Hi everyone, i got asked the question the other, does the ST170 box fit in the RS and is it worth doing?
I dont have the answer and was wondering if anyne knew/has done the conversion?
Obviously can you out the diff in it?
Cheers and hopefully someone will know.
Macca

 

Why would you want to? FRS is designed around the gearbox that is fitted to it from the factory with ratios, diff, etc to suit. Similarly the ST170 has a 6 speed box with totally gear different ratios to suit that car. Put it in the RS and you'll change the way the RS drives and how you drive it, although if you want a 6th gear for cruising on motorways then maybe thats the way to go

 

Like Alex said really, but if your adament about it, then it can be done. But 1st to 4th gears will be awkward and quick to change. You'll loose the whole drivability the Focus RS design posseses.

 

Hi guys if you read the bit i typed someone asked me and i was just wondering as much as they did. I have no intention in putting the box in my car.
To be honest i cant stand having six gears in my transit at work.
No need to get angry bout it.
Cheers for the help anyway i will let my mate know who asked me
Macca

 

No one getting angry boyo, just stating the general feeling about it. No worries

 

Hi guys, I am actully really wanting to put focus rs drive shafts into the st170 gearbox, threason for this is i'm looking to use 235 40 18 tyres and i'm about to order a set of Leda suspension but as my little track beasty keeps eating wheel bearings both front and rear well it seems like it sometime but getting a wider track and beafer bearings would be awesome for the long run and further idea's.

so in short dose the rs share the same gearbox side driveshaft dimansions and is it easy to modify if not.??

Please help guys/ girls

 

i believe the spline counts on the getrag are smaller and different.
not to mention the lengths will be off.
and they wont properly fit into the hubs.

 

I run a 6-speed in my Focus, although its a converted turbo ST170 to start with.

The ratios suit turbo applications to a tee!

 

A bit of misconception I'm afraid. The gap between 1st and Top gear is virtually the same, 1st is about 25%. The intermediate gears are reasonably equally spaced.

Overall, the gearing of the ST170 is, for some strange reason, higher. The equivalent of using a 3.56 FD in the MTX.

Martin

 

frow what ive been reading the st170 box with the rs dif is a good choose

 

By that I take it you mean an ATB diff; its what I've got fitted in my Focus estate. Changing the FD of the MT285 is really only feasable with a complete cluster change as it involves both layshafts and some machining of the cases.

With a narrow torque band NA engine the 6 speeds are used, but I find with a road turbo engine the torque band is wide enough to only need 5 speeds.

However, I'll admit the actual gearchange of the MT285 is a lot slicker/quicker than the double syncro of the MTX.

Martin

 

Got an ATB in mine, really helps off the line. Great for handling if you drive really aggressively.

 

Not quite so much in snow/ice for me though as it tried to drive me into a parked Focus at 04:30 in the morning.

Martin

 

what diffs are u both using?

 

I'm using a Quaife ATB. Its actually stamped with a part number for a BMW Mini Cooper S, but I was assured its exactly the same as the ST170 one.

Martin

 

From what ive heard the st170 gearbox works very very well with the rs engine. the ratios are pritty damm good for it.

Never driven an rs engine mated to an st170 gearbox but i know torque of the devil did one and they were saying the ratios were better in the st170 box

 

Its a LOT of work to put a MT285 box into a FRS, but apart from expensive flywheel/clutch issues, not to difficult with standard Focus running gear. Maybe ToTD were talking about Simon170's turbo.

Or possibly the earlier existence of the PE development tub. The aprociphal tale I heard on that was they fitted a pre-2003 MT285 with a post 2004 flywheel/clutch, and all the transmission oil came out of the resulting hole.

Anyway, on the road ratios, there insnt really a great difference between 1st gear ratio or top gear ratio on each box. The gaps are actually far better spaced on the MTX. Either way the rev drop should be well within the capability of the torque curve of even a mild NA and even beter on a turbo.





Martin