Like it says in the post, I'd be curious to know what rear differential ratio you guys are running. Are you happy with it?

I currently have 4.1:1 open differential. I like it, but I really want limited slip, and am thinking about changing the gear ratio to 4.3:1 as well.

3:90 J30 VLSD

I sourced out a 4.36 gearset back in my KA days. Didn't seem to make a real difference. If anything, it limited my 2nd gear a bit as far as sliding goes, and 3rd gear in a stock KA is abysmal to non-existent -- even with the 4.36.

I'd like to get another one now that I'm CA with the stock 4.08. I figure the powerband and wider rev-range of the CA over the KA might justify it, although it might just limit 3rd a bit. But it really didn't make a "feelable" difference in the first place so I dunno.

I went from a 4.08 to a 4.36 and I liked it. The issue I have with it is that as my horsepower needs went up, it's started to become un-usable. When I get this thing ready to start turning the boost up and making a lot of power, I have a feeling the 4.36 isn't going to work any more. It also SUCKS on the highway. I think I'm turning 3K at 60mph, and almost 4K @ 80mph, but in town it's great, it really helps with the CA's lack of bottom end.

I think for anything less than a 300whp setup, the 4.36 is a great ratio for the CA18. Over that, at least in an S-chassis car, it's too low and you need to move it up.

My Civic is 4.4, so driving on the interstate is... intense. It's like I'm in vtec just to keep up with traffic.

When my CA was stock I had the stock 4.09 rear gear (welded) and it pulled it fine I thought. After adding some boost with a red top t25 the swap the 3.90 felt great. With a little longer rear gear I got better highway milage too

Thanks everyone. That gives me more to work with.

Yea, if things go like I think they will, I'm probably going to go to a 3.90 as well, but this will be in the 400HP range.

Im going to do a bell housing swap with a KA trans so I get a longer 5th gear as well. KA 5th and a 3.90 rear gear should make mine a pleasure on the interstate since I drive 30mi each way to and from school 4 days a week.

I had a KA 5th install in my CA trans when I had it rebuilt and that did help a bit. I wonder what top speed is with the KA 5th, 3.90 and 8K rpm, LOL!!!

What's the formula to convert it? I'd actually like to know too

s13drifter88 wrote:What's the formula to convert it? I'd actually like to know too

There's a few web sites that do it for you:

http://www.grimmjeeper.com/gears.html

3.916 ratio with Nismo gt lsd pro, LOVE it

4.41 stock ca18de fwd tranny
3k rev = 55mph

imho it all has todo with your powerband. If you are running a larger turbo and boost doesn't come in till 5.5-6k, the 3.9 is a bit too long. You end up just barely staying in boost when you shift. This is from previous experience running 455whp/335wtq@20psi. It hit 20psi@6k and a 8.2k limiter was just enough to keep her in boost between shifts. I really wanted to run a 4.9fd and 275/50/15(28"tall) MT radials, instead of the 3.9 and 235/60/15 MT radials. Maybe with my next s-chassis car....

4.9 ring and pinion out of not sure what. 4x4 nissan truck of some sort. seller was tight lipped.

4.9 is the front gear set out of an exterra isnt it?

I'm running a 3.692 from an s14 diff'

And how its like 3.69 ? do you need more power than the "oem" Ca18 jeje ?
Because i plan do the same thing...

Luchitosan wrote:And how its like 3.69 ? do you need more power than the "oem" Ca18 jeje ?
Because i plan do the same thing...

more power?

well, I made app. 250HP on a dyno, with light mods, and I reached 242kmh on my GPS on German highways.......

I drive it a lot on highways, for the noise, and fuel consumption, and because it's my DD, for all of these reason I put it on the car.

And yeah, with 235/45/17 on the rear, the speedo is 1kmh precise with reality (that's a bonus :p )

here are speed i reach for each gear :

1st : 65
2nd : 110
3rd : 160
4th : 220
5th : not tested yet ^^

All speed are in KMH and approximative (I look at the road not the speedo when i drive)

Uff thanks man, thanks exactly what i looking for.
I just rebuilt the engine, and for now i' gonna' go with stock boost and do some km to care it.
But next is S15 hlsd w/ 3.62 ratio, w/ 225/40/17 and so here (Arg) read in km too so thats 100% what i need it to know.
My goal is 400 hp but i don't know if i' gonna make it

2 doubts: a- What is your rpm red line ?
b- What it "means" is your "DD", jeje.

Again thanks you, gonna post my rebuilt soon, you can check if you want to !

Luchitosan wrote: 2 doubts: a- What is your rpm red line ?
b- What it "means" is your "DD", jeje.

Again thanks you, gonna post my rebuilt soon, you can check if you want to !

1/ I stop at 7k
2/DD = Daily Drive

Real intersting data, let me know your top speed when you stay ready !

Salute !

Luchitosan wrote:Real intersting data, let me know your top speed when you stay ready !

Salute !

Hi mate,

I tested it last time I went to Germany, I stopped at 257 on the GPS.

Cheers.

Hey thanks for remember thats just good news to me ! Now just need to look for a S15 diff (:P

Now need to check a issue w/ the turbo it's "glowing red" at 120 kmh (75 mph) w/ 4.3 gear ratio,
oem exhaust line (maybe is blocked need to check) and bigger turbo.

Salute, thanks again !