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HammondCheese
2013.04.07, 09:05 PM
Hi all,
over the last few months I've pooled my extra bits and with a few small purchases put my first MR02 together. The problem I'm having is, quite often it just seems to want to turn all by itself. Driving slowly it doesn't seem to exhibit this tendency so I dont think its tweak or trim. Hitting the throttle after coming out of a corner (or when testing - part way down a straight) makes it want to dive right some of the time. Really annoying - definitely have to work on avoiding the wall when it happens. Anyway I've changed the chassis and steering assembly - not really any difference. Ive changed the H plate.
Its a little like when I've had wheels locking/rubbing on the body in the past, but I took the body off for a few laps and same thing still happens. Its usually happening under acceleration not braking anyway - almost all my previous rubbing problems were front end under braking. When I loosened the front wheel nuts to the point where they'd work off after a few laps (and the front wheels seemed to spin ok) still the same problem.

Its a WTF2 front end. I've seen some comments about issues with these and high camber steering blocks - but I'm running 1.5 degrees and this seems to give some clearance. Maybe I should try 0.5s or 0s... Apart from that - I'm stumped.


What next - new board? Any other ideas?

Thanks all

imxlr8ed
2013.04.07, 10:04 PM
Other than the H-plate, what else you got going on up top?... Disk dampener?, top shock?, tri-shock?. I had a similar issue with one of my chassis' last year , turns out the disk dampener wasn't operating smoothly and evenly and was causing a right hook on turn exit on throttle.

Personally, I rarely go above 1 degree camber on any of my kingpin style front ends. What surface are you running on?

HammondCheese
2013.04.10, 05:22 AM
Other than the H-plate, what else you got going on up top?... Disk dampener?, top shock?, tri-shock?. I had a similar issue with one of my chassis' last year , turns out the disk dampener wasn't operating smoothly and evenly and was causing a right hook on turn exit on throttle.

Personally, I rarely go above 1 degree camber on any of my kingpin style front ends. What surface are you running on?

I'm running one of the Atomic 98mm damper plates (Its actually one of their 96mm motor mounts) and the little v2 top shock they make to go with it. I removed the top shock at one point and changed the damper springs but didn't think to completely remove the damper plates. Seems an easy thing to check before I lash out for a new board :). What was your solution - fix the installation of the plate or completely new plate?

I've gone 1.5 camber simply because I got a good deal on an alloy knuckle that was 1.5 - the motivation of the project was to use leftovers and do it on the cheap with limited new purchases :). From memory the WTF2 has some inbuilt camber so in reality its probably pushing 2. I've got the plastic knuckle pack that I think does 0 and 0.5. I wouldnt be happy relying on plastic knuckles on an ongoing basis but they should be fine for testing.

We run on RCP - and this week was a temporary track (we rent out a hall 4 times a year to do larger races. Our regular venue is only HFAY sized). So its probably a little more bumpy than most. I thought bump steer for a while but this can be pretty extreme...

Thanks for giving me a few places to start. I had my MR03 running 12-13s for most clean laps, I think my best on the 02 was somewhere in the mid 14s and the average was woeful (too much time meeting the wall :) ). It was... frustrating.

imxlr8ed
2013.04.10, 08:56 AM
I'm running one of the Atomic 98mm damper plates (Its actually one of their 96mm motor mounts) and the little v2 top shock they make to go with it. I removed the top shock at one point and changed the damper springs but didn't think to completely remove the damper plates. Seems an easy thing to check before I lash out for a new board :). What was your solution - fix the installation of the plate or completely new plate?

I've gone 1.5 camber simply because I got a good deal on an alloy knuckle that was 1.5 - the motivation of the project was to use leftovers and do it on the cheap with limited new purchases :). From memory the WTF2 has some inbuilt camber so in reality its probably pushing 2. I've got the plastic knuckle pack that I think does 0 and 0.5. I wouldnt be happy relying on plastic knuckles on an ongoing basis but they should be fine for testing.

We run on RCP - and this week was a temporary track (we rent out a hall 4 times a year to do larger races. Our regular venue is only HFAY sized). So its probably a little more bumpy than most. I thought bump steer for a while but this can be pretty extreme...

Thanks for giving me a few places to start. I had my MR03 running 12-13s for most clean laps, I think my best on the 02 was somewhere in the mid 14s and the average was woeful (too much time meeting the wall :) ). It was... frustrating.

I just gave the dampener a light sanding and the disks got one too, then slathered them with some Ruby Lube. Since then I've found that running a screw up top that does not fully compress the top spring (green) on the dampener seems to let the car set itself up quicker out of the corners.

A member helped me out on finding this apparent tweak by using a simple old-school methodology... take the body off, give the front suspension a push straight down on each side individually. If you're running a kingpin setup, I would say to push down with a small allen wrench on the top of the kingpin. Once you give that push down until the front is fully compressed, watch what the rear tires are doing. They should react the same, side to side.

This is how I found that the dampener was hanging up on the one side, once cleaned up... problem solved!

I still think 1.5 is too extreme for a WTF front though... what offset wheels are you running?, 0 or -1s?

HammondCheese
2013.04.10, 07:30 PM
I just gave the dampener a light sanding and the disks got one too, then slathered them with some Ruby Lube. Since then I've found that running a screw up top that does not fully compress the top spring (green) on the dampener seems to let the car set itself up quicker out of the corners.

A member helped me out on finding this apparent tweak by using a simple old-school methodology... take the body off, give the front suspension a push straight down on each side individually. If you're running a kingpin setup, I would say to push down with a small allen wrench on the top of the kingpin. Once you give that push down until the front is fully compressed, watch what the rear tires are doing. They should react the same, side to side.

This is how I found that the dampener was hanging up on the one side, once cleaned up... problem solved!

I still think 1.5 is too extreme for a WTF front though... what offset wheels are you running?, 0 or -1s?

Makes sense. I'll check it out over the weekend. ..Or tonight if work is reasonable for once. Which damper are you using? I've thought of giving the new Reflex one a shot. If I cant get this sorted this may well turn out to be the chassis.... :)

I'll give the plastic 0 and or 0.5 a go next time I'm on the track ( I think next weekend is our next meet). I havent run the enough laps on the thing yet to check the tyre wear pattern properly to see which way that suggests the camber needs adjusting. If one of those works ok I guess I'll invest in a new alloy knuckle.

I'm running 0 offset fronts and +2s at the rear under a R8 body with dremelled out rear wheel wells (They seem to fit the 96 chassis well with really minor modification). +1s were definitely a little wide. I think 0's will turn out to be the right choice at the moment.

Cheers

blt456
2013.04.10, 08:46 PM
Be careful with the Reflex Racing damper disks. About a year ago when I purchased mine, the center hole was oversized and the Reflex damper post didn't make contact with the disks at rest. This made my car chatter a lot. Hopefully Reflex has fixed this problem so that people do not buy poor-fitting damper disks. The only way to resolve this issue is to use damper disks with a smaller hole, such as the PN pieces. The PN disks are undersized so they don't slide freely on the PN or Reflex damper posts. However, you can cut out the center hole slightly with an xacto blade to make the disks slide freely without any slop.

imxlr8ed
2013.04.10, 11:25 PM
Quite honestly, I can't recall exactly what dampener plate I have on any of my cars. They are all mix and match sort of beasts from years of collecting odds and ends. But I can tell you that the majority of my cars run the lightweight PN disks after I found some other brands seemed to gum up quicker than others.

I would agree on the zero fronts, a plus 3 rear wheel may help but technically speaking, a wide front end and a narrow rear should stabilize the car.

A harder front spring could also help out but as always, may take some of your cornering ability away.

Could your diff be hanging up on throttle? Any kind of interference between the diff and the motor mount?

Chasing issues like this can drive you up a wall, but once you figure it out you will definitely learn something. :D

imxlr8ed
2013.04.10, 11:28 PM
Worse-case scenario is an issue with the board, some kind of power surge to the steering system when on full throttle. This is rare but it has happened to me once or twice back in the AM days.

Oh, and maybe try some semi-worn tires on the front too?

Not sure what radio you have either, but if you go negative on the steering curve it can help take away some touchiness on the straights. Almost every one of my cars are in the negative curve between 10 and 45%.

HammondCheese
2013.04.11, 06:28 PM
Worse-case scenario is an issue with the board, some kind of power surge to the steering system when on full throttle. This is rare but it has happened to me once or twice back in the AM days.

Oh, and maybe try some semi-worn tires on the front too?

Not sure what radio you have either, but if you go negative on the steering curve it can help take away some touchiness on the straights. Almost every one of my cars are in the negative curve between 10 and 45%.

The tires will almost certainly be semi worn by the time I've finished all of this :). If the other ideas dont work out I will change the diff over too. I'm using an EX5-UR the steering curve is definitely somewhere around -20. I was messing with that on the weekend - don't remember where I left it.

Ill absolutely learn something from all this - you are correct. And again thanks so much for all your suggestions!.