Dominating Differential Difference

[swervin]

I'm not sure what to do on this one......... Ok hear's the situation got the "Ofna Dominator " ten years ago . Did some bashing some drag racing & even took her to the track a couple of time..... My power plant was the "Hyper 21(8port)".......The more comfortable i got with this motor the more aggressive my driving style became.....I started blowing differential gears ,after the second set of blown diff gears i started experimenting with silicone differential oils & actual real car ball bearing grease....... To make a long story short in my honest opinion it seems like my truck was faster when i had grease in the diffs than when i had diff oil in them......This is actually how the label reads (GS Racing Pure Silicone Diff.Oil 7000 cps. 2oz)he,he,he...... I didn't have the grease anymore, nor can i remember the brand....... The last thing i did was put both of them in the diffs ,ran it twice like that & the truck sat for 10 years........ Now up to day....... Project Dominator 2014: LRP. 28 now sits where the Hyper 8 port use to.........Since the rebuild i have had 2 test runs One on all asphalt & a11/2 tank street, grass gravel bash session...... The truck seems sluggish to me........(For the record i just got this: Factory Team Silicone Diff Fluid 1000cSt #5450)......I don't want the truck sluggish yet i want to protect the gears. ......... Help me out fellas. ............Help me understand. ......

 

[Greywolf74]

What size clutchbell are you using? With a .28 Id hop up to a 17T or higher pinion. Not only will it give you more top in it will reduce the low end torque which may be whats causing your diff issues.

 

[Snook Man]

Shouldn’t be sluggish with a well tuned .28 in it.
Are you running the center slipper or center diff ?
If the center slipper, check it: it may be too loose.
Diff oil wt only applies to power distribution from left to right per F/R diff and front to rear with a center diff; shouldn’t be a factor in sluggishness at all.

 

[swervin]

I just went up to a 14t clutch bell.....Greywolf74

W

Shouldn’t be sluggish with a well tuned .28 in it.
Are you running the center slipper or center diff ?
If the center slipper, check it: it may be too loose.
Diff oil wt only applies to power distribution from left to right per F/R diff and front to rear with a center diff; shouldn’t be a factor in sluggishness at all.

Shouldn’t be sluggish with a well tuned .28 in it.
Are you running the center slipper or center diff ?
If the center slipper, check it: it may be too loose.
Diff oil wt only applies to power distribution from left to right per F/R diff and front to rear with a center diff; shouldn’t be a factor in sluggishness at all.

I'm running a slipper....What i mean by sluggish is it doesn't seem to be free rolling with no motor.....Please explain diff oil & power distribution.....

 

[Greywolf74]

14T is a start but with a .28 in it I wouldnt run less than a 17T, especially if your torquing diffs outta wack.

Using thick diff oil is like having positraction...it keeps more power going to both wheels when one has more of a load on it than the other one. Using thinner diff oil is teh opposite...like when you get stuck in teh mud and only the tire with no traction is spinning.

 

[swervin]

14T is a start but with a .28 in it I wouldnt run less than a 17T, especially if your torquing diffs outta wack.

Using thick diff oil is like having positraction...it keeps more power going to both wheels when one has more of a load on it than the other one. Using thinner diff oil is teh opposite...like when you get stuck in teh mud and only the tire with no traction is spinning

 

[Greywolf74]

Heres a blurb i found on a buggy website that does a good job of explaining how you can use thicker or thinner diff oils to tune your kit. They explain the actual benefits in real world examples.

4.2 Set Up


A good starting point that will work for all cars is, front-centre-rear, 5000-7000-3000. This is a popular basic set up and if your car is terrible, and you have this diff set up, you can be sure that it’s not the diffs. It will be decent everywhere. However, on THE Car, I tend to like to run a thicker diff in the front, to smooth out the aggressive steering, and a thinner in the middle, to smooth out the acceleration and punch, so 7000-5000-3000.


Diffs can make you fast or slow. Everyone has their own driving style, and it is good to try different diff combinations for oneself, to see what feels best, and what is the fastest combination. Normally thinner oils will make the car easier to drive. On slippery, bumpy tracks thinner oils are better. On smooth high traction tracks thicker diffs will be better. Thicker diffs give more acceleration, more cornerspeed, and help to make the car more stable on a high traction surface. On special tracks, that are really smooth and high traction, asphalt like, the car will be a lot more stable and fast in the corners if all diff oils are made thicker. Front and centre by about 10000 compared to the normal set up, and rear maybe 5000. Because the track is so smooth you can get away with it.


The front diff mainly affects steering on and off power, and acceleration, the centre diff affects the way the car handles bumps, and acceleration, and the rear diff affects rear traction and steering. Next I will try to explain what each diff does when tuned separately.





4.3 Front Differential


Using thicker oil will make the car turn more on power, out of the corner, and accelerate faster. The car will turn less into the corner, as off power steering is reduced. It will feel more stable, and can be easier to drive in bumps. If the car is twitchy and feels inconsistent on a rough track, a good idea is to try a thicker front diff. A thinner front oil will have the opposite effect, less on power steering, more off power steering, less stability. Usually the oils used in the front diff range from 3000-15000. 5000-7000 is a safe bet on all tracks, and that’s what I use most of the time when I’m using a standard front diff. With THE Car it is also possible to use thicker oils as it has so much offpower steering, so 10-15k will work on most tracks.





4.4 Centre Differential


Using thicker oil in the centre diff makes the car accelerate a lot faster, but it can be harder to drive in bumps and on slippery tracks. It gets a bit confusing though, because if the track is soft, and it gets really bumpy, a thicker centre diff can actually make the car skip over the tops of the bumps, and thus it will actually be better and faster. But most of the time, thinner centre diffs are used for blown out tracks. A thick centre diff oil will also make it easier to get on power steering, as the rear of the car can be made to slide out when on power. The centre diff usually has the thickest oil of the three diffs, or the same as the front. The oils used normally range from 3000-20000. A safe bet is 5000-7000. I normally never go below this, because I feel that I loose too much acceleration, specially the first ”snap” when I get on the gas. And I don’t either use thicker oils than 10000 because I’m so aggressive on the throttle, I would fly off the track. Normally, if a thicker centre diff oil is used, the front diff also needs to have thicker oil, so the car still remains stable under acceleration.





4.5 Rear Differential


The rear diff set up is the one that varies the most between different drivers. This is because the rear diff has a big effect on rear traction, and each driver’s driving style determines what oil should be used. It is vital to get the right rear diff oil that suits your driving style, otherwise you will only be fighting your car. Some years ago it seemed like everyone always used the thinnest possible rear diff oils. I think it was because people were used to electric offroad. A thin rear diff oil will make the car have a lot of steering into corners, the car is easy to control when accelerating, even if it’s bumpy. So it seems like the way to go right? Yes and no. One drawback is that the rear can lose its traction suddenly. It will have traction, and then lose it all at once when entering a corner. A thin rear diff suits drivers that brake before a corner, keep a tight line around it, then accelerate hard after the corner, towards the next obstacle. This is not how I drive. I like to control the car a lot with the throttle. A thicker rear diff oil will make this possible, it will be possible to steer the car with the throttle. You can enter the corner aggressively because the rear is very stable, and won’t suddenly lose its traction, it will start sliding in a controllable way. After braking, it is possible to drift on throttle, like a rally car through the corner and onto the next straight. I’m on the gas before the corner, and halfway in the corner, or sometimes even before halfway I’m already on the gas hard.


The thick oil makes the rear tires pull more evenly. On a slippery or bumpy track the car can be too hard to drive. The rear diff oil is normally the thinnest of the three diffs, or the same as the others. The oils used range from 1000-7000. 3000 is a safe bet, no matter what your driving style, or what the track conditions. I nearly always use 4000-5000.

 

[swervin]

Ooooooooooh ok ...... won't that effect how the truck turns? The biggest clutch bell that OFNA has is a 18t..... I have a two speed 56/60 ....How about a 14/18 clutch bel for that (Not ready for all that yet) I want to get the diff's right first...... This is what I'm working with..... What should i do ? I want to take it to the track eventually...... Please help me.....

 

[Greywolf74]

Well a 10 year old Dominator really isnt a track tuck but if you were gonna run it on a track then really the best thing to do would be to talk to some people at your local track and see what they recommend for that particular track. other than that its really just gonna take some experiementing to see how it performs on the track with various set ups and go from there. a 14/18 wouldnt be bad at all. personally if it were me Id just put the grease in it and bash it. Other than that get an idea of what the local track guys think and buy whatever they recommend you try and then just branch out from there....compare how the truck drives comapred to the stuff in that article and adjust it how you see fit and then try it out and then compare the two. Not really any other way to do it.

 

[swervin]

Well there You have it.......I have some unfinished business with a first generation T-Maxx a Red cat Earthquake a Jatto 3.3 & a Nokier...... We're just trying to figure out where this battle is going too take place at...... I want them guys to know what's it like to be Dominated by a old school Dominator. ... Thank for the knowledge & you guys help.......I'm ready to give 1:8 on road a try ...... Any suggestions?

 

[Greywolf74]

OFNA, Mugen, & Kyosho make some good on-road 1:8 scale kits. check out www.nitrohouse.com