SR vs KA Gear Ratio??

[gounc14]

Just curious if anyone knows if the SR and KA gear ratios are the same? One of the things I want to do before actually investing in an engine and starting the swap on it is to make a decently sturdy transmission to go in the car...I think I've read somewhere that Nismo made a 4.60 ratio kit, and I'd like to get that and get the gears cryo treated. If I do the gears should I do the synchros too? Pretty much just rebuilding a transmission so I don't have to worry about those parts as much, just keep the fluid clean.

[IvoryJ30t]

if you mean the 4.6 final drive, thats the ring and pinion in the rear-end.

that has nothing to do with the transmission other than make each gear shorter vs. road speed.

probably not something you want to do. will cut you top speed considerably.

[gounc14]

Hmmms how badly? I'm undecided on the gears, definitely want to build up a decent transmission though...

[IvoryJ30t]

lets say that if you were to have a redline-limited top speed of 150, the 4.6 gears would reduce it to 133.

its a 12.7% decrease in top speed in each gear.

unless your going for 400+ WHP, theres no need for trans work other than a heavy duty clutch.

[gounc14]

*shrugs* I'm shooting for around 400 eventually, no more, but I want to have that transmission done for peace of mind well before I break into that range, as I really haven't started on the project much yet.

[Cyberkreig]

ratios are =

4.6 refers to the rear diff, not the trans.

[[Zero-S]]

besides, we run 4.08 stock, right? No real reason to bother with final drive gearing unless you're building an all out drag car.

[Got_Nissan?]

N/A 240s/200s/silvias -- 4.083 final drive ratio

Turbo 200s/silvias -- 3.692 final drive ratio

This is with the 5 speed manual gearbox

Info is from 200sx.org interesting site check it out.

[matt4pl]

is there any way to tell what the ratios in the diff are? i got what is supposedly a JDM VLSD, so could that have the longer gear in it?

[gounc14]

*shrugs* well anyone have ideas on how much the cryo treatment would actually help, or if I should just not worry about it?

[[Zero-S]]

I wouldn't bother.

[Cyberkreig]

Cryo would definatly help. But you dont need it.