scaled my car, help with adjustments please

Posted By: Mopar-Al

scaled my car, help with adjustments please - 02/09/13 06:28 PM

I just weighed my car using a set of longacre scales on all 4 corners. I went through some weight changes by changing engines and adding a few things to the car.

Without me in it, my car weighs 2,622 lbs. I am 250 lbs. so my car adding my weight is 2872 lbs. gained 25lbs being off work and on dissability since oct.

I go back to work the 25th, and will drop back to normal soon after, I hope

as the car sets right now, I have

LF 707 RF 639

LR 575 RR 706

I have srange dbl adj on rear coilover ladder bar
strange coilovers on the front.

I need some tips here while I'm on the scales for adjustments. I had a wobble/bobble lft to right in the car about 300 ft out as time went on last year. I checked the car for square and it is ok, but had found my lft rear shock adjuster screw had backed off some. I also noticed that the lft rear spring is wound up tighter on the shock.

My car is a round tube chassis mild steel.

I could use some suggestions on how to start getting this thing in balance again.

Posted By: Just-a-dart

Re: scaled my car, help with adjustments please - 02/09/13 06:38 PM

If those corner weights are without you in the seat you need to put your weight in the seat it will all change.

Posted By: B G Racing

Re: scaled my car, help with adjustments please - 02/09/13 06:42 PM

Assuming RR is passenger side and LR is drivers side.You want 20 to 30 pounds more weight on the passenger side.Try setting weight right to left and bias front to back to get the rear to get the back right to left near equal and the ladder bars neutral,then set the 20 to 30 pounds with slight preload adjustment.

Posted By: Mopar-Al

Re: scaled my car, help with adjustments please - 02/09/13 06:46 PM

I just now did that with me in it

lf 794 rf 667

lr 689 rr 723

total 2872 Tires are at race air psi . 3/4 tank fuel.

Me not in it

lf 707 rf 639

lr 575 rr 706

total 2622

Posted By: Mopar-Al

Re: scaled my car, help with adjustments please - 02/09/13 07:06 PM

Quote:

I just now did that with me in it

lf 794 rf 667

lr 689 rr 723

total 2872 Tires are at race air psi . 3/4 tank fuel.

Me not in it

lf 707 rf 639

lr 575 rr 706

total 2622

with me in the car, front to back weight is around 40 lbs heavier in the front. that is'nt to bad

front being 1461 and back being 1412. So I can assume all this will start changing fairly quick when I start trying go balance left and right?

Working by myself without any help, should I try to get the car lft/rt balance closer without me in it at first? Just not sure where to start with the first adjustment. And with me being handicapped right now, getting up and down and in and out can be a little painfull.

Posted By: Just-a-dart

Re: scaled my car, help with adjustments please - 02/09/13 07:18 PM

I use 60lb bags of ready mix + free weights to act as me in the seat (they don't move like a helper)

My

if you are hurting get a helper, don't hurt yourself.

Posted By: 70satelliteguy

Re: scaled my car, help with adjustments please - 02/09/13 07:29 PM

"I just now did that with me in it

lf 794 rf 667

lr 689 rr 723

total 2872 Tires are at race air psi . 3/4 tank fuel."

I'd say that looks pretty good! I always set mine up with both rear weights close to each other and about 50 lbs. more on the left front than the right frontto keep the launch even. That seems to work out well for me and My car leaves hard with a 1.30 60 ft.
Mike

Posted By: Mopar-Al

Re: scaled my car, help with adjustments please - 02/09/13 08:48 PM

It's the 127 lb difference in the LFT front to RT front that I am wondering about. It does not seem normal to me. Or is it acceptable? My left rear coil spring adjuster had backed off and I reset it a couple months back.

Does anyone know the life exspectancy of coil springs? I know it's a broad range question with some doing wheelies high up, hard launches, and other things to affect them. Mine may have around 300 passes on them. I am wondering if maybe I should buy another round of springs

I haven't driven the car since the coil spring adjustment and new engine install. Other than 4 engine breakin passes. a couple part throttle and a couple full throttle, but no hard launches at all. So I'm in the blind as of now, so it seems. I know the adjuster on the left rear is around 70% used up and the right adjuster has 70% to go.

Posted By: 70satelliteguy

Re: scaled my car, help with adjustments please - 02/09/13 10:13 PM

"It's the 127 lb difference in the LFT front to RT front that I am wondering about"

Yeah I missed that! I set it up to have only about 50 extra lbs. on the lf(drivers side front)
I usually get a friend to look at the scales while I am under the car(weight equal to my weight in the drivers seat) making adjustments with the torsion bars and ladderbars till I get it where I want it. I also take measurements on the front fenders to make sure they are fairly close to one another. With the extra 50 on the lf it usually ends up with the rf fender being 3/4 in. higher that the rf. If you don't do this you can get lost pretty fast.
Mike

Posted By: Cheatham

Re: scaled my car, help with adjustments please - 02/10/13 12:10 AM

Quote:

I just now did that with me in it

lf 794 rf 667

lr 689 rr 723

total 2872 Tires are at race air psi . 3/4 tank fuel.

Me not in it
First before you scaled the car did you make sure the scales were level front-rear side-side? then you want to set the car on scales and be sure tire psi set and should have measured rear tires and make sure your roll out is equal then climb in and scale. you have to remember that weight is affected in a X pattern. also check your ride heights and set them Then to change the numbers you posted i would turn the coilover adjuster 1 turn down ( clockwise ) on RF. 1 turn out ( counter clockwise ) on the LF. then on the RR 1 or 2 turns out and LR 1 or 2 turns in and rescale you should see the numbers equal on all 4 corners. Front and rear and side to side is affected by the ballast you move around. after you make a adjustment bounce and try to roll the car back and forth to settle the car. Play with air psi on 1 tire and watch the scales you can see a difference and better understand whats going on. i havent scaled a car in years since my dirt track days so i hope i gave you some helpful advice. o ya since the front is heavier and stiffer springed the front is more sensetive to changes such as 1 turn on front spring is equal to 2 turns on rear

lf 707 rf 639

lr 575 rr 706

total 2622

Posted By: Mopar-Al

Re: scaled my car, help with adjustments please - 02/10/13 03:50 AM

Thanks for that pointer. Yes the scales were set up level. And reading through what you said, out n down, clock and counter clock wise, I think you ment in for the right and clockwise, out on the left for counter clock wise.

I can see how just changing air pressure changes the numbers. I did try that. I do have a starting point pattern now to try out in the morning. Maybe this will shed some light on the 127 lb difference on the one side. It looked like it could just by the little air test cross patern I tried today.

Posted By: gregsdart

Re: scaled my car, help with adjustments please - 02/10/13 04:05 AM

Right side of car, you have 52 percent of the total right side weight on the rear. Left side weight, you have 45.5 percent on the left rear. The amount of diagonal weights are different, 167 more pounds on the rr lf than the other diagonal, rf lr. That is a lot of weight bias. If it were mine, I would reduce the percentages of the diagonals significantly. You do want some preload on the right rear, but not nearly that much.

Posted By: Al_Alguire

Re: scaled my car, help with adjustments please - 02/10/13 05:22 AM

I wont throw in any more set up info as to muddle the question but will share some things you need to keep in mind. Make sure you have the car set up as it is to be raced. Meaning preferably YOU in the seat, with your gear on. The amount of fuel you expect to carry in the cell. Make sure the car is on LEVEL ground. And lastly and likely most important is to make sure you have the tires at the air pressure you plan to run. A few pounds of difference in air pressure can move a lot of weight around. Once you have all that set then you will have a better idea how the car will be and what you need to do to address any issues you have.

Posted By: Mopar-Al

Re: scaled my car, help with adjustments please - 02/10/13 06:06 AM

Quote:

I wont throw in any more set up info as to muddle the question but will share some things you need to keep in mind. Make sure you have the car set up as it is to be raced. Meaning preferably YOU in the seat, with your gear on. The amount of fuel you expect to carry in the cell. Make sure the car is on LEVEL ground. And lastly and likely most important is to make sure you have the tires at the air pressure you plan to run. A few pounds of difference in air pressure can move a lot of weight around. Once you have all that set then you will have a better idea how the car will be and what you need to do to address any issues you have.

Thanks Al, these particular things you mentioned is what I am focusing on. all the tips and comments have really helped me to try to keep my car dialed in. I did replace my radiator, removed the alt from the passenger side,installed a vacuum pump, and added a few extra lbs when I switched over to B1 heads and took it off of methanol. So I new I had changed the weight bias some up front.

I'm still wondering about the average life of a coil spring, and if I should maybe consider replacing them.

Posted By: MR_P_BODY

Re: scaled my car, help with adjustments please - 02/10/13 07:41 AM

I'm still wondering about the average life of a coil spring, and if I should maybe consider replacing them.

Take them off the shock and measure the free length..
thats about all you can do... unless you have a
spring gauge(its just like a valve spring tester
but bigger... I've had my coils on for 8 years now
and they havent moved... if they were from one of the
good shock companies I wouldnt worry... normally if
the spring is getting weak you will have to dial it
up to keep the ride height... but now that your moving
weight around its gonna be different on the coils...
get it balanced right then see how much adjuster
thread you have below the adjuster nuts... if its
more than about 2" you might be looking at springs
(they're cheap)

Posted By: HP318

Re: scaled my car, help with adjustments please - 02/10/13 08:42 PM

switch rears side to side and rescale

Posted By: cudaman1969

Re: scaled my car, help with adjustments please - 02/10/13 10:47 PM

Don't forget to take the bolt out of the ladder bars at the housing(i like to take out the pass side top) can't level the springs if you don't. once you get the weight bias(put lead in whatever corner, don't over jack the spring ) the way you want, slip the bolt in, set whatever preload you want,see how it works. one other thing you can only jack weight corner to corner, not front to back,when adj. springs

Posted By: 70satelliteguy

Re: scaled my car, help with adjustments please - 02/11/13 12:35 AM

One thing about having access to a set of scales is the ability to fine tune your suspension and find out where you are at and exactly what you individual car likes without shooting in the dark.It was one of the best investments I have made when it comes to my racecar!
In years past I have had my car "adjusted" by so called guy's that know how to do this without scales and have ended up with the car looking all twisted and uneven in the back end after someone fooled around with my ladderbars..It is no fun letting go of the button and wondering what the car is gona do this week!

With the scales you can duplicate the set up from year to year after tear downs. I pull my motor and tranny every winter and this involves removal and reinstalling the drag torsion bars. This pretty much necessitates starting over but I only have to put it back on the scales and adjust the torsion bars till I have the weights I want. I have not touched the ladderbars in years!
Mike

Posted By: The Cuda Guy

Re: scaled my car, help with adjustments please - 02/12/13 06:32 AM

Did you ever get your weight ballance issues figured out?

Don

Posted By: ek3

Re: scaled my car, help with adjustments please - 02/12/13 09:01 AM

Quote:

I just weighed my car using a set of longacre scales on all 4 corners. I went through some weight changes by changing engines and adding a few things to the car.

Without me in it, my car weighs 2,622 lbs. I am 250 lbs. so my car adding my weight is 2872 lbs. gained 25lbs being off work and on dissability since oct. I go back to work the 25th, and will drop back to normal soon after, I hope

as the car sets right now, I have

LF 707 RF 639

LR 575 RR 706

I have srange dbl adj on rear coilover ladder bar
strange coilovers on the front.

I need some tips here while I'm on the scales for adjustments. I had a wobble/bobble lft to right in the car about 300 ft out as time went on last year. I checked the car for square and it is ok, but had found my lft rear shock adjuster screw had backed off some. I also noticed that the lft rear spring is wound up tighter on the shock.

My car is a round tube chassis mild steel.

I could use some suggestions on how to start getting this thing in balance again.

. .there has been some good advice in a few post here. think about this from a simple stand point. first ,get all front end settings correct,set all air pressures,set the chassis to desired ride heights-[this is a must do.] then you scale the car in race trim. then you start with trying to balance the front 2 tires with each other,then the rear 2 with each other. then you can add weight to the tire that actually needs more grip. this will get you started..remember that a componet that will not stay in adjustment[a bad part] will run you in circles.

Posted By: Mopar-Al

Re: scaled my car, help with adjustments please - 02/12/13 09:17 AM

I'm set. Ready to try it out. finished it up today.

My cross section was off do to me weighing 100 lbs more than the last owner. Also 1 loose bolt, and one set of adjusters had loosened up and started to back off the last few times out pryor. The car was built at a race chassis shop to start off with. I had done some weight changes with different engine, replacing items and adding items. I came up with a 49/51 balance with a 48.8 cross section. So I am going to give this a shot before I tweak any further. All the tips here really helped me out. Thanks.

Posted By: gregsdart

Re: scaled my car, help with adjustments please - 02/12/13 02:10 PM

Quote:

I'm set. Ready to try it out. finished it up today. All the tips here really helped me out. Thanks.

Good luck! Looking forward to a track report.