Looking for Expert Help on 1/8 Dirt Oval Setup
 

Hello,

I am a pretty experienced racer but I am having an issue with my car that I would like some help with...

I have an OFNA Dirt Latemodel Nitro 1/8 Scale car and I have the following questions that I would love some clear help on please...

1. The OFNA is equipped with the ability to adjust the left and right rear steer angles, when and why should you make adjustments to these items and what will be the effect of these adjustments.
2. My car is fast and I won the A-Main locally last week, however I cannot keep my car from kicking out about 3/4 way around the corner on power it wants to always power slide out of the corner rather than power off the corner. This behavior seems to exist no at some level no matter what I change at this point on the car... But I have not made any large radical changes lately.

Here is my setup...

Front End:
Dynotech One-Way Diff
60 Weight Oil
TC3 Shock with #3 Piston
Red Springs left & right

Rear End:
20K rear diff fluid
50 Weight Oil
TC3 Shocks with #3 Piston
Red Spring on left and Gold spring on right

Rear steer is about 2degrees negative on the left rear and about 0 - 1 degree positive on the right.

I had a gold spring on the left rear and have moved to a red spring and even jacked the pre-load spring down on the left rear to try and add some off the corner bit/push but have had no luck...

The car also does not turn in as well as I would like, I have a very small spoiler on the rear of the car and maybe the reason why the car kicks out coming out of the turn is because I am having to through it in harder than I would need...

How do I get the car to rotate into the corner under power better and bit coming off...

Again please keep in mind the car is very close and I can run almost track record pace, I am just looking for some very experienced help that can get my car to the next level.

Thank you for your help.

Alan

Alan, if by rear steer you mean toe then go slightly negative on the right rear or another way to put it would be go for a "little" toe in. I don't think you will ever want toe out on either side in the rear.

My reasoning may be a little rusty but as you accelerate forward thru the turn and transfer weight to the rear the right rear is still trying to force a left turn instead of trying to push the rear end back under the car.

Ed M.

Thanks for the suggestion, the adjustment of bringing the right rear wheel back in (-Toe) is something I will try next week and the more I think about it this problem really got worse when I added toe out to the right rear. This was done in an effort to get the car to turn in faster under power and rotate in the center more, however it may be keeping the rear end wanting to rotate under power off the corner rather than counter act the 2+ toe in on the left rear and push the car forward rather than to the left...

What are your thoughts on adding more or less toe on the left rear regarding better turn in or better push off the corner? When do you feel the left rear tire has the most influence on the car? I know that there is a very fine line in getting the balance right on a car so it turns in as fast as possible under power for as long as possible and carry that speed through and off the corner. That is where oval is won or lost...

Thanks, Love to discuss this stuff and learn more... Working together, we can all go faster!

Alan

I think the ideal would be no toe at all on the rear for speed, but in practice it does not work out that way, dirt is just too slippery..........even when its hooked up.

You can try taking toe out of the left rear a little at a time but at some point I think you will find it will come off the corner great, but you will lose going in.

It also depends on driving style so a of of experimentation is in order. With pillow balls at least its quick for you. I hate changing bushings out on my Losi since I am limited to 1/2 degree changes with a max/min of - 2 to 4 degrees. The King Headz arms are looking better all the time.

Ed M.

The dirt oval crowd on RCTECH must be a small bunch. Surprised there are no more replies.

Ed M.

yea- I've noticed this as well. I also keep tabs on Dirtoval.com and their even less active.

Brian

Yeah, there isn't very many places to find good info on oval setup. I've been watching your thread here just looking for some good info to try on my late model. I'd give advice, if I had any :) If anyone finds a good place to find info, they might post up and let us know.
Thanks, Andy

Let's keep this going...
 

Offer you opinion on the follow if you can...

Rear Steer/Toe Angle

1. What will effect the car turning in... Will adding more rt rear toe 0 or positive toe help the car turn in under power but hurt it coming off?

2. What effect will adding/removing left toe/steer have on the car coming in or going off?

3. What is the secret to getting a car to want to turn in still under power so you can drive harding into the corner without the car wanting to step out coming off the corner?

Fire Away, let exchange ideas...

I had that problem last weekend at Classics RC Raceway in Ohio and I took some out the left rear and put a little in the right front, Bam it was perfect. As far as toe, They have the right idea for you.

what size of a swaybar do u have in the rear? and do u run a side dam?

Well I can't offer too much info, I normally run the rear toe on my car square (same left/right). I have tried changing toe up and down, but my car isn't very sensitive to even large changes. I can only get down to 1.5* but I've tried that and all the way up to 3.5* with no big effect on handling. Then again I'm running on rubber tires on a loose dirt track. You guys have got me thinking about experimenting with different toe left/right. I might even have to try and make a new rear hinge pin holder so I can try positive toe. One other thing I was curious about is do you guys run different anti squat left and right? I wonder how much that might also affect how the car comes off the corner? Hopefully we can get some experienced oval racers to chime in :)

Currently I have the standard ofna sway-bar in the rear and yes we are running side damns, I have been actually making the side-damn lower and lower little by little as it is actually easy to get to large of a side-damn and slow down rotation in the corner I am finding. I am not running a bar in the front only the rear to get the car to rotate batter, The car works great on a rubber tire setup it is on the foams where it is a bit tougher to get the handling down because you have more traction to contend with at each end...

I know that a good starting point for even loose dirt is 0 on the right and -2 on the left, I have yet to find a need to run the rear square but I am now that not having enough on the right rear will cause it to step out on corner exit rather than push the car off the corner...

I am not sure if I would try different anti-squat from left to rear, that may upset the chassis more than help it during suspension compression and the problem you would be trying to solve really may be somewhere else such as more/less wedge or different spring rates and such.

I have found the OFNA car to be very responsive to changes in the rear toe/steer angles, especially if you are not running them square.

Have you tried running heavier weight oil in the right front and left rear. Also going soft spring on the right front

The first thing I would look at would be the ride height from front to rear. About 2mm higher in the front is about right.
Seeing as you are running a one-way with a sidedam, the car should turn in real hard. When you run a front one-way you remove the off power brake effect of the drivetrain. So drop down on your shock oil or go to larger hole pistons front and rear. You have to make the car transfer weight quicker.
The next thing to do is groove the tires, cross groove them also. This will give you forward and side bite.
You might also what to try a slightly harder compound tire, sometimes a soft tire won't hook up as well on a high bite track.

If the car is as good as you say, leave the toe were it is, anti squat will probably make it worse also.

Hope this helps.