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Old 06-15-2014, 06:31 PM   #406
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Got the chance to finally use my setup app yesterday at the track. It helped a lot. Track was loose and I was loosing the rear end in the corner. First had to figure if it was loose on throttle or off. It was on off throttle. Went down the 1. steps and came to a conclusion. I reduced front camber from 2* to 1.5* and kept rear at 2*. Lowered rear roll center and added 2mm shims to inside upper link and changed to a softer rear spring. That solved 90 percent of loosing rear traction. Which in result I TQ and took first in main. Thanks again Martin for doing what you do.
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Old 06-16-2014, 09:30 AM   #407
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Hey Martin,

If there is a free space on the wheel, is it better to add shims (0.1 ~ 0.4mm) before getting the first bearing on the CVA or after the last bearing (before installing the clamp kex pin) ?
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Old 08-10-2014, 12:24 PM   #408
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Hi Martin,

I have been working under the assumption that lowering the roll center will produce more traction on that end of the car, due to more roll. For instance, the Xray setup book states that "more chassis roll equals more grip."

However, I've been reading through your comments, and it seems that you suggest higher roll centers for the end of the car that you want to create more grip through a turn. For instance, "A higher rear roll center will give the rear more grip."

Could you help me understand what's going on and whether raising or lowering a roll center produces more grip through a turn.

Thank you
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Old 08-11-2014, 10:29 PM   #409
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Default Rear toe in

I've asked this question before; however, I cannot find where so I apologize if my question is a duplicate.

Is there any difference in handling by getting 3 degree rear toe in (for example) with one degree in the rear hub and 2 degrees in the suspension arm or getting all 3 degrees from the just arm?
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Old 08-12-2014, 01:59 AM   #410
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Default pulling to the right under acceleration and braking

Hey Martin, I'm running a Sprint 2 sport which i've upgraded to a vector pro and vapor 5900 motor.

Under heavy acceleration and braking the car is pulling to the right and if i attempt to turn right with any kind of throttle the car is just spinning out. I don't have anywhere near the same issues when turning left however. Any ideas on what i may need to look at?

Thanks, Dale.
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Old 08-12-2014, 08:57 AM   #411
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Check your drivetrain for any binding issues or bad bearings. Also check you diff; it may be bad due that kind of power being put through it. If itnhas a spool up front, check to make sure its not broken. Check your suspention for broken or binding parts. All of these things could cause these issues.
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Old 08-12-2014, 06:30 PM   #412
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Originally Posted by theproffesor View Post
Check your drivetrain for any binding issues or bad bearings. Also check you diff; it may be bad due that kind of power being put through it. If itnhas a spool up front, check to make sure its not broken. Check your suspention for broken or binding parts. All of these things could cause these issues.
there seems to be a fair amount of backlash in the rear diff. Would that cause it to pull to one side only though?
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Old 08-12-2014, 07:02 PM   #413
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What do you mean back lash? If youbare refering to rocking back and forth, is it the diff gear on the belt, the dog bones in the outdrives being worn, or play in the diff itself. If its the latter, your diff is blown out
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Old 08-12-2014, 07:15 PM   #414
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Quote:
Originally Posted by snailman View Post
there seems to be a fair amount of backlash in the rear diff. Would that cause it to pull to one side only though?
You need to strip that car down and rebuild it completely. Check everything for wear, bent parts, ect. We could go round and round on the topic but honestly I would do what I'm suggesting then see where you stand. Sometimes it's a combination of small things.
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Old 09-12-2014, 11:30 AM   #415
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Originally Posted by Martin Crisp View Post
For sure an outdoor asphalt track changes during the day based on air temp, the amount of sun etc. Mid day when the sun is out is when you get the least amount of grip. Raising the roll center slightly can help, but the car will not transition as smoothly, so you will need to find the balance that works for your driving. I would actually soften the swaybars or remove them, as a thicker swaybar will actually remove grip. If you are getting more steering then I would raise the rear roll center and soften the rear swaybar.



I have found that a spool is tight on entry and loose on power exit. So I will assume you are talking about loosening up the car on corner entry off power.

You can do a number of things to loosen a car up on corner entry off power.

1) increase rear up travel / droop
2) reduce rear toe-in
3) soften front springs & oil
4) add more front camber or reduce rear camber

If you are looking for more mid corner rotation then here are some things to try in addition to the list above

1) laydown rear shocks
2) lower rear roll center
3) raise fron roll center




someone just sent me the same question via email Maybe that was you?

Here is the response I sent...

The age old question…how to keep the steering but make it stable

You can try making changes to add more rear grip, but this will likely end up with a balance that has too much push in it if you go too far.

Things you can do to add more rear grip are numerous and depend on your current setup.

some of the more common things to try are…

more rear toe in
more rear camber
higher rear roll center
stand up the rear shocks a little more.





lmao!

Hi Martin,

Sorry for the dumb question. When you say raise the roll center, do you add or remove shim>

Thanks
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Old 09-12-2014, 08:38 PM   #416
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Originally Posted by fx35rc View Post
Hi Martin,

Sorry for the dumb question. When you say raise the roll center, do you add or remove shim>

Thanks
You can either lower your inner camber link pivot or raise the outer. Either will raise the roll center.
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Old 09-15-2014, 10:21 AM   #417
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You can either lower your inner camber link pivot or raise the outer. Either will raise the roll center.
I see now..thanks alot
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Old 09-20-2014, 08:45 PM   #418
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Martin, I know you don't support your app anymore. It's unfortunate because the new Apple os for the iPhone killed the app.
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Old 09-20-2014, 09:08 PM   #419
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Martin hasn't supported this thread since June
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Old 09-23-2014, 09:12 PM   #420
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Quote:
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Martin, I know you don't support your app anymore. It's unfortunate because the new Apple os for the iPhone killed the app.
Darn
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