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Author Topic:   Loose in, tight off??
UFnARacing
Dirt Full Roller

Total posts: 68
posted April 18, 2002 03:48 PM
My first year on a asphalt track. 3/8 high banked. 72' Nova. Haven't scaled the car yet, should get to this weekend. But, right now the car is loose in, bad. Then as I get it under control it's real tight in the middle and somewhat off the corner. I'm thinking the tight is because it's loose going in. I believe the car is heavy, my guess is around 3400#. It has 800#rf, 700#lf and I just changed the rear leafs. The leafs are stock leafs from a older 4 door nova, with one leaf out of the right rear. I run about 1.5" stagger on both front and rear tires.

I've read a lot about what causes this condition, but it seems that people will disagree on cross weight. Without knowing the weights, do I need more cross or less?

To add to the problem, I need to raise the front about 2" per ride height rules. I'm probably going to go to 1000#rf and 900#lf springs. This should raise the ride height and I think the 800#/700# springs are too soft. It bottoms out at times and I can feel the front dip quite a bit entering the corner.

Any help is much appreciated. I know that I need to scale the car, but I'm trying to get a handle on the car until I can scale it.

Randy

[This message has been edited by UFnARacing (edited April 18, 2002).]

snowman
Dirt Maniac

Total posts: 140
posted April 18, 2002 11:38 PM
Hi Randy, First I should say that I have no asphalt or 72 Nova experience. Perhaps some of the other guys can be of more help.

About cross weight.....More cross = loose on entry and tighter on exit. This is a general guideline. It is not always true but, most of the time, for most people, this is correct.

If it sounds like I'm saying you need less cross,I'm not. Cross is a fine-tuning tool.Your current problem is not cross weight.

Before You can adjust cross, You need to have proper springs and basic weight percents. Then adjust the cross by what the car needs.

Your problem is, Your front springs are too soft. You must keep the suspension from bottoming out.

I hate to make a spring suggestion since I am not familiar with the Nova on asphalt. I use lf 1000 rf 1200 lr 250 rr 225 on an 81 Monte. 3/8 medium bank dirt. Can't say how it would work on asphalt. You may have success with the 900 and 1000 with a anti-roll bar.

OK, I realize you are aware of the need to scale your car. The effects of adding/subtracting weight depends on what you have to begin with. When You do scale, I suspect you will find that you need more left and rear weight.

Dirt cars are toed out. I would toe in your car 1/8. Toe has a big effect.

Also, about your tire temp question, I notice there is a program in the tool box.....

Good luck,
Snowman

UFnARacing
Dirt Full Roller

Total posts: 68
posted April 19, 2002 08:24 PM
Thanks for the help. Now that I've already put the springs in, I'm starting to think that I should've went stiffer, but we'll see. The worst part is, I still need to get my ride height up another 1" or so, any suggestions on how to do that? I put in 12" springs and that still wasn't enough.

It turns out me and my help got the desired stagger a little confused. Turns out I had way, way too much stagger. I'll go back to about 1" of stagger and try it there. That makes sense on how loose it was, than I was messing with the cross and it made it lots worse!

When I bought the car, you could see where the right rear was running on the rubber bump stops. Thus I put more spring in, but I had the stagger added at the same time. Oh well, live and learn.

Randy

UFnARacing
Dirt Full Roller

Total posts: 68
posted April 22, 2002 06:04 PM
Well, got the car scaled yesterday. You were right on the rear weight percent. Car is heavy overall, 3420#. Left side weight is 53%. Rear is 43%, not too good. Cross was right at 50%, which is where I want it for now. So I need to loose 200# to get to the minumun weight. But, I also need more rear. The car is not gutted at all, so I have lots of work to do. I guess I'll figure out where to get weight out as I go along.

I guess the low rear weight explains my loose in condition, but why tight off? Is it because I'm correcting for the loose in? I changed my driving style a little last race and it seemed to help, but still not even close to the fastes cars.

nw15x
Dirt Full Roller

Total posts: 42
posted April 22, 2002 10:03 PM
Its your spings, they are way to soft. Because you are loose in you can't turn in without braking the rear tires. By the time you exit the corner you are way off the correct line and the car feels like its pushing. 900/1000 is a good place to start you shouldn't be to far off from where you need to be.

I had the same problem...Live and learn

snowman
Dirt Maniac

Total posts: 140
posted April 22, 2002 11:48 PM
Randy, Sorry it has taken so long to get back to you. I have been out of town.

I think you are basicly correct in assuming your entry problem is causing your exit problem. You must fix the problems in the order they occur.

You really need proper spring rates and weight distribution. Untill you have that, you will always be fighting an ill-handeling car.

Ok, so your car is going on a diet. Be at minimun weight. Gut everything in the engine compartment. You will find a good chunck of weight where the door hinges mount to the chassis. In short,start at the front,working back to about the center of the car, untill you get out enough. If it is legal to use ballast,then gut extensively, so you can add it back where you want. Wherever a body panel makes a bend, I like to leave the bend. So that the panel is self-supporting. Often a guy will cut out all the bends,only to have to go back and add some braces. Which can weigh more than the lip he cut out.

Ok, Do you have an anti-roll bar ? If so, I bet it's the small one. Put on a bigger diameter one. You can find them on station wagons,old police cars,ss models,bigger cars, etc.

Check your rear end for squareness AFTER you have your weight percents.

What is your toe setting ?

Ride height... You can install some hidden spring adjusters or make some shims out of steel plate or some aluminium.Taller tires ? Ride height is an important setting. What is required by the rules ?

I am confused about your rules.... You said (on tire temps) that your car was a pure stock. Usually, for pure stocks, racing springs are not allowed. So, the racer buys a set of stock height, stock appearing springs. Removes the paint....a little rust....

Usually, there is a tire rule.....Same size all the way around, DOT tires. Usually hard to find a lot of stagger. So,what are your tires and what kind of pressure are you running.

You mentioned that this was your first year on asphalt. Is this your first year racing or have you raced on dirt before ?

GOOD luck,
Snowman

UFnARacing
Dirt Full Roller

Total posts: 68
posted April 23, 2002 09:59 AM
By my calculations, I need to get 500# off the front to get to 50% rear weight. Obviously, that means taking off a lot of weight and adding weight to the rear. But I'll take it one step at a time. I can take 200# off the car right now and still be over the minimum 3200#. So I'll try and get as much off the front as possible, and that will still only give me about 45% rear weight. But, that should help my front springs some.

You are right, racing springs aren't allowed, but the undercarraige and suspension aren't checked well at all. I'm not really worried about raising the car until I'm told to do it either. I'm assuming that a lower ride height will give a "better" (lower) front roll center?? I do have to run DOT tires, but can use any combination to get the proper stagger. The rules call it a "hobby stock", but as we all know, rules are different everywhere.

I do have the stock front sway bar, maybe I will find a bigger one in the junkyard somewhere. I gave her more preload last weekend and it helped the push quite a bit, so I don't know if I'll need a bigger one, until I get my weight correct. That should be true with a lot of things that I can do to the car, I won't be able to tell what I need to do, before I get the weight right. The catch to that is that I want to keep up as best as I can until then!!!

I've raced on a 1/4 mile dirt track before, but it was years ago. I've raced in the desert for the last 10 years or so. One thing that's helped me already that I got from desert racing is to be patient.

Thanks,

Randy


marty
Dirt Maniac

Total posts: 111
posted April 24, 2002 12:55 PM
It might also be worth looking at your front to rear brake bias as too much rear would make it loose on entry also.

marty
Dirt Maniac

Total posts: 111
posted April 25, 2002 01:16 PM
Oh & also give the car a thorough checkover after each meeting. It only takes a bent shocker or someother kind of bind to upset your handling.

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