PDA

View Full Version : MR-03 Rear Chatter HELP!!!


twinkie
2011.11.07, 04:06 PM
Ok... been pounding my head against the wall trying to get my car to stop chattering in the corners...

Current set-up

94mm
PN Damper Disc
600 weight oil
Gold Spring on bottom
Green Spring on Top
PN White Spring in front - flipped king pin
PN33 Turn Motor
Pre-Load on damper plate is midway
Soft Kyosho Fiberglass T-plate


Things I have tried:
Softer springs in the front
Softer T-plate
Harder T-plate
Different spring combos on the damper disc
Different pre-load setting on the damper disc all the high to all the way low
Shaved the body to ridiculous amount thinking it was rubbing
Tried changing driving style to slower in faster out
Rebuilt the differential

Currently am pounding my head into the desk trying to figure this out...
In its current setting it isn't too bad but I know something is still off causing the chatter...

ANY HELP WOULD BE GREATLY APPRECIATED!!! THANK YOU

EMU
2011.11.07, 05:16 PM
What track material do you drive on, what tires are you using, do you tape/glue your tires? Are you chattering at the front end of the car or the rear?

If you dont have the tires glued/taped, then that would be the number one place the chatter is caused. If still chattering, try using a harder tire or softer spring and see if it still does it.

themelis factor
2011.11.07, 05:47 PM
The only way to solve your problem would be thicker grease on the damper plates. Try using 3000,5000,7000 viscosity. That should solve your problem.:D

twinkie
2011.11.07, 05:49 PM
Track RCP

Tire: Kyosho 20

Tires are taped using R246 tape. But I will definitely go back and double check to make sure the sidewalls aren't peeling. Thank you very much

blt456
2011.11.07, 07:43 PM
94mm
PN Damper Disc
600 weight oil - I used AE 35t at both regionals at ILR
Gold Spring on bottom - Try running green
Green Spring on Top
PN White Spring in front - flipped king pin (this spring is pretty hard, try running PN blue soft with slight tension)
PN33 Turn Motor - make sure highpoint isn't too high (low 50's should be fine)
Pre-Load on damper plate is midway (I have 2mm of preload on the bottom damper plate)
Soft Kyosho Fiberglass T-plate - try a PN 5 black carbon (stiff enough w/o need for top shock)


For the past Halloween race at ILR, I used a modified tri shock (reflex plates w/ PN shocks). Orange springs and 15k grease. It ran awesome without any chatter and you can lay down so much more power compared to a disk damper. The TDS got rid of all the chatter on my mosler at 94mm and gave the car a lot more corner speed (you can now turn up your highpoint because the tds handles mod motors really good)

twinkie
2011.11.07, 08:03 PM
The only way to solve your problem would be thicker grease on the damper plates. Try using 3000,5000,7000 viscosity. That should solve your problem.:D

wow... that thick...at this point i'd give my left nut to get this car to work(not like the world would want me to procreate anyhow)... i've been beating my head against the wall for about 8 months.


I am greatly appreciative for all the help and comments.

greenepa76
2011.11.07, 08:11 PM
How about a Tri-Shock setup with thicker grease in the damper tubes?

When I had a bad chatter problem, I had to use one damper plate on top to reduce the chatter with the tri-shock while paired with a PN #4 FRP t-plate on one of my cars with a 33T motor in a 98mm Mosler chassis. To reduce it a bit more, Grant still had to put an o ring on top of the damper plate spring to increase disc loading to get rid of the chatter completely without the use of grease. This setup was on RCP at Kenon. Super grippy track with full sized PN 6 rear radials along with PN 15 X pattern fronts trued down to 21mm.

twinkie
2011.11.07, 08:28 PM
94mm
PN Damper Disc
600 weight oil - I used AE 35t at both regionals at ILR
Gold Spring on bottom - Try running green
Green Spring on Top
PN White Spring in front - flipped king pin (this spring is pretty hard, try running PN blue soft with slight tension)
PN33 Turn Motor - make sure highpoint isn't too high (low 50's should be fine)
Pre-Load on damper plate is midway (I have 2mm of preload on the bottom damper plate)
Soft Kyosho Fiberglass T-plate - try a PN 5 black carbon (stiff enough w/o need for top shock)


For the past Halloween race at ILR, I used a modified tri shock (reflex plates w/ PN shocks). Orange springs and 15k grease. It ran awesome without any chatter and you can lay down so much more power compared to a disk damper. The TDS got rid of all the chatter on my mosler at 94mm and gave the car a lot more corner speed (you can now turn up your highpoint because the tds handles mod motors really good)

I am using the 600 oil... yesterday I tried green top and bottom and the chatter was worse.

TDS... basically I dont have the patience for it. So that set-up is just sitting in my parts bin.

I'm also thinking of converting to 98mm... will that help me with this problem?

So there are three parts of me on this car...

1. Just drop the car off with Binh @ ILR and plead on my knees to un-cluster @#$% my car. (dont wanna bug him more than I already do)

2. Just hang in there ask for help on the board and see if I can get it fixed... which will help me learn more about these cars (while going crazy)

3. Drop kick the car through the wall and start over.

I'm a crappy driver, and it doesnt help having a car that has the characteristics of dr. jekylle and mr. hyde.

unearthed name
2011.11.07, 11:06 PM
go wider offset, and go softer rear suspension. maybe try a fiberglass t-plate.

color01
2011.11.08, 06:21 AM
If you must stay with a disk damper, BLT's suggestions are good. the PN 4 or 5 carbon T-plate is in a good range of stiffness for most disk damper setups on RCP.

I would try out all sorts of oils on the disk damper while using the softest disk damper springs possible, this allows smoother damping without adding unnecessary "stiction" to the system. Like themelis' suggestion, I have bottles of 3000, 5000 and 7000CST oil in my box too for disk damper use. A little goes a long way and the thicker oil stays longer too.


Otherwise, I made the jump to a tri-shock a long time ago because tuning tweak with a disk damper car is a nightmare... and you have to do it often.

twinkie
2011.11.08, 11:06 AM
thank you all for your suggestions...

looking at the car last night it appears that the rear tires are rolling just a tad on the inside.

i'm going to first correct this issue, then go back to the suspension as well. On straights the car is fine just in turns its chattering making the car unpredictable. Sometimes it chatters going both in and out of the turn, other times its just coming out of the turn.

Hopefully I can make it to ILR tonight for testing.

twinkie
2011.11.10, 03:25 AM
ok... looks like the issue has been solved thanks to Binh at IRL.... he found that the damper plates had too much play. The center hole for the post opened up after a year of running... so what was happening was the motor pod was able to move without effecting the position of the damper disc. Therefore any oil added was no use.

So I replaced the plates, and also found a piece of slag on the post, which was not allowing the plate to slide up and down freely. So I was able to sand that out, and viola... the chatter is gone.

I was also told about maintaining the king-pins and the spindles. Driverside spindle was getting hung up while the passengerside moved freely. So that issue was taken care of as well.

The other problem was my bad driving habits... which is currently being sorted out.

Thank you all for your suggestion. As of right now I am a happy camper with my mod car.... I still have hair on my head, and I learned quite a lot this time around.

NoBrainer
2011.11.10, 03:46 AM
The other problem was my bad driving habits... which is currently being sorted out.

How do you fix this?
Been searching the net for some store that sells solutions to this hugh problem.
Was hoping for some tips...

:D

twinkie
2011.11.10, 07:42 PM
How do you fix this?
Been searching the net for some store that sells solutions to this hugh problem.
Was hoping for some tips...

:D

Valium....atleast that's what everyone was telling me to take lol... I'm still working on breaking the habits.

color01
2011.11.11, 01:22 AM
How do you fix this?
Been searching the net for some store that sells solutions to this hugh problem.
Was hoping for some tips...

:D
Chattering from driving style can occur if you give the car inputs too quickly and it is coincidentally setup to respond to said input very quickly. No biggie really, a simple change such as not turning in and letting off/braking at the same time can reduce the amount of chatter. I assume you're not getting chatter at the corner exit, that's strictly a setup issue.

NoBrainer
2011.11.11, 06:55 AM
Thanks for reply, but I stick to the first solution with valium....
Much easier to handle that than to change my driving

:D

twinkie
2011.11.11, 12:03 PM
Chattering from driving style can occur if you give the car inputs too quickly and it is coincidentally setup to respond to said input very quickly. No biggie really, a simple change such as not turning in and letting off/braking at the same time can reduce the amount of chatter. I assume you're not getting chatter at the corner exit, that's strictly a setup issue.

the chatter is gone.... when it was chatter it was all through the turn.

The biggest help though besides the set-up was Binh riding me on driving technique.