Anyone driven a 3.08 and a 3.27 back to back? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Kerazy S-Pak · 02-11-2003, 17:15

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...

Thnx

02-11-2003, 21:16

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

Bass Crazy · 02-12-2003, 00:17

Yep thats right, the higher diff ratio will use more fuel at high speeds, however, around town, the car should actually use less.

Ciao

Walkinshaw · 02-12-2003, 01:22

just a small point. The higher the ratio number, the lower the gear ratio...

ie 3.45 is lower than 2.77

NZ · 02-12-2003, 02:02

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.

WBT56 · 02-12-2003, 02:39

Quote:

Originally posted by NZinAUS
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.

NZ · 02-12-2003, 02:42

Yeah I know what you mean, If my car could do full rev in 5th with the 2.92 It would have been damn quick. ith the 3,23 I have now Im pretty confident it will do full rev in 5th.

jamesk · 02-12-2003, 02:48

i helped swap a 3.08 to 3.27 in an ea. it feels like it takes off a bit better but the owner of the car is always sooking that he has to change gears to quicly now on takeoff and it slows him down. i reckon he just neeeds to learn to drive properly though.

Kerazy S-Pak · 02-12-2003, 03:25

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)

WBT56 · 02-12-2003, 13:09

Quote:

Originally posted by Kerazy S-Pak
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).