Joelove
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| posted on 17/9/13 at 10:19 AM |
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Diff ratio for bec?
Hi all, will soon be looking at purchasing an lsd for my build but not sure what ratio I should be looking for?
I'm fitting a 2004 cbr 1000rr engine, and it would be nice to be hitting a top speed of about 125-130mph.
Haven't got a clue how to work the diff ratios out so any help would be great!
Thanks in advance joe
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twybrow
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| posted on 17/9/13 at 11:15 AM |
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Check out the 'Sticky' at the top of the BEC forum - or click
here
This is an in gear speed calculator which you can use to play around with combinations of engine, diff, wheel/tyre size. Enjoy!
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MK9R
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| posted on 17/9/13 at 11:52 AM |
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3.38 if you are going with the sierra lump
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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Joelove
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| posted on 17/9/13 at 01:30 PM |
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quote:
Originally posted by MK9R
3.38 if you are going with the sierra lump
So the lower the diff ratio the higher the top end?
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dave_424
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| posted on 17/9/13 at 01:58 PM |
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quote:
Originally posted by Joelove
quote:
Originally posted by MK9R
3.38 if you are going with the sierra lump
So the lower the diff ratio the higher the top end?
Correct
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MK9R
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| posted on 17/9/13 at 02:13 PM |
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quote:
Originally posted by Joelove
quote:
Originally posted by MK9R
3.38 if you are going with the sierra lump
So the lower the diff ratio the higher the top end?
Go too low though engine won't top out. You'll see the speeds you want with a 3.38
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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doobrychat
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| posted on 17/9/13 at 04:14 PM |
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I had a 3.92 in my bec which was only good for 110 top end.. changed it for a 3.62 because of the cruising rpm.. seen 126mph on my speedo (private
land) and still pulls away nicely..go too lower diff then it will be more rpm screaming to pull away...
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Joelove
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| posted on 17/9/13 at 04:14 PM |
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quote:
Originally posted by MK9R
quote:
Originally posted by Joelove
quote:
Originally posted by MK9R
3.38 if you are going with the sierra lump
So the lower the diff ratio the higher the top end?
Go too low though engine won't top out. You'll see the speeds you want with a 3.38
3.38 it is then! Thanks guys
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Brackers
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| posted on 17/9/13 at 08:01 PM |
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I agree. I have 3.91 and whilst you can get the speed, in a BEC it's not great for cruising. Thinking of reducing mine over winter.
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