FK05 mystery
#1

Having a problem with my FK05. I have an FK05 that keeps spinning out when turning left....it wants to break loose everytime. My car turns in and out of corners perfectly when turning right but when I turn left it is very inconsistent on the turn in and when coming out of the turn I have to be extremely careful with throttle control otherwise it will break loose. I have done almost everything I can think of...almost everyone at the track has looked at it and tried driving it and its just perplexing us all.
I race rubber tire on medium grip carpet. I do run a lipo but have it balanced out. I rebuilt all the shocks. I rebuilt both diffs. I equalled out lengths of rods all around with my calipers. Messed with dual rates,epa's.Ive pretty much have done everything I can think of as well as a lot of good drivers. Startign to get frustrated......just hoping someone here maybe able to offer a suggestion that we may have overlooked.
Any helpful suggestions is much appreciated.
Thx.
I race rubber tire on medium grip carpet. I do run a lipo but have it balanced out. I rebuilt all the shocks. I rebuilt both diffs. I equalled out lengths of rods all around with my calipers. Messed with dual rates,epa's.Ive pretty much have done everything I can think of as well as a lot of good drivers. Startign to get frustrated......just hoping someone here maybe able to offer a suggestion that we may have overlooked.
Any helpful suggestions is much appreciated.
Thx.
#2

Am I correct in assuming you have made sure the chassis is perfectly flat, that with the shocks removed the suspension moves smoothly without bind, that you've checked all alignment, that the shocks move through their travel smoothly and consistently?
Have you checked the droop settings? Both by setting downstop measurements and lifting the ends and seeing when a tire lifts? Someone mentioned their car is quite sensitive to droop settings. Hopefully more experienced will chime in. I set mine to 2mm droop as measured at the chassis, even it up with droop blocks, and then check that both sides lift tires at the same time by using a sheet of paper under each wheel while I lift the end with a ride height gauge.
Have you checked the droop settings? Both by setting downstop measurements and lifting the ends and seeing when a tire lifts? Someone mentioned their car is quite sensitive to droop settings. Hopefully more experienced will chime in. I set mine to 2mm droop as measured at the chassis, even it up with droop blocks, and then check that both sides lift tires at the same time by using a sheet of paper under each wheel while I lift the end with a ride height gauge.
#3

ride hight camber same shock oil all round???

#6

Chassis was checked by one of the top drivers at the track. Said it was fine.
C-hubs have been changed...3 degree mediums
Regular diffs. No one ways.
30wt oil all the way around.
All the shocks are in working order.
I rotate the tires every two heats.
I put it up on a board and have the settings at -
3 degree toe in on the rear
.5 toe out in the front
1.5 degree camber all the way around.
Ive done droop by the droop gauge and uptravel method. Always equal either way., Usually set to 1-2 mm droop up front or 5 on the gauge. 1 -1.5 mm droop on the rear or set at 4 on the gauge.
The way i have it set up , it should run. But it still oversteers severly when on throttle coming out of a left turn.
I had one person ask if the pulleys were the same tooth configuration...not sure if this would cause a spin out like it is ?
Ive checked and cleaned the bearings. Maybe i should get a new set just to make sure. Maybe one is not perfect on that side, maybe just enough to screw it up.
One note - I bent the rear bulkhead awhile ago. Replaced it but when I shimmed it out to get 3 dg of toe in, the right side needed an additional 1.5mm shim to get it to 3 degrees. That is the side that is creating problems. But the car has done this ever since I got it. It doesnt appear to be bent at all.
C-hubs have been changed...3 degree mediums
Regular diffs. No one ways.
30wt oil all the way around.
All the shocks are in working order.
I rotate the tires every two heats.
I put it up on a board and have the settings at -
3 degree toe in on the rear
.5 toe out in the front
1.5 degree camber all the way around.
Ive done droop by the droop gauge and uptravel method. Always equal either way., Usually set to 1-2 mm droop up front or 5 on the gauge. 1 -1.5 mm droop on the rear or set at 4 on the gauge.
The way i have it set up , it should run. But it still oversteers severly when on throttle coming out of a left turn.
I had one person ask if the pulleys were the same tooth configuration...not sure if this would cause a spin out like it is ?
Ive checked and cleaned the bearings. Maybe i should get a new set just to make sure. Maybe one is not perfect on that side, maybe just enough to screw it up.
One note - I bent the rear bulkhead awhile ago. Replaced it but when I shimmed it out to get 3 dg of toe in, the right side needed an additional 1.5mm shim to get it to 3 degrees. That is the side that is creating problems. But the car has done this ever since I got it. It doesnt appear to be bent at all.
#9

I noticed that the rear shock tower flexes quite a bit. Not sure how much flex should be coming from that but it seems to me a little excessive. It literally looks brand new but could be a problem.
#11
Tech Adept

On my FK05 I had a rear bent hinge pin cause this because it lets the droop change the side of the bent pin.
#12
Tech Apprentice

i would guess you checked ur tires?? soundslike u have a unglued right rear tire.
#14
Tech Addict
iTrader: (8)

I had a similat problem with my FK05, Check to make sure the reat bulkheads are straight. I had a 2.6mm tweak in a rear bulkhead. Youcancheck easily by removing all the bottom screws and make sure they line up with the holes. You should also give your car more up travel in the rear by your setup. Maybe 2mm up travel. You may just have too little travel in your suspension.
RedRocket
RedRocket
#15
Tech Adept

make sure your shocks are not binding somewhere. and that your weight is the same side to side