4.7 diff gears..

[mattysshop]

hi guys, thinking about getting a new set of diff gears.. i have 4.1 in there at the moment.. with stock T-50 ratios..

to keep the NA 4A on song it really needs to be a little closer together.. i know the g/box would help alot, but diff gears at $325 au for a 4.7 is awsome!

has anyone run something higher than 4.5... what sort of difference did it make to acceleration?

i don't care about speedo or top speed etc.. i just want to amp up the torque to get some hard core acceleration.. and most of the turns at QR when drifting are at the top of 2nd, but if you pick 3rd it dies in the arse.. hopefully this will make 3rd with a bit more speed the ideal gear of choice http://www.ae86drivingclub.com.au/forums/emoticons/wink.gif

right now with the setup i've got.. 8000rpm 2nd gear is 98kh/h and 8000rpm 3rd is 144km/h

opinions welcome!

the 4.7 gears i'm planning for is Techno Pro sprit one from Greenline..

matty

[Dxaqta]

hahah i was waiting for someone to post up this thread im keen on a 4.7 aswell....

just watching my 2 mates drive on the track with basicly similar engine and car setups the 4.5 clearly accelerated faster out of cornors then the 4.3

i personally want to go 4.7 myself from greenline...

[mattysshop]

thats exatly what i thought! if i'm going to do it.. i'll bloody do it properly so you can notice it! lol.. it also just happenes to be the cheapest.. hahaha! http://www.ae86drivingclub.com.au/forums/emoticons/smile.gif

[Dxaqta]

tell me how it goes ill be looking at doing this in like mid next month

[grassworkzgarage]

im running 4.6 it makes my ac go hard hahaha

[Hen is a total nutcase]

Upping your diff ratio without changing your corner speed wont make it easier to spin the wheels. Eg with a 4.7 you'll have to be at the top of 3rd not the top of 2nd and the overall gearing from engine to wheels will be the same. Therefore same torque at the wheels.

A small adjustment (say 4.3) may mean that at your normal corner speed you'll be revving a little higher in 3rd which could be useful.

However I'd recommend more speed and more angle to maintain a sik drift with lower power. I learnt a lot following Mumblez at Calder park a couple of years back. He was outfishtailing my ZE sprinter in his GE car. He just had the boot planted and serious angle at all times.

Hen

[Dxaqta]

the difference isnt as much as u say

between a 4.3 and 4.5 diff in 5th gear at around 100km/h is about 1000rpm

[psychofox]

I've been doing heaps of calcs of gear ratios and final drives of late, I'm looking at a 4.5 final drive for mine.

So assuming you are running 195/50/15 tyres and a standard T50 these are the speeds at these RPMs you will be running in each gear with a 4.778 final drive
Revs / 1st / 2nd / 3rd / 4th / 5th
4000 / 25.3 / 44.9 / 65.6 / 90.8 / 105.5
8000 / 50.6 / 89.9 / 131.3 / 181.7 / 211.1

I'm going for a 4.556:1 diff and it gives me:
Revs / 1st / 2nd / 3rd / 4th / 5th
4000 / 26.6 / 47.1 / 68.8 / 95.3 / 110.7
8000 / 53.1 / 94.2 / 137.7 / 190.6 / 221.4

It's also only doing 3500rpm at 100km/h, which is manageable. with 4.778 gears you're doing 3750rpm, which is getting a bit high driving on the highway to events for me.

[mattysshop]

the difference isnt as much as u say

between a 4.3 and 4.5 diff in 5th gear at around 100km/h is about 1000rpm[/b]

thats a huge difference to me! lol.. so if i'm going from 4.1 to 4.7.. it might be too much.. maybe i should get a 4.5...

[Dxaqta]

hahah matty i think u miss understood what i said.... the person above my post stated that it moving from a 4.1 to 4.7 would make it move like 8000rpm more saying instead of being in the top of 2nd u would be at the top of 3rd

and dont be a soft cock and get a 4.7 hahaha and tell me how it goes

[Hen is a total nutcase]

between a 4.3 and 4.5 diff in 5th gear at around 100km/h is about 1000rpm[/b]
Is that a typo, did you mean 100rpm?

The differrence between 4.3 and 4.5 ratios is about 5%. Revs at 100km/h in 5th with a 4.3 may be about 3400, so therefore a 4.5 will give 3400 x 1.05 RPM or about 3570.

The figures are rough, but you get the idea.

Hen

[darkon]

Upping your diff ratio without changing your corner speed wont make it easier to spin the wheels. Eg with a 4.7 you'll have to be at the top of 3rd not the top of 2nd and the overall gearing from engine to wheels will be the same. Therefore same torque at the wheels.

A small adjustment (say 4.3) may mean that at your normal corner speed you'll be revving a little higher in 3rd which could be useful.

However I'd recommend more speed and more angle to maintain a sik drift with lower power. I learnt a lot following Mumblez at Calder park a couple of years back. He was outfishtailing my ZE sprinter in his GE car. He just had the boot planted and serious angle at all times.

Hen[/b]

the idea behind it is that if ur already at top end in 2nd gear at the corner u cant rev any higher or spin the tires where as if u were chillin in 3rd somewhere a little lower u'd have the same gearing cept u'd have somewhere for rpm needle to go... unless u wanted to jump accross ur redline n take a chance

go big or go home 4.7 ftw!!!
how u gettin urs? u got someone i could contact... sounds like a cheap easy option for more speed so when the bacon brigade looks under ur hood mouth watering wondering which college hes gunna send his kids to after he busts you for this engine his v8 had trouble keeping up with... he sees nothing http://www.ae86drivingclub.com.au/forums/emoticons/biggrin.gif its all in tha diff http://www.ae86drivingclub.com.au/forums/emoticons/wink.gif

[SEXY 16]

i have a 5.1 in my car
when it was in my old rally car you just kept throwing gears at it

[Hen is a total nutcase]

Haul, yes, that is the whole point of changing the diff ratio slightly. However going to 4.7 may be too much of a jump and you'll end up at the top of 3rd instead.

And a higher diff ratio will not give you more power. The advantage is that you should hopefully have it set up so that the powerband in all 5 gears occurs at speeds that are actually achievable given the use your car gets.

For example the rally boys tend to have silly high diff ratios as rallying tends to involve lower speeds than say circuit racing at a open track.

I still suggest more speed and more angle.

Hen

[mattysshop]

yeh it doesn't give more power.. it just amplifies the torque multiplication..

[Spirited Away]

ATTN: Mattysshop where do you purchase this gear ratio? Me tinks they is well cheap

Thanks Blake

[dr1ft-pig]

It's also only doing 3500rpm at 100km/h, which is manageable. with 4.778 gears you're doing 3750rpm, which is getting a bit high driving on the highway to events for me.[/b]


man i rev at 6k on the highway in 5th with stocko s series and t50, what is wrong with my car?...i swear the signs said 180 http://www.ae86drivingclub.com.au/forums/emoticons/tongue.gif

[darkon]

Haul, yes, that is the whole point of changing the diff ratio slightly. However going to 4.7 may be too much of a jump and you'll end up at the top of 3rd instead.

And a higher diff ratio will not give you more power. The advantage is that you should hopefully have it set up so that the powerband in all 5 gears occurs at speeds that are actually achievable given the use your car gets.

For example the rally boys tend to have silly high diff ratios as rallying tends to involve lower speeds than say circuit racing at a open track.

I still suggest more speed and more angle.

Hen[/b]
well i spose if u end up at the top end of 3rd gear the only other option would be to cut sick n try n get enough speed to hit mid range 4th lol


yeh it doesn't give more power.. it just amplifies the torque multiplication..[/b]
yeah like selecting low gear on a mountain bike where the accelleration is inversely proportional to the top speed http://www.ae86drivingclub.com.au/forums/emoticons/biggrin.gif now matty... where to get it from?

*ignores pointless shitfight above* lol shitfights were the reason i left boost cruising http://www.ae86drivingclub.com.au/forums/emoticons/tongue.gif

[mattysshop]

Meh.. it's ok i just deleted the off topic ness..

yeh i'm getting it from

greenline (http://www.greenline.jp/catalogue/bccatpartlist.php?make=Toyota&carcode=AE86&intake=NA&category=drivetrain)

[RB20DET_Silvia]

i should be keen for 4.7's aswell but dont u think they could be a little to weak for drifting on track all the time....i mean well weaker then 4.1 by alot?

- Luke

[mattysshop]

weak!? how would they be weak?

[StockAE86]

I might have a 4.7 fs soon .. Just looking for brand new 4.3..
Unless anyone want to trade (for newish 4.3)? 4.4778 genuine TRD item, bought brand new, used for 1.5 years. No whining whatsoever.. Better than your 20y/o 4.1/4.3