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Old 12-20-2013, 05:49 PM   #1
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Default T/C Gear Ratio Question

I am running 16/47 in my T/C (1st Gear) right now and would like to know what would be the difference if I put a 15T on the clutch(keeping the 47T) VS putting a 48T on the spur(keeping the 16T). I know each change would give me more bottom end,which one is better or is it 6-1/2 dozen the same? thanks,mike.
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Old 12-20-2013, 06:15 PM   #2
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Originally Posted by Mikiehotrod View Post
I am running 16/47 in my T/C (1st Gear) right now and would like to know what would be the difference if I put a 15T on the clutch(keeping the 47T) VS putting a 48T on the spur(keeping the 16T). I know each change would give me more bottom end,which one is better or is it 6-1/2 dozen the same? thanks,mike.
I don't run 10th, I run GT8 and raced NHRA for a few years. The principles are the same where a motor with 'stump-pulling-grunt' can use the bigger 'pinion gears' and a 'high-revving' motor that needs 'a little head-start' would feel better with the smaller pinion and can still 'wave bye-bye'

Where does your motor/make and model stand in the 'brute force/nimbleness' factor ???? (350 chev 7,500 rpm versus old school 283 bored to 292 chev at 9,000 rpm)
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Old 12-20-2013, 06:43 PM   #3
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that's funny, I am also a NHRA Driver (T/S). I run a JP .12 and it is a little soft on T/Q. have tried pipes and headders. I know if I put the 48T it is like going from a 4.10 to a 4.30 or a 4.56. or a losser stator. was just woundering is the ratio the same with 1 tooth up or down?
I thought that the 48T is like the run out,(how far the car would travel before running out of motor) and the 15T would just give it more snot down low?
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Old 12-21-2013, 10:13 AM   #4
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Originally Posted by Mikiehotrod View Post
I am running 16/47 in my T/C (1st Gear) right now and would like to know what would be the difference if I put a 15T on the clutch(keeping the 47T) VS putting a 48T on the spur(keeping the 16T). I know each change would give me more bottom end,which one is better or is it 6-1/2 dozen the same? thanks,mike.
It would roughly be about a 1/3 difference.

What I mean is this....

Ratio/'s
16/47 ...... 2.938
15/47 ...... 3.133
16/48 ...... 3.000

So just going down 1 tooth on the clutch gear is like going up 3 teeth on the spur (Roughly)

16/50 ..... 3.125

So, with going down 1 tooth on the clutch gear you will see a bigger difference in acceleration (Gain) and loss of top speed (Loss) then by going up 1 tooth on the spur by about 3 times.

This is not the full picture but a good indication of what to expect

I hope that doesn't confuse you

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Old 12-22-2013, 12:21 PM   #5
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Originally Posted by British Menace View Post
It would roughly be about a 1/3 difference.

What I mean is this....

Ratio/'s
16/47 ...... 2.938
15/47 ...... 3.133
16/48 ...... 3.000

So just going down 1 tooth on the clutch gear is like going up 3 teeth on the spur (Roughly)

16/50 ..... 3.125

So, with going down 1 tooth on the clutch gear you will see a bigger difference in acceleration (Gain) and loss of top speed (Loss) then by going up 1 tooth on the spur by about 3 times.

This is not the full picture but a good indication of what to expect

I hope that doesn't confuse you

Regards
BM
thanks very much for the explanation.also since we are here,what would be the ratio of a 15/48 and its affects? thanks again,mike.
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Old 12-23-2013, 08:36 AM   #6
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thanks very much for the explanation.also since we are here,what would be the ratio of a 15/48 and its affects? thanks again,mike.
Thanks to BM for 'putting the numbers' to the answer.

Mikie.....48 divided by 15 is 3.2 and is a 'quick leave off the line' or less effort coming out of the corners for a T/C and GT8 etc than the 16/47. The 'bigger' that ratio result is, the quicker your engine max rpm is reached.

Are you 'cutting your tires'....(foams).....? There is also a 'ratio tool' there that I've seen the 'pros' using in their personal bag of tricks.



*Mikie......
(72 Chevelle, 350/350HD, 'stage 2 shift kit', not fast, just deadly reaction times in 'street legal heavy', no.6 for the 2001 season locally)
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Old 12-26-2013, 05:10 PM   #7
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Thanks to BM for 'putting the numbers' to the answer.

Mikie.....48 divided by 15 is 3.2 and is a 'quick leave off the line' or less effort coming out of the corners for a T/C and GT8 etc than the 16/47. The 'bigger' that ratio result is, the quicker your engine max rpm is reached.

Are you 'cutting your tires'....(foams).....? There is also a 'ratio tool' there that I've seen the 'pros' using in their personal bag of tricks.



*Mikie......
(72 Chevelle, 350/350HD, 'stage 2 shift kit', not fast, just deadly reaction times in 'street legal heavy', no.6 for the 2001 season locally)
thank you very much for the explanation.much testing to be done. I have a tire truer and it works the same like the big cars(shorter tire more giddy up out of the hole)PS,big toy is 622 CI BBC, inj alky.1,300 HP on motor and 1,800 HP on 2 foggers.small cars much cheaper!!!

Last edited by Mikiehotrod; 12-26-2013 at 05:12 PM. Reason: need to add more
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