4.7 final drive vs 5.1 final drive

[koevi]

Hi,

Im planning to upgrade to a 5.1 final drive but just wondering whats the difference between 4.7 and 5.1 on a final drive? Does it make a big difference in acceleration?

Thanks

[vtecing]

hope you dont do much highway driving

[koevi]

I kinda do lol, but I need to change my final drive as mine was is stuffed. Since i need to change it i thought i might as well go 5.1 like the FN2R's

[JDM EP3]

hope you dont do much highway driving

Isnt that what he has 6th gear for?

[C.I.SIvic]

Isnt that what he has 6th gear for?

My DC5S does about 2800rpm @100kph on stock drivetrain (4.764 FD) in 6th gear. Increasing FD to 5.1 will bring that up to just short of 3000rpm.

Sometimes I wish they just made the 6th gear really long.

[Super-DA9]

fuuuark what a difference in gearing for the DC5. my 4.7 in my dc2r box is at about 3850RPM at 100km/h.

[Bludger]

fuuuark what a difference in gearing for the DC5. my 4.7 in my dc2r box is at about 3850RPM at 100km/h.
6 speed box vs 5 speed box.

3850 @ 100km/h doesn't sound like 4.7 fd

[eg5civic]

Sounds like 4.9?

[JPR28610]

mine sits abit over 3ks @ 100kmph on a 4.7fd b18c

[Bludger]

oem dc2r is 3500rpm @ 100km/h & roughly 115-117km/h @ 4000rpm.

from memory.

lmzooooo

[joeyybruh]

6 speed box vs 5 speed box.

3850 @ 100km/h doesn't sound like 4.7 fd

my b18c7 4.7 LSD eg runs at a stable 3.5 at 100 kmh


oem dc2r is 3500rpm @ 100km/h & roughly 115-117km/h @ 4000rpm.

from memory.

lmzooooo

that sounds about right ! ... is 3850 normal at 100 ks !?

[dougie_504]

No it's too high unless you have a different (higher) FD.

[Super-DA9]

No it's too high unless you have a different (higher) FD.


my b18c7 4.7 LSD eg runs at a stable 3.5 at 100 kmh



that sounds about right ! ... is 3850 normal at 100 ks !?


oem dc2r is 3500rpm @ 100km/h & roughly 115-117km/h @ 4000rpm.

from memory.

lmzooooo

Hmm that is worrying haha!

I will check next time I drive it and let you guys know if I was possibly on drugs or if it really is as high as I remember. :P

[DC2-PWR]

oem dc2r is 3500rpm @ 100km/h & roughly 115-117km/h @ 4000rpm.

from memory.

lmzooooo

Sounds right, mines nearly the same.

I checked mine through the mfactory calculator and it's spot on

[Bludger]

my dc2r is hardparked.

only gets driven interstate.

lmzoooo


I have no interest in dc5r's so sorry for OT.

[DC2-PWR]

^ haha interstate travelling is fun, wish i could do that

here use this
http://www.teammfactory.com/gear-calculator

its accurate enough to give you a figure at what rpm's you will/be travelling with different FD's. check your own too - dw too much if its not the same as what your cars doing, because our rev gauge isn't that accurate.

[eg5civic]

As I said before it could be a 4.9fd or your tacho might be out?

[mocchi]

how come no one put up their tire spec when comparing?

[Bludger]

how come no one put up their tire spec when comparing?
because I (if not all the people replying) assume they are not the type to run 20" chromies.

http://www.ozhonda.com/forum/customavatars/avatar11984_10.gif

[DC5FTW]

Is a good idea for 6speed gear box

[pe45678]

i love 4.7 more

[_bORdO_]

....
anyway

OP - test it out but im sure in the long run you'll get over it & change back
if you do go through with it, give us some feed back on how crap it is...
or good.
:thumbsup:

[45SET]

How exactly do you break a final drive?

[r3ckless]

Im going the 5.1 FD from my 4.7. I am also isntalling the Accord euro/TSX 6th gear to keep rpms i think 2800 or 2500 rpm with the 5.1 fd at 110km/h . So that means I'll have more acceleration in gears 1-5 and 6th gear, the revs will be even lower!

I dont think the upgrade will have any downsides.. I mean on the FN2R/FD2R, their gear ratios are exact same as the dc5s, except for shorter final drive. So when i upgrade my FD to 5.1 and using 17inch wheels instead of 18inch, it should be a good increase in acceleration without over doing it.

[_bORdO_]

what would the top end speed be?

[r3ckless]

what would the top end speed be?

To answer your question, 6th gear, 4.7FD @ 8000rpm - 274km/h, 5.1FD and TSX 6th @ 8000rpm - 289km/h

I would never hit 6th gear at Wakefield, I'll be grabbing 5th gear with the new drivetrain setup so in 5th gear, 4.7FD at 8000rpm - 220km/h, 5.1 FD at 8000rpm - 207km/h



I used the mfactory calculator and tyre size used was 235/45/17 all throughout.

http://www.teammfactory.com/gearcalculator.php?kmh=1&tirewidth=235&tireprofile=45&wheelsize=17&tirediameter1=25.33&maxrpm1=8000&finaldrive1=4.764&gearratio1=3.266&gearratio2=2.13&gearratio3=1.517&gearratio4=1.147&gearratio5=0.921&gearratio6=0.738&trannytype=31&tirewidth2=235&tireprofile2=45&wheelsize2=17&tirediameter2=25.33&maxrpm2=8000&finaldrive2=5.062&gearratioa=3.266&gearratiob=2.13&gearratioc=1.517&gearratiod=1.147&gearratioe=0.921&gearratiof=0.659&trannytype=31&tranny=Calculate+Transmission+1+%26+2

[_bORdO_]

perfect answer.
thanks.

[mocchi]

perfect answer.
thanks.

youre welcome paul

[_bORdO_]

youre welcome paul

Ha Ha..? :confused:
Thanks Oscar?

Your welcome in my books as well
:thumbsup::thumbsup:

[r3ckless]

Hey guys, i just drove my friend car. I been talking to him about my drivetrain upgrade for awhile, then his gearbox blew :/ so he opted to install the parts i was going to install: exedy stage 2/exedy lightened flyheel / 5.1oem fd/ accord 6th. Now his car is just inejncai/toda header/amuse catback and shitty tyres. His car is fast. It accelrates like mine if not faster from 0-120km/h

Mycar has got decent tyres/injencai/toda eader/spooon n1 catback/hondata kpro/stock drivetrain. His car is defiantely on par with mine if not faster.

There has been alot of hate with the 5.1fd with ppl saying its too aggresive and u be shifting way
Too often... In my 10min drive, the shifting was same as mine but i can feel alot more getupandgo even at 2k rpm.

Looking at gear ratio calculators, the data hows it is a great mod... After the drve tonight, its great! I thiught his 3.7/3.8kg exedy flywheel would be too light... It felt great to drive, even with nike tn's lol. I think cos my car has the tuned kpro... I might stick eith my jdm flywheel .

I cant wait to drive his car again!

[r3ckless]

One thing i would like to test is also his cruising rpm at 6th gear. I wanna see some real life figures on the rpm at 110km/h. I will see if he can do it and report back here!

[_bORdO_]

very good, keep the info coming.

[dlai5552]

What fool looks at top speed these days... no one is ever going to hit that fast, not even down Eastern creek straight lol. The change in FD imo is all based on it's purpose. You can get a shorter final drive which can be 'torquey' but maybe around wakefield it forces you to hold out the gear until the corner? Then you're f**ked lol. Also, with the street car, definitely gotta check if YOU can handle the cruising speed. A droney exhaust at 4.2k rpm is probably the worst thing I've ever experienced!

[butterfingers]

How exactly do you break a final drive?

I would also like to know this

[DakDak]

A droney exhaust at 4.2k rpm is probably the worst thing I've ever experienced!

For me the "droney exhaust" would be the issue and not the Final drive.

[curtis265]

For me the "droney exhaust" would be the issue and not the Final drive.

That's more of a vehicle specific thing, I find that if I cruise in my car at 4000 it's quite quiet compared to 2500. it doesn't resonate through the chassis asmuch

[r3ckless]

Who cruises at 4000rpm? I cruise at 2-3k rpm, shift at 3-4k...

[butterfingers]

Who cruises at 4000rpm? I cruise at 2-3k rpm, shift at 3-4k...

nobody really but with very short FD cruising at 100-110 can start nearing the 4000 rpm mark

[Benson]

Real test would be a 1/4mile. Go out one night with stock 4.7 FD and see what top speed it can hit in 400m. When the 5.1FD goes in, see if top speed increases.

We just installed a 5.1FD into BYP EG n/a time attack, from data shown it there was no increase in top speed on the straight. If anything it might of made the car go backwards couple of the tenths.

[dlai5552]

Who cruises at 4000rpm? I cruise at 2-3k rpm, shift at 3-4k...

With a short FD! On the s2k with 4.77 peaking at 4.2k rpm at 110 kph. Had a 70mm j's which made life worst lol

[butterfingers]

Real test would be a 1/4mile. Go out one night with stock 4.7 FD and see what top speed it can hit in 400m. When the 5.1FD goes in, see if top speed increases.

We just installed a 5.1FD into BYP EG n/a time attack, from data shown it there was no increase in top speed on the straight. If anything it might of made the car go backwards couple of the tenths.


shorter gearing COULD give better times, but the effect is more noticeable over very short distances. it increases short term acceleration by delivering the same power curve earlier during the speed range. pulls harder, but shorter. in the end, over a longer distance where cars with tallers gears have a chance to catch up, result is roughly the same and since you'll be shifting more, might actually get worse times.

[r3ckless]

Imo i think the circuit is a better field to test which fd will be better as you will get on the power sooner. I think the 1/4 mile will test what top speed u will net when comparing gear ratios etc. benny, on ur track data with the EG, was the only mod that changed was a different fd?

[r3ckless]

Im happy to get some rough estimates on speed at redline in each gear so we can conpare a stock drivetrain and upgraded clutch/flywheel/lsd/shorter fd for everyone :)

[r3ckless]

nobody really but with very short FD cruising at 100-110 can start nearing the 4000 rpm mark

Hence why installing the 6th gear from accord euro should be complimented when going shorter fd.