Kf issues

[gd26]

Right folks who can help me my kf has issues on the race track.. Trying to put power down in corners and rear always wanting to swap ends in low speed and low/medium grip tracks.... (Mainly grass tracks)

Here's what I've tried

Lg chassis
Weight at rear
Dropped motor to from 7.5 to 8.5 maybe drop even further to 9.5
Esc mod and basic programs
Transmitter settings curve punch etc
Sorting and Harding rear end
Tried both gear and ball diff, ball slightly better
And thumb control

I kinda feel like JB at mclaren pottering around at rear as I can't actually race others... However when I run my sv2 different story lap time and count increase I can actually push and compete...


And finally does anyone know if Schumacher are making or developed a new mid motor car

[andy-aj]

Try:-

Carbon low grip chassis in shorty configuration.
76spur (to get motor as far back as possible).
High inertia side gears 35t and 21t (Found this makes a big difference).
Ball diff.

Front end :-
275cst oil and white core springs.
Inner hole on reversed wishbones, middle hole on tower.
Std camber link plate, link outside on hubs
5 degree hubs.
Alloy centre track rod or space std up by 4 mm and add 4mm under outer ball studs.

Rear end:-
200cst oil and white springs.
Inner hole on sv2 wishbones (or drill 3rd inner hole on std wishbones), middle hole on tower. Shocks will need internal limiting by about 4mm.
4degree tow in and 0 degree anti squat. Low inner pin height.
Std camber link plate, link outside on hubs.
Short wheelbase.

Should be very easy to drive

[paulc]

That set up is seriously soft take a look on www.petitrc.com set up page and and look at the set ups on there

[andy-aj]

Yes, it is soft, and is only a suggestion to try, and tune from there.

[andys]

I'm new to the KF - but mine is planted.
Built as per kit - but with 1.6 drilled pistons rear (not drilled front) and 25wt oil rear - 35wt front. Also long link on rear - that's it :)

Also - it appears from other local drivers experience at our track, that the original chassis with Saddles works better (all astro track) - I tried the low grip and went straight back to the saddle chassis after one run!

A friend though also has a KF2 and cannot get it to work right at all - same shock setups feel totally different on the bench - it's like his car is 'jinxed' and he can't get it to work at all - maybe some of them are just 'flawed' !

[wbridge]

i just ran a kf2 and for me was allot of fun , only had an issue with the back wanting to slide out so i increased the anti squat and i think it should be fine (on astro) also i moved the shocks inwards, seems a little bitey on the turns

[Ritchie T]

Isnt 200cst like 20wt :cry:

[neallewis]

A friend though also has a KF2 and cannot get it to work right at all - same shock setups feel totally different on the bench - it's like his car is 'jinxed' and he can't get it to work at all - maybe some of them are just 'flawed' !

He's gone Yokomo YZ2 now... KF2 is in the bin, literally.

I'll spin up my saddle kf soon as i can. it was great at RHR last YORCC meeting of the year.

[steveproracing]

Had trouble with my kf2 initially. I built as shorty car and no matter what I did it would just kick out under power. I tried every trick I know inc squat toe in shocks springs ride height wheelbase etc etc. then I did what I should have done in the first place ( and something I always do when I loose touch with a cars setup.). I went back to kit setup. Entirely. Removed all hop ups. Used kit oil kit springs castor blocks and most importantly saddle pack layout. Problem solved. Car was instantly drivable. I've now honed my setup to a sweet spot for me that I can adjust to the track conditions easily. If anyone was at the me regional this last weekend they will testify that grip was very low in places and it was hard to get the power down. I actually felt I had an advantage over many people as I didn't feel to be struggling for grip anywhere. My car was amazing. I was less so, but that's another story. For those wishing a setup sheet just pm me.

[Gayo]

If you are struggling with rear grip and have already tried everything else others said (LG chassis setup, shocks on rear, shocks inward), you can try to reverse rear arms.
That's all I do on mine when our astro track is wet (with a tyre swap obviously) and my car is ace!

Some weight under the lipo also helps calm the car.

[andys]

Interesting Steve that you also went back to the saddle chassis :)

I'm loving my KF - last week - even with 2 meetings old pins - coming put of the 90 degree astro corner (the one on the concrete section where you carry little speed around it as you are lining up for the big jump) - accelerating towards the big jump - I could get straight onto the gas out of the corner. At one point I was almost pulling wheelies along there as I was trying so hard to catch the leader - but it continued accelerating in a straight line!

[Rick-J]

So in general what should you do to get more grip and forward traction. Softer suspension, more antisquat, Shorter links or drop the inner link, short wheelbase etc. People say forward motor cars don't work in the wet but they do as long as you set them up correctly. Any more tips?

[gd26]

Thanks for all the input folks the only thing I've not done is revert back to normal saddle set up... I run on grass and mixed wood carpet at club... So an astro setup won't work

[steveproracing]

biggest things for forward drive are, saddlepack car, more antisquat and short wheelbase. balance your springs and tyres. i.e. don't have one end with way more grip than the other.