Changed the Diff OIl and now loose the back end

[Bad Inferno]

I just put diff oil in 3-7-1 MP7.5 and now find that I can very easily loose the back end whilst excellerating out of a corner. (To a point of doing a donut) Never seemed to get that problem when running without oil.

Upgrading a Sport thus no oils originally in diffs. Don't know if it was just the day, the oil.

Without oil the entire car might of power slide around a corner and now the rear just lets go.

Any idea's

 

[Error401]

Interesting. I assume that you're running the stock engine. Do you just nail the gas comming out of the corner, or ease into it? Do the diffs feel stiffer or looser with the oil (as compared to the grease)? If anything, it should be more driveable now.

 

[Bad Inferno]

Diff's feel stiffer compared to just the grease....I also installed the two extra planetary gears in each diff, I have the stock engine GX21 and thought I was easy on the gas coming out of the corners. I ended the day loosing a cap screw from the front knuckle so I will head back out on the week end.

I did also set the F/R camber to what I thought to be conservative -2 from what had been 0. The track is very loose at least 1/4" loose dirt

 

[Error401]

The 4 spider diff with oil should be smoother and a bit stiffer, which is normal. The first buggy I had (Lightning), the first thing I did was dump the grease and put oil in. I used 70K/100K/50K (yes, I went that thick), and it was pretty stiff on the traction. I was running a Hyper 8 in it too, and it would spin out on loose stuff fairly easily. I ended up changing the oil to 7K/10K/1K and it seemed to improve alot. The Kanai 3 I'm running now has the same oils you're using, but the front is a limited slip diff with special oil. It pretty much just straitens out and takes off out of corners. But one thing that is common between the two that had a big impact on handling was tire selection. I had a set of the hot bodies tires that come with the lightning, a set of Knuckles XTR, and some Ofna +='s. The knuckles were great for pavement and hardpack, but absolutely sucked on loose wet dirt. The +='s were awesome on the loose dirt, but had too much grip on hardpack.

As for camber, if you look at the car sitting, the angles are like this: /---\ and not like this \---/ right?

 

[Çh®i§tiªñ]

What hingepin blocks are you running? Degree?

I think you just need to dial in your suspension and toe a little to compensate. What springs in the rear?

Also, like Error was saying, tires... What tires do you run?

I like the knuckles a TON overall.

 

[dgrobe2112]

i had to go up in front diff oil to get rid of a push my car has.. here is the setup on my kyosho

Diffs front to rear
5k-7k-1k
shocks frot to rear
60-40
blue springs
spaced to level

Make sure you got everything right.. cuz if you get on power and it just spins out.. there may be a problem with the front diff.. cuz with the thicker front oil.. your car should pull out of the turns

 

[El Pirata]

That's rather interesting that you lose it in your rear diff. I currently have 30k in my rear diff, 100k in the center and 50k in the front and I don't lose traction in the corners.

 

[Çh®i§tiªñ]

Thats why I'm thinking its just how its dialed in. Not the diff fluid.

 

[Bad Inferno]

Thanks for the support

I run blue springs (kania 3) with a preload of 3 mm on the front.

Knuckles all round with slightly negative camber /--\.

Don't know the front toe angle however for setup if I put a ruler on the front rims and extend it to the rear the ruler is 1/4" from the rear tire nut ! (At least this lets me get both L&R the same.

Oil Wieght is 35 front and 30 rear

I do not know hinge pin blocks (standard sport) however I do have some integy front upper B & 20degree holders on order.

I was reading a setup thread and I may have too soft a front end = increase steering. Maybe I could increase the spring preload and go up to 50wt in the front.

 

[dgrobe2112]

50 in the front is what i used to run.. i just switched to 60..