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Author Topic:   Jammin - Scaling??? and Push Wet.....
24ksi Racing
Dirt Roller

Total posts: 13
posted May 18, 2000 08:15 AM
Jammin -

I followed the post on Scaling step for step, but never could get myself to understand or buy into the logic of increasing cross weight to cure a push on entry. A good while back on another forum, I took part in a discussion with someone who took the same position as you, but even then it sounded wrong to me (and a LOT of others). In any case, you wanted more weight on the LR to cure the push on entry.

Then, I read the other thread on Push on Wet/Loose on Dry and your recommendation was opposite of Scaling even though the problem was the same. In that thread, you offered fixes that went in totally the opposite direction - you wanted less weight on the RR to cure a push on entry.

I can buy into that one, but not the first, even though sixwillwin said he won the next night out after following the advise in Scaling. (I'm betting his win had more to do with other parts of the change).

In any case, I was just wondering what you thought the differences were between these two seemingly opposite recommendations for similar problems.

Thanks....

Bill
24ksi www.chasinracin.com/racers/24ksiracing

24ksi Racing
Dirt Roller

Total posts: 13
posted May 18, 2000 08:53 AM
But that's exactly why it does NOT make sense to me - decreasing the static weight (bite, as you call it) on the RR means that the car has more room to transfer weight from the left to right in a corner before you underload the left. An increase in weight on a corner only causes that wheel to be overworked if the other side isn't doing its job - so, the problem starts when the LEFT side looses enough weight that it is no longer able to contribute, and the right side has to do it all and can't.

In any case, you said the exact OPPOSITE between the two threads I mentioned - WHY?

And please don't misundertand me - I'm not on the attack here....

Bill

jammin
Dirt Administrator

Total posts: 3279
posted May 18, 2000 09:13 AM UIN: 16262997
In certain conditions, when you do put in crossweight, you will loose RR bite, when this happens, your car will not set (no rr bite). This will help the car enter easier into the turns if there is not enough weight to transfer to the RR tire to make it set. Its basically the same as overloading the RR but when you overload the left rear, you still have bite coming off the turns. If you bury the RR, you will skate.

jammin
Dirt Administrator

Total posts: 3279
posted May 18, 2000 09:18 AM UIN: 16262997
Also, look at where his lead is on the car and it will tell you that he has added too much left side weight(in this case) and that it needs to loose some weight off of the LR tire to make it work.

jammin
Dirt Administrator

Total posts: 3279
posted May 18, 2000 09:24 AM UIN: 16262997
If you look on the Scaling Post, the guys says he is running 48.5 percent cross. That means his opposite is 51.5. He has too much RR bite to set the car he needed to even the distribution up. The weight is already on the RR tire. So, when your dynamic distribution changes, there will be entirely too much weight on the RR. On the other one, with the weight that he has on the car, the car will not roll that much, which meanse we are working more on the left side. With his cross being 52% and the lead being placed where it is. There needed to be less left rear in the car for this one to turn. There is a huge difference between 48.5% cross and 52% and lead hung where it is.

Doing the same thing on both posts but in different ways, but actually achieving the same thing.

[This message has been edited by jammin (edited 05-18-2000).]

24ksi Racing
Dirt Roller

Total posts: 13
posted May 18, 2000 09:25 AM
So maybe what you're saying is that with a lot of cross weight, the RR is not able to contribute as much as it needs to, and the left is trying to do TOO much until the weight transfers. And until it transfers, the car is loose.

And on the left side weight issue, I race on a track that is super flat. They call it 10 degrees, but it isn't even close. For us, a ton of left side weight works wonders, even as much as 55% on a 3200# street stock.

What are your thoughts on that?

jammin
Dirt Administrator

Total posts: 3279
posted May 18, 2000 09:40 AM UIN: 16262997
Well, your crossweight will depend on several things. One, motor(how much), Two, roll(the more roll you have, the more cross you can put in the car and it will still unload for turning). But when you go over that point, it will push.

The left side weight is what is going to bring your car back down when the car rolls, or may keep your left side down if it doesnt want to roll because of your roll center....panhard, j-bar settings etc. But it is what keeps your left side on the ground, but that will not create the bite that is needed in accordance to the chassis, the cross will do that. But if the left side weight is too great, then you will not get enough weight on the RR springs to set the RR of the car either. Its all a give and take deal. Just finding that happy medium is where its at. Depends a lot on the driving style too, but just doing what I can to basically steer in the right direction.

[This message has been edited by jammin (edited 05-18-2000).]

jammin
Dirt Administrator

Total posts: 3279
posted May 18, 2000 09:41 AM UIN: 16262997
Make sure you read the post before your last one, I revamped it.

sixwillwin
Dirt Full Roller

Total posts: 35
posted May 18, 2000 10:53 PM
I thought I should respond to this discussion, I am the one that posted the original scaling question. For reference, I have electronic scales and use them weekly , I also use them properly. This was a new car last year that I could never get to handle like my old car. For the life of me, I cant stop it from pushing on entry and thru the middle, I had the cross down to 45% at one point last year and it still pushed like crazy on entry. Last week, when I won the feature, I had 50.2% cross in the car and needed some more(I think and will try Fri and Sat.) the car was very good, entry was good and I was a rocket off the corner, I was however very loose right at the apex. So for this weekend I have increased the cross to 50.6 % and I think the loose at the apex is too much rear steer when the car rolls. I have pulled the RR forward now 3/16"(it was even up with the LR.) I think this swill tighten me up thru the middle and off the corner. I ran this way with my old car with great success. My rear % is 49.9% and left is 53.5%. During the feature last week, people noted to me afterwards that my car was really rolling over in the corners, I dont really care at this point, cuz the car is much faster now,. I am getting about 3" of right side shock travel, so that does not seem excessive to me at all. Anyway, all I know is that 2.0% more cross made the car much better(not so tight) in the corner, I could then keep OFF the brakes and maintain more momemtum off, when it pushed bad entry before, I had to stab the brakes to drop the LF corner to get it to turn, and then my momemtum was killed for coming off. I will race with this setup twice this weekend, starting near the back both nites, so I will try to update my changes and results. BTW, tracks are both 3/8 mile medium to high banking. I stays tacky and one gets somewhat dry by feature time. Thanks sixwillwin

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