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Old 04-14-2006, 09:26 AM   #1
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Default RS4 High speed handling issue

I recently purchased an RS4 evo off ebay. Stripped it and dropped in an OS .18 CV-RX (which i'm converting to a CV-R now since it's to tight of a fit) I'm running the Tsais rear exit exhaust system. It seems as though I can't get past about 1/2 throttle in second gear before the front end starts to drift and the car spins out. I was told it could be toe or camber issues. I was also told by a guy at work who has real car racing experience that it really sounds like weight distribution. After doing a little measuring I found out that from moving that side mount pipe to the rear my new front/rear weight distribution is 43/57 which is horrible. Stock should be around 50/50.

Anyone have any input? I'm going to try and even the car out a bit by moving around compnonents. What are you guys running for caster/camber/ and toe on these cars?

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Old 04-14-2006, 09:53 AM   #2
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are you running it with or without the body on is there a wing on the body. i see a lot of people try to run a car without the body and it won't work like that. you have to have down force from the body and wing for a rc car to work
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Old 04-14-2006, 10:00 AM   #3
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Yes I am running a body with a rear wing. 04 Sti

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Old 04-14-2006, 10:05 AM   #4
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I have a friend who I dropped an OS .18 CV-RX into his RS4 3 . You can get it to fit with some creative careful trimming. I gotta tell ya I don't know if there is anything you can do to wrestle some control back into that car with that engine in it. He is all over the place with it body or not. We have tried adjusting shock preload, front/rear balance, toe and camber, foam and rubber tires, etc,etc.. I think the combination of being more rear heavy with too much power. He breaks loose constantly plus the evo needs alot of upgrades to get it even close to racing spec and that may or may not help in handling. I told him to go no larger than .15 preferably a .12. But he listened to the hobby shop guy and not his experienced friend. Good luck.
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Old 04-14-2006, 11:08 AM   #5
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assuming all youre trimming is straight I would suggest running
a thicker diff oil in the front. With more power and wheel spin
the thicker diff oil will act like a limited slip and get rid of some
torque steer.
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Old 04-14-2006, 02:39 PM   #6
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Jack the rear up....Get that weight forward more see how that goes. Also sounds like the diffs might be bad.
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Old 04-14-2006, 04:23 PM   #7
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Try it with the exhaust in the stock side position...the RS4 EVO is heavy enough in the back stock.
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Old 04-15-2006, 07:21 PM   #8
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Thanks for all the replies guys. Appreciate it. Yeh There was some trimming to get the CV-RX in there. I'm also going to try some smaller spurs. More top end but maybe it won't be so torquey. I have to make some new motor mounts though because the slots in the chassis aren't long enough to adjust to the 41/37 spurs. I can also lower the motor A LOT since I got rid of the pullstart and turned it into a CV-R. I'm also thinking about flipping the steering serbo up on top of the upper deck and putting the receiver pack right under that to get some more weight up front. I measured it out already and it gets me back to about 48/52 front/rear distribution. I'll place around with the diffs and ride height too. Thanks again!
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Old 04-15-2006, 10:34 PM   #9
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check the wheels for signs of rubbing the hub. Some wheels are just not big enought to clear the hub. check if any bearing is binding, check if the right rear wheel is rubbing the exhaust manifold at full throttle. Use thicker diff oil.
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Old 04-16-2006, 08:27 AM   #10
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I've found that tires have a lot to do with stability. What kind of tires are you running?

Also, not all bodies give good downforce. If your front is losing it, then maybe you're getting air under the front end, if the back is spinning, then not enough wing.
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Old 04-16-2006, 09:01 AM   #11
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dnitro, i checked the wheels and there does seem to be some type of rubbing somewhere. It's on every wheel though and its about 1/8" in on each one. Looks like it could be from the lower a-arm on the rear when the suspension is compressed. I'm not sure where the rubbing is coming from on the front.

I'm using 30mm X pattern radials.

TT120, Do you think to much of a rear wing could bring the front end up? I thought about running with the rear wing off a few times to see a different.

I'm also thinking about getting some foam wheels.
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Old 04-16-2006, 09:34 AM   #12
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foam wheels????
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Old 04-16-2006, 09:40 AM   #13
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If those X patterns have a rotation direction, maybe they're on backwards. I have some medial X patterns rubber tires and if I have them on backward, the car is uncontrolable at high speeds.

Foams might be better depending on the surface you're on.

Too much wing? Hmmm... dunno bout that one, usually too much wing just creates more drag. Never seen it bring the front end up.

Which end is losing it? Front or rear?
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Old 04-16-2006, 10:44 AM   #14
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It's the front losing it. After getting to a certain speed the front starts to wonder. I thought I put them on the direction it said. I'll have to double check.
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Old 04-16-2006, 10:45 AM   #15
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I also have a swaybar kit. running the soft bars front and rear.
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