What's the diff?

BABOSS · 24-12-2005, 08:53 AM

Hi there,

We all know what a diff is and does but my question is what benifits do you get from changing a stock LSD to a 3.45? And what LSD does a stock EF come with, or does it vary?

vegabass · 24-12-2005, 09:02 AM

Standard Falcons dont come with a Limited Slip Diff, only XR's fairlanes etc(i think you could option it)
the advantage is that instead of getting all the power to 1 wheel the lsd will provide power to both. the 3:4:5 gears in them are shorter than standard gears making engine rev through the rev range quicker but the top speed is slightly lower. (with long gears you need lots of power)

I hope this helps

BABOSS · 24-12-2005, 09:06 AM

So you're saying that the benefits are acceleration, are there any others?

niko · 24-12-2005, 09:16 AM

improved performance off the line and between gears with abit more kik with the same drive train setup!

BABOSS · 24-12-2005, 09:19 AM

Cool, thanks for the info. Is it worth the money @ over $500?

tex · 24-12-2005, 09:22 AM

Quote:

Originally Posted by FlasherEF

Hi there,

We all know what a diff is and does but my question is what benifits do you get from changing a stock LSD to a 3.45? And what LSD does a stock EF come with, or does it vary?

Your "stock" LSD diff (if fitted) would be most likely 3.23 to 1 (at least that's what was fitted as an option to my EF 6, the V8 is probably different again.) I think only XR6 / 8 were fitted with 3.45, or maybe it was just the XR6 ?

The 3.45 gives a little more urge off the line, and in gear acceleration is also obviously improved due to the engine spinning a couple of hundred rpm more at any given road speed.

jonbays · 24-12-2005, 09:35 AM

In E-A series falcons the base sedans usually came with 3.08 Single spinner diffs with the heavier fairmonts and wagons getting 3.23 SS or optional 3.23 LSD. the XR's and fairmont gihias had the 3.45 LSD.

The higher ratio lower diff helped improve the acceleration and around town pick up of the heavier models. the LSD juts gives improved traction mostly in powering out of corners where the SS diff could stupidly spin with modest power application.

Most Auto falcons will really benefit from a 3.73 to 3.9 diff for maximum street performance but they become busy or noisy on the freeway and will use more fuel.

MADED-6 · 24-12-2005, 12:58 PM

sorry to butt in here but i have a ed ghia as u may tell from my name and i got told it has 3:27 lsd so are u saying its actually 3:45.

Psycho Chicken · 24-12-2005, 01:04 PM

ED Ghia will most likely be 3.27:1. EF2 and EL Ghias got XR6 drivelive, meaning 3.45:1 LSD.

UNR8D · 24-12-2005, 04:34 PM

fairmont ghia's not fairlane ghia's get the 3.45LSD i have a 3.27SS in an NL 98' fairlane ghia.

EDXR6T · 24-12-2005, 05:03 PM

ED ghia's have 3.27lsd's i know mine does but it ss some time's thanks to warn cones:P

i recon the 3.27 are probally one of the best gears out ther for modest streat driving i recon ther the better fuel saver gear's (and thats my consern right know)

i know ive started somthing hear with the ppl that have changed to 3.45 lol:S

XR Martin · 24-12-2005, 05:16 PM

Id be surprised if the was a noticable difference in economy between 3.27 and 3.45.

EDXR6T · 24-12-2005, 05:21 PM

ther'd have to be some kind of saving thear

i wunted to change to 3.45lsd and i was told it would run down the fuel gauge a lot quiker so i deside'd not to bother and i'l just get mine recoed next year

EFFalcon · 24-12-2005, 05:41 PM

LSD gives a nice push through the corners too.
deffinately one mod i'm glad i did.
better striaght line performance and better handling.

Kenaz · 24-12-2005, 08:00 PM

I love my 3.45:1 LSD!!!1!!

Taking off sideways is fun

Psycho Chicken · 24-12-2005, 08:06 PM

Quote:

Originally Posted by UNR8D

fairmont ghia's not fairlane ghia's get the 3.45LSD i have a 3.27SS in an NL 98' fairlane ghia.

Yeah, should of pointed that. Fairlane Ghias are all 3.27, unless it's a Sportsman or FBT (Concord maybe?). Mine's 3.27.

EFFalcon · 24-12-2005, 08:07 PM

yeah i think concorde's got 3.45's

XR Martin · 24-12-2005, 09:00 PM

Quote:

Originally Posted by EDXR6T

ther'd have to be some kind of saving thear

i wunted to change to 3.45lsd and i was told it would run down the fuel gauge a lot quiker so i deside'd not to bother and i'l just get mine recoed next year

There would probably be 300rpm difference at highway speeds. I imagine state of tune, fuel quality, tyres, ride height would make a bigger difference in economy.

XR Martin · 24-12-2005, 09:16 PM

Just put the info into a gear calculator

With 3.45 doing 70mph (112.7kmh) you'd be doing 2300rpm
With 3.27 doing 70mph (112.7kmh) you'd be doing 2200rpm
With 3.08 doing 70mph (112.7kmh) you'd be doing 2066rpm

mcflux · 24-12-2005, 11:33 PM

3.27 --> 4.11 ratio change increased my rpm by 450rpm at 100kph

Gives WAY more oomph off the line, but you lose a little at highway speeds when planting it to overtake (dropping only to 3rd, rather than back to 2nd).

I see diffs as being related to cams. The diff increases or decreases the speed at which your car is most responsive. For example, someone's car's sweet spot might be 2nd gear, 40kph--->80kph. Swapping the diff might change that to 30--->65kph, or (if you went a 2.77 for some reason) 50kph--->95kph.

Whereas the engine's rpm "sweet spot" might be 1500-4000rpm with a standard cam (or cams), but a performance cam might alter this to 1500-5500rpm.

I love engine/drivetrain mods