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Old 02-18-2010, 12:14 PM   #1
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Default TC4 Top speed alignment

Hello, I have a TC4 that I have been playing around with. Steel cvds, steel rear outputs, one way in the front. I have a Novak Ballastic 3s 8.5 sytem with 66 spur and 35 pinion. I am trying to see how fast I can get this car to go with the ESC/brushless setup. Today we used a chase vehicle to pace the car. Using a 2s 4000 lipo the speedometer read 60 mph before I pulled full throttle and spun out. I am having a hard time getting the car to track straight. Does anyone have any recommendations for suspension and steering setups for this? I believe the car is capable of 75 mph on 2s if I can keep it straight. It tends to pull left or right and is not bias. Would 0 toe in the front and +2 in the rear be a good starting point?

BTW: We ran the car half throttle for 2 miles with the occasional full throttle and the esc or motor did not get hot to the touch.
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Old 02-18-2010, 01:03 PM   #2
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Default Spin city

A car will spin under hard acceleration because one side gets more grip than the other. As speed increases, even a momentary bit of extra grip will send you into the weeds. The grip imbalance can come from a lot of sources, Here's one to consider:

The TC3 is always off by a half degree or so in rear toe. I'm not sure about the TC4, but you might want to measure yours on a setup station. Because of parts slop, the rear toe will change a little under acceleration and deceleration. Under hard acceleration The effect might be enough to swap ends. Narrowing the track and extending the wheelbase are two concepts (like a Top Fuel dragster).

it's a start.
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Old 02-18-2010, 01:13 PM   #3
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Assuming you are running on a smooth flat surface, you many want to raise the ride height to avoid bottoming out the car over bumps/dips/pavement irregularties.. You may also want to put some fuel tubing on the shock shafts to also prevent the car from bottoming out.

Another thing to look at is making sure the body is mounted securely and the wheels aren't rubbing anywhere on the body. It is possible that when you went full throttle, that the wheels are ballooning up and rubbing the body causing the spin. I'd recommend using belted tires to prevent this.

Ride height and body/wheel clearance are critical at the speeds you are trying to achieve, because the slightest chassis/wheel rub will cause erratic handling issues.

Above all, good luck and have fun.
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Old 02-18-2010, 01:16 PM   #4
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Quote:
Originally Posted by rodster1955 View Post
Hello, I have a TC4 that I have been playing around with. Steel cvds, steel rear outputs, one way in the front. I have a Novak Ballastic 3s 8.5 sytem with 66 spur and 35 pinion. I am trying to see how fast I can get this car to go with the ESC/brushless setup. Today we used a chase vehicle to pace the car. Using a 2s 4000 lipo the speedometer read 60 mph before I pulled full throttle and spun out. I am having a hard time getting the car to track straight. Does anyone have any recommendations for suspension and steering setups for this? I believe the car is capable of 75 mph on 2s if I can keep it straight. It tends to pull left or right and is not bias. Would 0 toe in the front and +2 in the rear be a good starting point?

BTW: We ran the car half throttle for 2 miles with the occasional full throttle and the esc or motor did not get hot to the touch.
The best thing to do is to include some side dams on the body. At those speeds, aerodynamics become much more important. If you are interested in going fast, check out the ISC site.







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Old 02-18-2010, 01:27 PM   #5
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Front toe-in increases straightline stability at the expense of reduced cornering capabilities.
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Old 02-18-2010, 05:33 PM   #6
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Default B4Maz

Awesome speed run car. Looks like you've done your aero homework. Nice work.
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Old 02-20-2010, 09:26 AM   #7
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Thank you for the advice. The sloopy steering and the possible tire rubbing the body when ballooning are some of the things that I did not even consider. What belted tires would you recommend for running on clean asphalt.
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Old 02-20-2010, 10:00 AM   #8
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1 make sure your steering throw is equal on each side (this can be done with a set up station)
2 make the suspension as soft as possible so it would be associated green springs.
3 a R9F body would be the most stable body you can buy.
4 buy foam TC tires and true them down so you get a really fast car.
5 when you mount the body set the body as low as possible but, not to were the body will hit the ground when the suspension is under full load.
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Old 02-23-2010, 09:23 AM   #9
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You want some play in the steering to keep the wheels centred when running in a straight line. If there is no play the car will pull and weave all over the place.
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