Rearend ratio ?'s

[LEMHEAD16]

All right, after getting behind the wheel for a few days I have figured something out. The stock 240 rearend is not suitable for a VH powered car.

1.) It's an open diff (although it could be had with a viscous lsd)2.) It's 4.08 ratio is not well suited to the gearing and power band of the VH/VG

Anybody else running a different rear end?

I have to shift to third before I hit sixty and I think my top speed would be pretty low, although I haven't tested it yet . I think something in the 3.80 range would be about right.

What options do we have?

[95si4]

j30 might be a good option for you.

http://www.nicoclub.com/articles.php?id=168561

[elwesso]

Some people dont like the 3.54 Q45 gear but I think its fine with the 5 speed.. The downside is when its stock you have to keep the revs up or its easy to fall out of the power band.. if you keep it above 4 grand it really takes off.

plus I like having the lower RPMs on the highway.. Makes for better MPG and its quieter.

a 4.08 would be a good choice if you never wanted to exceed whatever the stock VH45 + ECU + Z32 5 speed.. however, you add even 50HP on top of that and you're gonna want your 3.54 back..

Im perfectly content with my 3.54 in my land barge + 5 speed..

[kingkilburn]

What about in an S chassis?

[Carl H]

the q's 3.52 final kinda sucks imho with a 5spd, it really feels like it could use a j30 final (3.86 iirc) and you'd get decent gas mileage and good accel without the drop off in power band...in my vh car it tends to fall in and out of the 'sweet spot' with the q final.

[LEMHEAD16]

I was kind of thinking the 3.5 would be a little too long. Glad to know the j30 is in the 3.8 range. Is it a limited slip?

3.5 seems like it would give you legs for days on a straight away but, be a little too long for my type of driving.

With a 3.5 at what speed does first gear redline?

That article says the J30 is

Infiniti J30 95+: No mods needed (3.96)Infiniti J30 pre-95: Needs new output flanges

3.96 doesn't seem like that much of a change to me. Although it would give a VLSD and slightly lower gearing

[T45]

Here is a Q with a 4.08 - speed reading 15% off

http://www.youtube.com/watch?v=Uu_7PGTIel4

And the stock 3.5

http://www.youtube.com/watch?v=8g76s8WXh_8

Granted both of these vids are with the Q a/t so the redlines in each gear would be different, but it gives an idea of the difference. The 4.08 revs out much faster.

I remember the 4.08 being really short in the Z, 5th gear in 45mph zones felt like it should have been 4th gear. It did move quite nicely though...

[Wes M]

With the VG box I have opted to go for a 3.9 ratio. Crunching the numbers it would still give a decent kick in the guts in 1st whilst keeping the revs reasonable at highway speeds. It also happened to be available from the old R31 solid rear axles so have stolen a crown wheel and pinion from there. Have yet to test it tho

[John Dixon]

Its funny but I'm looking to go the other way on mine, from the stock Z32 TT R230 3.56 to a ~4.1 - thinking R32 GTR R200 plate at the minute.With my powerband of 4-8.5k the 3.56 is just too long for my preference. Also, I use it mainly on twisty backroads rather than high-speed stuff so you're pretty much just always in 2nd/3rd.

[James K]

Im also looking at going the other way, with our shop car were building here in Sydney Australia. Our S13 will being starting out as a drag car so we are going to opt for the 4.3 r200. Should be quite fun.

Build thread to come

James

[Carl H]

its all a trade off tho...lower rear end helps with launching but will decrease accel but a higher will give killer accel but lots of wheel spin.

[kingkilburn]

Are you guys talking about swapping the whole pumpkin or just the ring & pinion?

[T45]

With a 4.08 and VH 1st gear is pretty useless...with stock tires.

Those wishing to go the opposite way can really appreciate this vid, click on "MWS NA rear end swap", save and enjoy.

http://www.mwsmotorsports.com/nfmwstv.htm

[LEMHEAD16]

Either or really.

I want to swap the whole differential because I currently have an open Diff.

I'm sure some of these guys have a lsd of some sort and would be interested in simply swapping the ring gear.

[kingkilburn]

I plan on getting a helical LSD and putting in the new ring and pinion.

[LEMHEAD16]

I have pretty decent tires on mine and even after they are warm if you let the clutch out above 2400 rpm you better plan on smokin' em.

[John Dixon]

Che

With a 4.08 and VH 1st gear is pretty useless...with stock tires.

Those wishing to go the opposite way can really appreciate this vid, click on "MWS NA rear end swap", save and enjoy.

http://www.mwsmotorsports.com/nfmwstv.htm

Cheers for the link, with my setup curently (cusco plate R230 / 285-30-18 goodyear eagle F1's) traction is very good, not bothered about launching particularly as drag racing isn't my thing, just want the acceleration

[Loch Ness]

Q45 diff will match up great with the VH......

[kingkilburn]

If you're driving a Q45. . .

[Q45tech]

Noticed noone actually speced the Q45 diff at 3.538 correctly! Same with 4.083.

[SuperHatch]

Noticed noone actually speced the Q45 diff at 3.538 correctly! Same with 4.083.

You know, you're RIGHT!!! And as a matter of fact, I've driven a car with a 4.080 and a 4.083 and the difference is so astonishing we should go out and lynch all the people who think rounding can be applied so recklessly!

[gs14racer]

we should go out and lynch all the people who think rounding can be applied so recklessly!

funniest thing ive read all week... lol.

[hannibal]

Using a G50 diff in an S chassis requires one Z32 axle and one G50 axle. Which axles are needed to use the G50 diff in a Z32??

Oh yeah, and the actual ratio for the G50 diff is 46/13.

[gs14racer]

or

3.5384615384615384615384615384615

[SuperHatch]

Using a G50 diff in an S chassis requires one Z32 axle and one G50 axle. Which axles are needed to use the G50 diff in a Z32??

I'm not entirely sure there are drop in axles to make the G50 rear work in a Z32... I'm assuming you mean Z32 NA sinceit has an R200 as well.

The rear track width for a G50, according to the FSM, is 61.8 inches.

The rear track width for a Z32, according to the FSM, is 60.4 inches.

I have a Z32 NA, a G50 rear, both Z32 TT axles, both G50 axles, and both R32 GTR axles. They're all different lengths. If I get really REALLY bored I might try to find out someday, but it's unlikely you'll get an answer before the summer.

I do plan on trying to put an R32 GTR rear in the Z32, since it uses the beefier axles like a G50 and it has a clutch type LSD. If I can make it work the G50 rear will use the same axles. I'll post about it once I know.

[hannibal]

Thanks! I hope some combo of those axles work...

[John Dixon]

I do plan on trying to put an R32 GTR rear in the Z32, since it uses the beefier axles like a G50 and it has a clutch type LSD. If I can make it work the G50 rear will use the same axles. I'll post about it once I know.

Any chance of keeping this thread updated with the details? I'm just about to get started on mine so I'll post up what I find.I'm sort of hoping that the NA subframe with the R32GTR diff will fit OK (looks right). I'm then going to probably use the TT driveshafts and make up some spacers. This will also mean using TT hubs / bearings / hub carriers I believe but not checked that side of it out yet.After I pull the motor for the cam change this weekend this is my next job, hopefully have some progress soon. I have all the parts, just got to find the time as ever!!

[Loch Ness]

good luck on that R32GTR diff swap hope u dont have to swap the sub frame

[elwesso]

Any chance of keeping this thread updated with the details? I'm just about to get started on mine so I'll post up what I find.I'm sort of hoping that the NA subframe with the R32GTR diff will fit OK (looks right). I'm then going to probably use the TT driveshafts and make up some spacers. This will also mean using TT hubs / bearings / hub carriers I believe but not checked that side of it out yet.After I pull the motor for the cam change this weekend this is my next job, hopefully have some progress soon. I have all the parts, just got to find the time as ever!!

For what its worth, the worst case scenario is that the ring and pinion may fit inside the stock Z32 case...

For instance, i know someone who took the FRONT diff from a GT-R (4.36 gears), and swapped it directly into the Q45 diff case.

[SuperHatch]

For what its worth, the worst case scenario is that the ring and pinion may fit inside the stock Z32 case...

It is likely itwould fit, since they are both R200 rears. But there would be no point since they are both the same ratio (Ok not exactly the same Tech, one is 4.08 [49:12] and the other is 4.11 [37:9]). We are talking NA Z here BTW.

The reason to switch to the GTR rear is not for the gears, it is for the factory Clutch Type LSD as opposed to the factory Viscous crap in the Z32, and for the larger, stronger, TT style axles that come along with the GTR rear.

For instance, i know someone who took the FRONT diff from a GT-R (4.36 gears), and swapped it directly into the Q45 diff case.

Then you know a liar, since the front diff in a GTR is a F160 and not an R200, the gears simply don't fit. (160mm ring gear diameter versus 200mm) Not to mention the ratio in the front of a GTR is 4.11:1, just like the rear, not 4.36:1.

By the way, 4.11:1 is for R32 and R33 GTRs, R34 GTRs are taller, but I don't have the R34 FSM in front of me so I can't be 100% positive.