Gear Ratios and FDs

Tonight I was driving down the highway going about 90mph and saw my tach was at like 4k, now I know an S13 KA has short gearing and all, so I was wondering, is the gearing on an SR longer? And if I wanna keep the KA, can another Final Drive make my ratios longer?

SR gearing is shorter than a KA. and you could put in a 300ZX TT rear diff 4:1 (i think) but it'll kill you accelleration..

i think a 3.84:1 will leave you some acceleration and give you a higher top speed than the stock 240 diff.. but remember that there are 4th and 5th gear rpm limiters.. if you have anything done to the ka or sr tranny it'll cost you enough money for it not to be worth it.. get a new diff and you'll get results

Once I turbo, it could make up for the acceleration. And D-Bo, which car has the 3.84:1? Also, what do you mean by anything done to the tranny? And I'd only do this once I turbo which would mean I'd have a tuned ECU which would mean no rev/speed limiters.

SR gearing is shorter than a KA. and you could put in a 300ZX TT rear diff 4:1 (i think) but it'll kill you accelleration..

SRs gearing is slightly shorter but the SR Still Revs to 7500RPM. the KA24E also has a slightly shorter gearing in the box.

Stock is 4.01 or something
Kouki 180SX is 4.10
300ZX TT is 3.69 (wont work R230)
J30s are 3.90.

theres no reason to make KA/SR gears longer. 5th will take you ro like 170 stock.

sorry, it wasn't 3.84.. i thought i had seen something about 3.84FD but the closest i can find is 3.69FD. but like lost180 said, there's a 4:1FD (4.01 to be precise) that would make a slight difference.. i don't have time to look right now but i'd say look on google for different nissan diffs. apparently a triumph can use the R200 diff but i don't know if that fits in the s13 (the R200 is a nissan diff).. but you don't need to forget about the 3.69:1 either, especially if you have plans for high hp.. i'll look around next time i'm on my comp

sorry, it wasn't 3.84.. i thought i had seen something about 3.84FD but the closest i can find is 3.69FD. but like lost180 said, there's a 4:1FD (4.01 to be precise) that would make a slight difference.. i don't have time to look right now but i'd say look on google for different nissan diffs. apparently a triumph can use the R200 diff but i don't know if that fits in the s13 (the R200 is a nissan diff).. but you don't need to forget about the 3.69:1 either, especially if you have plans for high hp.. i'll look around next time i'm on my comp


The 4.01:1 is the Stock Gear
The R200 is the stock Diff. (R180-Subarus R230-300ZXs)

If hes at 90 in 4000 that means if he didnt have the rev limiter he would only hit like....150 at 7000? Thats not right I thought the KAs gearing was good for at least 170 or more towards low 180.

The 4.01:1 is the Stock Gear
The R200 is the stock Diff. (R180-Subarus R230-300ZXs)

that may be the source of my confusion..

IIRC, the 300zx NA is a R200V diff, which is the identical to s14 vlsd diff., R230 is found on 300zx TT. It never appeared in NA through out the years.

IIRC, the 300zx NA is a R200V diff, which is the identical to s14 vlsd diff., R230 is found on 300zx TT. It never appeared in NA through out the years.

Thats Right

Acutally stock gear is 4.08:1

Agreed, leave it stock until you start making a lot of power. I can do 140 or so at 6k. But how often do you do that? And I also have shorter sidewalls on stock rims which is Teh GHeAAYYY!

Plus by the time you start going that fast, its time to get some suspension stuff.lol I would know...

Wrong.



Thats the Negative Downforce your feeling...

SAVE A HOUSE - BUY A WING :lol:

"SAVE A HOUSE - BUY A WING"
AHAHAH thats awesome

LOL too funny.

Ummm negative downforce is called "lift" its alot easier to say then negative downforce. Also a Spoiler would help but so would some coilovers...lowering = less lift

RW was just joking for anyone that is too caught up in trying to 3ducat3 da NooBZZzz!!!1

So true tho SRpower. People act like aerodynamics matter so much. Maybe if you cruise at 160mph everywhere..... Another factor in making aerodynamics matter is the weight of the car. Air can move a 1700lb F1 car much easier than it can a 2800lb 240sx. Naturally, the effects of aerodynamics are noticable at much lower speeds on the F1 car than the 240sx.

for some who may not know, a small lip spoiler will make you go faster. heres why.
when the air travels down the back it hits the lip and spins down behind the car making a vortex of air behind the car. filling in where there would usualy be a lower pressure area pulling back on the car.
canyards are the same way spinning air around the side of the car so theres less drag on the sides of the car. not to much downforce there.
lips cause downforce and the biga$$ parkbenches some people use are useless. think about it would you want 30-40 pounds pushing down on two little spots on your trunk. and if you lower the car, it can cause more lift. the air going over the car has futher to go than under the car. causing a lower pressure area on the top and if you lower your car 2 inches it will lower the space for the air to travel under the car, causing a high pressure area under the car. "LIFT"

just a little lesson in aerodynamics

thanks for nothin buddy, this thread is from 2005... dont bring back dead posts! Great first post buddy!

welcome to AF :-)

for some who may not know, a small lip spoiler will make you go faster. heres why.
when the air travels down the back it hits the lip and spins down behind the car making a vortex of air behind the car. filling in where there would usualy be a lower pressure area pulling back on the car.
canyards are the same way spinning air around the side of the car so theres less drag on the sides of the car. not to much downforce there.
lips cause downforce and the biga$$ parkbenches some people use are useless. think about it would you want 30-40 pounds pushing down on two little spots on your trunk. and if you lower the car, it can cause more lift. the air going over the car has futher to go than under the car. causing a lower pressure area on the top and if you lower your car 2 inches it will lower the space for the air to travel under the car, causing a high pressure area under the car. "LIFT"

just a little lesson in aerodynamics
That's good information but not for a thread that hasn't been posted in for more than a year. Please try to post in current threads or start new topics.