Trade: 4.11 R200 5 bolt (Locked) for R200 3.9

[Pr0x1mity]

Looking for a 5 bolt 3.9 diff (locked, LSD, open, what ever) to trade for my locked 4.11 diff.

 

Diff is very healthy, was welded by a professional shop and has NO bearing noise or anything.

 

Only trading because I want to try a different ratio.

[Birds]

Why not go for a more aggressive difference? 4.11 to 3.9 will make buggerall difference

[Pr0x1mity]

It's mostly just to drop only a few revs. I've done the math and it's where I want to head.

[Birds]

Fair enough

Back when I used to diff swaps people often expected a marked difference from this kind of ratio swap and were always a little disappointed with the end result, as opposed to those who had gone to something like a 3.7 etc.

[hy_rpm]

I just put a s15 auto vicous lsd diff in my r33 diff so went from 4.1:1 to 3.9:1
To drop revs alil to hopefully save fuel on highway driving
Plus my old diff had alot of backlash

I felt a difference definately noticable as it use to be alot more rev snappy and 2nd gear stayed in the powerband alot easier
At 80km now it a bit under 2krpm now in 5th gear not sure what it was with the std diff
Had to also get 6 bolt driveshafts as the skyline halfshafts didnt fit in the s15 diff

[hy_rpm]

Looking for a 5 bolt 3.9 diff (locked, LSD, open, what ever) to trade for my locked 4.11 diff.

 

Diff is very healthy, was welded by a professional shop and has NO bearing noise or anything.

 

Only trading because I want to try a different ratio.

Your diff abs or non ?

[Birds]

4 hours ago, hy_rpm said:

I just put a s15 auto vicous lsd diff in my r33 diff so went from 4.1:1 to 3.9:1
To drop revs alil to hopefully save fuel on highway driving
Plus my old diff had alot of backlash

I felt a difference definately noticable as it use to be alot more rev snappy and 2nd gear stayed in the powerband alot easier
At 80km now it a bit under 2krpm now in 5th gear not sure what it was with the std diff
Had to also get 6 bolt driveshafts as the skyline halfshafts didnt fit in the s15 diff

cbf looking for the ratios and rolling diameter to do a calculation, but it'd be all of ~150rpm difference IMO

[hy_rpm]

Hey mate guess is a guess
Im talking about real life experience
Have you even tried and tested it
No so keep you comments and guesses to yourself

[hy_rpm]

cbf looking for the ratios and rolling diameter to do a calculation, but it'd be all of ~150rpm difference IMO

Hey mate guess is a guess
Im talking about real life experience
Have you even tried and tested it
No so keep you comments and guesses to yourself

Just tryed it on the freeway to work
At 100km used to to sit at 3000rpm with the 4.11
Now with the 3.9 sits at 2500-2600rpm at 100km both in 5th gear so more like a 4-500rpm difference

[Birds]

3 hours ago, hy_rpm said:

Hey mate guess is a guess
Im talking about real life experience
Have you even tried and tested it
No so keep you comments and guesses to yourself

Yes, as previously stated, I used to fit diffs and do ratio swaps for customers. The problem with your real world experience is that it's also based on a guess - your recollection - and can be wrong too...and it is. Not only does this lead the OP to believe they'll have some drastic difference in engine speed, but anyone searching the topic may make the same mistake.

[Birds]

1 hour ago, hy_rpm said:

 

 

 

 

Just tryed it on the freeway to work
At 100km used to to sit at 3000rpm with the 4.11
Now with the 3.9 sits at 2500-2600rpm at 100km both in 5th gear so more like a 4-500rpm difference

 

 

 

 

3000rpm / 4.11 = 730

730 x 3.9 = 2847rpm

Looks like my guess wasn't far off.

That's one magic diff mate.

[Pr0x1mity]

On 8/7/2016 at 6:10 PM, hy_rpm said:

Your diff abs or non ?

Non ABS.

 

I've had a 3.9 diff before. I prefer it marginally longer.

[hy_rpm]

Too bad the one i have is abs
Depends what you want the car for and how much power you got