4:11 vs 3:90 diff which one better on street n freeway?

[jbuenviaje]

Currently i have modded l24 with n42 head and wild cam running SU..plus which of 5spd should i use if i go with 4:11..

[IdahoKidd]

either and either

[jbuenviaje]

me and friend was debating that 411 is too much on the street ,bad mpg and will whine on the freeway like a 4spd..pls help to clarify..

[IdahoKidd]

5 speed will lower engine rpm about 400 rpm. Later zx non turbo's had 3:90 gears to help move the heavier car. 280z's have 3:54 gears. 4:11's are a bit quicker off the line but you have to shift sooner. Early 5 speeds have taller 1st and 2nd gears. An early 5 speed with the 4:11's would make a good light to light car. In reality, you aren't going to notice a heck of a lot of seat of the pants difference. Neither are going to help mpg with "a wild cam", what ever that is.

[GreenZZZ]

I have a 3.9 in the back of a mostly stock L24. Had to go with a five speed eventually. Bought a $50.00 tranny off a nissan truck. Clunky 4th to 5th shift, but otherwise great. I think it was at 4000 RPM at 65 mph with the 4 speed. Love the 3.9 R200!!!

[jbuenviaje]

whats the capacity hp of r180 4:11 can handle..i know that r200 is lot powerful that r180..

[lubu]

me and friend was debating that 411 is too much on the street ,bad mpg and will whine on the freeway like a 4spd..pls help to clarify..

I think you are spot on, I was going with 4.11 but now I settle for 3.7, its has the best of both worlds. You could go with the 3.9 too, 4.11 is too much IMHO.

[jbuenviaje]

reason..someone trying to sell me a KR180 from 85' 200sx with 124k miles for $90..Dont know i should go for it or wait for 3:90..i just want something for street and autocross..

[Zedyone_kenobi]

Usually the better solution is always to wait. If you have to decide, go with the 3.9 or 3.7. It is always better to err on the side of caution. During an autocross, you do not want crazy short gearing. Having to shift between 2nd and 3rd adds time and usually mistakes. Its better to have taller gears so you can leave it in 2nd 95% of the time and you can concentrate on being smooth and driving the right line. Autocross is 80% driver, 15% tires, and 5% car. Do not obsess on making your car the fastest it can be. If you are serious about autocross, make your car reliable, predictable, and make yourself faster.

Go for the taller rear end, it will make you happier longer.

[gnosez]

The R160 found in WRXs handle 300hp. The R180 diff used in the US prior to the introduction of the R200 were raced for nearly 5 yrs with lots of cars making over 300hp.

The R190 (Z432 and Nismo) can handle over 300hp.

Unless you are putting out more than 300rwhp and don't make 5000rpm launches from the line that R180 will be just fine.

Depending on wheel size and tranny gearing the difference between the 4:11 and 3:90 is about just under 400rpm (4:11 higher than the 3:90). So at 80mph w/my 3:90 I do just under 3100rpm and if I had a 4:11 it would be around 3500rpm.

[Carl Beck]

The R180 diff used in the US prior to the introduction of the R200 were raced for nearly 5 yrs with lots of cars making over 300hp.

Not really.

The R180's that were raced ran 4 sypder gears - the OEM units have two. That is the weak point in the differential.

The R180's that were raced by winning teams - were checked/rebuilt several times per season and many ran differential coolers for longer races.

Nonetheless - I agree that the R180 in as new condition is strong enough - and stronger if you add a posi unit with 4 spider gears.

The R200's are stronger - and in many cases you can find units that are far newer and have less milege on them. Even if they have the same mileage - chances are good that because they are stronger - they will run longer in lower torque application.

Just my personal experience - but the R200's I've ran - all ran with far less noise in the cabin. For many reasons I'd take an R200 over an R180 every time for other than a single purpose race car - and even then the type of race would be considered.

FWIW,

Carl B.

Edited January 19, 2010 by Carl Beck

[jbuenviaje]

R180 4:11 with Nissan/Borg Warner T5 5-speed combo..is that good street and autocross