R/C Tech Forums

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

Like Tree1Likes
Reply
 
Thread Tools Search this Thread
Old 12-25-2013, 03:57 AM   #796
Tech Elite
 
Join Date: Nov 2009
Location: Woodinville, WA
Posts: 2,512
Trader Rating: 8 (100%+)
Default

Ivan, with your 17.5 car, is the steering from the back end stepping out, or the front end digging and turning too much? If it's the back stepping out, I'd first check that the gear diff isn't too tight. Maybe compare it to your mod car and see if it's thicker. Rear diff oil is a great way to tune how much the rear steps out on power. If it's the front digging in too hard, I find that's usually either too much steering lock (turn down dual rate) or the rear of the car being too soft.

For the mod car, I'd again start with the rear diff. My xray had horrible on-power understeer until I went up to 3000 (from 1000 and 2000) in the rear diff. You could try less front droop, but I doubt that would work well with the front gear diff, and might make the car harder to drive.

-Mike
grippgoat is offline   Reply With Quote
Old 12-25-2013, 07:03 AM   #797
Tech Elite
 
jeff jenkins's Avatar
 
Join Date: Oct 2006
Location: Snohomish, WA
Posts: 3,982
Trader Rating: 76 (100%+)
Default

Quote:
Originally Posted by BoneCrusher View Post
Hi Skypilot,

Thank you for you input and suggestions. My setup is 01.02.2013 Jim Chapman carpet setup: http://www.petitrc.com/reglages/arc/...etsARCR10.html

I am using a different car for each class. Also I'm using a speed 6 body.

I thought about the CA trick but for some reason I have a bias against doing that even though I tune that way for my Tamiya Mini and even my 12th scale and both chassis are
very competitive. But ultimately, I feel by doing that, it does take some steering away and hence corner speed and where I find I'm losing some time in those classes. I'm weak in terms of tuning which I want to work on and improve so I think in the future that would be my last resort. But again, know that I appreciate your advice.

Heavier oil is an option I've heard, but not tried yet. I've read a couple of threads on the subject of traction roll where some suggest a harder front setup to keep the car flatter versus a softer front setup to allow the car to roll and absorb the forces. Still confused. Anyone want a go on this topic?

For background, I use SXT 3.0 full sauce rear tires letting soak all the time and the run before I full sauce the front probably 5-6 minutes before I race?), then clean off the tires on run off carpet before I put on track.

For tires, our track allows open tires but I'm using Jaco Blues that were spec tires for our regional series but this year our serious is gonna stick with Sweeps 32's but I haven't tried them yet and most report they are a tad gripper than the Jacos and mostly everyone is using them (some test other tires) but I still have a few more Jaco sets left behind from the old series to burn off. I don't think I'm currently at a disadvantage because I'm using the Jaco's (10-100 runs old until they blow or rip) but no one else is.

Any help or insight is always much appreciated,

Ivan
first off if you are not running asphalt I would not use full sauce on the front tires. I would go 1/2 front . I usually sauce the rears for 20min and the fronts for 10min. I have a feeling that just this will help you out a lot. I have also heard stiffen the car but this can cause your sidewall of the tires to be over worked and there is potential to still traction roll. I feel a car that has more roll is actually better in conditions where you have ability to traction roll as it delays the time before your sidewall can fold over and catch causing a traction roll. I think of it as a dampener for my tires lol sounds stupid but sometimes it works.

also widening the track width can really help in these situations. I used to do the super glue trick when I ran schuie cars but that is because it was all I could do to stop it.
__________________
Maclan Racing Products-RC US Imports - Sworkz USA - Bellgate Distributions
jeff jenkins is online now   Reply With Quote
Old 12-25-2013, 01:07 PM   #798
Tech Regular
 
Join Date: Jul 2007
Location: The Netherlands
Posts: 264
Default

Hi guys,

A question about the ARC. Maybe this has been asked before, don't know. Right now I'm looking for a new touring car and the ARC is a serious candidate. There's only one problem for me: this car comes with the low profile shocks. My problem: I've got loads of 'normal profile' springs and not really planning to change to low profile. Is there any chance I can use normal lenght springs/shocks (for instance, maybe a different shock tower or something)?

Thanks in advance.
__________________
www.rcpit.nl , RC dealer

www.machheemstede.nl
..................................Youtube: https://www.youtube.com/watch?v=_-Gkh2xZcQU
Modified 4 life
Govert is offline   Reply With Quote
Old 12-25-2013, 04:29 PM   #799
Tech Elite
 
Josh-n-ya's Avatar
 
Join Date: May 2011
Location: Alameda, CA
Posts: 2,147
Trader Rating: 73 (100%+)
Default

Quote:
Originally Posted by Govert View Post
Hi guys,

A question about the ARC. Maybe this has been asked before, don't know. Right now I'm looking for a new touring car and the ARC is a serious candidate. There's only one problem for me: this car comes with the low profile shocks. My problem: I've got loads of 'normal profile' springs and not really planning to change to low profile. Is there any chance I can use normal lenght springs/shocks (for instance, maybe a different shock tower or something)?

Thanks in advance.
You can purchase the original R10 at; http://www.shopviperrc.com/searchresults.asp?cat=1851

That car has regular shock towers. I am a big fan of the new lower shocks. The springs that come with the R10 2013 work well. Or you can purchase a variety pack for around $20. Green/green is a great combo front/rear! Shorter shocks made my car planted and gave me major traction.
Josh-n-ya is online now   Reply With Quote
Old 12-25-2013, 04:47 PM   #800
Tech Regular
 
Join Date: Jul 2007
Location: The Netherlands
Posts: 264
Default

Quote:
Originally Posted by Josh-n-ya View Post
You can purchase the original R10 at; http://www.shopviperrc.com/searchresults.asp?cat=1851

That car has regular shock towers. I am a big fan of the new lower shocks. The springs that come with the R10 2013 work well. Or you can purchase a variety pack for around $20. Green/green is a great combo front/rear! Shorter shocks made my car planted and gave me major traction.
Thanks josh, but I'm not a fan of buying (almost) discontinued or previous models (no offence, just saying ). Since I'm starting after a 2 year break, I would like the 'freshest' model out there. So, that would be the R10 2013 (or maybe in a few months the 2014).
But there is no solution or way to make it work with regular shocks?

And if not, a variety pack of $20 would be an option, but I prefer not at this stage.
__________________
www.rcpit.nl , RC dealer

www.machheemstede.nl
..................................Youtube: https://www.youtube.com/watch?v=_-Gkh2xZcQU
Modified 4 life
Govert is offline   Reply With Quote
Old 12-25-2013, 05:13 PM   #801
Tech Elite
 
BoneCrusher's Avatar
 
Join Date: Mar 2007
Location: Calgary, Alberta
Posts: 2,170
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by Steve S View Post
For traction roll I'd suggest:
1. Softer front spring, or lay down shocks
2. Heavier front shock oil
3. Lightweight body
4. Add wheel shims, make the car wider
5. Lower front ride height

The 1M diff fluid will help reduce the on-power steering. You could also try lighter oil in the rear diff.
Thanks Steve! Your help and insights are always much appreciated. Just to understand:

1. Soft front spring is to allow the car to roll a bit more to absorb the forces a little more I think. But confused about the laying down the front shocks as wouldn't that increase front side bite, hence more grip and would catch the outer edge of the front tire with more force and cause traction roll?

2. Is heavier oil to increase the damping forces to slow down the transfer of force to the outside front wheel?

3. Lightweight body - I get that and it's like a 20 gram weight savings too. For people who don't hit a lot of things that would be a great option, for people who do, body is cracked after a few runs and when you tape for repairs, not much weight savings after that.

4. Add wheel shims, make the car wider - equals decrease front grip.

5. Lower front ride height - doesn't this actually increase front grip?

6. The 1M diff fluid will help reduce the on-power steering. Yes, that's my next step as the spool kinda wants to snap the car around on corner exit. It can be an advantage I guess if I could have more fine steering control. And the lighter oil in the rear diff I'm assuming is for a tad more rear grip hence less front grip mid and corner exit.

Quote:
Originally Posted by Besercoe View Post
Ivan. How much ackerman spacing are you running? If kit 3mm try dropping to 1mm that will make the car far smoother to drive. Also the 8.5mm steering bridge really made the car super smooth.
Hi Besercoe,

2mm I believe. 1mm is worth a try to reduce mid corner steering. I think I increased it to 3mm in the mod car to help with the opposite problem. Don't know why I didn't try this yet in the stock car.

As for the 8.5mm steering bridge, is there a Macguver option or suck it up and spent $10. And what does this option actually do?

Thanks!

Quote:
Originally Posted by grippgoat View Post
Ivan, with your 17.5 car, is the steering from the back end stepping out, or the front end digging and turning too much? If it's the back stepping out, I'd first check that the gear diff isn't too tight. Maybe compare it to your mod car and see if it's thicker. Rear diff oil is a great way to tune how much the rear steps out on power. If it's the front digging in too hard, I find that's usually either too much steering lock (turn down dual rate) or the rear of the car being too soft.

For the mod car, I'd again start with the rear diff. My xray had horrible on-power understeer until I went up to 3000 (from 1000 and 2000) in the rear diff. You could try less front droop, but I doubt that would work well with the front gear diff, and might make the car harder to drive.

-Mike
Hi Mike,

I actually can't tell. The first place it traction rolls is on the first 90 degree turn after the straight. If I push it (let go off the throttle too late) it seems like the front is bitting too much and I traction roll.

The second place is around the "lollipop" right at the apex. I don't have problems even on high speed chicanes but at the apex of the lollipop, I'll either traction roll with on power (too much) steering or my rear end steps out and I slam 90 degrees a foot or so after the apex / out of the turn. Sucks either way. Babying the throttle I can get out clean but of course slows me down a bit. Hope that makes sense.

I believe my stock rear diff is 2000k and mod is 1000k.

Steve first post suggested going to a heavier oil too. 3000k is my next tune.

Just want to clarify your thinking your rear of your car is too soft. To me that means that softer = more grip.

And why would decreasing front droop make the car harder to drive in a car with a front gear diff? Just want to know your rationale knowing as my base knowledge less front droop means less rear weight transfer so doesn't that also mean more oversteer on power after the apex?

Quote:
Originally Posted by jeff jenkins View Post
first off if you are not running asphalt I would not use full sauce on the front tires. I would go 1/2 front . I usually sauce the rears for 20min and the fronts for 10min. I have a feeling that just this will help you out a lot. I have also heard stiffen the car but this can cause your sidewall of the tires to be over worked and there is potential to still traction roll. I feel a car that has more roll is actually better in conditions where you have ability to traction roll as it delays the time before your sidewall can fold over and catch causing a traction roll. I think of it as a dampener for my tires lol sounds stupid but sometimes it works.

also widening the track width can really help in these situations. I used to do the super glue trick when I ran schuie cars but that is because it was all I could do to stop it.
Hi Jeff,

Thanks for your input. Unfortunately, the saucing routine I can't change due to time bluntly, I'll lose track of time and it's easier to sauce the start of the run before my race. It's consistent and I almost never forget this way. Also, saucing full fronts makes my runs more consistent as I know what I'm dealing with and I don't have the skill to adapt to understeer as I do oversteer......which really is driving less aggressively as oppose to losing time where I don't have corner speed. Your advice I appreciate.

In regards to stiffening your car, doesn't that actually "flatten" your car more therefore reduce roll, which would increase traction rolling based on your example?

And widening the front end is in my plans too as an option.

Thank everyone for your input!

Ivan
__________________
ARC R10, 12R5.1, Tamiya Mini, MTS FFv2 Pro, Exotek F1
carcar.ca
BoneCrusher is offline   Reply With Quote
Old 12-25-2013, 07:17 PM   #802
Tech Elite
 
Join Date: Dec 2011
Location: Raleigh, North Carolina
Posts: 2,183
Trader Rating: 44 (100%+)
Thumbs up

Quote:
Originally Posted by BoneCrusher View Post
Thanks Steve! Your help and insights are always much appreciated. Just to understand:

1. Soft front spring is to allow the car to roll a bit more to absorb the forces a little more I think. But confused about the laying down the front shocks as wouldn't that increase front side bite, hence more grip and would catch the outer edge of the front tire with more force and cause traction roll?

2. Is heavier oil to increase the damping forces to slow down the transfer of force to the outside front wheel?

3. Lightweight body - I get that and it's like a 20 gram weight savings too. For people who don't hit a lot of things that would be a great option, for people who do, body is cracked after a few runs and when you tape for repairs, not much weight savings after that.

4. Add wheel shims, make the car wider - equals decrease front grip.

5. Lower front ride height - doesn't this actually increase front grip?

6. The 1M diff fluid will help reduce the on-power steering. Yes, that's my next step as the spool kinda wants to snap the car around on corner exit. It can be an advantage I guess if I could have more fine steering control. And the lighter oil in the rear diff I'm assuming is for a tad more rear grip hence less front grip mid and corner exit.



Hi Besercoe,

2mm I believe. 1mm is worth a try to reduce mid corner steering. I think I increased it to 3mm in the mod car to help with the opposite problem. Don't know why I didn't try this yet in the stock car.

As for the 8.5mm steering bridge, is there a Macguver option or suck it up and spent $10. And what does this option actually do?

Thanks!



Hi Mike,

I actually can't tell. The first place it traction rolls is on the first 90 degree turn after the straight. If I push it (let go off the throttle too late) it seems like the front is bitting too much and I traction roll.

The second place is around the "lollipop" right at the apex. I don't have problems even on high speed chicanes but at the apex of the lollipop, I'll either traction roll with on power (too much) steering or my rear end steps out and I slam 90 degrees a foot or so after the apex / out of the turn. Sucks either way. Babying the throttle I can get out clean but of course slows me down a bit. Hope that makes sense.

I believe my stock rear diff is 2000k and mod is 1000k.

Steve first post suggested going to a heavier oil too. 3000k is my next tune.

Just want to clarify your thinking your rear of your car is too soft. To me that means that softer = more grip.

And why would decreasing front droop make the car harder to drive in a car with a front gear diff? Just want to know your rationale knowing as my base knowledge less front droop means less rear weight transfer so doesn't that also mean more oversteer on power after the apex?



Hi Jeff,

Thanks for your input. Unfortunately, the saucing routine I can't change due to time bluntly, I'll lose track of time and it's easier to sauce the start of the run before my race. It's consistent and I almost never forget this way. Also, saucing full fronts makes my runs more consistent as I know what I'm dealing with and I don't have the skill to adapt to understeer as I do oversteer......which really is driving less aggressively as oppose to losing time where I don't have corner speed. Your advice I appreciate.

In regards to stiffening your car, doesn't that actually "flatten" your car more therefore reduce roll, which would increase traction rolling based on your example?

And widening the front end is in my plans too as an option.

Thank everyone for your input!

Ivan
Ivan,
Not to push the subject too much but eliminate the simplest factor first.
Sauce just the inner half of the front tires.
You'll have less steering but I doubt you will have understeer. You should be fairly neutral, I know you said you didn't want to change your sauce routine but I'm willing to guess you have way too much front grip and without the primary or largest effect on steering accounted for (tires) you'll probably continue to chase setups.

I was having the same issue then changed to just half inner tire up front and it was dialed. This was on Sorex 28Rs. Gonna mess around with some other (less expensive) tires this weekend to see how she handles.

If you really must sauce them full then dial the dual rate wayyy down to where it's not enough steering and then slowly increment back up until you have just enough steering for the track you are at to drive your expected lap times.

I use the same sauce but I rotate my tires every round first front to back and then diagonally, I clean them off with simple green, wipe them dry, and then sauce them.

And oh yea you DO have the skillsets! You just gotta convince yourself of it!!! .
__________________
Aaron Moore

Desoto Racing, McFactory Motorsports, Team Trinity, Pro-Line/Protoform, Hobbywing North America/FalconSEKIDO, HRP Distributing, PTRC Racing, Ho B Max
Antimullet is offline   Reply With Quote
Old 12-25-2013, 07:37 PM   #803
Tech Elite
 
Josh-n-ya's Avatar
 
Join Date: May 2011
Location: Alameda, CA
Posts: 2,147
Trader Rating: 73 (100%+)
Default

Quote:
Originally Posted by Govert View Post
Thanks josh, but I'm not a fan of buying (almost) discontinued or previous models (no offence, just saying ). Since I'm starting after a 2 year break, I would like the 'freshest' model out there. So, that would be the R10 2013 (or maybe in a few months the 2014).
But there is no solution or way to make it work with regular shocks?

And if not, a variety pack of $20 would be an option, but I prefer not at this stage.
Yes newest model is the 2013 and as far as we have been informed there is no new model in the works. Current kit does very well. As far as your other question goes. You can use the taller shock towers # R108003 for the front and #R108004 for the rear. The bulkheads are the same and everything will bolt up just fine. Then you can use both shocks if 2013 kit is purchased anyway.
Josh-n-ya is online now   Reply With Quote
Old 12-25-2013, 09:22 PM   #804
Tech Fanatic
 
Join Date: Nov 2010
Posts: 972
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by BoneCrusher View Post
1. Soft front spring is to allow the car to roll a bit more to absorb the forces a little more I think. But confused about the laying down the front shocks as wouldn't that increase front side bite, hence more grip and would catch the outer edge of the front tire with more force and cause traction roll?
The idea is to get the front end low and soft so that the car leans until the front of the chassis drags on the ground. That limits the traction before it grips enough to roll.

Quote:
2. Is heavier oil to increase the damping forces to slow down the transfer of force to the outside front wheel?
If you make a sudden steering input, the suspension reacts to the weight transfer and allows the car to lean. The damping reduces the speed that the suspension reacts. If the front suspension reacts quicker than the rear, then there's a brief moment during transition where the front grips more and you can get a bit of oversteer and get the car sideways. Then when the rear suspension catches up, the rear starts generating grip again and the car flips. You can avoid this by slowing down the front damping so it doesn't react quicker than the rear. Your car may not have this condition, but it can't hurt to try.

Quote:
3. Lightweight body - I get that and it's like a 20 gram weight savings too. For people who don't hit a lot of things that would be a great option, for people who do, body is cracked after a few runs and when you tape for repairs, not much weight savings after that.
It's quite a bit of savings, and it's at the highest point on the car so it has a big effect on the center of gravity. I don't really find it to be that much less durable. Suck it up, Buttercup

Quote:
4. Add wheel shims, make the car wider - equals decrease front grip.
Making the car wider just makes it harder to tip over, not so much for handling reasons.

Quote:
5. Lower front ride height - doesn't this actually increase front grip?
See #1

Quote:
I believe my stock rear diff is 2000k and mod is 1000k.

Steve first post suggested going to a heavier oil too. 3000k is my next tune.
If you want less on-power steering, you need lighter diff fluid. I thought at Calgary WCICS we put in 500 and it got a lot better.
__________________
Team Serpent
Steve S is offline   Reply With Quote
Old 12-26-2013, 03:10 AM   #805
Tech Regular
 
Join Date: Jul 2007
Location: The Netherlands
Posts: 264
Default

Quote:
Originally Posted by Josh-n-ya View Post
Yes newest model is the 2013 and as far as we have been informed there is no new model in the works. Current kit does very well. As far as your other question goes. You can use the taller shock towers # R108003 for the front and #R108004 for the rear. The bulkheads are the same and everything will bolt up just fine. Then you can use both shocks if 2013 kit is purchased anyway.
Awesome. Thank you for confirming. That's some good news. The thing is, I've got heaps of HPI springs, so I would like to use them.
__________________
www.rcpit.nl , RC dealer

www.machheemstede.nl
..................................Youtube: https://www.youtube.com/watch?v=_-Gkh2xZcQU
Modified 4 life
Govert is offline   Reply With Quote
Old 12-26-2013, 02:17 PM   #806
Tech Elite
 
Join Date: Nov 2009
Location: Woodinville, WA
Posts: 2,512
Trader Rating: 8 (100%+)
Default

Quote:
Originally Posted by BoneCrusher View Post
I believe my stock rear diff is 2000k and mod is 1000k.

Steve first post suggested going to a heavier oil too. 3000k is my next tune.
Going to 2000 or even 3000 in the rear on the mod car will definitely help your on-power steering. Going thicker on your stock car may not help anything. In fact, you might want to go thinner. The thinner diff will let the back of the car rotate around better on corner entry and mid-corner, which might actually alleviate your traction roll issues. I'd suggest swapping the rear diff between your two cars as a quick test to see how you like it, before you go to the trouble of changing out oil on either of them.

Quote:
Just want to clarify your thinking your rear of your car is too soft. To me that means that softer = more grip.
Generally speaking, softer will be more grip. However, you can definitely go too far, especially on carpet. What often happens on carpet is that your car is actually understeering, and so you just use more steering throw and let the high grip level of the carpet force the car to turn. You won't necessarily realize that it's understeering. The car still turns, but it will result in traction roll on sharp corners, like low-speed hairpins, or high-speed kinks. And on less sharp but sweeping corners, it makes the car difficult to drive, because the car gets bound up. Then you're more likely to still have the wheels turned a lot and have a lot of slip angle when you get back onto the power, and that will usually either cause sudden massive understeer or oversteer, either the rear stepping out, or the front cutting hard into a pipe. It'll seem like the car is fast, because it has a ton of grip and you'll nail corners sometimes, but your lap times will be very inconsistent, and you'll hit a lot of pipes and have a lot of traction rolls.

What I would suggest is that you start by turning down your dual-rate until you literally can't turn the steering enough to make the car traction roll. That will force you to slow down to make the corners. Then work on your braking, how you turn the steering, and the setup to get the car through the corners with good speed. If you don't blow the corner in the first place, you don't need as much steering angle to get the car through the corner.

Quote:
And why would decreasing front droop make the car harder to drive in a car with a front gear diff? Just want to know your rationale knowing as my base knowledge less front droop means less rear weight transfer so doesn't that also mean more oversteer on power after the apex?
I was speaking specifically with modified in mind. On my T4'14, when I had a front gear diff with 2.5 million in modified and wanted more on-power steering, I tried less front droop, and it was horrible. I did get a bit more on-power steering, but I could feel the front end-diffing out, and it made the car unpredictable, and the net result was that I couldn't really put any more power down.

-Mike
grippgoat is offline   Reply With Quote
Old 12-26-2013, 08:16 PM   #807
Tech Initiate
 
Joe_Cathey's Avatar
 
Join Date: Nov 2013
Location: Kennewick,WA, USA
Posts: 48
Default

Back to the track tomorrow for practice. Ready to learn more!
Joe_Cathey is offline   Reply With Quote
Old 12-27-2013, 07:27 PM   #808
Tech Champion
 
skypilot's Avatar
 
Join Date: Mar 2007
Posts: 9,520
Trader Rating: 14 (100%+)
Default

Quote:
Originally Posted by Joe_Cathey View Post
Back to the track tomorrow for practice. Ready to learn more!
wheres your track.
__________________
#49, #25a, #91, #7, #12 the ones to watch.... UPDATE. #12 is your new AMA GNC #1

A Northwest Team of Positive actions
skypilot is offline   Reply With Quote
Old 12-27-2013, 10:45 PM   #809
Tech Initiate
 
Joe_Cathey's Avatar
 
Join Date: Nov 2013
Location: Kennewick,WA, USA
Posts: 48
Default

It is at the Kennewick Fairgrounds.

The car was stable and safe to drive. After some small changes( some of which didn't work) I put the 2.5 rear toe block on and the car has the rotation I have been needing.
Joe_Cathey is offline   Reply With Quote
Old 12-28-2013, 06:33 AM   #810
Tech Elite
 
Josh-n-ya's Avatar
 
Join Date: May 2011
Location: Alameda, CA
Posts: 2,147
Trader Rating: 73 (100%+)
Default

Quote:
Originally Posted by Joe_Cathey View Post
It is at the Kennewick Fairgrounds.

The car was stable and safe to drive. After some small changes( some of which didn't work) I put the 2.5 rear toe block on and the car has the rotation I have been needing.
17.5 or mod?
Josh-n-ya is online now   Reply With Quote
Reply


Tags
arc r10, rc-world, team titan


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 12:36 PM.


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