Fordmods Logo

diff ratios??? 

 

Page 1 of 1 [ 10 posts ] 

 
 Post subject: diff ratios???
Posted: Sun May 14, 2006 8:27 pm 
Smokin em up
Offline

Age: 34

Posts: 295

Joined: 3rd May 2006

Gallery: 8 images

Ride: falcon

Location: lower plenty
VIC, Australia

hello,
im not the best when it comes to mechanically minded stuff but i am unsure what all of the diff ratios mean. like some people have 3.45, some have 4.11.
whats the difference between different sizes and how does it benefit driving/racing?
am only asking coz i am still running my single spinner on my ef futura and wanna get LSD.
thanks guys
biff

 

_________________

Image

Top
 Profile  
 
 
Posted: Sun May 14, 2006 8:56 pm 
Getting Side Ways
Offline
User avatar

Age: 30

Posts: 2280

Joined: 5th Nov 2004

Ride: EF Falcon 95

Location: Rosebud
VIC, Australia

basically waht it means is, say 3.08:1 which is standard diff ratio for manual futuras (i think)

it means for every one turn of the gearbox/driveshaft the wheel/wheels turn 3.08 times, or for 3.7's it means 1 turn of the driveshaft is 3.7 turns of the wheel. the higher up you go (which is actually termed lower diff ratio, wtf?) means your cars speeds in each gear drop, and revs out quicker, but gives you better acceleration. lower diff ratios decrease top end speed, but in a falcon 6 it doesnt really matter all to much, unless you have had massive work done you wont get over 180km/h on the strip!.

the cars speed at a given rev's will change once diff gears change. so say with me, auto, i had standard single pegger with 3.08 diff gears, i used to sit on i think around 1600 rpm for example at 100km/h. Now i have 3.7 dif gears and i sit on 2300rpm at 100km/h. The lower the diff ratio, the more petrol you will use.

higher ratios (2.9:1) for example, decrease acceleration, as it takes longer to rev out because you will get to much higher speeds in each gear, and will increase top end speed.

3.7 or 3.9 is the highest i would go. 4.11's are a waste of time and make your car a pig to drive.

 

_________________

Cougar Zero makes my pants fit nice.

Top
 Profile  
 
 
Posted: Sun May 14, 2006 8:58 pm 
Getting Side Ways
Offline

Posts: 6449

Joined: 11th Nov 2004

3.08 diff gear mean for every 3.08 turns of the drive shaft there is 1 of the rear wheel. and so on and so forth through the different ratios

 

_________________

PERMANENTLY BANNED

Top
 Profile  
 
 
Posted: Sun May 14, 2006 9:18 pm 
Smokin em up
Offline

Age: 34

Posts: 295

Joined: 3rd May 2006

Gallery: 8 images

Ride: falcon

Location: lower plenty
VIC, Australia

so... if i want better take off but not as much top end speed, i would wanna put in a diff with a lower ratio. correct??? if i already have a 3.08, what would u recommend i should put in and how much would it be?
thanx
biff

 

_________________

Image

Top
 Profile  
 
 
Posted: Sun May 14, 2006 10:09 pm 
Getting Side Ways
Offline
User avatar

Age: 30

Posts: 2280

Joined: 5th Nov 2004

Ride: EF Falcon 95

Location: Rosebud
VIC, Australia

tickford wrote:
3.08 diff gear mean for every 3.08 turns of the drive shaft there is 1 of the rear wheel. and so on and so forth through the different ratios


i stand corrected. got it mixed up, listen to this bloke, hes got the knowledge. my bad! :oops:

ef biff wrote:
so... if i want better take off but not as much top end speed, i would wanna put in a diff with a lower ratio. correct??? if i already have a 3.08, what would u recommend i should put in and how much would it be?


try a 3.45 (standard xr6) or a set of 3.7's. i doubt u will notice top end power loss with those ratios

 

_________________

Cougar Zero makes my pants fit nice.

Top
 Profile  
 
 
Posted: Sun May 14, 2006 10:12 pm 
Smokin em up
Offline

Age: 34

Posts: 295

Joined: 3rd May 2006

Gallery: 8 images

Ride: falcon

Location: lower plenty
VIC, Australia

lol, thats cool,
so from my standard 3.08 diff, what size should i be replacing with to get better accelaration with LSD?

 

_________________

Image

Top
 Profile  
 
 
Posted: Mon May 15, 2006 8:44 am 
Parts Gopher
Offline
User avatar

Age: 29

Posts: 86

Joined: 29th Apr 2005

Gallery: 8 images

Ride: E series falcon

Location: Adelaide
SA, Australia

Im also looking at replacing my standard 3.08 with either a 3.45 or 3.7 lsd. What's the easiest to source?
Top
 Profile  
 
 
Posted: Mon May 15, 2006 7:10 pm 
Getting Side Ways
Offline

Posts: 6449

Joined: 11th Nov 2004

3.45:1 is the easiest one to fit. both are common though there is no speedo gear for ECU for the 3.7 to get correct speedo reading and shift points. with a 3.7 best of just relearning what the speedo is telling you

 

_________________

PERMANENTLY BANNED

Top
 Profile  
 
 
Posted: Mon May 15, 2006 10:01 pm 
Parts Gopher
Offline
User avatar

Age: 29

Posts: 86

Joined: 29th Apr 2005

Gallery: 8 images

Ride: E series falcon

Location: Adelaide
SA, Australia

Looks like i'll be going with a 3.45.1 lsd - and you can get them from EF/EL XR6's right?
Top
 Profile  
 
 
Posted: Tue May 16, 2006 9:43 am 
Getting Side Ways
Offline
User avatar

Age: 36

Posts: 1249

Joined: 5th Nov 2004

Ride: Falcon

Location: Melbourne
VIC, Australia

Quote:
4.11's are a waste of time and make your car a pig to drive.


It would make and I6 a pig to drive no doubt, but its all horses for courses, on a higher reving motor with a matched cam, 4.11's can play the key part in a potent combination

 

_________________

I couldnt fix your brakes so I made your horn louder
Image

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 1 of 1  [ 10 posts ] 

Who is online

Users browsing this forum: No registered users and 19 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Fri Dec 15, 2017 8:15 am All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names