Ford Forums banner

Anyone driven a 3.08 and a 3.27 back to back?

6K views 16 replies 8 participants last post by  Ghia XR8 
#1 ·
Has anyone ever driven EB-ED Falcons with 3.08 and 3.27 diffs back to back etc? I was wondering how big a deal the difference was. I was in an ED with the 3.27 (as a passenger) and didnt notice much difference(tho hard as a passenger), Would you only notice the difference on a drag strip, or would it be worth swapping for day to day caning? also anyone notice a differnce in NVH/fuel consumption between 2 cars with the different diffs?
Hoepfully someone can make sense ofallthis... :p
Thnx
 
G
#2 ·
the bigger diff (3.27) will use more petrol because it revs higher at 100km/hr than a 3.08.. My 3.45 LSD revs at around 2150rpm at 100km/hr while a GL with a 3.27??? or 3.08 (not sure) will rev at around 1700-1800..

On the dragstrip, the 3.27 should accelerate faster if the two cars were identical , conditions were the same, same driver etc, but we all know this doesn't happen...

All in all, the bigger the diff, the more fuel and faster acceleration.. The XR6 i have (EF) all came out with 3.45 LSD's..

Cheers,
Yagz
 
#5 ·
A 3.45:1 will take the tailhaft 3.45 turns to turn the wheels once, a 2.77 will take 2.77 tailshaft revolutions to trn the wheels once. From this you can see that the higher the diff ratio, the better the acceleration will be but the trade off is top speed.
 
#6 ·
NZinAUS said:
A 3.45:1 will take the tailhaft 3.45 turns to turn the wheels once, a 2.77 will take 2.77 tailshaft revolutions to trn the wheels once. From this you can see that the higher the diff ratio, the better the acceleration will be but the trade off is top speed.
Only if you run out of revs. Many (5 speed, anyway) cars can't push fifth and will go just as quick in fourth. Often lowering the diff will allow a higher top end as well.
 
#9 ·
JamesK, u changed the diff on a manual EA i assume?
do u know how much sooner the gear changes have to occur. Im hoping if i chnage to a 3.27 on my auto i can shorten the neverending story that is 1st gear (and hopefully increase acceleration somewhat) not that its bad atm anyway...

heres anotha q for everyone- how much more fuel would ne consumed running the 3.27 (over the 3.08) the difference at say 100km/h would only be 150 revs or something... (currently apprx 1600 wif 3.08)
 
#10 ·
Kerazy S-Pak said:
heres anotha q for everyone- how much more fuel would ne consumed running the 3.27 (over the 3.08) the difference at say 100km/h would only be 150 revs or something... (currently apprx 1600 wif 3.08)
It depends on exhaust and other factors, but don't be surprised if fuel economy improves as you approach 2000RPM. Most cars will run happily @ 1900-2000RPM and fuel economy taper off from there, as revs increase (at the same speed).
 
#11 ·
the owner of the cars says he didnt notice any change in fuel economy at all, either city or highway driving.
he changes from 1'st to second very quickly now. although a fair bit of that seems to be because of the manual. it used to have a auto and that would stay in first alot longer than when we changed it to a manual with no diff change at that time.
 
#13 ·
Ok I never understand diffs and stuff. So bare with me.
I’m pretty sure my EA is Stock and has a 2.77 diff. It revs at around 1800revs at 100kms.

Now you guys say if you change the diff to 3.27 then gear change happens faster. How much faster could it happen in my auto as it feels to happen really quickly anyway like at 20kms. And how does a faster gear change help take off speed. I thought the diff would extend the gear change to later so the car revs harder by staying in gear longer?

Anyways sorry for this post but i just dont get it.

Thanks for your help
 
#15 ·
Damien, i think ur EB2 Fairmont would have a 3.27 diff (ED fairmonts have that particualr diff ratio)

VBMan, is ur EA a3 or 4 speed? if it has the 2.77 diff odds are its a 3 spd, and it should rev at about 2300 revs @ 100km/h
if ur ea is a 4 speed then it shoudl be running a 3.08 or 3.27 diff

WBT-my car has headers and a 2.5" xhaust (standard cat)
with reagrds to fuel economy, I read that Ford chucked the 3.08 in the ED as opposed to 3.27 on EB2 (and EA2, EB1 can anyone confirm?) for better fuel economy. I take this as a simple principle that less revs=less fuel consumption. There are alot of factors affecting fuel consumption tho...
 
#16 ·
after changing diffs it may still change at 20km/h for eg. but it should get to 20 km/h faster than with the smaller diff. which is what i mean by faster gear changes. the shorter the diff (higher number) the faster the engine revs up so you find yourself having to change gears alot sooner than with a smaller diff. it speeds up take off up by letting the engine rev up faster into its optimal power band
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top