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Old 11-21-2010, 08:55 AM   #16
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I have used front overdrive last year in the local onroad championship. We race on a small technical carpet track. Briefly put, the sysem has some advantages but because of the high grip, the drivetrain doesn't last as long as one would hope. Eventually, the rear pulley was worn out, the ball holes having enlarged beyond the point where the balls were running true on the same track. The main upside was stabilising the car off power in the high speed corners as well as pulling fast out of tight turns (chicanes, hairpins). I gave it up eventually as it does take away some power. Remember the front and rear diffs are fighting each other and grip is a function of other variables mainly weight distribution which varies a lot as the car brakes, accelerates or turns.

I did not use a one way anywhere, and my overdrive was 1/42 ( I had a 42 tooth pulley on the front and a 41 tooth on the rear). That is just about 2% front overdrive.

The best way to find out what happens is to try it for yourself.

My opinion after running it is that you have other better adjustments you can use to improve your car's handling. This is not the best idea, because it causes loss of power. Remember this is the worst possible downside. We want to make use of all the power we have, not diminish it even by a smidgeon.
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Old 11-21-2010, 10:43 AM   #17
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We use this mor for Countersteer Drifting. On my Xray I have a over 100% overdrive on the rear wheels. The rear spins 2.13 laps per one on the front wheels.

More drive on the rear wheels makes drifting look moe to scale since you'll have to countersteer, just like real drifting cars. Looks way better and is way more challenging than normal 4wd drifting.

To acheive this we use pulleys and diffpulleys and belts from different manufacturers. I for example have both 34T on rear diff and 34T on center rear, with a 34T front diff and a 16T center front. Using a HB TC-D front belt at the rear.

Spools and oneways often has the same hole figuration, so its easy to take a pulley from another manufacturer.

Also, for the Ta05 there are shitloads of countersteer-kits with different belts and pulleys. Just bolt on
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Old 11-21-2010, 10:50 AM   #18
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My Losi xxx-4 had this as a box-option. It wasn't that great. As mentioned above, adding one tooth is adding between 2 and 3% power at that end. On low traction off-road where there is a lot of wheel spin, it's bearable. On higher traction on-road, i'd say you will have your hands full of over-steer or under-steer.
I'd say work on you driving technique and suspension set-up to generate the effect you are after where you need it rather than having it on-tap for the full track.
Also, it WILL create additional strain on your drive-train and shorten the life of your parts.
Still, i'd give it a crack. If everyone did what they were told on here, no-one would learn anything for themselves
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Old 11-21-2010, 02:45 PM   #19
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i fisrt came up with this design for drift, makeing the car rwd while at speed then when it slows down, it engages front wheel drive kicking the speed back up, like some sort of nos ^.^ from what ive thought about, 1-way diff wont work for this... or does it? hey hey u guys telling me about "overdrve" and "underdrive" do u put on a slow front one way and it doesnt put power to the ground when its got traction, then when it looses traction, it kick the front wheels into action?
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Old 11-21-2010, 05:42 PM   #20
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Thanks everyone for your input. I was planning on having a center one-way for my car so I would lose the brakes on the front anyways. I was thinking of this setup because I'd still get the advantages of the one-way and the disadvantage of the loss of brakes would be made up with the added acceleration. My theory being that the front wheels would kick in round the corners giving me acceptable cornering and then speed up past everyone on the turn exit. I find passing other cars to be easier on the straight so if I kept up around the corners then pass them on the straight. I know this is all just theory but trying something new couldn't hurt.

As mentioned earlier this is obviously not some new concept or an uber leet mod that's going to shake up the TC world, because as said before, everyone fast would be using it. I had already assumed that this was nothing new, but I couldn't find info on this anywhere(probably because I didn't know the correct terminology). Everyones setup will be slightly different and it's just about suiting your driving style.

I'm still liking the idea of this and I will explore it some more when I get the parts and let you all know how it goes.

Will the added strain on teh pulley be hugely damaging? How often would I need to replace pulleys? I have seen an aluminium pulley, which is now discontinued(as far as I know), would that make it more durable? Or are there other ways to stop it from killing itself?

I've already demolished a diff pulley already with my 10T brushless making it liquid... And I've only had my car for a month or so. :P
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Old 11-21-2010, 05:50 PM   #21
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I understand what they are trying to do. Think of the R34 GTR awd system. The car is RWD until it needs the front wheels. By overdriving the rear and a front one way the front diff will keep slipping as the belt will travel faster than the tires. Now once the rear looses grip the car will turn into AWD to get the front to pull out of the turns. I kinda want to see this in action now, DARN YOU NITRO DRIFTER!!!!!!
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Old 11-21-2010, 06:01 PM   #22
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Old tech. This was allready an option on the TA03 back in 1998 and done with touringcars running on foam even before that (different tire diameter F&R). I started a topic some years back on the first Trinity Tech Talk on using a rear ball diff and rear overdrive on a XXXS. Some weeks after that Ifmar rule 6.2.8 came to light.
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Old 11-21-2010, 06:07 PM   #23
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That's exactly what I'm thinking of. I assume that like a real car a 4WD system loses power with all four wheel taking power, so with the car acting like a RWD system you get better acceleration and top speeds but when the front wheels are needed they kick in and help it corner effectively. So in sumary I want added speed with as little disruption to cornering ability as possible. not so much drifting but a little oversteer is always good in my books(I have taken my real car around a skid-pan and loved every minute of it even tho it's only a V6).

And yeah, would be cool with a nitro drift car. ^_^
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Old 11-21-2010, 06:21 PM   #24
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BTW Square have all the parts you'll need for a TA05. Pully's, belts, ect..
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Old 11-21-2010, 07:10 PM   #25
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The ifmar rule doesn't apply as the one way id be using only affects the front.
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Old 11-21-2010, 07:19 PM   #26
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Quote:
Originally Posted by kb525 View Post
I understand what they are trying to do. Think of the R34 GTR awd system. The car is RWD until it needs the front wheels. By overdriving the rear and a front one way the front diff will keep slipping as the belt will travel faster than the tires. Now once the rear looses grip the car will turn into AWD to get the front to pull out of the turns. I kinda want to see this in action now, DARN YOU NITRO DRIFTER!!!!!!
this is exactly what ive been talking about. not power to front wheels till it needs it... so this would be called-"overdriving the rear wheels with 1-way front"? something along those lines...
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Old 11-21-2010, 07:20 PM   #27
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Quote:
Originally Posted by unsane_chimera View Post
The ifmar rule doesn't apply as the one way id be using only affects the front.
I know that. I was only giving an other example.
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Old 11-28-2010, 06:36 PM   #28
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hey guys, just an update.

i took my car out for a spin with the aforementioned changes and WOW you get a heap more acceleration out of it! The oversteer was a lot more noticeable but after 5mins of driving it became easy to manage. now thats all good news, the bad news it I over tightened the diff and the pulley melted, so sorry i won't be able to state any problems with long-term use until I get another 36T pulley. lucky for me i ordered a 37T as well, for if the idea didn't work, so i can at least take the car out for a spin.

The FDR's ended up being; F=7.194 R=7

Im pretty sure that if i hadn't over tightened the diff, the oversteer would have been much less. All i had to do with it as it was either half-power it around and blast it as it straightens up or wait till the wheels are straight and blast it then. for the long sweeping corners its just full power and has great grip and speed.

Thanks guys for the input, I am very pleased with the results and i hope this helps others.

Gaz
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Last edited by unsane_chimera; 11-28-2010 at 08:21 PM. Reason: typo
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