Evo Gearbox Upgrade (me dreaming)

[Adam.Findlay]

So here goes, me taking a stab in the dark.
All 5MT evos an VR4's have the same gearbox right, the W5M51.
But the only difference between evo's and VR4's is the bell housing (to mate the W5M51 to either 4g63t or 6a13tt)??

Now as my brain computes it, if the gearbox is the same it should have the same chassis mount point so the legnum/galant gearbox mount should bolt straight up to any evo W5M51
Also instead of going throught the trouble of what bradc did with transferring the internals of the gearbox, (correct me if im wrong) couldnt anyone just take the VR4 bellhousing and attach it to an evo W5M51 and bolt it straight up to the 6a13tt for a simple VR4-evo gearbox upgrade??
And (here comes th long shot) if by some chance the evo 6MT's (dont know the code) have the same bellhousng bolt pattern as the evo 5MT (W5M51)
Couldnt it be possible to put a evo 6MT into a VR4 with only changing the bell housing, linkages and having a custom gearbox to chassis mount??

If so this would be friggn amazing sounds to good to be true and probably is.
Any thoughts??

[rees]

surely someones thought about this?? anyone
?

[bradc]

Transferring the internals isn't a big problem though, it isn't like an auto where everything is incredibly complicated and mostly works by magic.

The procedure is to remove the gearbox (5hrs), open the gearbox up (10min) and the two shafts are right there. You can remove them and put new ones in in about 10 minutes. Re-using the 2nd part of the gearbox out of an evo isn't really going to help in anyway, and I beleive that side of the gearbox might be quite different as well, to fit into our engine bay, in regards to the chassis mount in particular.

Basically doing it the way I did, using a VR-4 housing with two shafts probably takes 10 minutes more in total, and means that you don't have to have an evo casing. (which I didn't have anyway)

[Adam.Findlay]

Sweet I thought swapping over the internals required you to know how to preload and shim which i dont know how. any thoughts on the 6spd idea tho i cant find any images or codes for the 6spd gearbox. Im defianatly loving the idea for that.

[peter thomson]

Have a look at post 35 and 36 here

http://www.clubvr4.com/forum/showthread.php?t=38272

[bradc]

Well, we just dumped the gears in and left them :)

The 6 speed is possible, but it's 6th gear isn't any taller than our stock 5th so it is suited to track days really, not long distance driving.

[Kenneth]

Don't forget you have to actually have the output shaft changed as well! So it isn't a direct swap.

The bell housing is integrated into the gearbox case, to swap it you would need to take the gearbox apart, at which point you might as well just swap the internals over.

[Adam.Findlay]

Oh cool so 5spd swap is easy as, but a 6spd would be wicked for the track.

[elnevio]

Oh cool so 5spd swap is easy as, but a 6spd would be wicked for the track.
Not so sure! The VR-4 has such a wide power band, that it is probably quicker using a 5 speed transmission than a 6 speed.

I've got no proof of course! But comments welcome! :)

[Nutter_John]

to drive a car with 6 gears you need to buy a MJ glove ( well so I'm told :p )

[bradc]

The 6 speed has similar ratios for 1st and 2nd, 3rd and 4th are a reasonable bit shorter, then 5th is only a bit taller than our 4th. 6th is then about the same as our 5th.

Stock at 6000rpm is:

52.5
83.1
124.3
169.6
229.5

Versus the 6 speed:

53.9
80.7
109.3
142.6
180.6
226.1

[Adam.Findlay]

so really a 6 speed is only needed if you plan to narrow the powerband by pushing power upwards (bigger turbo more lag route) still would add ultimate cool factor :)

[Kenneth]

Don't take my word for it as I don't know how much truth is in it...

I seem to recall hearing / reading that the 6 speeds were more prone to destroying gears at higher power outputs, due to some of the gears being narrower to fit the extra gear in the gearbox.

If you have the money to throw at it, it would be an interesting thing to try.

It could be a risky thing to try though, personally I wouldn't try it without being willing to write the expense off as a bit of R&D fun.

[bradc]

The 4th gear in particular seems to be a problem because it is fairly narrow and is still a gear used on the track quite a bit. 5th and 6th are quite narrow too, but it is rare to use them for a long period of time around a track. Basically the gear overheats and the teeth explode. 1st - 3rd are actually wider gears than in the 5 speed box and rarely cause problems.

Basically if you aren't tracking it all the time, or have 600hp, the weakness isn't going to be a problem.

[Adam.Findlay]

sweet thats my decsion made then steer away from the 6spd to much work and risk. evo 5spd it is!! when i have a job of course :( $$$$

[Johny]

so do we need a 6 speed evo box with gto gear ratios? lol

[bradc]

What you need is a 4.111 final drive with the evo 6 speed ratios. The stock final drive on the 6 speed is 4.583

[dinger1983]

[QUOTE=bradc]Transferring the internals isn't a big problem though, it isn't like an auto where everything is incredibly complicated and mostly works by magic.

the guy who invented the auto box went mad cos it shouldnt work and he couldnt figure out why it did