110 - 115kph = ~3000rpm in 5th
As someone speaking with a 4.36 final drive… you’ll be looking at 4500+ at 120km/h
Unless of course you’ve got an automatic, or you put massive tires on your car…
hmm, I may be wrong - I was told 70mph @ 3k rpm in 5th
regardless, do your own research if you plan to buy! 
The speedo will still say 130km/h 
thats assuming you have the same hp tho right, let say if you had tons more you’d be getting these speeds at a more resonable rpm no? being that i’m pretty shure this came off that car with the modded RB25 he wouldn’t have had any problems there… and if your buying it i’d assume u’d have that kinda power also.
power has 0 to do with it
it’s a gear ratio… x rpm at y speed whether you have 50hp or 500, it’s the same.
also, the figure jammin is quoting is with an rb25 tranny which has dif ratios than the s13 one.
anyway… clearly the person that this dif is for is not concerned with highway mileage.
move on with it.
This diff ratio will be almost useless with stock transmission. 1st gear will be good upto about 15 kmph, so basically you’ll convert your car to a 4 speed. You really need a close ratio transmission to take full adbvantage of this, 1st gear in these is way higher and the gears are spaced much close together so when youy shift you never drop out of the power band.
With stock trans 4.36 is about as low as you can usefully go with teh final drive. I ran a 4.625 all winter in the SR rally coupe for TSD rallies. This was perfect for the rallies but 3200rpm = 100kmph in 5th with 195-65-15 tires (verified with calibrated rally odo) was a bitch for daily drving.
-Martin.
Thanks for everyones input - any chance this thread can be cleaned up?
How does it make sense that a close ratio tranny would make this more useful? A close ratio tranny + this diff would make your car top out at like 110-120kph, THAT is useless.
A close ration tranny will only shorten the ratio even more.
How does it make sense that a close ratio tranny would make this more useful? A close ratio tranny + this diff would make your car top out at like 110-120kph, THAT is useless.
A close ration tranny will only shorten the ratio even more.[/quote]
Ah fair enough…
However, he’s still very wrong 
This was in an s13 for 5000 miles or so - only reason it’s coming out is the car is being parted.
Other than reduced gas mileage - it was completely driveable and HARDLY “useless” - thats hilarious. If anything it was barely noticeable – slightly shorter gears, faster car, little more noise from the diff and rediculous traction.
What is the top speed on this diff?
i.e. 5th gear 7200rpm on a SR… Can you find out from the previous owner?
it was on an RB so he wouldn’t know - but I’m sure someone here knows the simple math it would take to figure it out??
i’d imagine at least 220kph or so…
He’s not very wrong :roll: He knows exactly what he’s talking about having driver HIS car with a 4.625 for 6 months, and raced with one for years. A 4.88 would only make things worse. 1st gear would be almost useless. Barely noticeable my ass…
Before you make ridiculous claims about something you are selling, make sure you have a clue what you are talking about.
-Martin.
with 300whp+ on an RB25 1st gear was very useable with decent 255
s on the rear… I’ve spent a lot of time in the car and YOU have no idea what YOU are talking about if you think otherwise.
There are plenty of videos to prove it.
MOVING ON, I trust anyone who considers this purchase would do their own research.
what makes you think that this is one of only two in northamerica ??
thats just a foolish claim … and on top of that over 2grand for that lsd is crazy i can sell one new for that …
the ratio would be good for drift or drag but will be very limited in the top end … but props for the great las tomei makes very good gear.
it wouldnt even be usefull on a car for drag, you would be shifting into 5th if you have a slick on
If you guys use an RPM calculator you would find that at 120 klm you would rev around 600-700 higher. Not that much. If you wanted to do more then 220klm all the time, this may not be for you. But if you wanted to be the guy who can get up to 220 faster then anyone else, this is for you.
I would kill to have this in my car, however the price makes me think of other stuff to buy instead.
Good luck helping you buddy out Jammin
CVM07
Not sure what this guy means by owned…LOL. Who runs a 195/60r15 in these cars with sr20’s and buying an 2g lsd.
This shows that your top end is reduced by 30 mph. Sounds like a good deal to me…
cvm07