R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 03-09-2014, 09:30 PM   #106
Tech Elite
 
Join Date: Nov 2008
Posts: 2,132
Trader Rating: 7 (100%+)
Default

when i received my 6.1wc it had a 1.5mm shim behind the front arm front mount and a .5mm shim behind the front rear arm mount. im considering removing them. the car was setup for mod as it had a 13.5. i run scale spec and only a 25.5 and the car doesnt feel as good as i want it to be. im thinking i should remove the arm sweep. what do you think? car turns in good, mid turn slight push and exit is decent grip. but im not feeling confident that it is setup properly yet. now if i remove these shims what effect will it have on my car? ive never used arm sweep before, like i said it was on the car when i got it and ive left it alone.

do i really need any arm sweep running a 25.5 motor in scale spec? its such low power i dont really think its necessary? what say you martin?
dragonracing is offline   Reply With Quote
Old 03-10-2014, 11:22 AM   #107
Tech Initiate
 
Dukes2004's Avatar
 
Join Date: Dec 2013
Posts: 24
Trader Rating: 2 (100%+)
Default

Great thread and love your app.
Dukes2004 is offline   Reply With Quote
Old 03-10-2014, 03:16 PM   #108
Tech Fanatic
 
Martin Crisp's Avatar
 
Join Date: Oct 2003
Location: Toronto Canada
Posts: 822
Talking

Quote:
Originally Posted by blackshark3 View Post
Martin, I am a fan of your TC setup book, it has been the holy grail for me, and old fart who returned to r/c cars after over 2 decades...As a newbie, I keep all my cars according to stock recommended setup, so what I dare to change are only tyres and shocks. Lately I found myself lost in the setting up my cars, and would cherish your guidance.

I would like to know why would most TC uses stiffer springs in the front than on the rear? Won't that inhibit turn in?

Then, as I own different makes of cars, all setup under the factory recommendation, I found they turn differently from each other. Even though I tried to put same turn of motor, tyre and body shell and run them at the same track (I run at an outdoor asphalt track with a long straight, wide bends and good traction) each would perform differently. So my stupid question is that whether I could duplicate the control feeling of one car to the other? e.g. I like my TRF 418 driving feeling, as under default setup it gives a lot of initial turn in and mid corner. However, my T414 is stable but a bit pushy, The BD7-14 would feel midway amongst the two, and weirdly my A700 FFG was so finicky I could not touch the throttle mid of the turn or it just won't turn. I was wondering whether I could make all 4 cars to have the initial turn feeling of the 418, and if so how to go about doing it just by playing with springs.

Thanks for your help in advance
From one old fart to another ...

The reason why it is not uncommon to use a slightly heavier spring on the front than the rear is because the front springs are mounted more inward on the front a-arms than they are on the rear a-arms. Being mounted more inward means the springs have less leverage against the arm so a heavier spring is often needed to have a similar effective spring rate as the rear.

Having said that, I like to run the same spring rate on the front and rear of the car when running rubber tires. For example on the CSO v2 that I am running for fun at the up comming Canadian Nats I run the 2.4 spring front and rear.

To answer your other question,...yes you can make pretty much any brand handle like any other brand, but there is not short answer as to how you do this. You will need to work through adjustments one at a time is the only answer. So for example if you like the initial turn-in of the 418 and you want to match than on another brand then start working on setup changes that give you more off power steering, assuming the car you are working on pushes more off power than the 418.

Quote:
Originally Posted by chasingthepack View Post
i had already gone to 2* camber and 3* of toe and it wasnt enough,it would still slide,although it was very predictable and a quick stab on the throttle caught it,i then tried 2mm on the inner rear link and it improved alot,so i tried another 1mm and it was better again,pretty much stopped sliding,i was going to try removing 1mm from the outer ,but changed my mind and removed the rear graphite arm plates and it was cured completely,then today as the grip came up i was in need of more corner speed so after changing shock oil twice going up to 400 then 450 i settled on 450 and in q4 i managed to tq,it was close with a 19;317.13 vs a 19;317.78,i got off to a great start in the 1st final ,but made an error on the infield on lap 11 and put it on the grass,dropped to 8th,fought my way back up to 5th but i was on the bumper of 4th over the line,2nd final i kept it together and went from flag to finish 4 secs ahead of the rest,so your help does have an impact,thanks again and long may you keep it up
heres a vid of our tracks first set of finals,we had 17.5 blinky 13.5 boosted and superbikes,hope you like
http://www.youtube.com/watch?v=jtRX6...ature=youtu.be
I will take a look at the video later, but Happy to see that you are making good progress! keep experimenting.


Quote:
Originally Posted by rckimi View Post
Mostly I have been silently reading, studying and trying to understand every question and answer given in this thread. Just came back from the track today and I have to say it has been a rewarding practice day today after applying some things I learned in this thread! I want to thank Martin “Setup Legend” Crisp for his work and time I also have your app on my iPad and go through it from time to time, I want to thank also everyone asking questions and participating in this thread. Subscribed! Happy man
Awesome!!! ...and thank you!!!


Quote:
Originally Posted by dragonracing View Post
when i received my 6.1wc it had a 1.5mm shim behind the front arm front mount and a .5mm shim behind the front rear arm mount. im considering removing them. the car was setup for mod as it had a 13.5. i run scale spec and only a 25.5 and the car doesnt feel as good as i want it to be. im thinking i should remove the arm sweep. what do you think? car turns in good, mid turn slight push and exit is decent grip. but im not feeling confident that it is setup properly yet. now if i remove these shims what effect will it have on my car? ive never used arm sweep before, like i said it was on the car when i got it and ive left it alone.

do i really need any arm sweep running a 25.5 motor in scale spec? its such low power i dont really think its necessary? what say you martin?
I would need to see your complete setup to better help on this one. If you want more mid corner steering here are some good setup changes to try

1) raise the front roll center, by reducing the amount of spacers you have on the inboard upper link by about 1mm...maybe 2mm.
2) Increase caster from 4 degrees to 6 degrees
3) decrease your dynamic front toe (aka ackerman).
4) decrease your static toe in the front to 0.

Quote:
Originally Posted by Dukes2004 View Post
Great thread and love your app.
Thank you
__________________
Martin Crisp
SetupWorkbench.com | Power-Story.com | LearnSetup.com
Martin Crisp is offline   Reply With Quote
Old 03-10-2014, 03:21 PM   #109
Tech Fanatic
 
Martin Crisp's Avatar
 
Join Date: Oct 2003
Location: Toronto Canada
Posts: 822
Default

Quote:
Originally Posted by theproffesor View Post
So here is my set up sheet. Its the new VBC Ghost set up for VTA. The car handle pretty decenlty but very predicable. I am having 2 problems. The first is around sweeping turns, the car want to roll. Its never a violent traction roll. More like a slow lean. I can sometines stop it if I back out of throttle. The other is spees scrubbing. On the tighter turns the car wants to scrub speed in the mid to exit of corner off power. I know this because I van hear the tires sqeaking. The track is a medium grip carpet traxk. You can look them um on facebook. Its bish river racway. Its a great place to race. Any help would be apriciated. Thank you.
I don't have much experience with VTA cars, but from what I see in the cars that seem to be fast they appear to have a very low rear roll center to slide the rear end around. So you might want reduce the rear RC a little to reduce that speed scrub in the middle of the corner you mentioned. I see you have 2mm of spacers on the inboard upper link in the rear. Try 2.5mm and 3mm.

You may find that if you only lower the rear RC and not the front RC, the car might tend to traction roll with the front of the car lifting off the ground before the rear of the car does....so be prepared to also lower the front roll center a little if that happens. Your front RC looks fairly low already, so you should be ok...but watch for this.

your setup image is a little hard to read, so I am not sure what your ackerman setting is, but if you decrease ackerman by adding some spacers (or however you adjust this on the VBC) to move the inner connecting point of the steering links further forward, this can help reduce the mid corner push.

Regarding helping reduce traction rolling, here is a blog post I made about different techniques you can try...
__________________
Martin Crisp
SetupWorkbench.com | Power-Story.com | LearnSetup.com
Martin Crisp is offline   Reply With Quote
Old 03-10-2014, 04:07 PM   #110
Tech Elite
 
theproffesor's Avatar
 
Join Date: Feb 2005
Location: Lugoff SC
Posts: 2,423
Trader Rating: 44 (100%+)
Default

Thanks for the info. I cant move the inner steering links, they are set in one position. But I do have 3 options on the spindle. I have always wondered about ackeman set-up and how it effects the car. So by less ackerman, do you mean less of a difference in the angle between the front tires?
__________________
Tamiya EVO 6 with EXOSIX conversion
Tamiya TA07
tamiya box stock Mini (M05)
SMC - Motiv motors - Savox - Spectrum - Exotek.
The brighter the picture, the darker the negative. USVTA member #112
theproffesor is offline   Reply With Quote
Old 03-11-2014, 12:19 PM   #111
Tech Fanatic
 
Martin Crisp's Avatar
 
Join Date: Oct 2003
Location: Toronto Canada
Posts: 822
Default

Quote:
Originally Posted by theproffesor View Post
Thanks for the info. I cant move the inner steering links, they are set in one position. But I do have 3 options on the spindle. I have always wondered about ackeman set-up and how it effects the car. So by less ackerman, do you mean less of a difference in the angle between the front tires?
Yes...exactly...less ackerman means less of a difference in the angle between the front two tires under full lock. It depends on what the optimal slip angle of the tire is (each tire is different), but in general by having the front tires remain more parallel this reduces the slip angle on the inside tire, which tends to produce more lateral grip.
__________________
Martin Crisp
SetupWorkbench.com | Power-Story.com | LearnSetup.com
Martin Crisp is offline   Reply With Quote
Old 03-11-2014, 03:52 PM   #112
Tech Elite
 
andrewdoherty's Avatar
 
Join Date: Jan 2005
Location: ★Wylie, TX★
Posts: 3,763
Trader Rating: 47 (100%+)
Default

Hi Martin,

I haven't stayed 100% upt to date with your tuning threads so I hope this isn't redundant.
I haven't seen any discussion of traction rolling on-power. We have had a few layouts in the last year at our track with a sweeper that leads onto the straight including our current one. A few times each day I practice (Mod rubber tire sedan)when the car feels strapped and I feel courageous I keep my finger deeper in the throttle rounding the corner before the straight and the car rolls over under power before straightening up for the straight. I'm having a hard time wrapping my mind around how a car traction rolls on power. Can you shed some light on how an on power traction roll develops as opposed to an off power traction roll?

AWD
__________________
"Whether you think you can, or think you can't, you're right." -Henry Ford
"[Driving] Genius is 1% inspiration, and 99% perspiration" -T.A. Edison
|◤Hobbywing◢|◤SpeedzoneUSA.com◢|◤Pro-One◢|
|◤ReflexRacing.net◢|◤Protoform◢|◤AVID R/C◢|
andrewdoherty is offline   Reply With Quote
Old 03-11-2014, 07:53 PM   #113
Tech Fanatic
 
Martin Crisp's Avatar
 
Join Date: Oct 2003
Location: Toronto Canada
Posts: 822
Default

Quote:
Originally Posted by andrewdoherty View Post
Hi Martin,

I haven't stayed 100% upt to date with your tuning threads so I hope this isn't redundant.
I haven't seen any discussion of traction rolling on-power. We have had a few layouts in the last year at our track with a sweeper that leads onto the straight including our current one. A few times each day I practice (Mod rubber tire sedan)when the car feels strapped and I feel courageous I keep my finger deeper in the throttle rounding the corner before the straight and the car rolls over under power before straightening up for the straight. I'm having a hard time wrapping my mind around how a car traction rolls on power. Can you shed some light on how an on power traction roll develops as opposed to an off power traction roll?

AWD
Hi Andrew,

Sometimes what happens is that as you apply power the the front lifts off the ground too much which raises the CG, causing the flip. This can be a function of the rear springs being too soft or too layed down. Try standing up your rear springs.
__________________
Martin Crisp
SetupWorkbench.com | Power-Story.com | LearnSetup.com
Martin Crisp is offline   Reply With Quote
Old 03-11-2014, 08:20 PM   #114
Tech Elite
 
andrewdoherty's Avatar
 
Join Date: Jan 2005
Location: ★Wylie, TX★
Posts: 3,763
Trader Rating: 47 (100%+)
Default

Short and sweet. I love it. Thank you.
__________________
"Whether you think you can, or think you can't, you're right." -Henry Ford
"[Driving] Genius is 1% inspiration, and 99% perspiration" -T.A. Edison
|◤Hobbywing◢|◤SpeedzoneUSA.com◢|◤Pro-One◢|
|◤ReflexRacing.net◢|◤Protoform◢|◤AVID R/C◢|
andrewdoherty is offline   Reply With Quote
Old 03-11-2014, 08:26 PM   #115
Tech Elite
 
Join Date: Dec 2004
Location: Marietta, Ga
Posts: 2,087
Trader Rating: 57 (100%+)
Default

What does raising/lowering inner and outer camber links an equal amount change?
PROMODVETTE is offline   Reply With Quote
Old 03-12-2014, 08:38 AM   #116
Tech Fanatic
 
Martin Crisp's Avatar
 
Join Date: Oct 2003
Location: Toronto Canada
Posts: 822
Default

Quote:
Originally Posted by andrewdoherty View Post
Short and sweet. I love it. Thank you.
You could also try raising the rear roll center a little, but that could make the car traction roll in a slightly different way.....but worth a try.


Quote:
Originally Posted by PROMODVETTE View Post
What does raising/lowering inner and outer camber links an equal amount change?
Raising both the inner and outer camber links an equal amount will raise the instant center (IC) and thus the roll center (RC) will also be raised.

Cheers.
__________________
Martin Crisp
SetupWorkbench.com | Power-Story.com | LearnSetup.com
Martin Crisp is offline   Reply With Quote
Old 03-12-2014, 08:50 AM   #117
Tech Adept
 
Join Date: Jan 2012
Location: SGP
Posts: 218
Trader Rating: 2 (100%+)
Default

Hi Martin,

How do we set the anti roll bar properly so that both side is balance? How much play is needed before the other side move?
faifaisalfal is offline   Reply With Quote
Old 03-12-2014, 11:48 AM   #118
Tech Master
R/C Tech Elite Subscriber
 
Join Date: Oct 2008
Location: Grand Portage, MN
Posts: 1,362
Trader Rating: 39 (100%+)
Default

I just went through my FTTC4 and the length of the arm mounts of the roll bar sets the preload on the bar. I started with pulling the Bar off the car and ckecking to make sure it's still square and looks normal. My Front one was twisted where one side was lower than the other giving me an issue which I could not figure out before.

So with a replacement bar in hand I first removed the tires and Shocks, With the car on my setup board I measured the the height of the mount to the a-arm and set them the same then attached the roll bar

Making sure the roll bar was even in the upper mounts (ie. the same amount sticking out from the retainer)

now lift up on one arm until the other arm starts to move up. I used a ride height gauge and found the left side was moving up 5mm before it affected the right arm

put the left arm down and pick up the right and I had 8mm of movement before the left moved.

so from this I shrunk the length of Right one and increased the length of the Left one about 1/4 turn on the roll bar mount

Check each side again and I was about 6mm on both sides.

Just what i did not saying I'm correct but it works for me. I'll be testing tonight to see how this old girl makes out with 17.5 after having a tonne of traction rolling issues last sunday.
__________________
______________________________________________
Jason Deadman

I race toy cars for fun. If I need to explain, you'll never understand.
jdeadman is offline   Reply With Quote
Old 03-12-2014, 12:22 PM   #119
Tech Regular
 
Join Date: May 2013
Posts: 424
Trader Rating: 22 (100%+)
Default

Martin,

On the Awesomatix EVO, there 2 are upper camber links that adjust caster and camber in unison. There are also options to place a different number of shims under each link to adjust roll centers. I have looked at several set up sheets online for this car and some have a different number of shims in the top camber links FF and FR. I can not get my head around what sort of set up adjustment this is... different shims in the two front upper camber links would add what value. In my head, it doesnt change the angle of the shock or arm, it doesn't add anti dive or pro dive... what affect would it have to have different shims in two spots on the front top deck camber/caster link?
gocoogs is offline   Reply With Quote
Old 03-12-2014, 12:26 PM   #120
Tech Champion
 
hanulec's Avatar
R/C Tech Elite Subscriber
 
Join Date: Sep 2007
Location: @ the post office
Posts: 8,015
Trader Rating: 23 (100%+)
Default

Quote:
Originally Posted by gocoogs View Post
Martin,

On the Awesomatix EVO, there 2 are upper camber links that adjust caster and camber in unison. There are also options to place a different number of shims under each link to adjust roll centers. I have looked at several set up sheets online for this car and some have a different number of shims in the top camber links FF and FR. I can not get my head around what sort of set up adjustment this is... different shims in the two front upper camber links would add what value. In my head, it doesnt change the angle of the shock or arm, it doesn't add anti dive or pro dive... what affect would it have to have different shims in two spots on the front top deck camber/caster link?
hi martin-- just thought i could help here--
this config provides reactive caster. folks have tried it to make the steering even more aggressive. this is the same theory applied from the pan car space..
__________________
FJ / ROAR #2-122945 / Shop@ Awesomatix USA / Wild Turbo Fan / Mon-Tech Racing / RocheRC USA / Side Piece /
LRP / John's BSR Tires / TeamEAM / TQ Wire / R1 / Team Scream / PCR / MIX
RacerLog wiki Awesomatix A700 / 2wd offroad 4 life
hanulec is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 07:20 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net

SEO by vBSEO 3.5.0