignments at different shops within the past year, and they never got it right so I'm tempted to believe that there's something wrong, mechanically.

 

[Guest]

Erik, (this needs to go to a new or different thread)

Have you got a FSM? Have you read it?

Lets take a look at some things, since you have not mentioned any of this.

1. tire pressure

2. condition of brakes--stuck caliper?

3. possible tread separation problem with tire(s)

4. wheel bearing adjustment

5. steering gear/variable assist pump

6. center link--slop/movement? tie rods?

7. intermediate shaft flex joint worn?

8. condition of control arm bushings

When you went for an alignment, did each shop do adjustments? Any idea how much they changed?

If you still have a problem after all that....

Go to the Hunter.com website, look at the list of training facilities, see if there is one not too far from you, contact them, and make your car available for one of their classes. If it can be aligned (they should inspect EVERYTHING and tell you if anything is wrong such that they would NOT be able to align it), they will get it done.

And how are the body mounts doing?

 

[Guest]

I've got the info on the stock front SS springs written down somewhere at home - I'll see if I can dig it up tonight.

Bill,
As far as a lightweight hood goes, that'll be as big of a class modifier as big brakes (if I'm reading the rules correctly). One can use any wheel in the stock size in stock classes, if I recall correctly, so dropping some weight from the wheels is actually more practical from a classification standpoint.

 

[Guest]

Here's the link to the MVMA data--it lists checking height and rate, but spring wire size is not mentioned.
http://www.b-body.net/Technical/Reference/MVMA/11.html

Eric, I hear you on the hood--though I have no concern about what class I end up in when/if I am competing.

 

[Guest]

Thanks for the help, and sorry for going off-topic a bit there . As for the body mounts, most of them are back on now... I lost the bolts to two of them (time to call Dal)