Dyna Storm Set up, I need Help please

[GTodd]

Between tanks of my 801XT I have been running my TF EVO and DS. The EVO is doing pretty well minus the Rear Shock Tower/Gear Box issue. I'm at a lost with the DS. If I run the slipper as suggested by the manual it will scream and slip. I'm slowly tightening it. Should I tighten all the way down like a traditional slipper and than back the nut out a 1/4 turn? Secondly if I tighten the differential as instructed in the manual the car will spin right out when I add throttle. If I loosen the differential even just a 1/4 turn it slips badly. Any ideas? I love the car, it handles great, and I've gotten it to turn and jump well. But when I apply throttle it comes right around. Please help, or I might have to break the Astute out.

[Thommo]

Please help, or I might have to break the Astute out.

Just break the Astute out anyway!

[kontemax]

Ok, probably your car spins out when you add throttle for some reasons.

Keep in mind it's not a 4WD so you cannot open the gas in the same way, you must change your driving style, it must be more soft with the throttle.

The second issue is the car balance. The balance in a 2WD rear wheels drive is more delicate than a 4WD imho. You must have a balance between oversteering and understeering. Your car is oversteering so there's a problem somewhere in teh suspension set up.

1) the diff MUST NOT slip so thight it properly as manual instruction.

2) the slippery clutch is not involved in this problem but thight is ad instruction manual. Keep in mind that the DS clutch is noisy cause has the same concept of a Ducati clutch.

3) the suspension is a little bit tricky.

- Start with the spring. Put your car on a flat surface, with battery and in order to run. Press the rear end and release it. Check the rear lower arms looking the car from behind. After the extension of the rear end the rear arms must remain parallel to the flat surface. The damper should not extend totally, they must remain as compressed as the rear arms remain parallel to the ground. Sorry for my low skill english but I hope you can understand anyway. Same way with the front end but you can stay a little bit more stiffer on the front.

- Check the oil thickness. With my experience is better have smaller holes in the piston rods and lighter oil. The dampers must be softer as possible but not enought to make the car a bumper like the Grasshopper. When you press the rear end the car must extend the rear dampers until the rear arms horizontal position quickly. Softness is the key.

In the front end the oil must be lighter than the rear end, due the different weight balance.

- Damper position is also important, expecially in the rear end. Take the car in your hands and fully compress the rear dampers. Keeping the damper full compressed check dampers/rear arms angle. The dampers must be at maximum 90° with the rear arms, no more. Less degresses is better, more degresses is bad. Just to understand the rear damper and the rear arm must made an upside down T letter, hope I explained well. For the front dampers the rule is not so rigid.

When you did all this you can work on cabmer and caster angles, toe in and toe out and at the end with the tires.

Tire choice can save your set up, you can solve your problem with a different couple of rear tires but if you have a correct damper set up is better.

Keep in mind that the 2WD/RWD car is lightly understeerer in front of a 4WD so you must adapt your drivestyle to the car. These rules are good for other 2WD car I suppose.

Max

[GTodd]

Great explanation, thank you! Im going to take apart the rear today to rule out me messing it up, and than use your tips.

[kontemax]

Keep in mind that often if rear end doesn't work you must set up the front end and vice versa.

If your car is oversteerer could be the front end has too much grip.

The rules I posted are general rules but then is important understand what in your car is wrong. You also could mount the wrong rear tires for examples.

Not easy I can say.

Max

[bjr250]

From the other thread in the re-re discussions.

It really doesn't matter if diff is a little loose. As long as it doesn't slip. Always make sure the slipper slips first. If diff slips you will destroy the diff balls & rings.

Your slipper must slip first ( No diff slip at all) I run my diff to be smooth but not really tight. If diff action is really tight it will spin out on the corners. I back the slipper all the way off so it slips a lot than tighten it up till it slips for the first meter or so. My D/S runs well. I changed the front springs to stiffer ones and helped so much.

Hope this helps.

If your kit tires are worn down, or your driving them in soft dirt, the kit setup is no good. Once the ribs wear away, the front end has too much traction. Then you will not be able to apply any amount of throttle without breaking the rear loose.

Stiffer front springs are a good idea in this case.

Also you do want to run the diff as loose as you can without slip. This car is hard to setup the diff because you have to work the diff screws from both sides to adjust and lock it down.

I agree that using a stiffer spring in the front can help. I have had direct comparison with mine in stock set up and MAD RACER's here on a track and his does handle a lot better than mine.

Tyre choice can be the overall factor with controlling oversteer, as 94eg said. Sometimes you just have to choose the right tyre for the surface.

Thommo has a good point as well. I run both my Dyna and Super Astute and while they may be similar in that they are 2WD vintage cars they are different to drive and each have their own charms.

[GTodd]

Maybe I didn't explain my problem well enough. I'm not concerned too much about on power oversteer in the turns. When I start off at more than 1/2 throttle the rear will loop around with the front wheels point perfectly strait ahead. I rebuilt the diff and slipper last night and I think I originally built both incorrectly ( I had shims on both sides of the dif and installed the spring on the clutch incorrectly). Right now I have the differential adjusted so that it requires just a little force to move when Im holding both out drives with the wing mount as instructed in the manual so Im guessing that its tight but not locked. I'm heading to the track tomorrow (4 weeks leave!!!!) and Ill post some results. Thanks for the help gents.

I am running a Novak Brushless but its the equivalent of a hot stock motor so I dont think Horse Power is the issue.

PS

Im running on a hard, clay packed track with bow ties on the rear and the rib/spike super gripper Tamiya tires upfront (not the super astute/DS ones).

[GTodd]

Darn South Carolina rain! Well no day at the track for me. I guess I'll continue to work on the EVO. Im looking at Thursday to try and get the DS to hook up.

[kontemax]

There's the sun here in Italy.

Max

Darn South Carolina rain! Well no day at the track for me. I guess I'll continue to work on the EVO. Im looking at Thursday to try and get the DS to hook up.