Read this if you want to change your final drive!


elchunk

KCCO
VIP Member
Joined
Dec 22, 2008
Messages
6,968
not sure what FD you are using, but some FD changes require the first gear to be changes as well for it to fit and some may even require the housing itself to be trimmed!
 


eamon EK9

Member
Joined
Dec 11, 2010
Messages
186
Hi was wondern which would be a better box to put a lsd into a mb6 or ek4 vti? Is there any differce in 1st 2nd 3rd 4th 5th or are they the same thanks:woot:
 


EK4chris

New Member
Joined
Jan 3, 2012
Messages
173
i believe that they are the same execpt the ek4 cam with a s4c and the mb6 came with a s9b with lsd from standard depends on what sort of setup your looking for long ratio, short, higher final drive mean the engine will rev higher, which is a fail on motor ways lol.
 


Kozy

Bench Racer
Vendor
Joined
Aug 18, 2008
Messages
4,085
Hi was wondern which would be a better box to put a lsd into a mb6 or ek4 vti? Is there any differce in 1st 2nd 3rd 4th 5th or are they the same thanks:woot:
S4C is shorter ratio, better for NA B series engine.

Does a shorter FD gurantee better acceleration tho. I have gone against really short geared cars and I am on the stock 4.4 and will pull on them in 3rd and 4th. I am normally coming from half a car behind and end up in front. I think while they upshift and I am still in the lower gear I gain mega ground and pass them. And plus I can stay in 4th alot longer than they can and really open it out then. So is this just down to ratios or maybe i have a strong engine. Any help here appreciated.
I am pondering the idea of going to a 4.92 from the 4.4....but dont want it to hamper accelration, based on what I said above
You're not wrong. Here's an explanation from another forum.

Two identical cars, assume 150lbft of torque, one with 4.266 FD, one with 5.15.

Car A:
Top speeds and wheel torque in each gear for a 4.266:
1st - 41mph - 1751lb/ft
2nd - 65mph - 1114lb/ft
3rd - 91mph - 789lb/ft
4th - 126mph - 571lb/ft
5th - 155mph - 463lb/ft

Car B:
Top speeds in each gear for a 5.15: Wheel torque improved by 17.2%!
1st - 34mph - 2114lb/ft
2nd - 54mph - 1345lb/ft
3rd - 76mph - 953lb/ft
4th - 105mph - 689lb/ft
5th - 129mph - 560lb/ft

0-34mph Both in 1st - Car B has a 17.2% advantage
34-41mph, Car B is into 2nd, Car A still in 1st. Car B at a 30.2% disadvantage
41-54mph, Both in 2nd - Car B once again has a 17.2% advantage
54-65mph, Car B is into 3rd, Car A still in 2nd - Car B at a 16.9% disadvantage
65-76mph, Both in 3rd - Car B at a 17.2% advantage
76-91mph, Car B into 4th, Car A still in 3rd - Car B at a 14.6% disadvantage
91-105mph, Both in 4th, Car B at a 17.2% advantage.

Obviously there are other factors at play here, but you can see that once rolling over about 40mph the gains are negligible as the longer geared car can claw back ground while it stays in the lower gear. Your advantage is mainly focussed on that initial launch, so 0-60ft times at the strip would be improved and this will carry throughout the run to give you your improved times.

In gear acceleration is a different matter and is clearly improved significantly, but that's not making the car faster necessarily.
 






Paintballer3000

Active Member
Joined
Aug 17, 2010
Messages
317
Want to change my FD .... @ the moment i have the standart ek9 transmission ... so s4c / 4.4fd right ?
Want to going for 4.785 final because 4.928 is to short imo because i drive my car @ the Nordschleife...

is the 4.785fd plug and play ? or change more ?
 


b16 mini

Ek9 obsession
Staff member
Donator
Joined
Mar 10, 2008
Messages
3,207
Car(s)
1997 Ek9,1996 ek4 siR, 1972 b18c4 mini
Most aftermarket fd's are,
if using a 4.78fd from a s80 itr box you will require the itr first gear and sleeve to fit the shaft as well.
I replaced some bearings and used a new lock nut as well
 


JDM_DAVE

Active Member
Joined
Nov 13, 2013
Messages
194
I am still trying to figure out what I have in my dc2.. at 70mph in 5th gear the rpm is just over 4100rpm. But I do have 16inch wheels on at the moment with 215/45 tyres. the gear box is a 96spec going off the stamp. could the wheel size make that much difference? Or are my dials way out?
 


jesse888

Ek9+Turbo+Nurburgring= Heaven
Staff member
Donator
Joined
Oct 16, 2012
Messages
8,931
Want to change my FD .... @ the moment i have the standart ek9 transmission ... so s4c / 4.4fd right ?
Want to going for 4.785 final because 4.928 is to short imo because i drive my car @ the Nordschleife...

is the 4.785fd plug and play ? or change more ?
I've used a 4.9fd s4c at the ring, i didn't find it too short. You do catch the limiter after flugplatz and at foxhole but it's only briefly and I feel you gain more time elsewhere from it being abit shorter(long hill up towards karrousell for example)
 



jesse888

Ek9+Turbo+Nurburgring= Heaven
Staff member
Donator
Joined
Oct 16, 2012
Messages
8,931
No not if you buy from mfactory for your box.
If you use one from an integra then yes you will.
 


JDM_DAVE

Active Member
Joined
Nov 13, 2013
Messages
194
No not if you buy from mfactory for your box.
If you use one from an integra then yes you will.
you only need the dc2 first gear if your putting the dc2 4.7fd in a non lsd s4c, and the dc2 input shaft and all the spacers. putting a dc2 4.7fd into a ek9 s4c there is no reason you would need anything as the s80 dc2 and ek9 s4c are the same box.
 



oifovo

Well-Known Member
Joined
Jan 11, 2011
Messages
2,235
you only need the dc2 first gear if your putting the dc2 4.7fd in a non lsd s4c, and the dc2 input shaft and all the spacers. putting a dc2 4.7fd into a ek9 s4c there is no reason you would need anything as the s80 dc2 and ek9 s4c are the same box.
I'm pretty sure that's not true, the FD differs between LSD and non-LSD S4Cs but gears are the same. 98 spec S80 uses different 1st gear from any other Honda box as far as I know. 96 spec S80 and EK9 S4C are pretty much the same, yes, 98 spec S80 is different. If you check Mfactory close ratio gear set application list for Honda you'll see they sell one 1st gear for B16A, B16B and B18C and another for B18C 98 spec - which is what Honda 4.7 is from.
 


JDM_DAVE

Active Member
Joined
Nov 13, 2013
Messages
194
im pretty sure im correct but now that you have mentioned it im starting to doubt myself.. I was pretty sure s4c lsd from ek9 and a 96 s80 are the same.. the 4.7fd from the 98 spec should fit in the either box without issue.. the 98spec s80 has longer 4th and 5th that's the only difference. putting a s80 4.785 final drive in s4c non lsd wont work with out 1st gear shaft and spacing rings from the s80
 

Last edited:

JDM_DAVE

Active Member
Joined
Nov 13, 2013
Messages
194
stand corrected, jesse888 is right.. you need dc2 s80 1st gear shaft and spacing to fit the 4.75 into a ek9 s4c... my bad:(
 



Top