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Author Topic:   Accidental handling cure
blanep
Dirt Maniac

Total posts: 105
posted January 04, 2005 03:51 PM  
Caution: Long winded post ahead.

A couple years back I had a metric running on a 3/10 medium banked clay track. As far as the set-up goes, it was ok... depending on the track conditions at the time it would sometimes push and sometimes be loose, but generally speaking it seemed to push off the corners most of the time. On occaision I even had to deal with a 4-wheel drift coming out of the turns... it would just skate up the track. But again, the car wasn't terrible, it just wasn't perfect.

Now to my questions(s). One night the car just started working like a champ. The more laps that I made that night the better the car ran. From the seat the right front just seemed to be getting closer and closer to the track in the corners to the point that I started worrying that the rf of the car was going to actually dig into the track and flip. It was leaning on the rf extremely HARD. But again, the more this happened the better it ran.

After getting it back to the shop the rf was obviously lower than what I had set it at. Upon examination I found that the upper part of the stock spring pocket had given way until the spring was way up inside the shock tower. Of course I fixed it and set it back to ride height and didn't think much more about it and the car, though still driving well, never again drove as well as it had that night.

So I'm wondering now why this occured. I mean the car was scaled out and the weights were fine so dropping the rf would of course add weight there and take it from the lr. How could this have helped it run so good? Or did it cause some other change that accounted for the difference? I know that there are so many variables to the car and the track that it may be impossible to account for the improvement, but was hoping that some of you might help me brainstorm the question of why.

Eljojo
Dirt Forum Champ
Total posts: 968
posted January 04, 2005 05:37 PM  
Generally springs don't push themselves thru a spring pocket. It's my suspicion that something was binding up-especially from your discription of how erratic the car had previously handled.

snowman
Dirt Freak

Total posts: 241
posted January 04, 2005 05:46 PM  
More Roll steer.....by allowing thr RF to roll over more you induce more roll oversteer.......apparently just what you needed......

Good Luck
snowman

o5racer
Dirt Freak

Total posts: 402
posted January 04, 2005 06:27 PM  
Drop your crossweight. You said your self that the car handled better with the rf spring mount pushing through the frame. When the mount was like that it took some preload off of the right front and left rear lowering the crossweight. The best way sould have been to scale it before you fixed the mount, fix it, and then set the numbers like when it was broke.

Nick

kevinwardracing
Dirt Full Roller

Total posts: 35
posted January 11, 2005 06:46 AM  
Nick is right...

You, however, was mistaken in saying the lowered right front added weight to that corner and took it from the LR. It does not work that way. A lowered RF removes weight from both RF & LR and adds it LF & RR.

...more than likely, your car is asking for less cross weight. Try taking 3% off the cross and see what that does. Despite a 1/2 track lead/win on opening night, I actually added over 5% to my car this season just because it asked for it.

Good luck..

340duster
Dirt Maniac

Total posts: 195
posted January 11, 2005 11:53 AM  
Kevin and Nick are right on. Sounds like you have way too much crossweight and/or to still of a rf spring. What is the crossweight?

49mtmod
Dirt Maniac

Total posts: 127
posted January 11, 2005 12:47 PM  
What were your weights and ride heights before the spring problem?


blanep
Dirt Maniac

Total posts: 105
posted January 11, 2005 04:03 PM  
The cross was right around 49%, the springs were RF-1200, LF-1000, RR-225, LR175 if memory serves me right. I had tried RF-1000, and LF-800 and tried about every rear combination between 150 and 250, even switching the stiff spring to the RR. The ride heights at that exact time I don't know. Again, this was a couple years ago and I no longer have that car, just got to thinking about it and couldn't stop. I agree that getting weights and measurements before fixing it would have been wise, but was too concerned at the time with getting that spring pocket fixed back to normal and wasn't linking the two events until later.

I guess I'm still not looking at the weight thing correctly. In my mind if you scale the car, then lower the ride height of one corner and then scale again, that lowered corner is going to weigh more than it did before. I reckon I'm going to need to do it on the scales before I understand.

blanep
Dirt Maniac

Total posts: 105
posted January 11, 2005 04:12 PM  
Cross may have been as high as 51%. I'm looking through my set-up notes from that general time period, but like I said, at the time I didn't link the two events together so there's no reference in my notes as to when exactly this occurred and what set-up was in it at the time.

49mtmod
Dirt Maniac

Total posts: 127
posted January 12, 2005 07:30 AM  
The others are right about the scaling, dropping the rf will reduce weight on the rf and the lr. So, you took cross weight out of the car which it liked. You also said in the first post that the car was skating up the track - maybe the change in ride height improved the roll center and allowed the car to get some side bite.

speedyd1
Dirt Maniac

Total posts: 170
posted January 12, 2005 09:26 AM  
it appears to me that both conditions would have been improved. the right front spring would have in theory been lightened and the cross weight lowered. sounds to me like you have found your answer. lower your RF spring weight and adjust the crossweight down and you should see similar improvements.good luck.

    

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