Toyota OEM 4.5 FD Part number

[troek]

Almost every single 86 race car here has a 4.5-5.1 final swap, depending on the track. Those who dont have 400ish hp.

[fooyc]

http://www.supertaikyu.com/entrant/o...etin_no.08.pdf

may be this info will help on part number? sorry guys I don't read Japanese too...

page2 , page4 & page5 all hv diff FD ratio used by Gazoo racing & etc in the supertaikyu race.

[Wyattkb]

Just curious if someone has a link to where I can order this?

Most links in this thread are in another language or are terrible sites to navigate.

[nikitopo]

Originally Posted by troek

Almost every single 86 race car here has a 4.5-5.1 final swap, depending on the track. Those who dont have 400ish hp.

Do they remove the speed limiter (180 km/h)? If not, then it makes a sense. But if they remove it, then I cannot imagine driving a "race car" on a track using overdrive (6th gear). This is pretty much nonsense. With a 4.5-5.1 final drive ratio, the 5th gear is very very short. Don't forget that the gear box ratios are also quite short!

The short final drive ratio gives better results only in smaller gears like 1st and 2nd. It makes more sense in gymkhana events or for playing going sideways. That's the main reason they even install the 4.1 final drive ratio.

My car has a 3.7 final ratio and it is lighter and I am very happy with the result. Almost the same acceleration and a top speed in 5th gear! I'm using the 6th gear just for fuel economy! It is very funny to go side by side with a bmw 535d f11 (313ps και 630nm !!) in the autobahn up to 230km/h. And don't forget that such a bmw costs more than double! This is simply not possible with a shorter final drive ratio. Secret is to use the engine power band wiser

[troek]

Originally Posted by nikitopo

Do they remove the speed limiter (180 km/h)? If not, then it makes a sense. But if they remove it, then I cannot imagine driving a "race car" on a track using overdrive (6th gear). This is pretty much nonsense. With a 4.5-5.1 final drive ratio, the 5th gear is very very short. Don't forget that the gear box ratios are also quite short!

The short final drive ratio gives better results only in smaller gears like 1st and 2nd. It makes more sense in gymkhana events or for playing going sideways. That's the main reason they even install the 4.1 final drive ratio.

My car has a 3.7 final ratio and it is lighter and I am very happy with the result. Almost the same acceleration and a top speed in 5th gear! I'm using the 6th gear just for fuel economy! It is very funny to go side by side with a bmw 535d f11 (313ps και 630nm !!) in the autobahn up to 230km/h. And don't forget that such a bmw costs more than double! This is simply not possible with a shorter final drive ratio. Secret is to use the engine power band wiser

Not many tracks here go over 200kph. Fuji speedway and suzuka are about it. Cant speak for suzuka, but fuji and tsukuba, almost every car that is fast and na is running shortened final drives. On fujis strait even with the shortened final drive u would only hit 6th gear for a moment, and the benefit of getting there faster outweighs having to hit 6th gear for 1-2 seconds at 220kph.

[nikitopo]

Originally Posted by troek

On fujis strait even with the shortened final drive u would only hit 6th gear for a moment, and the benefit of getting there faster outweighs having to hit 6th gear for 1-2 seconds at 220kph.

But you are not getting there faster. You accelerate faster up to the mid of 3rd speed and then you gain speed slower. I tried once with a 4.5 fd ratio in nurburgring gp and the final speed in the big straight was actual the same! And my tests were from full stop which give a favour to the shorter fd.

There is not such a magic thing that gives you more "power". The only thing that the fd ratio changes is the area in which you are stronger. Shorter ratio gives you more strength in lower gears and speeds. Higher ratio gives you more strength in higher gears and speed.

[troek]

Damn, all these professional time attack teams have had it wrong all along. i'll go let them know they are wasting their time.

[nikitopo]

Originally Posted by troek

Damn, all these professional time attack teams have had it wrong all along. i'll go let them know they are wasting their time.

This is an entirely different story. They are playing with the final drive ratio and the gear ratios for having better power bands in specific corners. It is about having the correct rpm when exiting the apex. With this way you have a better car for a specific track, but you have to change everything on another track. Such cars are pretty much useless in ordinary roads. They might make a lot of noise but nothing else. I am sorry if I seem a bit offensive, but we should understand that there isn't a magic solution. With such short ratios, you cannot even achieve the factory top speed.

[nikitopo]

Here are some calculations with changed final drive ratio and everything else stock:

[churchx]

nikitopo: even if there cannot be "one ratio fits all tracks best", there can be "one ratio mostly fits to most tracks (or way it's DD driven at particular tuned powelevels). And something tells me, that big numbers of NA track racers, that have installed different ratio final drive, signifies, that at least for them, at least relative to stock, it benefits them there.

[troek]

Your wasting your breath. He wants to ignore the simple physics of the mechanical advantage of a shorter final drive. Its not something that is up for debate. Is there one final drive that is a perfect match for every track? No, no one is saying that. The simple fact here is that a 86 with a 4.5 will accelerate faster than one with a 4.1.

[nikitopo]

Originally Posted by troek

He wants to ignore the simple physics of the mechanical advantage of a shorter final drive.

Please explain to me in simple physics why a 4.5 fd ratio car is accelerating really really faster in a higher gear comparing to a 3.7 fd ratio car.

3.7 fd ratio
5th gear 184 - 223
6th gear 223 - top speed

4.5 fd ratio
6th gear 184 - top speed

Can't you see that there is no thing such an overall improvement? You gain acceleration in lower gears (1st, 2nd, 3rd partially) and you loose in other gears (4th, 5th, 6th).

If you want to have an overall faster car try other things. Changing the final drive ratio is a waste of money for the majority of people. It might give a wow effect, but nothing really actual that worth the money.


And it is not about a debate. It is that we should be very careful of what we write and suggest. People over here are reading and spending money in modifications and we should be very clear of what to expect.

Thank you and bye.

[troek]

first of all, your top speeds are horribly incorrect, 2nd of all top speed is not acceleration. Not sure why you keep getting that conused. And why on earth would the mechanical advantage dissapear after 3rd gear? If anyone besides this tool wants evidence of shorter final drivrd improving acceleration, and you cant find it on google, let me know id be more than happy to link to the plethora of articles and tests proving quicker acceleration.
Herrs one quick reference, i think you are not fully understanding the purpose of a final drive http://www.badasscars.com/index.cfm/...rod/prd398.htm

[Aztec]

Originally Posted by troek

first of all, your top speeds are horribly incorrect, 2nd of all top speed is not acceleration. Not sure why you keep getting that conused. And why on earth would the mechanical advantage dissapear after 3rd gear? If anyone besides this tool wants evidence of shorter final drivrd improving acceleration, and you cant find it on google, let me know id be more than happy to link to the plethora of articles and tests proving quicker acceleration.
Herrs one quick reference, i think you are not fully understanding the purpose of a final drive http://www.badasscars.com/index.cfm/...rod/prd398.htm

You know it's useless trying to convince him of anything :P

Troek's right, EVERY gear will be putting more torque down directly comparing the stock 4.1 to a 4.56. For example, This is about a 10% increase in torque applied to the wheels and it WILL be faster ACCELERATING until you reach 100-120mph which at that point, it doesn't matter as the shorter gears would have either won the drag race or reached the next corner of a track.


On a side note, my 4.56 ring and pinion arrived yesterday going to have it installed August 6th