Higher 5th ratio - K8DE V6



  • i did read somewhere, that its only a case of removing the black cover on the end of the gearbox and swapping in the new gear.
    There is an aftermarket 5th gear which is even taller than the probe/mx6 one.
    I know that marco knows the answer to both of these as he has done it on a couple of boxes now.



  • Thanks Everyone!

    Hi Stuz, (rember you from Club 323f :D ) I heard that 5th on the MX3 v6 was 0.84… then I got this from wiki...

    The Mazda G5M Five Speed Manual Transaxle came in three gearsets:[1][2]

    Trans # First Second Third Fourth Fifth
    G5M 3.307 1.833 1.311 1.030 0.795
    G5M 3.310 1.830 1.310 0.970 0.750 (Probe2.5L)
    G5M-R 3.666 2.059 1.310 1.030 0.837

    I would be happy with 0.795 or even 0.75 off a 2.5 probe - aparently.

    I did some calcs on a program I have (email me if you want a copy!)

    With the 0.75 5th gear i'll be pulling 21.5 mph per 1000 rpm (instead of 19.3. That would be much better. All I have to do is find a knackered probe gearbox to try it!

    Really want to know how to do it with the gearbox in the car… Id rather not take out or change a good gearbvox...



  • Think the 5th gears and selectors are held in place with staked nuts like this:-





  • i'm totally with you on this. living where i do i have an A road thats 40 miles long to get to the nearest city (60mph) and a duel carriageway thats 40 miles long to get to the other closest big town (70mph) and would love to save some fuel driving to these places as i do it on a regular basis. personally, i dont really think that the probe 5th will make much difference to the performance anyway as the little V6 is a strong little engine so i really dont think you will lose much accel in 5th by adding a taller 5th.

    and besides, most "races" are between the lights anyway (ali g style haa) so its all about acceleration. :)



  • We need to sort this out Dan…

    I just found this on ebay...

    http://www.ebay.co.uk/itm/toyota-corolla-gearbox-DOHC-1-9D-2001-2002-G5M-/360372586012?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53e7e1461c

    Seems that Toyota use this gearbox too?

    Hope someone knows where to get replacement 5 gear sets for reasonable money?



  • well, i was going to buy this myself for a 2.5 conversion but there is a breakers near me that have a ford probe V6 in stock. i popped over there and asked about price for engine and box. they offered it to me for £100 which is a bargain in itself but i cant get the engien out and seeing as im thinking about freezing my project for a min i wont bother. i'm sure if you offered them £50 for the box you could get it for that but you would have to come to cornwall and get it out yourself. i am assuming they still have it seeing how rare probes are getting now. if you are interested let me know and i will contact them to see if they still have it



  • Thanks Dan.

    There's a probe breaking just up the road from me too - 2.5 v6… If I had the money I'd be rushing out to get one.. but to be honest I'm a bit broke for a couple of months.

    Im not in a rush, and I have other things to do such as rocker cover gaskets, exhaust, etc etc... but if a cheap solution comes up I might take it :-)



  • how about this for a corker.. i won a bid for a klde..wen i went to pick it up the guy gave me the box for £1..as the engine was £99

    :D



  • @a64c8668c8=jay1987:

    how about this for a corker.. i won a bid for a klde..wen i went to pick it up the guy gave me the box for £1..as the engine was £99

    :D

    Lucky bastard.



  • I run a .717 in both my Gearboxes. Certainly seems to help my mpg. As does megasquirt. It's very easy to swap as you can see it's in the extension housing. Much easier than a final drive swap.



  • Hi Marco, Where can I get a set of 0.717 gears.. also do I need to get just the gears or do I need to use matching synchro rings etc? PPs what does it drive like? must be a big drop from 4th to 5th! :shock:



  • @3cfcf27149=Ice:

    Hi Marco, Where can I get a set of 0.717 gears.. also do I need to get just the gears or do I need to use matching synchro rings etc? PPs what does it drive like? must be a big drop from 4th to 5th! :shock:

    Car / Engine MX-6 FS-DE & 626 FS-DE GearboxG25M-R

    Gear Ratios (Input:Output)
    1st 3.307:1
    2nd 1.833:1
    3rd 1.233:1
    4th 0.914:1
    5th 0.717:1
    Final Drive 4.105:1

    The 0.717 can be found in the G25M-R I think you will need the syncro ring too so get it just incase. . .



  • You could also try to take the 5th gear of the 2.0 Probe.

    This one would create a big gap between 4th en 5th though.



  • @1a35ae77b5=whitefinish:

    You could also try to take the 5th gear of the 2.0 Probe.

    This one would create a big gap between 4th en 5th though.

    A gap that you would not even notice, I very much doubt it would make any difference to performance etc. . .



  • Oeps.. now I see Marco posted thesame information about that gear.

    Anyways… There is a member here that has a big RPM drop when shifting from 4th to 5th...



  • Approx figures from today's driving with .717 in a k8 gearbox.

    60mph = 2700rpm
    70mph = 3250rpm

    It was never for performance for me. Boosting in 5th gear is a brilliant way destroy the gearbox! Drag racing is 1-4. So I went for the eco 5th gear, and it sets motorway cruising at the bottom of the powerband.



  • Perfect! Where can I get a set of 0.717 gears?



  • @8732510926=Stuz:

    @8732510926=Ice:

    Hi Marco, Where can I get a set of 0.717 gears.. also do I need to get just the gears or do I need to use matching synchro rings etc? PPs what does it drive like? must be a big drop from 4th to 5th! :shock:

    Car / Engine MX-6 FS-DE & 626 FS-DE GearboxG25M-R

    Gear Ratios (Input:Output)
    1st 3.307:1
    2nd 1.833:1
    3rd 1.233:1
    4th 0.914:1
    5th 0.717:1
    Final Drive 4.105:1

    The 0.717 can be found in the G25M-R I think you will need the syncro ring too so get it just incase. . .

    @8732510926=Ice:

    Perfect! Where can I get a set of 0.717 gears?

    I will post it in a different colour for you. . . .

    Car / Engine MX-6 FS-DE & 626 FS-DE GearboxG25M-R

    Gear Ratios (Input:Output)
    1st 3.307:1
    2nd 1.833:1
    3rd 1.233:1
    4th 0.914:1
    5th 0.717:1
    Final Drive 4.105:1

    The 0.717 can be found in the G25M-R I think you will need the syncro ring too so get it just incase. . .

    Stu



  • Apologies, let me re-phrase that. I mean I have seen sets of new gears available ( but probably expensive) - do i need to break up a whole gearbox? Or can I get the parts from a specialist? Or is anyone on here selling a set?


 

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