Where Do I Put The Money ?

[Guilt-Toy]

I have a R33 RB30det with a 4.39:1 dif ratio 5 speed and when driving down the freeway at 110ks an hour its reving at about 3300rpm which is way tooo high.

Idealy I would like to change 5th gear ratio to bring the revs down to somethng like 2300rpm at 110ks an hour or even less. The engine is very tourquey at that rpm and should handle it fine. Is it possible to do that ?

Or do i spend the money on the diff and change it to a 3.8:1 or 3.9:1 or something to bring the revs down ? the 3 litre would like this anyway..... I have access to a cheap R33 rear end so I could get one changed to a long ratio and keep the 4.4s for racing..... or change 5th gear and have the best of both worlds ?

I do lots of freeway driving and would like to bring the fuel consumption down also.

Anyone have any ideas how much it will cost to do modifications for those 2 senario's and what would be the best option. No i dont want a 6 speed and I would like to take the car drag racing every now and then.

The car will have 300rwkw + once it awakens so once i sort this issue out it should be good.

So the question is.. Does the box get a long 5th gear or the diff gets a long ratio or i just keep putting the extra $$$ into the tank for all my long trips.

[Bl4cK32]

Just put in either the 3.7 or 3.9 ratio crownwheel and pinion in the diff. It will make the most diifference to bring the revs down and get taller gears.

I hate the 4.3 with my 3lt, as first is useless, and will be going to a 3.9 hopefully when money permits...

Edited January 19, 2006 by Bl4cK32

[Guilt-Toy]

Just put in either the 3.7 or 3.9 ratio crownwheel and pinion in the diff. It will make the most diifference to bring the revs down and get taller gears.

I hate the 4.3 with my 3lt, as first is useless, and will be going to a 3.9 hopefully when money permits...

<{POST_SNAPBACK}>

any idea how much it will cost ???

my first gear is useless tooo !

[Abo Bob]

Go the diff. The gears in your gear box are all suited to each other.

$1200 to get a 1.5 way fitted roughly. Less for second hand and less again for non mechanical LSD.

[BHDave]

SR's with r200 rear ends run 3.9s i think.

Maybe it's worth buying a full unit second hand, swapping out your internals (or even getting an aftermarket lsd) and selling off the 4.4 r33 diff on nissansilvia to some wannabe drifter?

[Bl4cK32]

any idea how much it will cost ???

my first gear is useless tooo !

<{POST_SNAPBACK}>

best bet is to try the wreckers, or one of the importers of the forum. You can just fit the cw & pinion (keep you current centre), or fit the new ratio to a 1 (or 1.5 or 2) way centre.

From memory a couple of hundred dollars might be about right. Trouble is you may have to buy one in the whole housing still, cos people dont like to separate the diff parts.

S13 auto and manual ratios are 3.9 or 3.7 (i cant remember which one is which )

[Abo Bob]

Auto are usually longer. Ie 3.9 in the above case.

[Busky2k]

Interesting. I too wouldnt mind trying a longer diff in my 200SX. Its a 3.69 ratio... Maybe a swap is on the cards? hehe

[discopotato03]

Food for thought but depending on the intermediate gear ratio spread maybe ~3.7 for wide ratio (GTST/GTS25T ~ 3.32 1st) or 3.9 for closer ratio taller 1st set .

Anyone know the ratios for aftermarket gearsets - 2.9 1st and rest std works well in the Aust spec 260Z , I really hate the 1-2 spread in most Nissan boxes ie around 3.2-1.9 .

I think the VLT Comode used a wide ratio version of the GTS25T box ie 3.6 1st but with tall 3.45 diff gears .