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Old 05-11-2004, 06:27 PM   #2116
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I understand that :

High R/C = less roll = less grip
Low R/C = more roll = more grip

But would'nt a more parallel upper link to the lower arm have a lower R/C compared to the upper link being more angled on the inside point.
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Old 05-11-2004, 08:56 PM   #2117
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Quote:
Originally posted by rcspeedo
I understand that :

High R/C = less roll = less grip
Low R/C = more roll = more grip

But would'nt a more parallel upper link to the lower arm have a lower R/C compared to the upper link being more angled on the inside point.
When you lower the inside connection point of the upper link this raised the roll center and decreases roll and thus grip at that end of the car.

Likewise when you raise the inside connection point of the upper link this lowers the roll center and increases roll and thus grip at that end of the car.

However, Once you raise the inside connection point of the upper link so that the upper link is past being parrallel to the lower arm, then the camber actual goes positive when the suspension is compressed, which can take away grip mid and late corner. This can be a good thing or a bad thing depending on what you want the car to do.

When the upper link is parrallel or less than parrallel, the shorter the link the more camber change you will get when the suspension is compressed, which can help keep a larger contact patch during cornering for the outer tire and thus more grip. So in addition too using a low roll center to gain grip, you can also use a short upper link. This is important to remember because if you go to far with lowering the roll cente to gain grip you risk flipping the car and/or the car takes too long to transition from left to right (i.e. lazy).

hope that helps.

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Old 05-11-2004, 09:16 PM   #2118
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Default Spur pitch ?

I think this has been answered in this thread before but what is the pitch of the kit 102 tooth spur ? looks like 64dpi but not compaired it to my other spurs to find out.

And yes this does mean my 415 is here at last , just got to build it now ready for racing either this sunday in the Torc series or the following sunday in the BRCA meeting.
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Old 05-11-2004, 09:49 PM   #2119
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ditto to what Martin said!

Now can you say this fast 3x...shesellsseashellbytheseashore!

j/k

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Old 05-11-2004, 10:05 PM   #2120
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I would assume also though that if your car is leaning or rolling too much, you could be killing corner speed. Or would this be wrong?

Let me try and get this straight. Say we are on a parking lot track were it is slippery. You would want to let the chassis roll more in a turn to gain traction. But are you really gaining traction? Or are you slowing the car down in the turn (thru time of weight transfer) so that it won't slide out?

On a high traction track you don't want too much chassis roll or you'll flip the car (traction roll) into a turn. So people think less roll less traction. When I think you gain more traction with less roll (on high traction tracks) because you are able to keep all 4 tires down and not tossing the weight around as much. So it's the weight transfer causing the car to flip. Low Roll Center=More Roll. The Rolling point is lower in the chassis making the car more or less be "top heavy" when leaning into a turn. Thus causing it to flip (the high traction doesn't allow the tire to slide like it would on low traction tracks). So you Raise Roll Center. This brings the rolling point closer to the Center of Mass. Thus making the car less top heavy (not really top heavy but a good way to explain the point).

And blah blah blah. Of course I'm referring to High R/C and Low R/C in general and not the effects it would have on changing it at one end of the car vs the other.

Hmm maybe I'm just blowing something out my buttucks.
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Old 05-11-2004, 10:07 PM   #2121
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The kit spur is .04 metric pitch. Very close to 64 pitch. But not exactly the same. You can run 64pitch pinions on it. But it'll be noisy and wear out quicker.
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Old 05-12-2004, 05:49 AM   #2122
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Just got my spools from speedtechrc and they are a work of art! Lighter than the ones troy did for the evo 3 just goes to show evolution. Cannot wait to try one. Rick
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Old 05-12-2004, 06:38 AM   #2123
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Quote:
Originally posted by KilRuf
I would assume also though that if your car is leaning or rolling too much, you could be killing corner speed. Or would this be wrong?

Let me try and get this straight. Say we are on a parking lot track were it is slippery. You would want to let the chassis roll more in a turn to gain traction. But are you really gaining traction? Or are you slowing the car down in the turn (thru time of weight transfer) so that it won't slide out?

On a high traction track you don't want too much chassis roll or you'll flip the car (traction roll) into a turn. So people think less roll less traction. When I think you gain more traction with less roll (on high traction tracks) because you are able to keep all 4 tires down and not tossing the weight around as much. So it's the weight transfer causing the car to flip. Low Roll Center=More Roll. The Rolling point is lower in the chassis making the car more or less be "top heavy" when leaning into a turn. Thus causing it to flip (the high traction doesn't allow the tire to slide like it would on low traction tracks). So you Raise Roll Center. This brings the rolling point closer to the Center of Mass. Thus making the car less top heavy (not really top heavy but a good way to explain the point).

And blah blah blah. Of course I'm referring to High R/C and Low R/C in general and not the effects it would have on changing it at one end of the car vs the other.

Hmm maybe I'm just blowing something out my buttucks.
You are correct! One interesting consideration is when you run foam tires on carpet which provides a tone of grip. In this situation most top drivers seem to run a low roll center which seems to go against what we are saying here. However the droop screws (which are typically set to almost no droop) affects the roll center. In this situation you will want to run a lower roll center geometry to help the car keep it's overall center of mass closer to the ground to prevent flipping.
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Old 05-12-2004, 06:07 PM   #2124
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Sounds good to me.

Anyways, I'm gonna mess around with roll centers this weekend at the track. Mainly adjusting the roll center all around. Not just front and rear. Gonna add some 2mm shims under the front and rear blocks and see what that does at the track for one qualifier. Then I can pull them out and test again for the 2nd qualifier. Compare lap times and maybe make another adjustment for the 3rd qualifier. See what's the best for the main. This'll be on a medium traction asphalt track.

Should be interesting...
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Old 05-13-2004, 04:03 AM   #2125
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Hey guys here are some of the new things to come for the 415

-Dave
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Old 05-13-2004, 04:04 AM   #2126
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Thumbs up more pic`s

new parts..
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Ȼ4.5 Centro+α ◊ TRF 501ӽ ◊ TRF 502ӽs ◊ TRF 503 ◊ TRF 511 ◊ TRF 201ӽr ◊ TRF 211ӽ
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Old 05-13-2004, 05:08 AM   #2127
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Hey Martin thanx alot for the set-up info!! This car is super smooth. Maybe because of the dual one-ways. Anyways I ran it in 19T. Unfortunately there was to much last minute rushing to get it set-up and dialed in. In the main I was second but the motor backed off the spur. So that ended my day in dissappointment. But it was GOOD TIMES. Between me setting up my brother's car getting my car race ready and trying to custom paint a body in the back of the pits it was very hectic but very fun. I enjoyed every minute of it. Just hopefully they stick with this 415 for a little while. But Great car fast and easy to drive. Can't wait to get some of those TRF hop-ups.



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Old 05-13-2004, 05:21 AM   #2128
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Dam some sweet TRF hop-ups. Can't wait to get some of those!
Sweet more blue parts!! Make the car even more stiffer then it already is.
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Old 05-13-2004, 05:23 AM   #2129
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Anyone know where I can get a hold of a TRF tool set? Within Canada or North America?
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Old 05-13-2004, 05:23 AM   #2130
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Anyone know what the pulley/guide bit is for?
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