Final Drive Ratio Help

[kbraun94]

Originally Posted by ZDan

I think that changing diff gearing is a hugely overrated mod. It's not like its going to magic you any more power/weight. Overall acceleration performance is going to be close to the same. There is more pull in each gear, but you have to upshift sooner. So there are some speeds where "gears" will give you greater acceleration, but at some speeds acceleration will be far worse due to having to be in the next taller transmission gear.

If it's not specifically 0-50mph you are interested in, I wouldn't bother. If you want to be speedier, just keep the revs up and shift later with the gears you have.

Well, I'm not really looking to increase power, per se. Like I said before, I want to make it feel like it's faster without actually making it faster. I have absolutely no interest in moving faster. I like having to row through gears. I know. I'm weird. To each his own, I suppose, haha. Or her. 0_0

And yeah, shorter final drives concentrate torque to the first portion (the first half, if my maths are right) of a gear's travel through the RPM band. After that portion is run, it'll slouch off speed-wise, in comparison to longer final drives. It sounds like a decent compromise, for what I'm trying to achieve.

Originally Posted by kingpenny

I have a 5.1 pair with cusco lsd type rs spec F , acceleration between 0-100 almost no different , the gain time don/t out run shifting time .


I think the advantage on track condition , is 100-180km acceleration, other benefit is more option to choose gear in corner cause even +1 higher gear have power .


When I run the 5.1 FD with stock diff. , it was having difficulty get back on throttle on corner exit and bump , it feel the lsd was too active cause lost of grip and control , it may be also cause by the Tein SRC being too stiff .But these are fix , once I got my cusco lsd type rs spec F install .


If you go 4.88 or higher , please consider the clutch type lsd .

Holy guacamole, batman! 5.1?! I'm guessing you're running an AT, haha. I think I'm steering away from a 4.88, from what I've read here. 4.67 is increasingly sounding like the sweet-spot. With that said, you brought up something I hadn't thought of before--rearward capabilities. The stock axles/lsd would handle the increased mechanical torque, so long as I cap out at 4.67, right? :o

[churchx]

In his descibed case it looked not so much if 'can handle the load', but if 'have enough grip', no? IIRC clutch type diffs can improve traction on track above that of torsen's. Of course in return for more maintenance/noise.

[ZDan]

Originally Posted by kingkenny

I have a 5.1 pair with cusco lsd type rs spec F , acceleration between 0-100 almost no different , the gain time don/t out run shifting time .

I think the advantage on track condition , is 100-180km acceleration, other benefit is more option to choose gear in corner cause even +1 higher gear have power .

If there is any advantage it should be in 0-100km/h (62mph) as both setups need to upshift twice. 100-180 km/h, or 62-111mph, with 5.1 gears you have to upshift to 4th almost immediately, whereas stock you don't have to until 84mph, but by then 5.1 has to upshift to 5th. At 106 mph, stock upshifts to 5th and 5.1 upshifts to 6th. Overall, more upshifts with 5.1 gears, and similar overall gearing from 67mph on up, my money goes with stock 4.1.

You don't have more options to choose gears in corner. Actually, fewer...

OP, if you want to know the effect of changing to 5.1 gears at just about any speed, just drop down a transmission gear. If you can't, then know that at that speed you'd most likely have to be in a higher transmission gear with 5.1.

I'll say it again, if it's not 0-XX acceleration you're interested in, but just want more oomph in general that you think diff gears will get you, just wind out the engine more and delay upshifting with stock diff and get the same effect for free.

[kingkenny]

Originally Posted by churchx

In his descibed case it looked not so much if 'can handle the load', but if 'have enough grip', no? IIRC clutch type diffs can improve traction on track above that of torsen's. Of course in return for more maintenance/noise.

In my case , the FD itself is loud and the CF shaft make aircraft noise after 140km , the lsd itself have no change in noise , I can only hear very little bit chatter noise if I turn my steering wheel full lock and accelerate together .


I had a cusco rs lsd in S2000 , it last too long and I sold the car with it , over 30K+ mix with daily , autoX and track duty .

[kingkenny]

Here is two of my record video ,

[ame="http://youtu.be/tnrY4rrxaRE"]http://youtu.be/tnrY4rrxaRE[/ame]

The sudden loss of grip was cause by the lsd act up weird over bump and in wheel lift .

[ame="http://youtu.be/7qPlyFXZotk"]http://youtu.be/7qPlyFXZotk[/ame]

It was 5.1 FD , OEM diff. , Tein SRC with Super Pro sway bar front and rear , Tomei EL & over pipe + nameless muffled track pipe , 235/40R17 NT01 . Just for you to get a idea . I drive the car around if it is the day i work alone , i don't see any issue .

[nextcar]

Originally Posted by ZDan

I'll say it again, if it's not 0-XX acceleration you're interested in, but just want more oomph in general that you think diff gears will get you, just wind out the engine more and delay upshifting with stock diff and get the same effect for free.

Hmm... I find it much easier to break the rear loose on a 1-2 shift with my 4.56 gears than with the stock 4.10. Acceleration is not always the goal...

I suppose you could achieve the same effect by revving the engine mid shift - but that is not something I want to do on a regular basis.

[Bfranklyn86]

Has anyone used increasing the whee size to slightly lower the final drive?

[TRAKRAVN]

Originally Posted by kingkenny

If you go 4.88 or higher , please consider the clutch type lsd .

I completely agree. I have a 5.29 with a 1.5way MFactory LSD.

[fika84]

Originally Posted by TRAKRAVN

I completely agree. I have a 5.29 with a 1.5way MFactory LSD.

Fun! I'm rocking the 4.88 with the MFactory 1.5 way. How do you like the diff?

[TRAKRAVN]

The diff makes a lot of noise when it's cold under low speed and tight turns. More so when releasing. I've only had the diff on the car for about 2000km. It's mostly just for track use and driving to and from the track. Overall I wouldn't go back to a helical LSD for tracking. I also have the Whiteline diff and subframe bushings so the noise is transmitted to the chassis more so then without them.

[kingkenny]

Originally Posted by TRAKRAVN

The diff makes a lot of noise when it's cold under low speed and tight turns. More so when releasing. I've only had the diff on the car for about 2000km. It's mostly just for track use and driving to and from the track. Overall I wouldn't go back to a helical LSD for tracking. I also have the Whiteline diff and subframe bushings so the noise is transmitted to the chassis more so then without them.

I guess these may have to do with the lsd configuration , mine cusco is set to 1.5 way , minimum intial torque and lock , with motul 75W140 . More lock up = more noise ?


Those solid diff. & frame mount and diff. brace both make noise , with or without the FD or LSD , i have them and i like it very much , the noise just make the drive more exciting . That me only , other may hate it ...


Back to kbraun94 question , the car feel pull harder , more torque , more shifting , it is more fun for me but can't argue if it is actual faster .

[TRAKRAVN]

Originally Posted by kingkenny

I guess these may have to do with the lsd configuration , mine cusco is set to 1.5 way , minimum intial torque and lock , with motul 75W140 . More lock up = more noise ?


Those solid diff. & frame mount and diff. brace both make noise , with or without the FD or LSD , i have them and i like it very much , the noise just make the drive more exciting . That me only , other may hate it ...


Back to kbraun94 question , the car feel pull harder , more torque , more shifting , it is more fun for me but can't argue if it is actual faster .

My LSD is set up the same way. Minimum initial torque, full lock and I'm using the same oil. I have a Greddy diff cover and I change the oil every time I change the engine oil.

I completely agree, the car "feels" like it pulls harder, more shifting, more fun but I don't think the car is actually faster on the street. On the track it does make a difference though as you can hold different gears for different corners now but that's track dependent.

[~el~jefe~]

Smash the 4.3 and hit past 4.55.

if you cant floor it in 6th gear and get pressure, your FD is not too low.

4.3 fixes it and makes it able to daily drive and go on long trips still. Racing? rip that mofo. Crank it up. It cannot hurt with a 7400 RPM redline engine right?

[Greddy86]

Currently have a jrsc w/ hbp on 6AT frs. I'm thinking about going Cusco 5.1 FD w/ Cusco RS 1.5 way. Hopefully this setup will help me get off the lines faster and quicker corner exit speeds.