Fordmods Logo

Diff Gear Ratio Question. 

 

Page 1 of 3 [ 39 posts ] Go to page 1, 2, 3  Next

 
 Post subject: Diff Gear Ratio Question.
Posted: Wed Feb 21, 2007 3:26 pm 
Stock as a Rock
Offline
User avatar

Posts: 190

Joined: 30th May 2006

Location: Third Rock From The Sun
Oustide Australia

A friend has a stock EB XR8 running 3.27 gears and would like to know if there is signifigant power improvement changing to 3.45 gears.

thanks ed_man

 

_________________

God save Allan Moffat, God bless d**k-Johnson and thank Christ for Marcos Ambrose.........

Top
 Profile  
 
 
Posted: Wed Feb 21, 2007 3:47 pm 
Fordmods Junkie
Offline
User avatar

Posts: 11739

Joined: 17th May 2005

Gallery: 11 images

Ride: EL Fairmont, VFR400 racer

Power: 144 rwkw

Location: Melbourne
VIC, Australia

He will get a better launch and when sitting at 100km/hr he will be sitting at higher revs then with a 3.27. Slightly better economy in city driving but that depends on how heavy his foot is. Not sure if the power actually changes, though I know you would have a better launch which will improve the quater times a tad.

phong =P~

 

_________________

phongus = Post whore 2006
EL XR6 motor, EL ECU + J3 chip, WADE 1673 Camshaft, 3" S/S intake, Pacy 4480, 2.5" Hi flow cat, 2.5" Lukey exhaust.
Max Power = 144.6 rwkw (03/05/2008)

Top
 Profile  
 
 
Posted: Wed Feb 21, 2007 4:51 pm 
Getting Side Ways
Offline

Age: 37

Posts: 661

Joined: 2nd Dec 2004

Ride: AU XR8

Location: Wollongong
NSW, Australia

The engine wont make anymore power.

But the shorter gearing will increase torque at the wheels by 5.5%...
Top
 Profile  
 
 
Posted: Wed Feb 21, 2007 5:08 pm 
Technical Contributor
Offline
User avatar

Age: 32

Posts: 3097

Joined: 5th Nov 2004

Gallery: 29 images

Ride: VU SS

Location: Ivanhoe
NSW, Australia

I just went from 3.23 to 3.45, and you feel a slight difference.
I only did it to get an LSD in there, not for the ratio change.

If he's got an auto the shorter gearing helps, if it's a manual I wouldn't bother.

 

_________________

EF Fairmont now Sold!
Guides: Polishing|Modifications |Manual Conversion

Top
 Profile  
 
 
Posted: Wed Feb 21, 2007 6:01 pm 
Stock as a Rock
Offline
User avatar

Posts: 190

Joined: 30th May 2006

Location: Third Rock From The Sun
Oustide Australia

His eb is an auto and I think he is after a bit extra in exceleration on take off.

thanks for your replies.

 

_________________

God save Allan Moffat, God bless d**k-Johnson and thank Christ for Marcos Ambrose.........

Top
 Profile  
 
 
Posted: Wed Feb 21, 2007 11:03 pm 
Getting Side Ways
Offline
User avatar

Age: 31

Posts: 2450

Joined: 5th Nov 2004

Gallery: 1 images

Ride: NL V8 Fairlane

Location: Sydney
NSW, Australia

I didn't feel a whole lot of difference. Go to 3.7s.

 

_________________

There are 10 types of people in this world.
Those who know binary and those who don't.

Top
 Profile  
 
 
Posted: Thu Feb 22, 2007 12:32 am 
Parts Gopher
Offline
User avatar

Posts: 70

Joined: 17th Feb 2007

Gallery: 4 images

Location: Melbourne, Australia
VIC, Australia

Also, if I can slightly hi-jack this thread.

I've got 3.45 LSD in mine at the moment, and I'm planning either 3.7 or 4.11, do they come out with 3.9?

What fuel economy increase will I be looking at from 3.45 to 4.11?

And how high would the revs sit at 100?, at the moment it's on what.. 2,000?
4spd 5ltr
Top
 Profile  
 
 
Posted: Thu Feb 22, 2007 12:26 pm 
Getting Side Ways
Offline

Age: 37

Posts: 661

Joined: 2nd Dec 2004

Ride: AU XR8

Location: Wollongong
NSW, Australia

[HMASEL] wrote:
I've got 3.45 LSD in mine at the moment, and I'm planning either 3.7 or 4.11, do they come out with 3.9?

Yep, I've got 3.9's and im pretty sure we have the same diff....BTR 78.

3.9's will be either 3.89:1 (2nd hand from Nissans), or 3.91 (brand new).
Top
 Profile  
 
 
Posted: Thu Feb 22, 2007 6:46 pm 
Getting Side Ways
Offline
User avatar

Age: 49

Posts: 6467

Joined: 18th Dec 2006

Ride: 93 ED sedan

Power: 161 rwkw

Location: Rockhampton
QLD, Australia

[HMASEL] wrote:
Also, if I can slightly hi-jack this thread.

I've got 3.45 LSD in mine at the moment, and I'm planning either 3.7 or 4.11, do they come out with 3.9?

What fuel economy increase will I be looking at from 3.45 to 4.11?

And how high would the revs sit at 100?, at the moment it's on what.. 2,000?
4spd 5ltr


Here's how to work out speed verses diff ratio.

 

 

Attachments:
Speed calculator with example.jpg
Speed calculator with example.jpg [ 353.25 KiB | Viewed 54 times ]

 

_________________

http://youtu.be/jJTh9F3Vgg0

Top
 Profile  
 
 
Posted: Thu Feb 22, 2007 7:07 pm 
Smokin em up
Offline
User avatar

Age: 31

Posts: 264

Joined: 5th Jan 2007

Ride: E-Hybrid Falcon

Location: nowra, nsw
NSW, Australia

economy through higher range gears... lol

 

_________________

crow cam,cai,exaust,bbm,190 reg & el injectors,xr6 interior,guages,white cluster,pioneer/mtx stereo,big boot install w.i.p, 17"rims,koni/pedders shocks&springs with nolathane re-bush,ssv kit,stainless inserts,clear lights,t5 & short shifter,chardonay/pearl paint

Top
 Profile  
 
 
Posted: Fri Feb 23, 2007 1:35 am 
Parts Gopher
Offline
User avatar

Posts: 70

Joined: 17th Feb 2007

Gallery: 4 images

Location: Melbourne, Australia
VIC, Australia

vibr8n wrote:
economy through higher range gears... lol


Technically, if you've got 4:11's instead of 2.9's and you're driving start stop 40k traffic and nothing but - in theory, maybe, somehow, kinda, you'll save fuel.

you won't need the revs to get the car moving, and won't need to be on the gas as much because it won't bog down any.

Kinda?
Top
 Profile  
 
 
Posted: Fri Feb 23, 2007 1:36 am 
Parts Gopher
Offline
User avatar

Posts: 70

Joined: 17th Feb 2007

Gallery: 4 images

Location: Melbourne, Australia
VIC, Australia

cjh wrote:
[HMASEL] wrote:
Also, if I can slightly hi-jack this thread.

I've got 3.45 LSD in mine at the moment, and I'm planning either 3.7 or 4.11, do they come out with 3.9?

What fuel economy increase will I be looking at from 3.45 to 4.11?

And how high would the revs sit at 100?, at the moment it's on what.. 2,000?
4spd 5ltr


Here's how to work out speed verses diff ratio.


yeah, maths and I don't get along much anymore, not since I thought I won lotto :(
Bastard maths.

So, if my EL 5ltr revs at 2000 at 100 with 3.45:1 diff gears, what will 4:11:1 diff gears do?

On 18"s if it helps.
Top
 Profile  
 
 
Posted: Fri Feb 23, 2007 2:38 am 
Getting Side Ways
Offline
User avatar

Age: 40

Posts: 1780

Joined: 31st Jan 2005

Gallery: 10 images

Ride: 07 BF mk2 E-gas wagon + eb 5.0

Power: 174 rwkw

Location: Adelaide
SA, Australia

she'd be up around 2500rpm i'd guess. i have 3.9's and although i don't have a tacho i'm pretty sure its up around 2400rpm.

 

_________________

eb v8: low loud and fast. just how a v8 should be. i guess the big question is, is it fast enough...

Top
 Profile  
 
 
Posted: Fri Feb 23, 2007 8:07 am 
Smokin em up
Offline

Posts: 235

Joined: 15th Jan 2006

Gallery: 11 images

Location: central coast
NSW, Australia

[quote="[HMASEL]"][quote="cjh"][quote="[HMASEL]"]Also, if I can slightly hi-jack this thread.

I've got 3.45 LSD in mine at the moment, and I'm planning either 3.7 or 4.11, do they come out with 3.9?

What fuel economy increase will I be looking at from 3.45 to 4.11?

And how high would the revs sit at 100?, at the moment it's on what.. 2,000?
4spd 5ltr[/quote]

Here's how to work out speed verses diff ratio.[/quote]

yeah, maths and I don't get along much anymore, not since I thought I won lotto :(
Bastard maths.

So, if my EL 5ltr revs at 2000 at 100 with 3.45:1 diff gears, what will 4:11:1 diff gears do?

On 18"s if it helps.[/quote]

Dunno bout 18s but 16s, prydey pretty spot on, when cruising at 100/110 with lockup sits nicely 2500 rpm. As for fuel I didnt notice a big difference when on highway. 4.11s are the go IMO
Top
 Profile  
 
 
Posted: Fri Feb 23, 2007 7:55 pm 
Getting Side Ways
Offline
User avatar

Age: 49

Posts: 6467

Joined: 18th Dec 2006

Ride: 93 ED sedan

Power: 161 rwkw

Location: Rockhampton
QLD, Australia

[HMASEL] wrote:
cjh wrote:
[HMASEL] wrote:
Also, if I can slightly hi-jack this thread.

I've got 3.45 LSD in mine at the moment, and I'm planning either 3.7 or 4.11, do they come out with 3.9?

What fuel economy increase will I be looking at from 3.45 to 4.11?

And how high would the revs sit at 100?, at the moment it's on what.. 2,000?
4spd 5ltr


Here's how to work out speed verses diff ratio.


yeah, maths and I don't get along much anymore, not since I thought I won lotto :(
Bastard maths.

So, if my EL 5ltr revs at 2000 at 100 with 3.45:1 diff gears, what will 4:11:1 diff gears do?

On 18"s if it helps.


I made that as easy as possible to follow. You need to measure the outside diameter of the tyre and it must be in inches (old school).
This equation is 100% accurate when measured and worked out properly.
You also need to know the ratio's in the g'box too.

 

_________________

http://youtu.be/jJTh9F3Vgg0

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 1 of 3  [ 39 posts ]  Go to page 1, 2, 3  Next

Who is online

Users browsing this forum: Google [Bot] and 12 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 Sun Dec 17, 2017 4:29 am All times are UTC + 11 hours

 

 

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