Diff Ratio's

[Nee-san]

Morning Gentlemen,

Just curious to see what people have in terms of options for changing the Diff ratio, particularly for a 32 gt-r.

Looking to go 4.3 but its a massive pain in the proverbial finding the diffs in the first place and then getting them in good condition..

What have people done ?

[fatz]

800 bux sss automotive has em

[Nee-san]

800 bux sss automotive has em

Legend, is that an exchange sort of dealio or do you just sail down with 800 in cash money and they sell you a couple of new diffs ?

[Strik3r]

I'm guessing they are gts-4 diffs ?

I've put them in mine. Took the crown wheel and pinion out of the gts-4 diffs and put them inside my GTR diffs after having them cryo treated for extra strength. Difference is definitely noticeable in 3rd and 4th.

[fatz]

was a while ago but yea you need to swap them into your housings

give ema call to getg a price may be more/less now

[Beer Baron]

yeah going rate these days about $1000 for a set. still good value if you ask me. the biggest head f**k is you have to remove the engine to replace front diff so if you're not doing it yourself the labour bill for a simple ratio change quickly becomes a grand or two making it not exactly cheap.

so if you're bothering to put the 4.4 GTS4 gears in your GTR may as well grab a front LSD while you're at it and do the rear nismo LSD clutch pack upgrade too.

so:

$1000 for front and rear GTS4 ratios

$1000-$1600 for front LSD (depending on new or used and what brand)

$300-$350 for set of nismo clutch packs for rear LSD

engine removal and replacement (dunno maybe $1000-$1500)

remove sump and get new lsd and gears fitted and set (maybe $200)

remove rear LSD, fit clutch pack upgrade and CW and pinion (again maybe $200)

makes it an expensive upgrade all round but very nice once it's all done. it will handle like a different car and drive out of corners much improved.

[mr 32]

yeah going rate these days about $1000 for a set. still good value if you ask me. the biggest head f**k is you have to remove the engine to replace front diff so if you're not doing it yourself the labour bill for a simple ratio change quickly becomes a grand or two making it not exactly cheap.

so if you're bothering to put the 4.4 GTS4 gears in your GTR may as well grab a front LSD while you're at it and do the rear nismo LSD clutch pack upgrade too.

so:

$1000 for front and rear GTS4 ratios

$1000-$1600 for front LSD (depending on new or used and what brand)

$300-$350 for set of nismo clutch packs for rear LSD

engine removal and replacement (dunno maybe $1000-$1500)

remove sump and get new lsd and gears fitted and set (maybe $200)

remove rear LSD, fit clutch pack upgrade and CW and pinion (again maybe $200)

makes it an expensive upgrade all round but very nice once it's all done. it will handle like a different car and drive out of corners much improved.

i belive you dont need to remove the engine, well thats straight from terry at award diffs,

he told me ha can do it in the car takes a little longer he said but no problems.

i was going to do it when he was doing my diff swap to the new sump but as i hadnt sourced gears yet he said he can do it later when its in the car.

[Beer Baron]

yeah I have heard one of two people say they can do it with engine in car but it would be a massive c u next tuesday of a job. getting all the sump bolts out with engine and box still in the car is going to be tough. would still be a fair few hours labour to remove + replace sump even if they can do it with engine in car, and at $800-$100 an hour the labour bills add up quick!

still it's a good mod. worth doing.

[Strik3r]

You don't need to remove the sump to do it in the car.

[fatz]

someone get terry to quote up a front diff change if he can do it?

[mr 32]

You don't need to remove the sump to do it in the car.

thats what i was getting at

fatz my quote was for new diff gears front and back but ill try and dig it up

[Beer Baron]

You don't need to remove the sump to do it in the car.

yeah makes sense. I guess once driveshaft is out and diff cover off you can get enough room to get it out. in that case... rock on.

[Nee-san]

yeah going rate these days about $1000 for a set. still good value if you ask me. the biggest head f**k is you have to remove the engine to replace front diff so if you're not doing it yourself the labour bill for a simple ratio change quickly becomes a grand or two making it not exactly cheap.

so if you're bothering to put the 4.4 GTS4 gears in your GTR may as well grab a front LSD while you're at it and do the rear nismo LSD clutch pack upgrade too.

so:

$1000 for front and rear GTS4 ratios

$1000-$1600 for front LSD (depending on new or used and what brand)

$300-$350 for set of nismo clutch packs for rear LSD

engine removal and replacement (dunno maybe $1000-$1500)

remove sump and get new lsd and gears fitted and set (maybe $200)

remove rear LSD, fit clutch pack upgrade and CW and pinion (again maybe $200)

makes it an expensive upgrade all round but very nice once it's all done. it will handle like a different car and drive out of corners much improved.

Definitely looking at the 4.4 the car is mostly street driven and will be doing some test and tunes until I feel it is ready for trackdays.

I feel having a huge top speed...260km/h plus Isn't necessary as I won't be pulling that sort of trap speed at Willowbank or QR.

Would definitely like to redo the rear LSD but is the front necessary, particularly on a street car ?

[Beer Baron]

front lsd not necessary on a street car. but a good idea for a track car. especially if you are changing ratios, may as well do it together. have a look at any serious track GTR... front lsd.

it's not like you'll fail without one, but on the track a front LSD transforms the car. just like a rear LSD does for a GTST etc. needs a fair adjustment in driving style though.

[fatz]

yea my difff guy says adjusting the backlash onthe front diff is the arsehole when its still in the car

[N1GTR]

I asked Award about 4 weeks ago, labour quote was about $900 (i forget exactly but it was pretty damn close to 900 so i just remembered 900)

[Risking]

Why does the sump need to come off for??

There is 3 bolts retaining the NS drive shaft axle, 9 bolts from memory holding the bearing retainer plate in the OS of the diff housing and the flange nut on the pinion shaft.

The center falls out the front, the pinion and shaft also get knocked out the front. A small slide hammer can pop the old bearing cones out easily and a tappered nylon drift can knock the new ones back in.

Bearing preload and backlash is easy to set up with shims.

We used to service the quaife center in my old race car every 6 meetings and inspect the crown wheel/ pinion gears afte every race meet. Never had any problems getting the diff center in and out.

[N1GTR]

Brad how long does that take in total including putting it back together?

[Risking]

If there was no backlash adjustment or bearings replaced it took an hour with 2 of us doing it.

If it needed a new crown wheel, pinion or bearings it could take up to 4 hours max depending on how the assembly went.

Typically we were smashing crown wheel and pinion teeth off the start line so we were doing it all the time, never fixed one at the track though, just drove it RWD in most trophy races after it broke in the heats.

That's a car which was constantly apart and we knew it inside out

[Burgz32]

it took me 5-6 hour's to do my first 1, which was drive in hoist, CV's out, prop shaft out, pop the diff cover pull the centre,

pop the pinoin, then new bearing's 3 or 4 goes to get the pinoin height right same with back lash..

Take's about half hour less each time, far from a hard job just gotta take your time and you'll knock it out no drama..

Cheers