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Author Topic:   turns right when you lift the throttle
dan murray
Dirt Full Roller

Total posts: 34
posted March 01, 2005 04:15 PM  
4 link left and swingarm rt.- Which links need moved to take this away from the car without giving up bite? Left lower bar down? Thankyou in advance for your input. Car is very good on entry middle and exit. Turns right when you lift toward end of straightway or if there is traffic in the way.

mod4
Dirt Freak

Total posts: 223
posted March 01, 2005 06:22 PM  
My situation may not apply to yours, but I've had the same thing happen in a few different cars - and every time for me, it wasn't the rear end doing the steering, it was the front end. I was steering further right then straight because of action of the rearend, and when lifting and getting weight back on the front wheels, the car took a sudden right. One type of rear suspension I was driving ( I didnt own or setup the car and just got to "deal with it") was bad enough I learned to snatch the wheel left just before I lifted - and then the car would actually go straight.
May not apply to your situation, but it took me forever to figure my problem out, when the part that really needed tuning was the drivers' head ....

dan murray
Dirt Full Roller

Total posts: 34
posted March 02, 2005 11:11 PM  
Thanks, never thought of that aspect. Will try it this Sat. Sounds pretty logical to me.

mod52
Dirt Full Roller

Total posts: 30
posted March 03, 2005 05:44 PM  
There was somebody on here awhile back that addressed an entry push. the explaination that was given could be applied to the turn to the right deal you have. I couldn't find that post but here is the easiest way I can explain it:
If you take a floor jack and jack up the chassis just in front of the LR. This will resemble being up on the bars- LR forward, rear steered to the right, etc.
Now, imagine the rear tires glued to the ground.(NASA type glue!!)
The car would basically stay up on the bars, even when jack was removed. It would stay that way (locked axles) until the front of the car was moved to the right.
The glue and locked rearend simply illustrates the available traction trying to maintain the rearsteer present just before you let off. Sort of like holding the light bulb & spinning the house!
This just gets it started. From here on, I think everything that Mod4 posted applies.

donslink1
Dirt Freak

Total posts: 318
posted March 03, 2005 06:01 PM  
Its not that the car is turning right, It is staightning out. as your left rear is tucked under your seat your car is going down the straights sideways. As you let off the gas the left rear goes back and the rearend steers to the inside of the track,

So I think Mod4 is right you just have to get a feel for it.

The guy I help said his car would do that when we would run 4 bar on both sides. A lot of roll steer.

uforacing51
Dirt Forum Champ
Total posts: 570
posted March 04, 2005 03:20 PM  
Yikes!!!

sdracer12
Dirt Maniac

Total posts: 180
posted March 04, 2005 11:02 PM  
I agree with Donslink. My guess is what you are feeling is the rear steer going away when you lift the throttle. Does it feel like the car is all hiked up on the straightaway, and then it drops out from under you when you lift? If so, you could try the hold-up shock on the left rear. Another thing which sometimes works is using a little trail braking while you are still on the gas entering the corner. This can keep you up, and keep some steer in the car to help turn you left. Also some static lead/trail in the RR could possibly help, but I'm not a big fan of static lead or trail.

One other thing to try: is your front-end geometry good, and are your front-end settings right? Toe-out, caster/camber, and bump steer are all very, very important to a good handling racecar. Bent balljoints, tierods etc. all make a car do funny things.

showtime13
Dirt Full Roller

Total posts: 60
posted March 05, 2005 06:32 AM  
try putting stagger in the front end

flyin353
Dirt Full Roller

Total posts: 49
posted March 05, 2005 06:49 AM  
Stagger in the front end makes no difference...the two front tires are not attached to the same rotating "axle". They are independent of each other and front stagger has no affect on steering. Caster however does. I would increase the caster split on the front end and also try to figure out how to make the car "drop" slower when you lift the throttle. You could try braking before you lift, this keeps the rear of the car "loaded" longer and allows you to set the car down easier. Bar cars are very sensitive to radical on/off of the gas. I have seen some pretty strange things happen even in LM's when you get off the gas real hard. Good luck...which track do you race at so everyone knows not to be on the outside of you entering the corner (just kidding, )

andykmod
Dirt Freak

Total posts: 351
posted March 06, 2005 05:21 PM  
How is your lr brake caliper mounted is it solid to the rearend, floated on the birdcage or on it's own seperate brake floater. Donslink is right on about the steer but thats only if it gets off the bars fast and the way your brakes are set up can help fix your problem i think. My car is sort of like that on stop and go type tracks. I also learned my car is alot like me it never likes to leave the bars.

[This message has been edited by andykmod (edited March 06, 2005).]

dirtywrench13
Dirt Freak

Total posts: 324
posted March 07, 2005 11:29 AM  
id try changing bar angles to minimize the motion of the axle when lifting or optimize it. a longer swingarm may help.

donslink1
Dirt Freak

Total posts: 318
posted March 07, 2005 12:25 PM  
HA, HA, HA, That is funny, also very true. (about the bars)

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted March 07, 2005 02:38 PM  
It's not really the bar angle's, or the way the brakes are mounted. How are you running your rear end in the car in comparison to the front tires. Is the Left rear ahead of the rr, or is the lr behind the rr?? A lot of times guys with 4 link stuff try to get the roll steer out of the car by moving the lr back or rr ahead (bad choice) when the rear steer is what helps get you up off the corner. You might try a stiffer shock on the left rear to help the car from coming down so hard. If the car is just plain slamming down onto the shock, you need to look at your pull bar. You may have too much angle for a 4 link and as soon as you let off the gas it is just planting the chassis onto the rearend and in turn trying to make the car feel like it is turning right.

As a last resort you can take angle out of your left rear bars, but you'll lose the foreward bite you had. You might consider how you are entering the turn also. If you are driving straight and then letting off the gas to turn, you might try getting the car turning before you lift, that way the weight is starting to transfer and keeps the left rear up in the air a little so it doesn't drive so akward.


Overall it is just the way a 4 link, or short 2 link car drives.

andykmod
Dirt Freak

Total posts: 351
posted March 07, 2005 03:15 PM  
If you have your lr brake floated on the birdcage or a seperate floater it will hold the chassis up on the bars longer during braking,(due to axel rotation and brake force) the trick is to be on the gas and brake at the same time during entry which will try to keep the car on the bars longer or all the time which also helps promote forward bite off the corner. If you have a seperate lr brake floater try more angle in it it might loosen entry alittle. my2cents

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