Xray T4 '13

Old 05-23-2013, 02:09 PM
  #3706  
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I know it sounds weird but he is right about softening the front to reduce traction roll. If you think about it, the weight being transferred during cornering, on a stiff setup, would cause the car to flip. Softening allows the car to lean and dive more. Lowering the ride height helps too.

Before I used to think the remedy for traction roll was to go even stiffer in front, but it actually made it worse.
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Old 05-23-2013, 02:17 PM
  #3707  
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Originally Posted by Dan View Post
I know it sounds weird but he is right about softening the front to reduce traction roll. If you think about it, the weight being transferred during cornering, on a stiff setup, would cause the car to flip. Softening allows the car to lean and dive more. Lowering the ride height helps too.

Before I used to think the remedy for traction roll was to go even stiffer in front, but it actually made it worse.
I'm all for trying things. I only have 2.5, 2.7 and 2.3-2.6 springs. Perhaps I should put th e 2.3-2.6 in front and the 2.7 in back? I'll take every suggestions and try them one at a time to see what helps. I'd love to have the low speed steering a full front sauce gives w/o the higher speed traction roll I get entering a few corners.

Dave
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Old 05-23-2013, 03:24 PM
  #3708  
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A lot of what can cure a TR won't even show up in a set up sheet. First thing to do is make certain your car is balanced L-R. Get a fast local to help if you're unsure. 2nd, try using motor spray to clean the front tires if you aren't already. Third, when you sauce 2/3 of the fronts be certain you aren't wiping the sauce from the inside of the tire onto the outside 1/3 as you're wiping before your run. 90% of the guys who have TR problems at our track find a solution in one or more of the above, regardless of setup. If those don't help go 2.3R/2.5F with 350 4H 1.1 in the center roll centers all around and 1.5* camber F and R and the rest the stock carpet set up. If that TR then post how you're prepping the track cuz it would have to be some amazing club grip!
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Old 05-23-2013, 03:35 PM
  #3709  
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Originally Posted by andrewdoherty View Post
A lot of what can cure a TR won't even show up in a set up sheet. First thing to do is make certain your car is balanced L-R. Get a fast local to help if you're unsure. 2nd, try using motor spray to clean the front tires if you aren't already. Third, when you sauce 2/3 of the fronts be certain you aren't wiping the sauce from the inside of the tire onto the outside 1/3 as you're wiping before your run. 90% of the guys who have TR problems at our track find a solution in one or more of the above, regardless of setup. If those don't help go 2.3R/2.5F with 350 4H 1.1 in the center roll centers all around and 1.5* camber F and R and the rest the stock carpet set up. If that TR then post how you're prepping the track cuz it would have to be some amazing club grip!
There is no track prep on the new ozite carpet. I have 4 corner scales and have my cross weight w/in about 6g but how/why would that influence traction roll? I clean tires w/ motor cleaner and ensure I am not wiping compound onto the rest of the tire. Even after using motor spray the tires feel sticky to the hand. If I run w/ no compound the car is loose though. I don't have 2.3 springs so I'm trying to make due w/ what I've got spring wise (2.5, 2.7 and 2.3-2.6). I have 1.5deg camber all around and the exact shock setup you mentioned.
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Old 05-23-2013, 03:49 PM
  #3710  
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Originally Posted by TT_Vert View Post
There is no track prep on the new ozite carpet. I have 4 corner scales and have my cross weight w/in about 6g but how/why would that influence traction roll? I clean tires w/ motor cleaner and ensure I am not wiping compound onto the rest of the tire. Even after using motor spray the tires feel sticky to the hand. If I run w/ no compound the car is loose though. I don't have 2.3 springs so I'm trying to make due w/ what I've got spring wise (2.5, 2.7 and 2.3-2.6). I have 1.5deg camber all around and the exact shock setup you mentioned.
Softening the front increases lateral weight transfer. Since tires can only make maximum grip with a certain load, you can "overload" the tire and it becomes less efficient. Softening the springs, lengthening the camber link, and lowering the roll center (to -.75 for example) can all help reduce traction rolling. Thickening the shock oil works in the same manner in that it works the tire more, which can make them less efficient, and it can also help prevent "suspension jacking", which will cause what appears to be traction roll.
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Old 05-23-2013, 03:51 PM
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Originally Posted by TT_Vert View Post
Guys, what would your input be for a traction roll issue I've got on a high traction carpet? If I only sauce the inside half of the tire I don't traction roll but I'm about .2-.3 seconds off my pace due to slight push I get in the infield. I've got the carpet setup on it except I have the +.75 rear arm mounts. I did this to try to get the car to rotate more while using 1/2 front tire sauce but I'm still a bit off the pace. I was thinking of maybe going to a 2000 cst diff oil from the 1000 to get it to rotate more and then half the front tire being sauced would be ok. I also reduced rear droop from 5 to 6 as I noticed I was lifting the rear inside tire when cornering. That helped a tad and the rear tire seems to stay planted but I'd like to resolve this traction roll problem. This is in vta at a 1550g race weight.

Thanks much

Dave
II I were in your shoes I'd most likely lengthen the camber links. Whenever I tried the shortest links I always started to traction roll so I'd switch to middle length links. After longer links for sure lower the roll center to middle position or 0 and 100% lower ride height and if its a bumpy track add more droop (2mm above ride height front and rear or 5-4.5 front on the blocks and same for rear). In my expierence with traction rolling has nly been on nitro cars but softening everything and making the car roll more would always fix it.
And also if I sauce toe whole front tire sometimes would cause traction roll
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Old 05-23-2013, 04:20 PM
  #3712  
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Originally Posted by TT_Vert View Post
1. Lower front/rear ride height or just front? I have a bit of a bumpy track which is why I was at 5.5 but I can try to lower.
2. Is this in refence to just the front camber link?
3. So you recommend going softer in front? Wouldn't that just cause more roll or is your thinking that it'll roll further before it traction rolls?

Thanks for the input/clarification!!
Ok if you can not lower your ride height, no problem...
Camber link - that was all 4. you are in the hole on the bulk head that makes them short...
Like others have commented... when you soften the car in the springs it allows the car to roll more before hitting the wall and traction rolling...
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Old 05-23-2013, 04:35 PM
  #3713  
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Would thicker diff oil (2k perhaps )help any also? Making it rotate more?
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Old 05-23-2013, 05:16 PM
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Originally Posted by TT_Vert View Post
Would thicker diff oil (2k perhaps )help any also? Making it rotate more?
Thicker oil gives more on power steering. I like 2000 I've tried 3k and 1k but always go back to 2k
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Old 05-23-2013, 06:38 PM
  #3715  
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Originally Posted by TT_Vert View Post
Would thicker diff oil (2k perhaps )help any also? Making it rotate more?
But you already have to much bite.... I really don't think changing your diff oil will help, but if you want to try this, go thinner not thicker...
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Old 05-23-2013, 09:30 PM
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can I get a starting point for Mod TC FDR, 4.5 Thunderpower, 20 degrees timing, no boost, similar to the recent outdoor electric roar in florida
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Old 05-23-2013, 09:59 PM
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Originally Posted by regets ama View Post
can I get a starting point for Mod TC FDR, 4.5 Thunderpower, 20 degrees timing, no boost, similar to the recent outdoor electric roar in florida
8.5:1
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Old 05-23-2013, 10:23 PM
  #3718  
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Originally Posted by bvoltz View Post
But you already have to much bite.... I really don't think changing your diff oil will help, but if you want to try this, go thinner not thicker...
This is not always true . It really depends where in the corner the car traction rolled and if its on power or not . Thicker rear diff will make the car easier to drive entering the corner ( where traction roll is more common)
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Old 05-23-2013, 10:35 PM
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Changing diff oil will have little affect for traction rolling. Roll center adjustments and shock oil will definitely affect traction rolling.
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Old 05-23-2013, 10:39 PM
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Originally Posted by clparsons123 View Post
This is not always true . It really depends where in the corner the car traction rolled and if its on power or not . Thicker rear diff will make the car easier to drive entering the corner ( where traction roll is more common)
Can you explain why you feel this way?
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