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2wd saph what are flat out speeds on standard drivetrain ?

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Old Jun 22, 2007 | 06:32 PM
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Default 2wd saph what are flat out speeds on standard drivetrain ?

hi was just wondering what speeds in each gear people are getting from 2wd saphs on standard drivetrain when hitting the limiter?
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Old Jun 22, 2007 | 09:39 PM
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standard size wheels amd tyres?
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Old Jun 23, 2007 | 06:15 AM
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Road speed at given RPM =
60 X Engine RPM / Divided by Wheel Revs(mile) X Axle Ratio X Gearbox RATIO.
So that is, 60 X 6500(rpm) / 897X3.64XGearbox ratio.
I don't have the gearbox ratio(to hand) so I looked in the FORD booklet instead.
Cossie max speed is as stated
1st = 40
2nd = 62
3rd = 89
4th = 119
5th = 149
This is what ford say in the booklet that came with the cossie, so if inaccurate down to them.
tabetha
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Old Jun 23, 2007 | 10:55 AM
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From: st neots cambridgeshire
Default reply to tabetha

as always your a fountain of knowledge mate thank you.
im gettin 105 mph in 3rd and my speedo isnt far out, my rev clocks saying 6500 rpm so really im probably over 7000 rpm anyway.
thanks mate
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Old Jun 23, 2007 | 11:06 AM
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"fountain of knowledge", no I just looked in the booky.
tabetha
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Old Jun 23, 2007 | 04:46 PM
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Originally Posted by tabetha
Road speed at given RPM =
60 X Engine RPM / Divided by Wheel Revs(mile) X Axle Ratio X Gearbox RATIO.
tabetha
Just a little change :
60 x RPM x wheel rev / (axle ratio x gear ratio)

Regards
Claude
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Old Jun 23, 2007 | 07:35 PM
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Beg to differ matey but you are incorrect.
It is as I said, example,

60 X 5000(rpm) = 300,000
897(wheel revs/mile) X 3.62(diff ratio) X 0.73 Gear ratio(top) = 2370.4122
= 300,000 / 2370.4122 = 126.56
NB this is just an example not necessarily applicable to the cossie.
tabetha
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Old Jun 24, 2007 | 10:53 AM
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From: st neots cambridgeshire
Default tabetha

just got gearbox ratio and added up. your right tabetha.
at 7500 rpm 1st 43 , 2nd 71 , 3rd 103 , 4th 138 and 5th 173
my rev clock must be showing 6500 rpm when its really 7500 rpm.
i think il stick to no higher than 6000 rpm on me rev clock dont wana kill the old girl
thanks people
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Old Jun 24, 2007 | 01:48 PM
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They have rev elimiters(ecu), but safe to 8000 all day long anyway!!
tabetha
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Old Jun 24, 2007 | 03:12 PM
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From: st neots cambridgeshire
Default tremec t56

ive just done the ratios for a tremec t56 at 7500 rpm would be 1st 46, 2nd 66, 3rd 96, 4th 138, 5th 173 and 6th 223.
does anyone know if speedo would be correct if this box fitted ?
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Old Jun 24, 2007 | 03:25 PM
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So long as the drive(cable) turns at 1000 times a mile then it is correct.
tabetha
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