final drives 4.44 vs 4.77

[NOPSTNS]

shootin the breeze with another tech at work yesterday led to a discussion we cannot resolve....if a cars final drive is, say, 4.44 , would a ring and pinion change to 4.77 make a diff? the number seems like such a small difference...if a car can be geared to achieve 185mph but wind resistance, drag etc etc onlyallows it to run to 150...would the final drive change help reach its higherspeed? now i kno goin from 4.44 to 4.77 would lower a cars top speed, but itd accelerate faster tho, even tho itd be limited in gearin to say.....150 mph?

would going from a 4.44 to a 4.77 really make that much of a diff?

[Dave]

yes, nsx table

Speed
0-MPH 	Baseline 	Japanese
5-speed 	4.235 R&P 	4.55 R&P 	Japanese
5-speed
4.55 R&P 	Japanese
5-speed
4.235 R&P
0-30 	2.16 	2.16 	2.08 	1.94 	1.94 	2.08
0-40 	2.92 	2.92 	2.80 	2.62 	2.62 	2.80
0-50 	4.16 	4.11 	4.11 	4.02 	3.91 	4.04
0-60 	5.56 	5.34 	5.45 	5.27 	5.00 	5.22
0-70 	6.99 	6.60 	6.82 	6.54 	6.60 	6.42
0-80 	8.46 	8.52 	8.23 	8.45 	8.24 	8.44
0-90 	10.74 	10.46 	10.65 	10.42 	9.94 	10.28
0-100 	13.13 	12.48 	12.91 	12.49 	12.33 	12.58
0-110 	15.66 	15.67 	15.31 	15.40 	15.39 	15.64
0-120 	19.02 	19.25 	19.02 	18.72 	18.38 	18.98
0-130 	23.56 	23.27 	23.24 	23.42 	23.26 	22.72
0-140 	28.93 	27.91 	28.13 	28.90 	30.36 	30.04

[Dave]

it got all screwed up in reposting, its at this link:
http://www.scienceofspeed.com/produc.../NSX%2DR%5FRP/

[Nors]

http://www.mustangforums.com/archive...i-30293-1.html


Explains it pretty well. If you knew your gear ratios you could figure out the % of torque increase that would give you.

[NOPSTNS]

i read both the nsx table and the mustang excerpt.....good reads....thank you all....and dave, the fact that ur biscuit band has a parental advisory is even more amusing!

[Raven18940]

With a 4.77 instead of a 4.44 you'd see a torque increase of about 7% in all gears. You theoretical top speed will drop from 185 to 172, but your actual top speed will increase due to have more power at the wheels. It won't increase by 7% though cause wind resistance is an exponential force, say maybe 155-ish. The down side to this is your gonna get even worse fuel economy and you're gonna be grabbing gears more often.

[NOPSTNS]

yea i knew about the fuel thing, but id apply that to only on the highway where id be stuck in 6th, i skip gears now as it is so a shorter final drive would be evn more beneficial. i go from 1st to 3rd when im drivin easy (on the rare occurance) . drivin thru the town i wont see an mpg diff but the highway will hurt a bit. at 60mph in 6th gear im at 3k as it is! haha!

[Gorilla Unit 33]

to give you an idea i have went from a 4.9 final drive to a 4.4 to a 3.2 (now)


FWD honda in 5th gear
4.9- 60mph 5500rpms
4.4- 65mph 4200rpms
3.2- 60mph 2000rpms

[Raven18940]

Originally Posted by Gorilla Unit 33

to give you an idea i have went from a 4.9 final drive to a 4.4 to a 3.2 (now)


FWD honda in 5th gear
4.9- 60mph 5500rpms
4.4- 65mph 4200rpms
3.2- 60mph 2000rpms

I have similiar plans should I up my power so I can actually use my lower gears.

[Renegade_]

4.77 is crazy short - I know people throw 4.44 boxes on high revving suby motors and fly through the gears (8k redline). The rotaries have another 1000 rpm (well, at least... you guys can go higher than 9 without trying too hard) to play with though so it might make more sense.

All I can say is that be prepared to be cruising at like 60 and at like 4k at the minimum. I don't know what the gear ratios in RX8s are so I couldn't tell ya exactly. I say go for it, you'll fly through the gears and a useable powerband will always be on hand.

Unless gas mileage is a concern

[NOPSTNS]

gas mileage?! ha! no rotary owner cares about gas mileage man, if they did they wouldnt be in a rotary....imo 4.44 isnt really all that short when it comes to an engine thats powerband STARTS at ppls REDLINES....

my power is from 6250 untill rev limit at 9500. in first gear i can go to almost 50 before 9500, right now in 6th at 60 im at 3k.

my biggest need for a shorter final drive is two things, 1) i need it geared shorter so i can get to my powerband quicker.....2) the shorter gear will help give me more punch out of a turn....i got my ass kicked on road courses at corner exit and most obviously the straights....the twisties i am comptetitive in but an entire road course cant be a slalom! the car is physically geared to achieve 184 mph....the car can no way in hell reach that. iv had it to 148mph and hit a bump, got scared, and slammed down on the clampers....imo i have no need to be exceeding 150 so i got 34 mph of complete waste since the car doesnt have enuff power to reach 184 and the drag is so insane that it cant fight its way up to 184 anyway!

a shorter gearing would drop the top speed,(say down from 184 to maybe 160) and help me achieve that lowered top speed anyway, win-win situation...

FEED sells a 4.77 for my car (thats both a ring and pinion) for 670 dollars i dont think thats TOO outrageous for a part thats special order from japan. i think ill prolly go for it for next summers events. maybe itll be a christmas present to myself....itll be good for my autox too bc right now i run most courses just in first gear, if i had the 4.77 id be able to put it in 2nd and not have such a jumpy/awkward transition with the gas pedal....

[Gorilla Unit 33]

i forgot your car is a 6spd. If i had a 6spd i wouldnt worry about final drives until you get close to a 4.9

[04 Turbo Spec]

yes because a 4.77 gear change into an S2K is a very common mod. and the 4.77 gear swap make a huge difference.

[NOPSTNS]

arent s2ks 4.10s tho? thats a huge jump.....id expect huge jumps in performance...im tryin to weigh if id even be different. 4.44 to 4.77 doesnt seem like much.....id rather it bo TOO agressive than not enuff which makes me consider 4.91 etc etc etc

[04 Turbo Spec]

Originally Posted by NOPSTNS

arent s2ks 4.10s tho? thats a huge jump.....id expect huge jumps in performance...im tryin to weigh if id even be different. 4.44 to 4.77 doesnt seem like much.....id rather it bo TOO agressive than not enuff which makes me consider 4.91 etc etc etc

yea the two popular swaps are the 4.57 and the 4.77

but i would rather have it be a little more mild and not risk haing to run very high rpm on the highway.
if it were me in my car i would would go with the 4.57 because the 4.77 in my cay in 6th gear at 70mph is like 6000 rpm!!! and top speed at like 120 something. (im not 100% sure on the numbers, i would need to recheck to be more certain)

[NOPSTNS]

yes man but my cars gearin is diff, im gonna get the gear ratios for each gear and show ya what i mean.

an s2k is geard in the trans to work with a 4.10
an rx8 is geared in the trans to run with a 4.44

my 6th at 60 is 3k.
hypothetically, IF urs was the same, going from 4.10 to 4.77 would be a HUGE jump. instead of u bein 3k at 60 urd be 6k at 60, i see how thatd be bad.

but the rx8 is at 4.44, im halfway to 4.77 compared to u so the jump wouldnt be all that agressive. my 6th is ungodly tall (considering the 4.44 final drive) so at 4.44 with 6th at 60 im at 3k, so from 4.44 to 4.77 would be like 60 in 6th at maybe 4250....not a huge jump.


but my big prob isnt highway, im concerned that goin to 4.77 isnt gonna make a diff.

my overall Q i guess now is....is .33 shorter gonna make a useful gain on a trans geared tall as a circus clown?! should i move to 4.90s or somethin....

[04 Turbo Spec]

Originally Posted by NOPSTNS

yes man but my cars gearin is diff, im gonna get the gear ratios for each gear and show ya what i mean.

an s2k is geard in the trans to work with a 4.10
an rx8 is geared in the trans to run with a 4.44

my 6th at 60 is 3k.
hypothetically, IF urs was the same, going from 4.10 to 4.77 would be a HUGE jump. instead of u bein 3k at 60 urd be 6k at 60, i see how thatd be bad.

but the rx8 is at 4.44, im halfway to 4.77 compared to u so the jump wouldnt be all that agressive. my 6th is ungodly tall (considering the 4.44 final drive) so at 4.44 with 6th at 60 im at 3k, so from 4.44 to 4.77 would be like 60 in 6th at maybe 4250....not a huge jump.


but my big prob isnt highway, im concerned that goin to 4.77 isnt gonna make a diff.

my overall Q i guess now is....is .33 shorter gonna make a useful gain on a trans geared tall as a circus clown?! should i move to 4.90s or somethin....

yea i know what you mean and fully understand what your talking about. i was just talking my car.

anyway i think a 4.77 may not give you what you want but 4.90 is definitely going to be too much.

[Raven18940]

Go with 4.9 I says, by my maths you'll only lower your top speed to 167. If you've got a good shifting trans and no traction problems then the more torque the better.

[NOPSTNS]

yeah id go with at least a 4.90, if im gonna do it im gonna go insane with it.....bump bc i found specs on the rx8/s2k ratios....

2004 honda ratios (final drive 4.10)
1st Gear Ratio: 3.133:1
2nd Gear Ratio: 2.045:1
3rd Gear Ratio: 1.481:1
4th Gear Ratio: 1.161:1
5th Gear Ratio: 0.942:1
6th Gear Ratio: 0.763:1

2004 RX8 ratios (4.44)
1st - 3.760
2nd - 2.269
3rd - 1.65
4th - 1.187
5th - 1.000
6th - 0.843

and the s2k STILL kicks the rx8s ass in a race, wtf man....! haha! im goin 4.90 AT LEAST

[04 Turbo Spec]

any way just talked to a s2k owner with 4.77 and at 70mph he is at 5,000rpm. i think in my previous post i said higher.

my brother is gonna get a RX8 very soon. what mods do you recommend .