Toyota OEM 4.5 FD Part number

[CBR600RR]

Originally Posted by diss7

Sigh.
I get so sick of reading about these final drives.
They DONT give the car more power. All they do is shorten the gearing. Remember the mountain bike you had as a kid. Lets say stock car 6 speed is like only using gears 3,5,7,9,11,13. Changing the final drive in the car is like those 6 gears now being 2,4,6,8,10,12.

Get it?

Its the same reason the car feels faster in 2nd than 3rd, and 3rd to 4th.

You are making 3rd shorter, say like a 2.75, so its going to FEEL faster than 3rd was, but not quite where second was. BUT it won't go AS fast, because the gear is shorter.

Here is the easiest way to look at it.

Car has 4.1 now

If you are looking at getting 4.5, thats roughly 10% shorter. So go drive your car. Which ever gear you are in, look at the tacho, if the tach is reading 3000rpm, with a 4.5FD it will be 10% more, so 3300rpm, at that speed, in that gear.

a 4.8 would be roughly 20%.

IMO a 4.8 is too short, both for track and daily. On the track you DONT want to use 6th, as the drop from 5th to 6th is a big rpm drop. A 4.8FD will mean you'll top out 5th on the track, and have to chop into 6th.

For the street, a 4.8 means it'll suck on the open road. In 6th where it was revving 3000 - 3200 (depending on where you cruise) it'll now be 3600 - 3800.

Going to something even further like a 5.1 is even crazier. It makes 1st useless, and puts all the other gears close to where the previous gear was. 3rd will now be as short as 2nd etc. You'll just end up having a 1st gear like a van; and just use 2nd to take off.

Go on youtbue and search autofactory 86. They have a 5.1 FD in their car, on Fuji. Which was a stupid move. You see how soon down the back straight the car has to get into 6th, and you can hear the car just die in the revs.

IMO the need to make a shorter 6th gear available, that had much less RPM drop. Then you could use it as a track gear and really shorten the FD down. But this would also worsen the 6th gear cruise RPM. Which is why the 6th is where it is.

Sure you could argue its but the closer gears where you want them, and if thats what you want thats great. But you'd only do that if you only needed upto 160 - 170km/h on a track (which is slow) as thats all 5th will get to. Tyre dependant obviously.

Look at the track you are using it at. See what the max speed you're going to get is, and using ratio calcs, make sure 5th can reach that speed.

If its just for a street car, that you will use to cruise at 100 - 120km/h (60 - 70mph) get a 4.55. If you get a 4.8 it will ruin the car on the motorway. (Unless you like it singing at near 4000rpm) If you don't care about that get a 4.88.

I strees that you should do your OWN calcs. Its dependant on what you want, the compromises you are prepared to make. The wheel/tyre size you run. I run 205/40/17 tyres at the track, and I have a 4.55 sitting in my garage. However I wont put it in yet, as with that tyre and that FD I will outrun 5th at the track. So I'm waiting till I need to go to a wider tyre, which will mean taller, which will then mean using the 4.55FD, mainly to regain the gearing I have just using the smaller tyre.

Asking how a FD feels. It feels faster, in that gear. Because its shorter. But it doesnt go as fast in that gear now.

ALso, if you're getting a FD, consider underdrive pulleys. Because you are logically going to be revving the car more, so why give the ancillaries more drive than they need. Although there seems to be a massive fear/misconception of under drive pulleys on this forum, so its not even worth going there.

/rant.

Sorry to quote such a long post, but what I think you are missing here is this: two bone stock cars, one with 4.1 FD, the other a 4.5 FD. the one with the 4.5 will do the 1/4 mile faster than the 4.1,,, and it will accelerate out of corners at the track faster too.... will the 4.5 have a higher top speed? Fuck no.

[diss7]

Originally Posted by CBR600RR

Sorry to quote such a long post, but what I think you are missing here is this: two bone stock cars, one with 4.1 FD, the other a 4.5 FD. the one with the 4.5 will do the 1/4 mile faster than the 4.1,,, and it will accelerate out of corners at the track faster too.... will the 4.5 have a higher top speed? Fuck no.

Its not that simple.

You're 1/4 mile comment is valid. However I disagree on the track car comment.

The shorter gearing might need you to chop into 6th on the straight.

The shorter gearing might mean you need to change from 3rd to 4th, or hit 3rd gear limiter before a corner, where as before you could do it without either.

Again, its a compromise. Its not "Its better always" it just isn't.

I know this because thats the bind I am in now.

If I put the 4.5 in I will need 6th on the straight. But more so, I will hit 3rd gear limiter on some sections of track that I JUST get away with not hitting now.

I still think I would possibly be faster with the 4.5 actually, well it would be close.

The point I am trying to really stress, is its not always better. Understand the compromises, and make the decision thats right for you.

[diss7]

Originally Posted by gt1680

:I am gratefull they have an auto trans for this car, since you are leaving in a country of 4.4 something million people, try to live in a city of 12 million people with estimated 14 million cars registered and used within that city

We get traffic here too, chum.

Driving a manual in traffic is hardly hard work.

[Sellout]

Originally Posted by gt1680

:I am gratefull they have an auto trans for this car, since you are leaving in a country of 4.4 something million people, try to live in a city of 12 million people with estimated 14 million cars registered and used within that city

What city are you talking about? NZ has some of the worst traffic in the world, according to Tom Tom.

[FrsDuke]

You are unlikely to ever hit top speed in this car even with the 4.8 let alone the 4.55. But you will get to your desired speed faster with the more aggressive gears. It will be quicker. As for faster... Who cares? I've had my car up to 125 at TWS and ran out of front straight. It actually WOULD be faster there even if in theory my top speed would drop a bit. I never hit top speed and don't plan to. Higher rpm on the highway wouldn't be a big deal. 10-20%

[FrsDuke]

Odd lag double post

[gt1680]

Originally Posted by Sellout

What city are you talking about? NZ has some of the worst traffic in the world, according to Tom Tom.

I am in Jakarta, Indonesia. Sometimes it took me 3 hours just to travel 30 km (18.6miles).

[diss7]

I don't know how many times I've said in this thread alone it's about what 5th can do, not 6th.

The 5th to 6th gap is awful. You don't want to use it on the track.

You need to look at this box as a 5speed plus an overdrive.

No one is talking about top speed.

I'm over it.

[Captain Snooze]

Originally Posted by diss7

Understand the compromises, and make the decision thats right for you.

+ 4.35x10^5

[Fast_Freddy]

Originally Posted by diss7

We get traffic here too, chum.

Driving a manual in traffic is hardly hard work.

LOL! You obviously don't know what real traffic is like. Try commuting between Baltimore and downtown Washington DC during weekday rush hour traffic 5 days a week for a year and see if you still feel the same.




I agree with most of what you've said on the FD ratio subject but please understand that there are places on this planet where driving a MT is pure torture. Just because the 86 is a car best enjoyed with a MT doesn't necessarily mean that those of us who require an AT because of our work commute shouldn't be able to enjoy an 86 at all.

[diss7]

Originally Posted by Fast_Freddy

LOL! You obviously don't know what real traffic is like. Try commuting between Baltimore and downtown Washington DC during weekday rush hour traffic 5 days a week for a year and see if you still feel the same.




I agree with most of what you've said on the FD ratio subject but please understand that there are places on this planet where driving a MT is pure torture. Just because the 86 is a car best enjoyed with a MT doesn't necessarily mean that those of us who require an AT because of our work commute shouldn't be able to enjoy an 86 at all.

Is it really that hard to raise your left foot off the clutch as you press down with the right? Seriously?

It has the softest pathetic clutch imaginable, it's far from a struggle.

But of that's enough extra effort to justify getting an auto for some, then that's your choice.

[Fast_Freddy]

Originally Posted by diss7

Is it really that hard to raise your left foot off the clutch as you press down with the right? Seriously?

Hundreds of times during a 30 mile commute that takes 1.5 hours? YES!

[diss7]

Originally Posted by Fast_Freddy

Hundreds of times during a 30 mile commute that takes 1.5 hours? YES!

How to you manage pressing the accelerator that many times?

Moving your foot on and off the brake as well.

1st world imaginary problems

[CBR600RR]

Originally Posted by diss7

Its not that simple.

You're 1/4 mile comment is valid. However I disagree on the track car comment.

The shorter gearing might need you to chop into 6th on the straight.

The shorter gearing might mean you need to change from 3rd to 4th, or hit 3rd gear limiter before a corner, where as before you could do it without either.

Again, its a compromise. Its not "Its better always" it just isn't.

I know this because thats the bind I am in now.

If I put the 4.5 in I will need 6th on the straight. But more so, I will hit 3rd gear limiter on some sections of track that I JUST get away with not hitting now.

I still think I would possibly be faster with the 4.5 actually, well it would be close.

The point I am trying to really stress, is its not always better. Understand the compromises, and make the decision thats right for you.

very good point.. i was more thinking along the lines of pulling out of a corner faster, and not along the lines of being faster around the track in general. I understand that some gearing is better on one track and worse on another when looking at the track as a whole