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Old 07-22-2007, 11:32 PM   #3031
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Personally, I keep my diffs as loose as I can get them without seeing diff slip. It does seem like having loose (but not slipping) front diff and tight rear diff can cause oversteer/s#^thooks. Beyond slipping or non-slipping, I measure diff tightness by grabbing one wheel and the spur, then trying to turn the other wheel. I 'measure' with my hand how much torque it takes to slip the diff.

A diff that is tighter than it needs to be takes away traction from that axle during a turn.

Having the front diff slip on corner exit will make the car pretty much impossible to drive, as the car ends up in rear-wheel-drive, which leads to huge oversteer on corner exit in our touring cars. [fronts have full traction available for causing cornering, while rears have almost none and so break loose instead of supporting cornering].

brew, you are flat out smoking your diffs. If I were you, I would pull apart both diffs and sand the thrust washers until the ball tracks disappear, then reassemble and follow the instructions. Page 7 of the 007 manual has the diff setup procedure.
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Old 07-22-2007, 11:54 PM   #3032
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Personally, I keep my diffs as loose as I can get them without seeing diff slip. It does seem like having loose (but not slipping) front diff and tight rear diff can cause oversteer/s#^thooks. Beyond slipping or non-slipping, I measure diff tightness by grabbing one wheel and the spur, then trying to turn the other wheel. I 'measure' with my hand how much torque it takes to slip the diff.

A diff that is tighter than it needs to be takes away traction from that axle during a turn.

Having the front diff slip on corner exit will make the car pretty much impossible to drive, as the car ends up in rear-wheel-drive, which leads to huge oversteer on corner exit in our touring cars. [fronts have full traction available for causing cornering, while rears have almost none and so break loose instead of supporting cornering].

brew, you are flat out smoking your diffs. If I were you, I would pull apart both diffs and sand the thrust washers until the ball tracks disappear, then reassemble and follow the instructions. Page 7 of the 007 manual has the diff setup procedure.

Wouldn't it end up with understeer while exiting. FWD gives more steering I thought.
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Old 07-23-2007, 12:32 AM   #3033
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Originally Posted by adamge View Post
Personally, I keep my diffs as loose as I can get them without seeing diff slip. It does seem like having loose (but not slipping) front diff and tight rear diff can cause oversteer/s#^thooks. Beyond slipping or non-slipping, I measure diff tightness by grabbing one wheel and the spur, then trying to turn the other wheel. I 'measure' with my hand how much torque it takes to slip the diff.

A diff that is tighter than it needs to be takes away traction from that axle during a turn.

Having the front diff slip on corner exit will make the car pretty much impossible to drive, as the car ends up in rear-wheel-drive, which leads to huge oversteer on corner exit in our touring cars. [fronts have full traction available for causing cornering, while rears have almost none and so break loose instead of supporting cornering].

brew, you are flat out smoking your diffs. If I were you, I would pull apart both diffs and sand the thrust washers until the ball tracks disappear, then reassemble and follow the instructions. Page 7 of the 007 manual has the diff setup procedure.
I believe you have it the wrong way round. A loose front diff will give you more steering entering the corner and less coming out of the corner. A tighter diff is the exact opposite of this. Having any kind of diff slip just makes the car slow and handle inconsistantly

Mike
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Old 07-23-2007, 12:46 AM   #3034
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Although a looser front diff does help steering entering a corner, Adamge was correct with his statement.

Consider the most extreme case, where a diff is SO loose, its like it has no affect, and a diff SO tight, its basically a spool.

When you exit the corner and get on power with an extremely loose diff, the car can not put any power to the front wheels, and it will act like a 2wd car, spinning the rear wheels.

But if the diff in the front is extremely tight, like a spool, when you exit the corner on power the front of the car will provide plenty of pull, and keep the rear end from spinning out.

Again, this is kind of a blanket statement that depends largely on the surface and your particular set up.

At nats, I went from a one way to a diff in the front set fairly tight. My set up performed extremely well with both, and I made no other changes to the car. I did lose a little speed going into the corners, but the car worked very well mid and corner exit. It also helped settle the car down through the high speed chikane and "festival", and was much more predictable. Overall, my lap times acctually improved slightly because the car was more stable and could be driven harder if I needed to. Also, I went with the diff just incase I had contact with other cars on the track. The diff car will usually win against the car with a one-way for some reason. So it was a safety play.
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Old 07-23-2007, 12:46 AM   #3035
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Originally Posted by ixlr8nz View Post
I believe you have it the wrong way round. A loose front diff will give you more steering entering the corner and less coming out of the corner. A tighter diff is the exact opposite of this. Having any kind of diff slip just makes the car slow and handle inconsistantly

Mike
I certainly could be wrong. I welcome everyone's input on this.

I want to clarify, though. I was discussing what happens when the front diff is so loose that, under power, it totally slips, so that no drive power is exerted on the front wheels, and all the drive power ends up at the rear wheels. This is not the same as having the front diff set slightly looser than the rear.
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Old 07-23-2007, 12:50 AM   #3036
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Pitcrew, speaking of oneways, I've been routinely racing asphalt/rubber on a track that demands braking at the end of the straight. It's simply a dot hairpin, so very tight, and it's entered at full speed. Does this single corner render a oneway silly to try, or could it still work?

-Adam
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Old 07-23-2007, 12:55 AM   #3037
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You are very correct in the extreme case of a slipping front diff, but in racing terms, you should never set you diff that loose.....

Mike
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Old 07-23-2007, 12:58 AM   #3038
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It's worth a shot, but a car properly setup with a spool will be much easier to drive in traffic, and when pushing the car really hard. That one hairpin can cost a lot of time in the end if you mess it up. I feel a spool will be more consistant as well since it is easier to drive. Even if the fastest lap maybe be a tad slower than a one way at times, Its better to do that lap over and over again rather than one slightly faster lap and one BIG crash hahaha.

-Korey
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Old 07-23-2007, 05:12 AM   #3039
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Thanks for the info... I did find some info in the manual is there a "standard" procedure for tightening the diffs ? some manufacturers tell you to tighten and then back off x amount of times is there such a thing for x ray to get in the ball park ?? or is it all feel ??

thanks
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Old 07-23-2007, 05:43 AM   #3040
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I run stock rubber with oneway on carpet.Using a diff just doesn't allow me to keep up...does anyone use or recomend a spool on rubber on carpet?
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Old 07-23-2007, 05:47 AM   #3041
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Quote:
Originally Posted by brew View Post
Thanks for the info... I did find some info in the manual is there a "standard" procedure for tightening the diffs ? some manufacturers tell you to tighten and then back off x amount of times is there such a thing for x ray to get in the ball park ?? or is it all feel ??

thanks

Thats a safe rule of thumb as starting points. Bottom out the diff and then back out 1/8th to 1/4 turn out is normally safe starting points.
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Old 07-23-2007, 10:02 AM   #3042
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Originally Posted by Korey Harbke View Post
I just have mine setup so it only slips when you really reeef on it. The car will never put that much load of the diffs so it works well. My diff when spun feels really free... but it doesnt slip.

-Korey
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I have mine set probably just a touch tighter than what Korey has described. But, as he says, it should not slip.


But, yes, it should always be a little looser in the rear than the front.
Thanks Guys, I think mine is a tad loose, but thats easily fixed.
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Old 07-23-2007, 12:00 PM   #3043
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Quote:
Originally Posted by adamge View Post
Pitcrew, speaking of oneways, I've been routinely racing asphalt/rubber on a track that demands braking at the end of the straight. It's simply a dot hairpin, so very tight, and it's entered at full speed. Does this single corner render a oneway silly to try, or could it still work?

-Adam

A one way might be a quicker set up overall. I agree with Korey about a spool in traffic. A one way makes it easy to get out of shape if you have contact.

I personally prefer a diff over a spool. But that is just my feel. Like I was saying, in the circumstance where a spool would be good, I run a diff set up tight. I just feel its easier on the drive train.

And, if you need to use alot of breaking, a spool or diff will be your better choice.
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Old 07-23-2007, 01:18 PM   #3044
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let me tell you guys somthing this car is the shit i am a nitro race all the way eighth scale onroad is my gig but the guy at our track in florida had several cars and let me run it at the ft meyers track and the car handled like it was on rails it was my first electric race and i ran the fastest lap at a 15 flat most nitro sedans are running mid 15's so i was flying may have to get me one
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Old 07-23-2007, 02:39 PM   #3045
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Quick questions guys, just bought a new Futaba S9650 and it doesnt mount up with my alum posts? Are my posts not drilled correctly or is it that the Futaba doesnt fit the car. Thanks!
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