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Old 10-17-2002, 05:06 PM   #1636
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Wish I could help you with the weather problem but were I race even damp ground means no race.

I have a question on the pipe, did you make your own or retrofit one from another car? If you did make it did you do it out of steel or aluminum?

From my experiences with a centax is that it is used to get a real on/off feeling. My friends that run 1/8 scale say it is real hard to drive a shoe clutch car because it lags to much. This is probably not what you want to hear but I have stuck with the shoes because it is much faster in the fact that you can tune slip into it. IMO the centax clutches don't slip enough because of the ammount of material that is in contact.
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Old 10-17-2002, 05:18 PM   #1637
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Quote:
Originally posted by Boomer
You could also try putting a little overdrive in it (run larger fronts than rears - foams) - I've found that to pull itself around corners a bit better. . .don't go dramatically different sizes, just a touch.
Wouldn't larger front tires underdrive the front seeing as how the front would rotate less?
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Old 10-18-2002, 12:39 AM   #1638
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Quote:
Originally posted by rod_b
Wouldn't larger front tires underdrive the front seeing as how the front would rotate less?
They rotate at the same rate. It is just that at the contact point where the tire is, the larger tire's tangent velocity is higher, hence the front overdrive.

Assuming rotational speed (w) is the same for both wheels because it is spinning from the same source, using a larger diameter tire (or radius if you may, where r1 > r2) on the front will generate a higher tangent velocity on the front.

This is based upon the v = rw formulae.
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Old 10-18-2002, 04:28 PM   #1639
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They rotate at the same tranny rate but that doesn't mean they go the same distance. A smaller wheel will complete 1 revolution faster and in a shorter amount of distance than a larger wheel. Your formula is good for calculating the max velocity possible for a particular sized wheel. However, overdriving is about the number of revolutions per distance. A smaller wheel will turn more times to cover the same amount of distance as a larger wheel.
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Old 10-20-2002, 11:09 AM   #1640
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Quote:
Originally posted by rod_b
They rotate at the same tranny rate but that doesn't mean they go the same distance. A smaller wheel will complete 1 revolution faster and in a shorter amount of distance than a larger wheel. Your formula is good for calculating the max velocity possible for a particular sized wheel. However, overdriving is about the number of revolutions per distance. A smaller wheel will turn more times to cover the same amount of distance as a larger wheel.
Ok, maybe the example of using the tangent velocity was not such a good example for explanation purposes. I thought it would be simpler to explain it that way. I guess not... I'll go a shorter way and maybe the correct way, which is by calculating the FRONT and REAR tire rollouts INDIVIDUALLY.

Lets assume now that we use a FRONT tire which has a diameter of 64 mm and the REAR to be 60 mm i.e. FRONT tires larger diameter than REAR tires to create a FRONT overdrive on the NTC3.

Tire Rollout = (Tire Diameter x PI) / Final Gear Ratio

For the NTC3, for argument sake, lets use the stock gears i.e. 1st pinion 22T, 2nd pinion 26T, 1st spur 54T and the 2nd spur 50T. This gives a final drive ratio of 6.14 and 4.81 respectively for the 1st and 2nd gears, taking the drive train ratio of the NTC3 to be 2.5.

Looking only at 1st gear engagement, Using a 64 mm diameter for the FRONT tire, the FRONT tire rollout will come up to 32.75 mm per engine revolution.

Using a 60 mm diameter REAR tire, the REAR tire rollout will come up to 30.7 mm per engine revolution.

FRONT tire rollout does NOT equal REAR tire rollout i.e. the FRONT tire goes a "longer distance" than the REAR tire when using larger diameter tires for the FRONT.

The same also goes when you take the 2nd gear final ratio as an example. Tire rollout for the FRONT is and will be more than the REAR, hence the FRONT overdrive when using larger FRONT tires than the REAR.
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Old 10-21-2002, 01:37 AM   #1641
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Default Restrictor on the stock manifold????

Last day I dissasembled completely the exhaust of my RE NTC3 and noticed that the stock manifold comes with some kind of restrictor where comes in contact with the exhaust window of the engine. I noticed that is of slightly diameter than the 'optimum diameter'.

Anyone has noticed it? rather than being less diameter seems that need some dremel on the upper side to provide better exhaust.

Other question, how many uses the stock composite and how many uses the optional graphite parts? only options on my car are the front sway bar, AL sway bar holders, some alu screws and the lightweight parts of the 2 speed transom.
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Last edited by Corse-R; 10-21-2002 at 01:42 AM.
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Old 10-21-2002, 04:10 AM   #1642
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yeah i noticed that the second i took it out of the packge so i gave it a hit with the dremal untill the headder port was the same as my exhaust port on my rossi also the gasket that is provided need to be opened up too but i dont ues it anyways i use i temp gasket seelent

i havent got my car full togeather but 2 of me mates do who also race and one is bone stock other than the tank mod and on the other all that has been changed is the springs and the gearing and they are holding up fine

also anybody here produced smoke of their wheels from doing a burnout

i have
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Old 10-21-2002, 04:12 AM   #1643
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sorry Corse-R i was talking about the side exhaust

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Old 10-21-2002, 05:51 AM   #1644
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Default Conversion to Electric

Off the subject, but who would be interested in buying a carbon fiber chassis kit that would use the NTC3 Suspension for electric use?
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Old 10-21-2002, 08:43 AM   #1645
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Default Re: Restrictor on the stock manifold????

Only option I have right now is aluminum handle. Tank modified, shock tower modified.

I thought about buying carbon fiber upper deck but the stock plastic one is working fine and I don't have to worry about glitch.

I may be recplacing all the parts to lighter ones once I'm on track with racing it.


Quote:
Originally posted by Corse-R
Last day I dissasembled completely the exhaust of my RE NTC3 and noticed that the stock manifold comes with some kind of restrictor where comes in contact with the exhaust window of the engine. I noticed that is of slightly diameter than the 'optimum diameter'.

Anyone has noticed it? rather than being less diameter seems that need some dremel on the upper side to provide better exhaust.

Other question, how many uses the stock composite and how many uses the optional graphite parts? only options on my car are the front sway bar, AL sway bar holders, some alu screws and the lightweight parts of the 2 speed transom.
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Old 10-21-2002, 09:47 AM   #1646
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Quote:
Originally posted by InitialD
Ok, maybe the example of using the tangent velocity was not such a good example for explanation purposes. I thought it would be simpler to explain it that way. I guess not... I'll go a shorter way and maybe the correct way, which is by calculating the FRONT and REAR tire rollouts INDIVIDUALLY.

Lets assume now that we use a FRONT tire which has a diameter of 64 mm and the REAR to be 60 mm i.e. FRONT tires larger diameter than REAR tires to create a FRONT overdrive on the NTC3.

Tire Rollout = (Tire Diameter x PI) / Final Gear Ratio

For the NTC3, for argument sake, lets use the stock gears i.e. 1st pinion 22T, 2nd pinion 26T, 1st spur 54T and the 2nd spur 50T. This gives a final drive ratio of 6.14 and 4.81 respectively for the 1st and 2nd gears, taking the drive train ratio of the NTC3 to be 2.5.

Looking only at 1st gear engagement, Using a 64 mm diameter for the FRONT tire, the FRONT tire rollout will come up to 32.75 mm per engine revolution.

Using a 60 mm diameter REAR tire, the REAR tire rollout will come up to 30.7 mm per engine revolution.

FRONT tire rollout does NOT equal REAR tire rollout i.e. the FRONT tire goes a "longer distance" than the REAR tire when using larger diameter tires for the FRONT.

The same also goes when you take the 2nd gear final ratio as an example. Tire rollout for the FRONT is and will be more than the REAR, hence the FRONT overdrive when using larger FRONT tires than the REAR.
Great info, however "Overdriving" is basically understood as overdriving the front...meaning making the front wheels turn faster. So your calcs are fine. However, it's the smaller diameter wheel that goes in front. Some thing non-scientific to think about. If the front wheels were turning faster, than the front end would pull the back end of the car around the turns...the basic theory of overdriving. Why would you want the rear of a car to be going faster than the front of the car?

Last edited by rod_b; 10-21-2002 at 09:55 AM.
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Old 10-21-2002, 10:22 AM   #1647
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Such precise and complicated explanations. . .

But it's Monday morning and I haven't finished my cup o' J yet. . .

All tires are driven at the same speed. Our cars don't have a center diff (some do - I believe the new HPI does. . .) so they all are driven at the same speed.

Larger tires will go faster than smaller tires (see above explanations) so if you put larger tires on the front you will "pull" the car more.

Smaller tires on the front will go slower than the rear so you would "push" the car - I don't know anyone who does this - well, I think some do a tiny bit because we tend to wear the rears out faster. . .something of a compensation.

Okay, there's my simple, non-caffeinated version. . .
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Old 10-21-2002, 11:29 AM   #1648
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Corse-R, Dremel it out. Here's a before and after photo to compare.
Attached Images
File Type: jpg mods 001.jpg (59.8 KB, 237 views)
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Old 10-21-2002, 05:07 PM   #1649
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Hey Nut, can you tell any difference?
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Old 10-21-2002, 10:40 PM   #1650
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NTC3NUT what bit did you use to Dremel it out?
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