thanks for that, trying to cost up a BEC build here in my head into a new chassis
just curious as to what diff lads use for a BEC? Im guessing its not the big heavy sierra diff most of us CEC lads use?
cheers
Certainly is, some people have used the Landrover Freelander Diff.
Mainly the Sierra Diff
Mike
i still think a robin hood is to weighty for a bec mate.
i know my old one was to weighty for a cec.
ah ok cool
thanks for that, trying to cost up a BEC build here in my head into a new chassis
Same diff, although most look for 'faster' ratios like 3.38 or 3.14 (gold dust) due to the rev / gearing characteristics of the bike
engine.
[Edited on 25/10/07 by matt_claydon]
quote:
Originally posted by graememk
i still think a robin hood is to weighty for a bec mate.
i know my old one was to weighty for a cec.
I have a sierra 3.62 diff in mine and for the road it is OK. 1st is a nice fast gear. 6th will take me up to 120 MPH at the red line.
The problems are that 70 MPH is at 6800 RPM in top and peak power at 103 MPH. On the track it seems slow above about 105 / 110.
A 3.38 or 3.14 diff will be no quicker or slower accelerating over all but will be slower in each gear. You'll need more revs to pull away and
acceleration in 1st will be about 10% (3.30) or 15% (3.14) slower. 6th gear is much more like it though. Revs will be 10 or 15% lower and peak power
speed 10 or 15% higher. Top speed will be higher too.
If you want to do 100 MPH+ on the track or do lots of motorway cruising, you need a lower ratio diff. Otherwise, don't bother.
100mph on track would be sufficient
You'll be wooped every 5 minutes though!
I will be using the RS200 axle (3.54 open diff).
quote:
Originally posted by 2b_pablo
100mph on track would be sufficient
its fine for the track I use, currently hitting 85/90 in the hood.
quote:
Originally posted by 2b_pablo
100mph on track would be sufficient
In my opinion it depends on the engine.
An R1 with a 3.62 is fine - topping out at 120ish but I love the acceleration (got used to it now and could do with more).
A new ZX10 on the other hand would be a nightmare with a 3.62, bigrich did some calcs and he uses a freelander.
HTH.
Yep, like fesycresy says 'it depends on the engine'
Phil
It does indeed, but from my CEC point of view, although "much over 100" isn't much use in a 7 as its not much fun for any length of time, my car gets to that sort of speed from standstill in around 8 secs so its not like you'll never need it!!!