sweet rack

[dfhotlm33c]

Car came with sweet rack, external servo. Rack has a "3" stamped in front of big fitting at front. Is that a 3:1? If so, is that too slow? Also, how do I determine what valving the servo is?

[Matt49]

Car came with sweet rack, external servo. Rack has a "3" stamped in front of big fitting at front. Is that a 3:1? If so, is that too slow? Also, how do I determine what valving the servo is?

It's driver preference but 3:1 is too low for me and most I would say. You'll have your hands full if the car gets out from under you with at 3:1 rack.

[Brian Gray]

I believe the 3 means 3in per turn. A very popular dirt rate is 4.19 per turn.

Most racks are measured in inches of slide travel per turn

[rakracing]

both sweet racks I have are 3 stamp and I know there 1-1/2 turns lock to lock, I believe there numbered 1 to 4 for speed, and the servo numbers i've had .185, .220, .235 which is the feel. I don't remember but I think the higher the number the softer the feel, I now I liked the .220 the best for feel.

[hucktyson]

Rack numbers are expressed in " inches per turn " a 3" would be fine if u you had a Rayburn with 3.5" steering arms on the spindles but super slow on a masters or rocket with 5" steering arms. The servo numbers refer to the thickness of the torsion bar in the rack. When you twist the torsion bar it directs fluid to the opposite side you are turning to help force the wheels that direction. The higher that number the thicker the bar which will require more effort to turn the wheels.

[dfhotlm33c]

I see. I guess I'm not sure then. It's an 01 Masters. Uses a 13" tube on LF, and 15" tube on RF for steering, if that's what you are referring to.

[hucktyson]

Measure from the center of the lower ball joint to the center of the hole where the steering link attaches. That is the steering arm. If it's a masters it's prob 5" in which case a 3" rack would be very slow.

[keeks]

Could you use a quickener with a slower rack?

[Brian Gray]

I don't see why not but it's prolly cheaper to just get the speed changed.

[dfhotlm33c]

Well isn't that interesting...we have a 2:1 Howe quickener, but would that actually make it so that I get 6" to one turn? That would be outrageous I imagine.

We do have a 3.6 Appleton rack on the old car. Will probably just swap them (Same center to center)

[fastford]

if you put that Appleton on there , be sure to check your bump steer, every time ive switched one way or the other, I had to readjust for bump.

[hucktyson]

The fastest rack on the market is a 4.5 and that's lighting fast and a 3.0 is brutally slow so yes a 6.0 but be undriveable

[drtrkr244]

Theres a interesting tech article on Sweets website. It shows a table with rack ratio on the side and steering arm length across the top. Then it shows the final ratio, based on those criteria, which is a lot higher than most realize.

[rakracing]

I would recommend you just run what you got and see how you like it, to many guys speed up there steering and then complain the car has a push on entry, which is usually caused by over steering in. a 3 is plenty quick, and the servo number, to soft you can steer with one finger but cant feel the track, to hard it can be tough on the arms. you have to see what you like first.

[dfhotlm33c]

Ok, so this is for a small 1/3 mile, tight turn, relatively flat track. Max speed entering corners about 90. Don't know if that has any effect on if you think a 3 would suffice. But, I am inclined to take that advice and see what happens.