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| falcongli6 | 
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							wats ur revs at when ur doing a 100
 with 3.9 diff gears in a eb-au falcon??? 
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| azza | 
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							i just changed my diff to a 3:45 from a 3:08 and it went from doin roughly 1700-1800 to about 2200 with the new diff... so i would imagine urs would be close to the 3000						
						
						
								
							 
 _________________ BA XR8 manual ute black | |||
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| falcongli6 | 
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							hey azza wen u went to 3.45 gears did ur speedo go out 10ks						
						
						
								
							 
 _________________ 04 BA XR6t auto  | |||
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| voids | 
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							hey azza what sort of ecconomy did you loose with your 3:45 diff? much difference from a 3:08?						
						
						
								
							 
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| Damoz 6 | 
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							Falcongli6 ive got 3.73 diff gears in my auto ef 6 and it revs at 2200rpm with my 17's on it. And i got better fuel economy when i put the gears in kumn up from 3.08						
						
						
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| XR8Chic | 
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							you can easily work it out yourself
 Just need the ratio of the gear, and the circumference of the wheels, and the diff ratio (which you already have). 
 _________________ 1993 ED XR8 - Poly Green | |||
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| XR8Chic | 
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							oh... in case you dont know what I mean..
 Engine RPM divided by gear ratio, divided by diff ratio = the number of spins of the wheel per minute multiply it by the circumference of the wheel = distance per minute multiply by 60 to get distance per hour. easy peasy 
 _________________ 1993 ED XR8 - Poly Green | |||
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| Bassfreak55 | 
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 | {USERNAME} wrote: oh... in case you dont know what I mean.. Engine RPM divided by gear ratio, divided by diff ratio = the number of spins of the wheel per minute multiply it by the circumference of the wheel = distance per minute multiply by 60 to get distance per hour. easy peasy I think its time to bring out the calculator!     | ||
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| wild6 | 
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							in my xr8 the speedo is currently out about 15kms and when i sit on 115kmh it sits at 2400 rpm 
 regards from adam 
 _________________ series3 xr8 5 speed manual, pacemaker extractors, 3' exhaust, lowered  cold air intake, k&n filter, interior, 3.9s 
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| jonbays | 
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							You should be doing about 2400rpm at 100kmh in a 4spd auto with a 3.9 diff and 235/45ZR17's 
 Kmh/1000 rpm for a falcon BTR auto in fourth with 235/34ZR17 tyres and diffferent diffs are: 3.08 diff 54.8kmh/1000 rpm 100kmh = 1825 rpm 3.23 diff 52.4kmh/1000 rpm 100kmh = 1910 rpm 3.45 diff 48.8kmh/1000 rpm 100kmh = 2050 rpm 3.73 diff 44.2kmh/1000 rpm 100kmh = 2260 rpm 3.9 diff 41.5kmh/1000 rpm 100kmh = 2410 rpm | ||
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| bowsaw | 
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							Mine is doing nearly 1900 at 100.						
						
						
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| djmikey | 
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							Mine is a stock ED and i sit on 1700 doing 100k/hr						
						
						
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| dark_realm | 
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							my mates eb hardly rev's at 100km's its like 1500 - 1750, but its got a good top speed of around 220 i think.....						
						
						
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| azza | 
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							sorry for late reply.. but yeh i noticed a drop in fuel economy..... i sat on around 12.8L per 100km with 3:08 and now im on about 14L per/100km.... so a small difference i would mostly say bcoz i do alot of freeway drivng and the higher revs is lifting me fuel consumption.... but a small increase in fuel consumption is a small price to pay for a LSD diff... it drives so much nicer... feels so tight around corners						
						
						
								
							 
 _________________ BA XR8 manual ute black | |||
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| NUTZEF | 
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							i know u can buy different speedo gears but can u get speedo gears for a 3.9 ratio because that is not a standerd ford ratio and what color are the speedo gears for 15 inch rims and 17inch.  also what happens to the computer controled shift does the speedo gear correct this.						
						
						
								
							 
 _________________ WOLF V500, t66(ar70 compressor), rochester 550cc injectors, borgg 265l fuel pump, 48mm turbosmart gate, turbosmart plumb back bov, 600x300x100 cooler, 3 inch zorst , 3.45 lsd, xr6 head, wade 1604 cam, adjustable cam gear, K&N pod filter, on 10psi and manual convertion exedy button clutch. 285.6rwkw | ||
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