Couple of handling issues

[kx250ryder]

I have got the setup pretty dialed on my 9.5 pro. There are two issues I would like to improve though and was looking for advice:

1) I could use a little more on-power steering. When coming out of this left hand turn onto the front stretch of our track, my car pushes while accelerating.

2) On short jump faces, I have to keep the throttle pinned up the face to keep the car from doing an endo.

My current setup:
OFNA 9.5 pro
light blue OFNA springs (medium, I think)
stock shock pistons
40 wt. oil
5k/Torsen/1k diffs (front/middle/rear)
1 degree tow out front
2 degree tow in rear
stock caster
stock c-hubs
stock front swaybar (black)
green rear swaybar (about half the thickness of stock)

 

[CorradoPsi]

put a thicker swaybar in the back, reduce front droop, raise your rear roll center.

 

[CorradoPsi]

one at a time obviously.

 

[kx250ryder]

Which of those cures which symptom?

 

[CorradoPsi]

they all can. however they all also have different handling traits to them as well.

a thicker swaybar in the rear will increase all steering, on and off power.

raising your rear roll center will decrease rear traction at all times as well. enabling the rear to come around easier.

decreasing front droop reduces rearward weight transfer and keeps more of the cars weight over the front tires increasing traction. this would be the one that i would start with, however if your on a bumpy track this may cause the car to bottom out more because it essentially decreases suspension travel.

you can also increase your rear ride height, but again that will affect on and off power steering.

 

[kx250ryder]

Thanks for the suggestions, I just had two things I was unclear on:

1) When you say decrease droop in the front, do you mean increase front ride height or do you mean limit down travel using the grub screws in the arms?

. . .raising your rear roll center will decrease rear traction at all times as well. enabling the rear to come around easier.

. . .you can also increase your rear ride height, but again that will affect on and off power steering.

2) Aren't the rear roll center and rear ride height adjusted the same way, by increasing rear spring preload?

Also, I was thinking thicker weight rear shock oil to cure the endos off of short jump faces (to slow the rebound), but I didn't want to make too many changes at once.

By the way, if it seems like I pick your brain too much, I appologize.

 

[slothy]

hrmm try going to a normal center and try 7k (but cor seem to have a good heap of things to try that will help)

 

[Diver6127]

Roll center is done with position of shims or swapping out different blocks (depending on your r/c). Ride height is done with either spacers or threaded shocks. Increasing your spring rate will do noting but make the suspension harder.

 

[CorradoPsi]

on buggies, rear roll center is adjusted by raising or lowering the rear camberlink on the shocktower. all those extra mounting holes do have a purpose. raising the link on the tower, raises the roll center, and lowering the link on the tower lowers the roll center.

 

[kx250ryder]

Aha. That makes sense. I will start with the rearI can't wait until Saturday to give all this a try. This time hopefully I will remember my camera. We have an evil rythm section. If you don't nail the setup double perfectly(the one I keep endoing over), you case out the second double that follows with a vengance. Its tough to decide within like a 1/10th of a second whether to pin it for the next jump or lock em' up, makes for quite a show when you guess wrong.

 

[Plaidfish]

if you're diving off the jumps make sure your brakes aren't dragging at all....if you can't set your buggy on the ground (w/ radio gear on) give it a push and have it roll freely for a few feet then they are dragging....I see so many guys at the track doing this......(I never did )

 

[kx250ryder]

That's a good idea Plaid, I could see how that is easily overlooked. In my case I think the problem is suspension though, I have recently been messing with my brake bias, so I am pretty sure it isn't dragging. How did your 9.5 Pro handle in respect to more modern buggies? Mine seems to hold its own pretty well compared to my friends' cars (Mayhem and Hyper 7 PCR Pro).

 

[vgibbens]

here is a link that describes the physics involved with the different aspects of setup:

http://users.pandora.be/elvo/

 

[Diver6127]

on buggies, rear roll center is adjusted by raising or lowering the rear camberlink on the shocktower. all those extra mounting holes do have a purpose. raising the link on the tower, raises the roll center, and lowering the link on the tower lowers the roll center.

Good info to know. I was just gonna rig a small flapole in there to fly when I race! :jk:

 

[Plaidfish]

That's a good idea Plaid, I could see how that is easily overlooked. In my case I think the problem is suspension though, I have recently been messing with my brake bias, so I am pretty sure it isn't dragging. How did your 9.5 Pro handle in respect to more modern buggies? Mine seems to hold its own pretty well compared to my friends' cars (Mayhem and Hyper 7 PCR Pro).

I actually loved it...I still think it was one of the best driving....I liked it better than the mugen (the quick steering part of it)....just a little....it did plow on turns but I think it's because you can set it to turn too much.....I saw a post from mikeburgin that said after 40% they just plow....I never limited mine but if I got excited on turns it would just oversteer and not get enough traction to pull the front.....the only thing I didn't like was the weak C-hub setup...but by the time I got a PBS set a friend of mine got a 9.5 and I had my Xray so I sold him the setup.....it works really well and makes the front pretty damn tough.....I used to bust the knuckles all the time...then I tried the CnC knuckles and CnC C-hubs....nothing broke but it bent the crap out of the knuckles......it ended up being just the CnC Knuckles and left the C-hubs as a breaking point if it gets in a bad wreck those would be sacrificed......nice buggy but parts are few and far between around here for OFNA......