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Hello all,

I've been asked by another member to do a review on the MFactory products for our MTX75 transmissions; here it goes:

When we first built our rally car in 2010 we ran with a stock trans. and engine for a couple events. Seeing very quickly that an open diff. made the car push to the outside of the corner if you got on the gas too soon, we added a KAAZ plated limited slip diff. But I digress.

My point with the explanation is that we could now start to take advantage of the stock gearing in corners and in straight lines. The stock gears were ok in first and second but 3rd was pretty long, 4th was extremely long and 5th pretty well useless. All of them above 2nd lacked power but were perfect for a beginner. We managed to get some very low profile sidewall gravel tire Pirellis which shortened the final drive enough to use some of the other gears to a point.

Knowing that we needed some transmission upgrades we started looking around. Dogboxes are ~$5000 for the parts. Close ratio sets are ~$3200 for the parts IIRC. We found the MFactory 4.75 final drive (ring and pinion) $580 after that. You will need a July of '01 MTX-75 trans. or newer as 3rd and 4th were machined as part of the output shaft in 00'-'01 and you need the one that isn't; basically get a confirmed low km '02 trans. at a wrecker and you're good to go. Installation is about a 1-1.5h if you have a shop do it. You need a 20 ton press to take 3rd and 4th off of the output shaft to swap them to the new shaft so if you aren't experienced you will break things.

The 4.75 FDR is listed to take ~300whp and at ~110whp+ we haven't had any problems in terms of longevity obviously. 1st is now used only for launching on starts, 2nd is a decent acceleration gear which we don't often get back into on gravel, 3rd was still a touch too long but where we found ourselves spending most of our time for most events. It's a good power gear but starts to pull just a little too long after you start getting faster and use 4th etc.

I should mention that we shift around 6400rpm

Running the FDR for around a year and a half I felt that 3rd and the upper gears in general were really hindering my performance so I went looking for another option (especially after a rock pinched my exhaust down to about an inch making it downright terrifying to shift to 4th as the lack of power does not lend itself to mistakes on gravel. Some time ago another member mentioned a 3-5 close ratio set offered by MFactory ($800) but due to a somewhat different web site design it was hard to see it and impossible on some computers. We did this set for the last event and WOW is it ever just the thing the car needed. Next is a little more power as I can now intimately feel the powerband and lack thereof in 4th and 5th.

MFactory provides a gear speed calculator based on tire size ratios etc. on their site and using it we're mechanically limited to 155km/h at 7000rpm in 5th. At 5000rpm the car is doing about 105km/h iirc. For a street car I would not recommend the gears with the final drive as with our shift points I get about a 20km/h+ increase in speed in 3rd (third pulls a little harder than second) and 4th with around about a 30-35km/h increase in 5th. The fuel consumption is not drastically different than before which is nice with the 50L tank. As a proper close ratio should, 'every gear sort of feels like it's the same gear' (that's how my teammate described it at least lol).

The difference on stage was seconds/km and helped me match/fight with cars at the top of my class with double the hp and all of the goodies including the MSport engineered R2 Fiestas and much more experience. Some of you might balk at the speeds etc. but with rally the road is very twisty at most events/most sections and the acceleration over top speed is much more important in a 2wd car, especially having useable torque all of the time.

I noticed that MFactory has added a 3.789 FDR for the MTX 75 as of the last couple weeks for who ever needs/wants it. Possibly Turbo guys or Duratec guys?

So there it is. If anyone has any questions feel free to fire away!
 

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Good write up and info.Appears that the parts work well in this conversion.A note on the late '3 piece' output shaft with shrunk on gears.Even on a stoc late unit these gears have to be removed to service 1st & 2nd blockers /syncro hub etc. The Ford tools are OK but,over the years,we have made up our own jigs,fixtures,press plates etc that make this very easy...without damage to gears on removal and refitting. A lot of 'tricks' are needed on the late units .The Ford manual is OK but without some experience a normal shop can make a real hash of an MTX75...Experience is the key here and 'trick' tools help a lot.Owners should always us a shop that has a lot of experince with the MTX75...Keep us posted on how you new gear sets fair Re wear etc over the season...
 

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Thanks for the write up. So the older box I just refreshed is not eligible. To be clear, could I use the 4.75 final drive with an older box or is the limitation only for the gears?

Thanks again.
 

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To change the final drive ratio on an early output shaft you will need a crown wheel AND the matching output shaft gear which must be of the 'splined to output shaft' type and not m/c as part of the output shaft on late types.
 

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'Machined' as in the pinion on the later output shaft is a machined part on the solid shaft and cannot be removed Vs early type shafts wher the pinion is a splined fit to the output shaft. There was no fixed change over date for this ...some early units have late type output shafts and vice versa...
 

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..FYI..to go from an early type output to a late is a no no..Overall shaft length changes/need shrink on 3rd an 4th gears(as they cannot be removed from early type shafts)/need late type input shaft to match late out put as the cut etc on the late output will not match early input...the list goes on and when you add up costs of parts to go from early to late...very expensive.Only FDR option on an early output is to go with the early type V6 ratio(4.06) with its splined pinion and matching ring gear..
 

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Don't know how I missed this thread-found it in a google search...


Juggernaut-thanks for the review-lets hope this Mfactory stuff holds up-it's our only hope..Quaife is just too much $$$.

A couple questions.....

How noisy is the gearset?

Pretty brutal?-I know it's not for the street-but just wondering...

Also-are you still running the Kaaz diff?

Any problems with that?

And what oil do you run in the trans?

Thanks!
 

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Discussion Starter #10
Hey sorry to take so long to get back to ya but I almost forgot about this thread. The MFactory gears are synchromesh and make no more noise than usual. The exhaust is of course much louder now but we invested in transit headsets so not an issue.

Yes we are still running the KAAZ diff. which I checked the preload on back before our November race and it was still in spec after a couple seasons on the original plates (set at 60%). Love that diff. and it would be one of the few things that I would say you need in the car to race.

As for gear oil we're running Motul Gear 300LS as it suits the diff. and seems to work well. Coincidentally it's also what one of our sponsors carries.

So far all parts have held up well. I had a shop do the 3-5 and I do get a touch of whine in 5th only while off the gas at certain speeds so I've been meaning to get it to Terry but geography and budget can sometimes be limiting factors.

The next thing the car needs is more high rpm power since it's always up there now with the short gears.
 

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Thanks for the reply.
Hoping to see you over at www.rallyanarchy.com some day as you've been mentioned over there
If I remember correctly anb there's been some decent focus related posts lately.....
 

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Hey Lads, Is there anyway to tell which output shaft is in a gearbox? Does the part number have a year designation?

I would really like to go this route with the MFactor CR gearset but would like to know if my 'box is suitable before building my hopes up!
 

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Welcome Mfactory.

My biggest concern is with oil compatibility.

I am talking-with a plated diff here.

The MTX-75 needs a certain an oil, with a specific rating,and viscosity(and one that doesn't eat at the yellow metals in the trans).

Plated diffs have certain oil needs(for performance and longevity) that don't always align with the oil requirements above.

Is the Motul Gear 300LS mentioned by Juggernaut above recommended?

Any other oils recommended?

How familiar are you guys with the MTX-75,and what are your thoughts on choices of oil with this trans and your plated diff?

I mean- we have Dino oil(which I don't believe would be an option here),Semi_synthetics, and full synthetics.

Any longevity/performance feedback from any of your MTX-75 customers?
 

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Oh,and I just remembered Juggernaut has a KAAZ-not Mfactory plated diff.

But my questions above were meant pertaining to YOUR plated diff......
 

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Plate Type LSD + Special Oils is a myth, fabricated by Japanese manufacturers who want you to buy their own brand gear oil. These type of gear oils are a "one size fits all" and generally do not offer the best performance nor reliability.

The best fluid (and only fluid) to use is one that runs well with your transmission i.e not too thin, not too thick, shock additives, yellow-metal friendly.

There is no LSD on the market that requires a "special" type of fluid. All that is "special" are the additives added to control friction i.e friction modifier. This can be bought inexpensively from various oil companies (you need Type-F for the MTX-75).

If you race your car, then you should not be worrying about noise. The only reason to use friction modifier is to fine tune how much your LSD locks. The more modifier, the more the discs slip, the less lock you will have.

If you drive your car on the street, then you probably are concerned about noise, especially when driving in a parking lot and everyone thinks your car is broken! How much modifier to add, depends on personal preference. The more modifier, the less noise there will be, and the less lock you will have. HOWEVER, as this type of friction modifier is designed to make your discs slip, it ALSO makes your synchros slip more which is not good at all, especially when shifting at high rpm's.

Being from a Honda background, I'm not too familiar with the MTX-75 transmission, but for our FWD Hondas (of which the transmissions were designed to be run on 10w30 motor oil), I always tell our customers to stay away from gear oil (i.e has a weight on the bottle) and use Transmission Fluid instead (similar viscosity to motor oil, but with extra additives designed for the transmission).

If your service manual tells you to run Transmission Fluid, then I would highly recommend Torco MTF (for road cars) and Torco RTF (for race cars). We use this fluid in all of the transmissions we build for both our own race cars and those of whom we sponsor (we will not allow our sponsored drivers to run another brand as our reputation is at stake if the transmission has problems).
 

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Sorry for bumping an old thread, but i think the OP would be able to bring some knowledge to us. I'm currently looking into purchasing the 4.7 final drive, but I'm looking for some more info. How would i benefit from it for time attack/circuit racing. The gear calculator is a bit confusing, so I'm looking for proven use. I figured a pm wouldn't benefit anyone else, so hoping for your insight.

The car will be a bolt on zetec for now, and eventually a turbo.
 

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Great write-up. I wish there were more options for taller gearing. I have a 4.06 gear currently and even with still less than 300whp, I am shifting more than I want to. With the built motor and more boost, 1st and 2nd gear are going to become pretty much useless cause even if I can get traction in those gears, it goes through them too fast. I'm a drag racer and I don't want to be shifting into 5th before I hit the 1/4 mile which I'm almost doing already. It seems the 3.41 ratio FDR is pretty much impossible to find so I'm at loss for a solution. Something in the 3.00-3.30 range would be awesome! It would also lengthen out 5th gear quite a bit to help with mileage on the highway.
 
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