im looking into getting a 4.5 or a 5.1 final drive kit.
does anyone know who sells them?

Quick google search brings up:
http://www.rhdjapan.com/toyota-oem-final-d...0-altezza-56042

thats about $760

I also believe TRD produced a 4.5 for the TRD Altezza but i wouldnt know where to start looking.
it would be best to call your local toyota dealer about that one. expect it to be over $1k.

It's an F-series (7.5") rear if you have an RS200. It's a common size, various ratio's are readily available from the 4x4 world (4.1, 4.56, 4.88, 5.29's, etc. ).

http://www.nitro-gear.com/ring-pinions/
http://www.precisiongear.com/toy712.htm
http://www.richmondgear.com/07Apdfs/page30.pdf

IF you have an IS300, it may be a G-series (8"). And should be just as readily available.


I was running Nitro 4.88's gears in my car up until about a month ago (with W58 & MA4x diff). I swapped BACK to 4.3's, but not too sure if I'm 100% sold on keeping them. I may try 4.56's eventually, but the 4.88's were way too much gear for my small car and the BEAMS. With the 4A-GE though the 4.88's were great.

Andrew

just found out i have a 4.3 in mine.
would i see much difference with a 4.7 final drive?
or should i go for 5.1 to see a difference?
thanks

Since you have a 6-speed vs my 5-speed you will notice more of a difference than I would. Given the advantages of the gearing.

I had the W58 & 4.88's and it was waayyy too much. 1st gear was almost unusable, literally shifting after 1-1.2k rpms into 2nd when driving around, and in 5th by 25-30mph. Basically all I would use 1st for was to bump my car into movement and then shift into 2nd... granted my car is much lighter.

I ran the #'s and with 16" or 17" tires the J160 & 4.56's, 1st - 3rd is fairly similar, if slightly lower geared when compared to my car with W58 & 4.88's. Of course, given the difference in weight it's probably closer to ideal to what would move your car well.

Top speeds in each gear (1-3)
W58 & 4.88 = 32.6 / 56.5 / 83.9
J160 & 4.56 = 31.9 / 56.4 / 82.6


Top speeds in each gear (8k rev limit on mine with 14" tires)
W58 & 4.30 = 37.0 / 64.1 / 95.3 / 121.5 / 155.1
W58 & 4.88 = 32.6 / 56.5 / 83.9 / 107.0 / 136.7

225/45r17 & stock 7.8k rev limit
J160 & 4.10 = 35.5 / 62.7 / 91.9 / 111.6 / 136.4 / 157.0 (3100rpm @ 100 kph)
J160 & 4.30 = 33.8 / 59.8 / 87.6 / 106.4 / 130.0 / 149.7 (3250rpm @ 100 kph)
J160 & 4.56 = 31.9 / 56.4 / 82.6 / 100.3 / 122.6 / 141.1 (3450rpm @ 100 kph)
J160 & 4.77 = 30.5 / 53.9 / 79.0 / 95.9 / 117.2 / 134.9 (3600rpm @ 100 kph)
J160 & 4.88 = 29.8 / 52.7 / 77.2 / 93.7 / 114.6 / 131.9 (3700rpm @ 100 kph)
J160 & 5.29 = 27.5 / 48.6 / 71.2 / 86.5 / 105.7 / 121.6 (4000rpm @ 100 kph)


Link to calculator if you want to play around with it:
http://www.car-videos.net/tools/speedrpm.a...&B1=Recalculate




Are you tracking the car, or just going for best straight line acceleration? The use will also factor into gear ratio selection...

Andrew

Need to define the use for the car, also tyre and wheels sizes play a big part too.

If doing any sort of road driving at all a 5.33 will drink the gas reving that high at road speeds.

cheers for the great info,
17" alloys,tyres are 215/45/17.
it will be for road and track...
will the 5.1 be too much for the road
4.7 is looking like the better option for best of both worlds


225/45r17 & stock 7.8k rev limit
J160 & 4.10 = 35.5 / 62.7 / 91.9 / 111.6 / 136.4 / 157.0 (3100rpm @ 100 kph)
J160 & 4.30 = 33.8 / 59.8 / 87.6 / 106.4 / 130.0 / 149.7 (3250rpm @ 100 kph)
J160 & 4.56 = 31.9 / 56.4 / 82.6 / 100.3 / 122.6 / 141.1 (3450rpm @ 100 kph)
J160 & 4.77 = 30.5 / 53.9 / 79.0 / 95.9 / 117.2 / 134.9 (3600rpm @ 100 kph)
J160 & 4.88 = 29.8 / 52.7 / 77.2 / 93.7 / 114.6 / 131.9 (3700rpm @ 100 kph)
J160 & 5.29 = 27.5 / 48.6 / 71.2 / 86.5 / 105.7 / 121.6 (4000rpm @ 100 kph)

are these speeds in mph or kph?
thanks

MPH, sorry. I just put the 100kph as a guide to RPM's at road speeds.

I'd say 4.56 or 4.77, but truthfully what you need to do is figure out what the speed is you'll need just before getting on the brakes at the track(s) you'll be taking the car too and selecting one which will have you just hitting rev limit right when your supposed to brake. And then figure out the slower corners entry speeds to make sure your not going to be in the wrong gear for a good exit.

Gear selection is a compromise.

Andrew

thanks very much for all the info.

i think ill be going with the 4.88

i have been looking and i see there is a standard rotation or a reverse rotation ring and pinion.which one am i looking for?

also do you know where i would get the set up specs for 4.88
backlash settings etc

thanks again

You want STANDARD rotation. Use the MFG backlash settings if provided, otherwise use the factory spec which is .0051-.0071" IIRC.


Reverse rotation is for the newer pickup front ends (hilux/surf/etc).

Andrew

thanks for all the great help assassin10000

i have it narrowed down to to different branded ones.

nitro or yukon.
would you recommend nitro,as you were running them?

Yeah, I went with Nitro because according to one of the 'trusted' guys that do gear setups for 4x4 rigs here in the states says they are one of the best quality/strength.

His site is here: gearinstalls.com


When you get it setup, I would definitely recommend getting a solid crush sleeve made. Or using one from TRD for a AE86. It's the same size but with a slightly different length. Then you add an extra .5-1.0mm of shim to make up the difference (what I did).

Andrew

thats great,
ill add solid crush sleeve to it so.
is there anything else you would recommend doing when installing it??
i want to do it right once and be done with it.
thanks

As always, new bearings/seals.


If you have $$$ to blow you could always cryo & MPC it.

Andrew

i had planned to run new bearings and seals.
i found a cheap second hand diff,going to buy it and build it with new ring and pinion
that way if i dont like it i can sell it and go back to my 4.3.
will update this when i have it done.
thanks again for all the great info!!

I doubt that your car will be faster by installing a 4.88 or 5.** final drive.

It just effectively turns 3rd gear into 2nd, 4th into 3rd, 5th into 4th etc.

With a normal gearbox, you can only shift gears so fast, so if you're introducing more gear shifts over a set period then it offsets the gained accelleration.

It's worthwhile for racing gearboxes where you can slam through the gears instantly though, or if you've raised the rev limit significantly. (As it brings the effective speed of each gear back down to normal)

I've got plans to change mine from a 4.3 to a 4.5, but its only worthwhile once I can raise the rev limit on the engine, otherwise there is no gain.

^Agree

Racing teams change the final drive to suit the track to a: obtain the highest top speed possible on the track and b: to get the majority of the corners in the ideal power band (ie not between gears).

Drag racing is a little different again. on the drags you want to hit the sweet spot between few gear changes and staying inside the power band for the maximum amount of time.

For the road, low final drives are ideal for highway cruising going past 4.5 on a J160 on standard height tyres is going to be painfull....

And if you fit different sized tires to compensate, then you've just undone your final drive ratio change... haha.

Roman,

I have to disagree with you on this one. Gearing, if selected correctly for the track/car/tire dia/etc can definately make the car faster. This is due to the gain in mechanical advantage due to torque multiplication (it makes a much bigger difference in a heavier/underpowered car), as well as utilizing the engines available torque band/output to it's max.

This applies to a road course, or even drag racing. Key words of course being, 'selected correctly'. Because just as you said, one can only shift so fast. You can get the gearing wrong and have it put you in parts of the powerband/torque curve that can slow you down around/exiting corners or on the final shift on the 1/4 mile.


The difference between the final gear ratios listed is not enough to make as big a difference as you gave in your example. With the exception of 5th. As its the only gear, that works with your example. This is because 5th is direct drive (1:1 ratio). But all the other ratio's, due to the additional multiplier that the other transmission gear ratios are, will never be an across the board drop as the example you gave.

A 4.3 4th is almost the equivelant of the 5.29 5th speed wise (within 1mph). As the overall ratio works out to be near identical (trans gear ratio x final drive). But the other gears are still not close.


EDIT: damn, I should check for fresh replies before posting. :D

Andrew

You said it better anyway lol

It multiplies torque, but at the cost of reducing the speed at which the torque is generated. Same(ish) to just being in a slightly lower gear.

You need to change the gear ratios themselves, to change the percentage of rpms by which the engine speed drops from gear changes. (and so the spread of power used by the engine to propel the car)

Yeah for sure, was just trying to provide an exaggerated example by saying it makes one gear like the next gear down.

If you load a program like cartest

And change nothing but the final drive ratios, its interesting to see the actual difference in accelleration. (or not, in some cases)

The problem with cartest... is that it doesn't have an input for a real engines torque band/curve... amongst other things (IIRC). Which can make things IRL wildly different from what it shows/simulates.

Andrew

There is a way you can specify a car's hp at each 500rpm increment.

However yes, it's a double edged sword...

It doesnt take into account things like having tits for hands, and being slow to change gears :D

But for testing comparatively it's good for isolating a variable, where everything else is static.

I guess you could try the same thing in forza or similar with the performance tests too.

But in my opinion, unless you've had a big increase in torque, or changed the rpm that the engine can run to, there's little point in changing final drive unless suiting it specifically to a track.

I love it when people say this! FORZA and GT4 ARE NOT DRIVING SIMULATORS!!!

These games are about as realistic as going to a IMAX film and saying you've been to space...

The car's accelleration is still defined by things like weight, gearing, etc.

It's not unrealistic in the sense that you change your final drive ratio, and YOUR CAR TURNS INTO A BOAT! haha.

You change your final drive ratio, and the same thing happens as if you'd change your final drive ratio in a real car.

There's a section in there where you can run a performance test without driver involvement, so isolates your changes down to one variable.

The suspension, tire grip blah blah blah may not be realistic, but for gaining an understanding of the differences of purely mechanical changes like gear ratios, it can be worthwhile.

It's certainly cheaper to gain an understanding of this in a game, than spend $$$$ on a modification that wont give the gains that you were expecting.

That is still going to be the most important thing! Just try using 3rd or 4th as top gear, whichever corresponds to the diff you're after. Go on a trip on the weekend for a few hours in the country with a full tank of gas and see what its like cruising at 4500rpm for noise and how much gas it uses.

If you're strictly a city driver it won't matter so much, you just won't need 1st gear.

We used a 4.6 in the rally car, but when we were poor we drove it to a rally with 3.7 then changed it before scrutiny.

Adding to that, if your final drive is to short you wont beable to utilise your power band effectively as you will spend to much time changing gears. This is especially painfull if you have a turbo because you'll spend too much time spooling.

One of the reasons Nascar only has 4 gears because they have such a huge power band. Not many corners either lol

hmmm,ill have to think about it a bit more before i order it.
thanks