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diff ratio choice 

 

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 Post subject: diff ratio choice
Posted: Fri Feb 18, 2011 11:43 pm 
Parts Gopher
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Age: 29

Posts: 89

Joined: 30th Jan 2009

Ride: EF Injected Gas T5 Convert

Location: Trafalgar
VIC, Australia

hi all
i need a some help with a diff ratio for my falcon its a ef with a mild sports mod engine wade cam 2000-5500rpm and a EA 5 speed conversion with the standard 3.08 auto diff.

At 100km/h its sits on around 2000rpm at 110 is about 2200 which is fine for me doin highway work but its a bit of a slug around town i would like somethin in the middle a lil more revs when cruising would be fine if it was nicer around the streets or maybe i need to go the other way i dont know enough about the possible ratios out there or if i need to go up or down or maybe i need to move to a EB-EL-AU 5 speed with different box gears to even it all out?

any help would be good to hear

Thanx
STADIC
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 Post subject: Re: diff ratio choice
Posted: Fri Feb 18, 2011 11:54 pm 
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Ride: ford falcon au3 xr8

Location: a shit suburb in sydney
NSW, Australia

with the ea t5 a nice ratio would be either 3.27 or 3.45..

keep in mind that the ea t5 with a 3.27 diff ratio, the 1st, 2nd and 3rd is similar to a ed/ef t5 with a 3.45 ratio 1st, 2nd and 3rd..
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 Post subject: Re: diff ratio choice
Posted: Sat Feb 19, 2011 12:14 am 
Parts Gopher
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Age: 29

Posts: 89

Joined: 30th Jan 2009

Ride: EF Injected Gas T5 Convert

Location: Trafalgar
VIC, Australia

so you would say 4th and 5th would go up or down in revs when cruising? atm 4th at 60km/h is a bit low in the revs and same with 5th at 80
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 Post subject: Re: diff ratio choice
Posted: Sat Feb 19, 2011 12:28 am 
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Ride: ford falcon au3 xr8

Location: a shit suburb in sydney
NSW, Australia

a 3. 27 or 3.45 ratio will give you slightly higher revs when cruising but also give slightly better acceleration..

eg,...with 3.45 ratio you would be at about 2400 rpm at 110 .. instead of the 2200 its at with the 3.o8 ratio
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 Post subject: Re: diff ratio choice
Posted: Sat Feb 19, 2011 9:45 am 
Getting Side Ways
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Age: 25

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Joined: 10th Jan 2010

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Ride: EL XR6

Location: albion park, wollongong
NSW, Australia

My el 5speed has 3:45 (from factory) it's quick off the line, very zippy and good on the highway at 100 km/h I sit on 2300Rpm (give or take)

 

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Aiming for 300 rwkw

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 Post subject: Re: diff ratio choice
Posted: Sat Feb 19, 2011 12:09 pm 
Parts Gopher
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Age: 29

Posts: 89

Joined: 30th Jan 2009

Ride: EF Injected Gas T5 Convert

Location: Trafalgar
VIC, Australia

my main problem is that i hav a ea box which has different gearing to the others as follows

3.2&3.9 4.0
1st 3.50:1 3.25
2nd 2.14 1.99
3rd 1.39 1.29
4th 1.00 1.00
5th 0.78 0.72

if someone can do the maths and tell me what the end rev/speed rate is for the 3.23-3.27-3.45 would be to give me a defined answer that would help i only want to do this once if it means goin and buy a new gear so i would like to be fully informed

STADIC
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 Post subject: Re: diff ratio choice
Posted: Tue Feb 22, 2011 9:41 am 
Getting Side Ways
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Posts: 836

Joined: 1st Apr 2005

Gallery: 4 images

Ride: EF XR6 Wagon, AU2 XR6 VCT

Power: 148 rwkw

Location: Auckland
New Zealand

Assuming 100kmh at 2000rpm in 5th on your EA box with 3.08 gears, you should see 2090rpm with 3.23s and 2240rpm with 3.45s at the same speed.

5500rpm should give the following (theoretical) kms in the gears:

gear 3.08 3.23 3.45
1 61 59 55
2 100 96 90
3 155 147 138
4 215 205 192
5 275 263 246

Hope this helps.

 

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 Post subject: Re: diff ratio choice
Posted: Tue Feb 22, 2011 6:36 pm 
Parts Gopher
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Age: 29

Posts: 89

Joined: 30th Jan 2009

Ride: EF Injected Gas T5 Convert

Location: Trafalgar
VIC, Australia

thanx this does help alot now just hav to work out which one would suit my needs best i do alot of hwy work mostly 100km/h but then a bit also around town nick down the street and back

thanx again
STADIC
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 Post subject: Re: diff ratio choice
Posted: Tue Feb 22, 2011 7:37 pm 
Getting Side Ways
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Age: 28

Posts: 4326

Joined: 30th Oct 2006

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Ride: Envi EF

Location: Grafton
NSW, Australia

Just grab a 3.45 from an XR6. easy.

 

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