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Old 05-27-2008, 01:31 PM   #64
John Stranahan
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Barry-Thanks for the additional detail on setting tweak. Note to all that Barry has years more oval experience than I do. Thanks for the general setup guide. I'll look back over it in a bit.

Track Report
Track 93F air temp, track dusty but not as bad as before, traction medium

Oh my Gawd the car was perfect! Anyone could have driven it. Here are the changes I made. Note that I don't follow the one change at a time reasoning after I get some experience with the settings. There is not enough time in a life to do this. I use more of a shotgun approach and make several small changes to move the car in the right direction.

Left Down Tweak- 16 oz
This adjustment does two things. It loads the left rear and makes the car tighter (less oversteer). I also can't discount some possible benefit of having decent loading on the diagonal wheel the right front. This might be important on corner exit. Anyway the corner exit hooking was gone completely. The picture shows the adjustment I used with the copper springs. It also shows the Losi ball cups beefing up the shock ends which are at their limit of strength with these heavy springs. One note from Barrys post is that If I needed this right rear shock longer, i would not do it by screwing the ball cup out. This will cause bending of that aluminum stud. Instead cut a longer Losi truck ballcup and screw it all the way down after tapping it. A stiffer set of side shock springs may be in order for this car. Here is a link posted by Mike OBrien.


Wheel offset
Imagine your center of mass of the car with the two back wheels offset to the side both pushing forward equally. This is the desired effect on road. Both have equal torque (twisting clockwise or counter clockwise on the vertical axis) on the center of mass. Now let's say we put a 1/8 inch spacer inside the left rear tire. This side has more torque now. The lever is longer. There is now torque steer. There is a tendency to twist the car clockwise and aim it out to the boards.

I added 1/8 behind the left rear. The car was perfect. I took it out. It was OK but after a few laps I had a corner exit oversteer (still some dust on the track). I put it back the car was good again.

Front Springs
Generally stiffer front springs reduce your steering traction and cause more push (understeer). I found out the first time I ran a wide pan car on the big high speed sweeper that you can go too soft and reduce steering if the spring is going into coil bind or collapsing fully. You need at least a minimum amount of spring stiffness so it never collapses fully in the corner. For this reason I went up to Windtunnel Red cylindrical spring from the blue spring. Steering was superb. If I increased throttle 2/3 of the way into the corner, I could get the rear to slide out maybe an inch or two on hard power. This is where Barry was kicking the back end out on cornering so its where he likes to start adding power. I corrected with counter steer just like you would with a full size car. Anyway the steering is just right for me. I will race it. I can add more left down tweak with a stiffer spring to kill a little steering if I want. I went to a stiffer, stock silver, center spring to balance front and rear bump stiffness.

Motor Spacer
I found with my previous car that putting on a motor spacer 1/8 inch aluminum ring between the motor and the right side plate tightens the car. I added one. This also helped increase that left down tweak without such a huge spring preload.

Motor Forward
I ended up using 2.010 inch rear tires (almost used up). For this reason the motor ended up farther forward after gearing it correctly. On my previous car adding weight to the rear of the pod made the car ovesteer horribly. For this reason I think moving the motor (or weight) forward on the pod with a bigger pinion helps tighten the car. I need more tests here.

I am happy with the current setup. I'll post it after I race it. I was able to get a little rear wheel spin once in a while coming off the corner with the 13.5. What a thrill for this motor!

In the pic you can see. The high preload with the copper spring. The lightened motor spacer I used. The large pinion which moved the motor forward a bit.
John
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Last edited by John Stranahan; 06-09-2008 at 06:50 PM.
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