R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 12-09-2003, 11:39 AM   #1
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default How to use different Silicone WT on differentials

Need some help on theory behind when, why and how to use different weight silicone grease/oil on the differentials.
For example 100,000 front and 30,000 rear, what effects does it generate on the cars handling. Why not use 50,000 on front with 15,000 at the rear, and so on.
Lets say you are running on rubber tires on a medium to low traction track with a layout that combines some very fast sectors with some very technical slow sectors with 180 bends.
Somebody ...show me the light....... I've lost track on this issue.
AFM
PD: I run a Yokomo GT4-PRO
afm is offline   Reply With Quote
Old 12-10-2003, 02:00 AM   #2
Tech Master
 
Im2lazy's Avatar
 
Join Date: Oct 2002
Location: Hawaii!
Posts: 1,967
Default

Okay, I've done this a couple times before for others, and I tend to get long-winded and confusing... so I apologize in advance....


Well, the best thing of course is to get a differential setup from a seasoned and very consistent (and obviously fast) driver than go from there as track changes and how you feel driving.
Quote:
Lets say you are running on rubber tires on a medium to low traction track with a layout that combines some very fast sectors with some very technical slow sectors with 180 bends.
Well, under this situation, I'd probably go with a relatively thick front diff setting (depends on what diff you're running for the proper viscosity seeing as many things change the tightness of a diff)... but let's say 30,000 in front and a relatively thin rear diff oil around 3,000-7,000. If it is really tight in the 180 bends I'd say go with lighter so that you won't need as much room to rotate (but you'd have to do all the rotating off-power). But if it is more open I'd say go with a thicker rear diff so that when you are entering you can enter wider and keep up more corner speed, then get on the throttle very early (and the thicker rear setting will subsequently cause the rear to rotate) as you exit wide again.



In general, if you need more high-speed turn-in, go with a lighter front diff oil... but not so thin that you lose on-power corner-exit stability. Then with the rear, if you need more low-speed turn-in go with a thinner oil... if you need more low-speed corner-exit rotation (less corner-exit push) use a thicker rear diff oil.


Just experiment and notice closely to what you're car is doing, because it is much easier to see what you need to do, than explain it because the situations are limitless.

And doesn't the Yokomo use grease in the diffs? Or do you have the new one (that I think) can use diff oil?
Im2lazy is offline   Reply With Quote
Old 12-10-2003, 08:08 AM   #3
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Thanks im2lazy:

Yes, Yokomo sells only two types of grease; hard and medium, so i found very little tuning options there. What i do is seal the housing with some silicone in order to use oils, had no problem with leaking. Yokomo's diffs are straight gear type, like Serpent's.
I was using 100,000 front and 30,000 rear, and what happens is that the car has good initial turn-in on both slow and fast corners, but once you go on throtle the car goes wide open, also on a fast sweeper you have steering all locked up and the car still pushes wide open, allways have to cut throtle to correct steering.
I've tried different tire combinations, suspension settings and still can't correct handling so i thought it had to be diffs. setting.
I'll try going with 50,000 front and 10,000 rear, see what effect it causes.
AFM
afm is offline   Reply With Quote
Old 12-11-2003, 02:34 AM   #4
Tech Master
 
Im2lazy's Avatar
 
Join Date: Oct 2002
Location: Hawaii!
Posts: 1,967
Default

I personally know what a Serpent gear diff feels like... and around here you need to go with around 50,000 up front. But I don't know how it is at your track. I'd say feel the diff setups for the other racers, and try to get your diff setup to be similarly stiff. That is certainly the safest way to go about deciding how you want to change things. Overall, changing both front and rear diff oil settings sounds like the best idea.


But if you didn't want to go that far from your present setup, I'd say that going with a stiffer rear diff oil (50,000) would be a good option to try (in order to get the corner-exit performance you're looking for). This way, the rear will want to rotate more coming hard out of the corner. It could cause some oversteer, and if you need to get rid of it, just go with an in-between mix of 30,000 and 50,000 wt. oil.


But first, I'd just try and limit the front droop some more... this way you don't have to mess with your diff setup, as it is obviously more messy, much more drastic and takes more time.

Also, when you are in a fast sweeper and have to turn a lot in the middle of it, that usually means that the chassis balance isn't quite right (because in the middle of the turn, you aren't really accelerating or decellerating... just trying to keep the grip consistent until you can punch it on out of there) so I'd say that you may want to try some suspension fix for that part of the track. Have you gone with a softer front spring, or shock position to see if that helps the mid-corner balance?

But if your car right now just feels like it is almost drifting or floating away from the inside line on the sweeper, I'd say for sure change the diff oil. It would fix just about all your problems (or so it seems from here).
Im2lazy is offline   Reply With Quote
Old 02-19-2004, 09:19 AM   #5
Tech Adept
 
IDrinkNitro's Avatar
 
Join Date: Feb 2004
Location: MA
Posts: 161
Default How much oil in the diff?

How much oil should be added to the diffs? I have no clue
IDrinkNitro is offline   Reply With Quote
Old 02-19-2004, 10:01 AM   #6
Tech Elite
 
Tabushi's Avatar
 
Join Date: Feb 2003
Location: Chile - Southamerica
Posts: 3,029
Trader Rating: 1 (100%+)
Send a message via AIM to Tabushi Send a message via Yahoo to Tabushi
Default

AFM,


As you know here in Brazil we run on rubbers (well, the regionals this year will be 100% roar based so we will have the freedom to go on rubbers and/or foams).

Now ... i usually run just 3 diferent setups on my diffs on rubbers ... thats :

1.- Front 100.000 and rear 50.000 mugen diff oil (the yokomo diff does not leak at all). That apply very godd for a track with some high-speed orientation like this :




2.- On the other hand, i run front solid OR 100.000 mugen diff oil and rear 30.000 mugen diff oil when the track have some high and low speed sections with 180 turns ... like this one :



3.- Now for a VERY HIGH SPEED track i just use front and rear solids ... but this setup eats a lot of belts/side pulleys.


Hope this help ...
__________________
Patricio "PATO" Concha

E-Mail : [email protected]
Facebook : http://www.facebook.com/patoconcha
Whatsapp : +56 9 66165085
Tabushi is offline   Reply With Quote
Old 02-19-2004, 10:10 AM   #7
Tech Elite
 
popsracer's Avatar
 
Join Date: Oct 2002
Location: "Hot, Sunny Southern California"
Posts: 3,120
Default How to use different Silicone WT on differentials

Guys;

In General, the heavier the oil in the diff, the LESS grip you will have at that end of the Car. (Front: push, Rear: looser)

Short, tight tracks will usually require lighter weight oils than flowing high speed tracks. Also the greater the traction (on any track), heavier oils can be used to an advantage.
popsracer is offline   Reply With Quote
Old 02-19-2004, 10:43 PM   #8
jas
Tech Apprentice
 
jas's Avatar
 
Join Date: Oct 2001
Location: Hong Kong
Posts: 90
Default

The manual on the Kyosho V-One S recommends 30k for the front diff. and 5k for the rear diff.
The guy at the hobby shop said if running foam tires, he suggested 10k for the front instead of 30k. If what he said make sense, what's the logic behind it?
jas is offline   Reply With Quote
Old 02-20-2004, 11:52 AM   #9
Tech Elite
 
popsracer's Avatar
 
Join Date: Oct 2002
Location: "Hot, Sunny Southern California"
Posts: 3,120
Default How to use different Silicone WT on differentials

jas;

Putting thinner oil in the Front Diff will give more grip and less push, both on and off power. Depending on the availible traction at your track, could make the car loose in the Rear.

Start with the kit recommened oils. These have been determined to be the best starting point by the factory and many fellow racers.
popsracer is offline   Reply With Quote
Old 02-22-2004, 07:53 PM   #10
jas
Tech Apprentice
 
jas's Avatar
 
Join Date: Oct 2001
Location: Hong Kong
Posts: 90
Default

popsracer: Thank you for the reply!
jas is offline   Reply With Quote
Old 02-22-2004, 10:31 PM   #11
Tag
Tech Master
 
Tag's Avatar
 
Join Date: Sep 2001
Location: Arcadia CA
Posts: 1,589
Trader Rating: 31 (100%+)
Default

hi guys, well i am in the process of building another MTX-3 for parking lot race. i will still be running the front one way diff, as for the rear diff, what weight of oil should i start with ? again, the car is build for smaller parking lot. thanks !
__________________
* Serpent 966 TE Novarossi 35+21, Airtronics M12 *
Tag is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can someone breakdown Differentials for me ?? IL_AudiRacer Rookie Zone 6 03-02-2008 03:47 PM
(2) Revo Differentials Crazy Phantom R/C Items: For Sale/Trade 0 12-10-2007 08:27 PM
what are the differentials ferrariboy69 Rookie Zone 3 06-26-2004 10:18 PM
HPI Ball Differentials for PRO 2 skiptomylou6 R/C Items: Wanted to Buy 1 09-11-2003 05:01 PM
Tamiya Ball Differentials taybelZ Electric On-Road 9 11-12-2002 09:28 PM



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 05:01 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net