
falcongli6 



wats ur revs at when ur doing a 100
with 3.9 diff gears in a ebau falcon???
_________________ 04 BA XR6t auto 

Top  
azza 



i just changed my diff to a 3:45 from a 3:08 and it went from doin roughly 17001800 to about 2200 with the new diff... so i would imagine urs would be close to the 3000
_________________ BA XR8 manual ute black 

Top  
falcongli6 



hey azza wen u went to 3.45 gears did ur speedo go out 10ks
_________________ 04 BA XR6t auto 

Top  
voids 



hey azza what sort of ecconomy did you loose with your 3:45 diff? much difference from a 3:08?
_________________ ' 96 Xh XR6 Ute 

Top  
Damoz 6 



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


Top  
XR8Chic 



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).
_________________ www.XR8Chic.com 

Top  
XR8Chic 



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
_________________ www.XR8Chic.com 

Top  
Bassfreak55 



XR8Chic 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! 

Top  
wild6 



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


Top  
jonbays 



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 

Top  
bowsaw 



Mine is doing nearly 1900 at 100.


Top  
djmikey 



Mine is a stock ED and i sit on 1700 doing 100k/hr


Top  
dark_realm 



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.....


Top  
azza 



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 

Top  
NUTZEF 



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 

Top  
Who is online 

Users browsing this forum: Google [Bot] and 13 guests 