Nova Corner Weights/What To Do With It?

[sunsation540]

thanks mike, i wake up confused and i agree there is no magic bullet every car is diffrent that's why i keep a log book of changes so when it works i can take it apart and put it back in the same place.. now if i could just find the 1.5 tenths i lost since may.. i didn't think about the need to restore the car to a flat condition with no preload and start over when it goes straight , rescale take a note,, i think i will go to the CDRA this weekend ardmore been a long time john cook..

[5448]

I finally got a new set of trick front springs installed and let settle for a couple of weeks. I cut 1.5 coils off each spring, dropping the front down to 3/4" from the lower A-arm stops. I also weighed the car with the suggestions made earlier in the thread--no preload on the Cal-tracs, with and without shocks installed.
Since the last set of weights was done with 3/4 turn of preload on the Cal-Tracs, I repeated this as a baseline. The tire pressures and shock settings were the same as the first set of data--36psi front, 15 psi rear, 10 gallons fuel, front shocks 90/10, rear Rancho RS9000 setting 5.

No Driver, 3/4 turn preload, lower hole
LF 753 RF 779
LR 770 RR 733 Total 3035

With Driver
LF 813 RF 821
LR 870 RR 743 Total 3247

No Driver, No Preload
LF 755 RF 778
LR 769 RR 733 Total 3035

With Driver, No Preload
LF 831 RF 804
LR 855 RR 756 Total 3247

No Driver, No Preload, No Shocks
LF 757 RF 776
LR 769 RR 734 Total 3036

The advise about the soft left front spring was right on the money!
Removing the preload without me in the car made little difference, but changed noticeably with me in it. I will be installing a set of the Calvert Split Mono's before I take the car out again, so I'm going to pick their brains about preload and I'm sure I'll have a bit of a learning curve when I get to the track.

I know there are several posts regarding Cal-trac preload on this site, so I won't try to get into that right now!

I'll update when the new rear springs are in.

Thanks guys!

Eric

[novaz]

Good point about the LF maybe being soft. The scale info is interesting but lord knows what's going on in regards to weight at launch and going down track when the car is putting the power down. Not to mention wheelstands.

It would be interesting to find the center of the front end and jack the front up at that point and see how evenly the weight distributes to the rear tires.

I had the scales out today as I have made some changes to the rear end and I did just what John said in this post my 72 is pretty light 2720# so not sure if the effects would be the same in a BB car anyway I took readings with the car on the scales and then raised it 3 1/4" and there was no front weight indicated on the scale screen the rear weights increased but not evenly LR 66# + RR 15# this was with me and all liquids (5 gallons in the cell).
not sure what this means exactly perhaps the car is not totaly square ?perhaps someone can post an opinion

[sunsation540]

i still don't have all the answers but the way it was explined to me was the weight on the rear tires..... inital hit is what makes it leave straight..and the pre load in the rear if any will make it push down track.. i know every car is diffrent my rear weights are + or - 4 lbs on the rear static and the car leaves very straight... i had a slight amount of preload in the rt upper bar and on a hard pass it would push to the left, if it got out of the grove.. i took the pre load out of the bars and put 1/4 turn in the anti roll bar rember mine is an A body this makes a diff.. and the push is gone and the car still leavs straight... the anti roll bar on my car.. again MY CAR 1 turn adds 25 lbs to the side i lengthen and removes 15 lbs from the other side i only use this example as i am not a chassis guy and no 2 cars are the same..