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3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6 

 

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 Post subject: 3.45 to 3.7/3.9 is it worth the swap? 5 speed el xr6
Posted: Sun Nov 23, 2008 5:34 pm 
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Hey guys,

I know there are alot of threads out there about diff gears but i cant seem to find the information im after!

Ive been thinking about changing my diff gears from 3.45 to 3.7 or 3.9's.
Which is the best way to go? 3.7's or 3.9's?

Is there much of a noticable difference between the 3.45 and 3.7, like it is really worth it? I guess if i had a 3.08 and upgrading you would go the 3.7 or 3.9 since your doin it anyway but is it worth the swap from what i have?

Ive got a 5 speed manual el xr6

cheers!
Rat

 

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Posted: Sun Nov 23, 2008 5:42 pm 
Getting Side Ways
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I wouldnt go 3.9's behind a manual unless you like changing gears for fun :)

As it is with my 3.73's first gear is pretty short, although im running an EA box. Thing is, your running 14.3 down the track which is very good for the mods so i wouldnt change a thing.

Going to 3.73's might not do anything, might even go slower on the track but it defintely would feel nicer to drive and more responsive
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Posted: Sun Nov 23, 2008 5:57 pm 
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Me either,

I went back from 3.45:1 to 3.23:1

In an auto yes, but a manual... meh.. no point.. unless your engine can do 6000+ rpm!

 

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Posted: Sun Nov 23, 2008 10:10 pm 
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FordFairmont wrote:
I wouldnt go 3.9's behind a manual unless you like changing gears for fun :)

As it is with my 3.73's first gear is pretty short, although im running an EA box. Thing is, your running 14.3 down the track which is very good for the mods so i wouldnt change a thing.

Going to 3.73's might not do anything, might even go slower on the track but it defintely would feel nicer to drive and more responsive



I agree totaly with this i have 3.73's in my manual ef xr6 and i wish i got 3.90's. the 3.73's did not make a big enough difference I was just worried the 3.90's would be too bigger jump but i reccon they would have been good in hine site.

 

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Posted: Sun Nov 23, 2008 10:40 pm 
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xr6eat 50 wrote:
FordFairmont wrote:
I wouldnt go 3.9's behind a manual unless you like changing gears for fun :)

As it is with my 3.73's first gear is pretty short, although im running an EA box. Thing is, your running 14.3 down the track which is very good for the mods so i wouldnt change a thing.

Going to 3.73's might not do anything, might even go slower on the track but it defintely would feel nicer to drive and more responsive



I agree totaly with this i have 3.73's in my manual ef xr6 and i wish i got 3.90's. the 3.73's did not make a big enough difference I was just worried the 3.90's would be too bigger jump but i reccon they would have been good in hine site.


i was actually advising against 3.9's :wink:
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Posted: Sun Nov 23, 2008 10:51 pm 
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I've had 3.9's in a manual EF, definitely recommend them for a NA setup and i'd get them again if I was going NA.

 

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Posted: Sun Nov 23, 2008 10:57 pm 
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Just depends what you use the car more...getting from A - B? or getting from A - B faster in different situations...or just to get the car faster off the line at the track.

Getting from A - B in normal traffic...stick with what you got.

Getting from A - B quicker in metro area majority of the time...get 3.7s. more freeway, stick with 3.45...and 50/50 3.45s

Faster off the line...3.9s

personally...3.23s is what I'm sticking with cause I use it for commuting more then track days.

phong =P~

 

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Posted: Sun Nov 23, 2008 11:32 pm 
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And BTW it seems our cars ran fairly similar times at the track, with 3.9's it crossed the line in 4th at fairly high revs (can't remember what exactly) you'll probably get better 60' times too with the 3.9's my best was 1.9

 

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Posted: Mon Nov 24, 2008 12:11 am 
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woah thanks for all the info guys!

i only really drive the car on weekends, everynow and then it will be used for a down south trip but im willing to sacrafice a few rpm if its going to chop a bit of 1/4 mile time off and people keep saying its much more fun to drive with the 3.7's/3.9's.

definately a gain to be had with the 60 ft times by the sounds of things my best 60ft was a 2.2 i think!

i have been thinkin about what you said xr6eat 50 about there not being much difference between the 3.45 and 3.7 so i might go with some 3.9's and see how i go!

going to install them myself so if worse comes to worse and i dont like the new ratio ill put the 3.45's back in a guess its all about trial and error!

cheers for all the help!
dame

 

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14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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Posted: Wed Nov 26, 2008 7:47 pm 
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one diff place has told me that 3.9's wont go in an el diff!
does anyone know if this is true??

 

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El xr6
14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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Posted: Wed Nov 26, 2008 9:49 pm 
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twindongs wrote:
one diff place has told me that 3.9's wont go in an el diff!
does anyone know if this is true??


lies lies i till you they do go don't believe them go to another place

 

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Posted: Wed Nov 26, 2008 10:19 pm 
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twindongs wrote:
i have been thinkin about what you said xr6eat 50 about there not being much difference between the 3.45 and 3.7 so i might go with some 3.9's and see how i go!



so you want to fit 3.9's because its more of a change than 3.7's?

running a 2.0 or less 60" footer can be done with 3.45's, people like "smoke" for example done it in his EF with just upgraded exhaust and 3.45 lsd.
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Posted: Thu Nov 27, 2008 11:37 pm 
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FordFairmont wrote:
twindongs wrote:
i have been thinkin about what you said xr6eat 50 about there not being much difference between the 3.45 and 3.7 so i might go with some 3.9's and see how i go!



so you want to fit 3.9's because its more of a change than 3.7's?

running a 2.0 or less 60" footer can be done with 3.45's, people like "smoke" for example done it in his EF with just upgraded exhaust and 3.45 lsd.


i want to experiment with a more extreme difference in ratio not just a slight change. i have seen in a few threads people saying they have gone from 3.45 to 3.7 and wished they went 3.9.
i know a sub 2 sec 60 foot is achievable with a 3.45 but it just might make it more achievable for me with different diff gears!
i guess you could say im still undecided, most quotes of 1200 bux has put me off a bit so i am trying to work soming out with a mate of mine.

 

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El xr6
14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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Posted: Mon Dec 29, 2008 11:16 pm 
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hey guys,

Iv bought some diff gears from ebay.

They are 3.89:1 ratio and advertised to fit borgwarners ea-au.

just noticing most people put 3.91's in instead of 3.89's. is there any reason for this??

My gears will fit in okay yeh?

cheers

 

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El xr6
14.268 @ 96.77mph--- motorplex 4/3/08

549 crow cam
chiptorque chip
pacemakers
hiflo cat
cai w/ k&n panel filter
3.89:1 diff gears

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Posted: Tue Dec 30, 2008 10:25 pm 
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twindongs wrote:
hey guys,

Iv bought some diff gears from ebay.

They are 3.89:1 ratio and advertised to fit borgwarners ea-au.

just noticing most people put 3.91's in instead of 3.89's. is there any reason for this??

My gears will fit in okay yeh?

cheers


there is no set of diff gears that will all diffs EA to AU. there was a change over part way through the EF model run.

 

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