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Old 10-30-2002, 07:33 PM   #1
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Default the 1st time you drove your TC w/front 1 way--

Did you see your rear break loose a lot more?
Put one into my Ob4 last year, and was a better (sa weet). My Racer 2 this year, OMG what a mess. A little bit of off throttle steering input and it swaps ends, ERf, what a pig. I had the Racer2 very respectable last year, without the 1 way. But lacked hi speed steering. SO I have backed off on the rear down stops, to allow for more suspension travel, had 50wt in the shocks, put 60 in the front. 8 degree castor blocks now, I'm thinking put the 10 degree blocks in. Also stiffer springs in the front. what a mess.
LOL.

A slightly different question: OB4 with front 1 way- - I still have silicon (50k) oil in the rear gear diff. IF I go off throttle on a staight, (Coasting) after a little delay the car swaps ends, Could this be from some drivetrain drag? Maybe a bearing thats providing a little more resistance? I have lightened up my clutch shoes but I dont that its the shoes disengaging- it occurs a little
too fast to be that.

thanks,
roj
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Old 10-31-2002, 01:19 AM   #2
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Generally, that's how a one way will act up in a car when it is not set correctly. First of all, the car needs to be tweaked correctly. Put it on a tweakstation and make sure that all 4 shocks on all tires are balanced. The droop settings must be set the same values for left and right rear and left and right fronts. For a one way diff which gives you back wheel brakes only, any slight tweak in the chassis will be blown out of proportion when you apply even the slightest brakes.

Secondly, I feel that using a stiffer rear diff helps in the handling department of the car when using one way front diff. I don't think the 50K silicone gresse will help you much in making the rear diff stiff. In my opinion, when the car has front and rear loose, the car tends to fish tail a lot. Rear end is also more stable using a stiffer rear diff and a front one way diff. If you're daring enough, try solid rear with one way. To be honest, that's the fastest way around a high speed track.

Braking endpoints need to be toned down. You must set the car so that it brakes just enough not to let the rear tires lock. Driving style in this case must also change i.e. earlier braking into the corner.

Also, when braking, the reason why a stiffer rear diff will help is because it will put equal amounts of pressure on both sides of the rear wheels and does not unload like on a loose diff. When the diffing action of the rear wheels occurs during braking, the rear of the car will definitely swap ends.

Check to see if your car is already set to have drag brakes. It could be too much for the one way front diff.
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Old 10-31-2002, 01:40 AM   #3
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... and yes, I forgot. You also need to take steering out as with a one way front diff, you may be experiencing too much of steering.

Some of the ways of taking out steering is as follows;

1. Front sway bar

2. Harder tires / inserts

3. Harder shocks

In order to get the rear more planted, you could go with softer rear shock springs and softer tires. Front sway bar adds to rear end traction.
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Old 10-31-2002, 02:24 AM   #4
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The things you said should work.
Also a loose diff in the rear will only diff out when braking if you've locked up or exceeded the grip of the braking tires (the rears). A tighter diff in the rear will cause both braking wheels to lose grip at a similar rate rather than a loose differential diffing out and causing only one wheel to lock up, therefore causing a spin out.

I think that dialing out brakes using your servo's endpoints should stop your problem when braking. If you need more traction while braking, you can add more uptravel to your using the droop screws.
It might be better to put the differential back in and decrease front droop in order to get more on powersteering.

Your OB4 problem is probably, as you guessed at one of the four corners in the drivetrain. If the problem has just begun to occur, then it may be that your oneway has not been lubricated enough. This problem is more perplexing. Bearings are the likely culprit.
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Old 10-31-2002, 11:01 AM   #5
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You guys rock! My COlt 10 comes with the 1way & solid rear, love it. A loose rear during braking is not the issue, I dialed out most of the brake a long time ago before the 1 ways went in. My OB4 started out as a RTR, & still has the original plastic disk, LOL.
Both the OB4 & Racer 2 were set up nice before the 1 ways went in. Both cars are fresh off a major breakdown, Measured the shock length, all the bearings came out, etc. I did replace the left rear wheel bearings on the Ob4-- but not the right side hmmmmm whaddiya think that could be the root of that problem, LOL.

The Racer 2- post 1way is in need of a complete new set up. Sounds like from what you 2 guys have said thats normal to a degree.
50k oil in rear diff: yeah Ok, I see what you mean, I could go to 100k in the rear gear diff.

Bearings are the culprit, LOL. Ok, I'll bet its in the back 1/2 of the OB4 too. I just got my Ofna/picco 7 port (OB4) running well, 7 tanks so far, I was blowing plugs, reshimming, etc. I think I have .5mm in shims for 20% nitro (Byrons) its (its cool in NJ) about 50 degrees these days-- with the Ofna/Picco turbo plug. The 7 port has tons of torque-- 1st time I drove it the rear squirmed a lot. I had to check my rear toe & camber! !

Thanks always to the guys at Rc tech for keeping me headed in the right direction.
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Old 10-31-2002, 12:24 PM   #6
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Quote:
Originally posted by Im2lazy
The things you said should work.
Also a loose diff in the rear will only diff out when braking if you've locked up or exceeded the grip of the braking tires (the rears). A tighter diff in the rear will cause both braking wheels to lose grip at a similar rate rather than a loose differential diffing out and causing only one wheel to lock up, therefore causing a spin out.

I think that dialing out brakes using your servo's endpoints should stop your problem when braking. If you need more traction while braking, you can add more uptravel to your using the droop screws.
It might be better to put the differential back in and decrease front droop in order to get more on powersteering.

Your OB4 problem is probably, as you guessed at one of the four corners in the drivetrain. If the problem has just begun to occur, then it may be that your oneway has not been lubricated enough. This problem is more perplexing. Bearings are the likely culprit.
Some good suggestions there on the droop settings And yes, thanks for a more detailed explanation. Couldn't have done better... At this hour, I'm actually brain dead

Foger Rox;

Depending on which type of 100k silicone diff grease you use, you may still be too loose. Try putting in some thick grease or alternatively try some cleaning putty by Tamiya or by Serpent. Else you can use a product called diff lock by Ofna if I'm not mistaken.

Checking the length of the shocks are one of the ways to check for tweak. But for me, the best way is to put the car's 4 wheels on a tweakstation and there you can see any tweak that is a result of chassis slightly bending, hinge pins slightly bent, plastic arms slightly off shape etc or any combination thereof. You know what I mean...
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Old 10-31-2002, 01:40 PM   #7
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Quote:
Originally posted by InitialD
Some good suggestions there on the droop settings And yes, thanks for a more detailed explanation. Couldn't have done better... At this hour, I'm actually brain dead

Foger Rox;

Depending on which type of 100k silicone diff grease you use, you may still be too loose. Try putting in some thick grease or alternatively try some cleaning putty by Tamiya or by Serpent. Else you can use a product called diff lock by Ofna if I'm not mistaken.

Checking the length of the shocks are one of the ways to check for tweak. But for me, the best way is to put the car's 4 wheels on a tweakstation and there you can see any tweak that is a result of chassis slightly bending, hinge pins slightly bent, plastic arms slightly off shape etc or any combination thereof. You know what I mean...
I Dont have tweak set up yet. Both chassis's are new. I did raise both cars and measured droop. And I replaced the shock mounting hardware on the OB4, which was tweaked.
On the Racer 2 the 1st thing I did was to increase rear suspension travel with the down stops, then went for up to 60 wt in the front shocks, each helped a bit.
The OB4 has delrin rear arms, they are bullet proof and dont add unsprung weight like alloy would.
Ofnas 50k wt silicon oil is the stiffest they offer, they do call it Diff lock though. I have the Mugen 100k oil too.
I have a mashinist friend who I'm going to approach to make me a solid rear for the OB4, something Ofna really needs to address.
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Old 10-31-2002, 01:41 PM   #8
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try 4 postal scales instead of a tweak station - you can check weight distribution and tweak at the same time.

Also, don't be afraid to try loose rear diff with one-way. I run 7000 weight rear with a one-way with relatively soft springs and it's very good on a medium traction, tight track. To me if you're going to lock your rear up with heavy oil you might as well just go solid and save the weight.

you can set-up solid or diffs for any track, large or small, you just have to make adjustments in other areas accordingly.

I have also run solid-rear, one-way on very small track recently. Driving style had to be adjusted but once I get the hang of it I'm very happy with it.
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Old 10-31-2002, 02:11 PM   #9
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I run on totally unprepared black top. Rubber tires for T/C's.
Big track, doubles as a parking lot 28 days a month, LOL, 180+ ft main straight.
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Old 10-31-2002, 02:29 PM   #10
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woa - rubber tires! disregard anything I posted...lol. I never run rubber on nitro so I'm pretty certain my experience should be disregarded for your situation.
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Old 10-31-2002, 04:05 PM   #11
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On an unprepared surface? Foams slide around. A little less neg camber, and softer springs and oil for the shocks.

The Physics dont change, so dont you worry. Every thing else doesnt change. Just think low bite, LOL. No need to over react.
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Old 11-03-2002, 01:03 AM   #12
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I have been having the exact same problem with my racer2 with front one way. I tried everything. I have a ball diff in the rear and I loosened it so far, it was slipping and still the spinning. I tried softer, harder, more droop, less droop, toe in, toe out, more camber, less canber, different shock oils, softer tires, harder tires. Some of the adjustments helped a little, but I couldn't drive nearly as hard as I wanted. I did some testing with the rear really loose and found that it would only spin when I get off of the throttle. My conclusion to all that is that the the drag from the drivetrain is just enough to act like a bit of brake when off throttle, causing the spin. I'm going the put my locked front diff back in and give it another go.

Just so you know. I had the car set up perfectly for foams on a permanent track. Front one way, and read ball diff tightened down really tight. It drove just like a 1/8 scale car. That back end would just swing around turns as nice as you please and then snap back upon exiting the turn. I guess I'll just have to have 2 different setups for parking lot and prepared track.
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Old 11-03-2002, 01:06 AM   #13
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Oh, one last thing. You might want to use the pro linear springs and lower you car and go to 60 wt in the rear.
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Old 11-03-2002, 09:50 AM   #14
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Last year I was running Proline Purple double Purple foams, 50wt silicon in the rear diff. 50wt in the shocks, and could not get the rear to come out, it was like a rock, planted. I only lacked on throttle steering, & only at hi speed. But the joke was on me, I had a big block .15, 8 port in the RS4. Now its got a .12 in it. The 15 went onto my COlt 10.

Roy: I have 50 wt in the rear- 60 in the front shocks. Next thing I'll do is to lay out the rear shocks a little more. Then go to firmer front springs, then 10 degree caster blocks, I have the 8 degree in now.
I'm disappointed: Last year the front 1 way went into my OB4 (it just tuned harder & better), and I was running with some Impulses, I only had a modded Colt 12, with 13-18 clutch bell gears. The 13 tooth gave me the punch in the twisties that the Colt 12 lacked.
So now I go with the front 1 way in the RS4, and I'm starting over, LOL ! ! !

So I guess the lesson for me is that you throw out your old set up after you put in the front 1 way into a car, especially if its an HPI RS4, LOL.

So Roy when you say that the drivetrain drag is just enuff to induce a spin yeah I know what you mean. So i tired to drive with as little off throttle as possible, this also helped,,, a bit. then I was faced with the rear coming out on me when powering out of a turn, I know that I can fix that.
Or maybe I'm just stupid enuff to think I can make a Racer 2 behave nearly as good as an Ob4 or similar pivot ball car, I must be a jerk, LOL LOL LOL.
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