View Full Version : gearbox's : need more top end
jimbob-mcgrew
26-03-09, 12:39 AM
due to recent job & accomodation changes im doing alot of motorway miles and the petrol costs are killing my wallet, not to mention the annoying drone of 4000 rpm on the ears. she currently has a 4 speed f10.
what options have i got on the gearbox front for more speed for my 1.2 ?
cheers.:thumb:
^^. And if you can't find an f13 wide ratio then an f13 close ratio would rpob still be an improvement!
mikey14sr
26-03-09, 09:48 AM
Just fitting a 5-speed F10 would be an improovement tbh. Easier to get hold of too, as was fitted to plenty of corsa's and astra mk3 1.4 merit's.
^^That be the same as an SR gearbox yeah?
mikey14sr
26-03-09, 10:18 AM
yeah pretty much (final-drive ratios vary a bit).
find a diesel box with a 3.5 diff in it!
Sorry for giving more options taf.
Let me know if you want one, F13 WR. might make the car ****e slow down the rest of the gears but it will bolt onto a 1.4 or even a 1.6 should you decide to change.
MSN me
I have heard everything now...
the f13cr has the same top gear & diff as the f10 4 speed.
f10/5 from anything other than an sr will actually have a higher top gear & a tall diff (3.74:1 i think)
f13wr is pretty much the same...
having a wr box will actually help the 0-60 times cos with a cr box you need to find 3rd to get to 60, but with a wr box, you can do it in 2nd
f13wr boxes are cheap & plentiful, and fit straight on
It all depends on the final drive!
the 1.2 4 speed has a 3.74 diff ratio
the f13cr has a 3.74 diff ratio
the f13 wr has a 3.74 diff ratio....
jimbob-mcgrew
27-03-09, 01:06 AM
hmmm lol - anyone got a link to a page with vauxhalls gearbox's and the ratios in each gear plus final drive ?
which boxes will fit my 1.2 ? f10, f13, did gte's/gsi's have f15's ?
gazjoiner
27-03-09, 01:46 AM
hmmm lol - anyone got a link to a page with vauxhalls gearbox's and the ratios in each gear plus final drive ?
which boxes will fit my 1.2 ? f10, f13, did gte's/gsi's have f15's ?
i,m thinking you would be ok with a f13wr 5 speed box tbh! dont get a f13cr(gte/gsi) box!! it will scream on the moterway imo, go for a f13wr / f15 5 speed!! the f15wr is of astra / cav carb engines iirc?? econemy class :D
gazjoiner
27-03-09, 01:50 AM
the 1.2 4 speed has a 3.74 diff ratio
the f13cr has a 3.74 diff ratio
the f13 wr has a 3.74 diff ratio....
are we talking obout final drive? and 3rd and 4th gear ratios?
gazjoiner
27-03-09, 01:54 AM
hmmm lol - anyone got a link to a page with vauxhalls gearbox's and the ratios in each gear plus final drive ?
which boxes will fit my 1.2 ? f10, f13, did gte's/gsi's have f15's ?
i do! i,m tired now though, have all the books / info in the loft :roll:
jimbob-mcgrew
27-03-09, 10:19 AM
i found this posted by stuart in the articles section, tis in german or something, but has the info:
http://oege.ie.hva.nl/~jelsma02/Overbrenging%20Corsa%20A.jpg
jimbob-mcgrew
27-03-09, 10:27 AM
f10 wr and f13 wr are exactly the same ?
friend of mine has a f10 5 speed that i tried out on a previous nova, wasnt happy with it tho, only got an extra 1 mph outta 5th prety much.
could try it again, but is it worth the hassle again for 1 mph i doubt it, i guess its just the crappy 1.2... if it were a beefier engine, it wouldnt rev so high, but the beefier the engine, the more fuel used anyhow, hmm, this seems like a loosing battle. i think im just gonna have to accept my wallet getting raped
edit : no wait, i have an 12ST which says 3.74, mates 5 speed is from a 14NV which is 3.94.. what does that mean ?
get a 5 speed f10 and put your final drive into it. theres a guide somewhere for final drive swaps
jimbob-mcgrew
27-03-09, 10:34 AM
why my final drive ? the lower the figure the longer the ratio is it ?
so in theory i could make that slightly longer 5th slightly longer still ?
that what u mean burgo ?
yes but not by much. wil only gain you about 5mph
jimbob-mcgrew
27-03-09, 11:10 AM
http://www.pngclub.com/forum/showthread.php?t=93756
^ stuarts guide, sounds waaay too hardcore for me, cant make head nor tails of that.
only 5 mph ? bollox, hardly seems worth it.
what might be quite cool tho, is to stick the 3.94 final drive in the 4 speed for added acceleration.
infact lemme re-phrase, "put the 5 speed on"
just gonna have to live with it then. put a normal exhaust back on it and alls good :)
jimbob-mcgrew
27-03-09, 11:18 AM
standard system on it, still bloody loud.
i think ill switch the box for a 5 speed when i get round to changing the clutch.
would be good to switch that final drive into the 5 speed, but i cant make out how to do it from stuarts guide, sounds too much
switching to a 5 speed will gain you nothing tho
jimbob-mcgrew
27-03-09, 11:22 AM
in theory a tad of acceleration thru 1-4, and roughly the same top end in 5th
lol its not hardcore.. its a piece of piss. hence the guide with a lot of bollocks in it lol
Taf if i can do it anyone can do it.
I reckon you could do one in an hour. I've also got a neat tool for taking out the castleted nut which you can buzz it out with an impact gun!
jimbob-mcgrew
27-03-09, 07:44 PM
so how'd you do it ? lol
stuart was going on about popping driveshafts out, sliding the gears out and allsorts, is all that needed ?
what are you trying to do (CBA to read 3 pages of toss lol)
jimbob-mcgrew
27-03-09, 07:56 PM
take the final drive out of a gearbox
i was after more top end with a longer final drive swap, but as im only going to benefit in top gear, and only 5 mph at that, i might aswel go the other way and shorten the final drive in my current box to gain a bit from each gear and screw the top end, things slow as it is.
just change the 5th gear pair for a lower numbered set. easier job (end of gearbox off, piss about with circlips etc and done
so many people are petrified of playing with gearboxes, but will happily do some serious engine work ...........apart from the ability to measure properly, gearboxes are dead easy to work on..
I will put the gearbox dilemma into plain speak. the lower the diff ratio, the higher the gearing, the lower the gear ratio, the higher the gearing.
so if you are after refinement & economy, choose a f13wr with a 3.74 final drive (or diff) the numbers are stamped on the gearbox casing.
as for how long it would take to swap. I can do them in around an hour as long as I have a 45minute break in the middle.
a F13CR with a final drive of 4:18 would be a nice box too.
yes, it would be a 1.3 sr box
novaguy08
28-03-09, 07:35 AM
im going to be doing the same........... But im going to fit an F10/5 I was originally going to change the diffs over and use the 4 speed one in the 5 speed, but i decided not to as all it will end up doing is putting an extra gear on the end. No difference what so ever (all the g/r are the same according to my manual apart from the final and 5th) so im just going for the 5 speed............. mainly as i think my 4 speed is about to drop out! Makes a sodding horrible noise when turning right and a nice little whine!
So next weekend a nice shiney (hopfully painted) F10/5 is going in there!
im going to be doing the same........... But im going to fit an F10/5 I was originally going to change the diffs over and use the 4 speed one in the 5 speed, but i decided not to as all it will end up doing is putting an extra gear on the end. No difference what so ever (all the g/r are the same according to my manual apart from the final and 5th) so im just going for the 5 speed............. mainly as i think my 4 speed is about to drop out! Makes a sodding horrible noise when turning right and a nice little whine!
So next weekend a nice shiney (hopfully painted) F10/5 is going in there!if its only when turning i would surgest you check your outer cvs before doing the box :thumb:
novaguy08
28-03-09, 08:13 AM
already have
they fine, im doing the box regardless as i want 5 gears! in the same situation as this guy, getting fed up of the 4k drone and 80mph! lol
already have
they fine, im doing the box regardless as i want 5 gears! in the same situation as this guy, getting fed up of the 4k drone and 80mph! lol
as stated before, get a wr box, or you have made no gain.
novaguy08
28-03-09, 04:27 PM
Dont want top end gain, the ratios would be too wide for a 1.2..... the 5th gear would mean the same top speed but extra hit at top torque & power
exactly so you still get the same 4k drone. you gain nothing
gazjoiner
28-03-09, 07:49 PM
personaly i would like said ^^ fit a wr 5speed box!!! no performce gain and no more top end! but better for moterway cruising at lower revs in 4th and 5th, i may be wrong?
i ran a 4speed 1.2 for several years, and the gear spacing was fine. if i had fitted a cr box, the 0-60 would have gone up by a second due to the extra gearchange.
unless you have built a 100+hp screamer, a cr box is hardly worth fitting
I wanted an overdrive 5th for improved cruising.
I am actually fitting a f13wr to my gte engine for the same reason.
novaguy08
28-03-09, 09:14 PM
meh im sticking with the F10 mainly as i know its just going to bolt in without trouble I know i know, F13 will go in without bother too, but I already got an F10/5 and i couldnt find a 13wr so till i get either some cash to tune the thing or another car thats the way its going to have to be
thats unless i find out that the diff on my 4-speed is ok then im going to lump that into the 5-speed
the diffs rarely knacker up on 1.2's the noise is usually the wheel bearings
novaguy08
28-03-09, 09:20 PM
well its only when i turn right and i have heard knackered CV joints before so i know that its not them........ Its confused me something cronic so im still debating on what to do
it could be wheel bearing, mudflap hitting wheel, bent chassis, huge wheels catching somewhere, loose wheel bearing catching the brake backplate, steering joint on the way out, tatered shock absorber etc.....
novaguy08
29-03-09, 01:12 PM
Well i dont have huge wheels (14x6 at the mo) Chassis not bent, there is no play with the wheel that can be spoken of, backplate is not rubbing on discs shock if flubbered and being change, bottom ball joint has just flubbered so is being changed, im going to try to buy a "donor" car at some point so im going to be changing over the entire suspension setup after i done the box, but what im going to do is change box, if noise goes away i know its the box, if it doesnt then ill change the diffs over lol making one cr 4-speed (good for sprints?) and one wr 5speed
novaguy08
29-03-09, 01:17 PM
Mind you i just read the box ratios on thread, if i did that i would end up with an F13 box lol
you wont be able to make a CR 4 speed. Unless your thinking of a 4 sp cluster from a mk1 astra, mind you they go for about £350 each!
you wont be able to make a CR 4 speed. Unless your thinking of a 4 sp cluster from a mk1 astra, mind you they go for about £350 each!
if you use the lowest 4 gears from a 5 speed box, you could get a 4 speed cr box, but it would be crazy low geared for road use.
novaguy08
29-03-09, 06:55 PM
Well the F10/4 and F10/5 box ratios (1st 4) are the same, the 5spd one has a different final to get the top speed the same and shorten the ratios, so if i were to put the shorter final drive into the 4 speed i would end up with effectivly a 4speed box with 5 speed ratios so the top speed would be what ever the 4th gear is in the 5 speed (ie making it a Closer Ratio or CR g.box) i wasnt on about making a proper cr box....... yes would be crazy low ratios, but might be good for sprint races! Something big accel is needed but not top end (banger racing?) hey neva mind im not going to do it all at once as ill only have a day to change box and clutch as well as probably most of the suspension so im not going to bugger about with the diffs till i can check the old one.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.