Big turbo transmission ?

[Kevin8433]

So I am planing on putting a mountune MRX big turbo in my 2016 Ford Fiesta st. I have seen all the plans on how much Hp I can get but no one is talking about what the transmission or axles could hold?

 

[Fusion Works]

Consider the input shaft your fuse for the transmission. It is relatively unsupported. There is no pilot bearing so basically its hanging out in the clutch disk and thats all the support it gets from flex. I would expect spider gears and the stock open diff would be the next weak link inside the transmission.

 

[kivnul]

All transmissions of course vary. Having said that, the reason nobody is talking about it is because nobody is having problems. The stock transmission is pretty robust. Some folks break the axles, but they drag race running upwards of 450+HP with hard launches. The MRX is not capable of those kind of numbers.

 

[MRX330]

If your tranny isn’t acting up stock it is more than adequate for the MRX. Clutch is a problem for me on E50 with the 4 port.
Spec 3+ will take care of that. Start a build thread when you get going 👌

 

[MRX330]

I don’t launch and never did (well maybe a few times) and I have had zero probs with my axles at 110k miles with 3k miles on the new setup

 

[JDG]

All transmissions of course vary. Having said that, the reason nobody is talking about it is because nobody is having problems. The stock transmission is pretty robust. Some folks break the axles, but they drag race running upwards of 450+HP with hard launches. The MRX is not capable of those kind of numbers.

There have been a number of Fiesta ST transmission failures ranging from stock power levels all the way up to 400WHP. The transmission in these cars is definitely a weak point but unfortunately there are not any solutions to the problem. @MFactory came out awhile back saying they were going to make upgraded axles for our platform but that never happened.

If you search these forums there are multiple instances of people blowing up transmissions including a few people who got rid of their Fiestas because of so many failures at the 350WHP power level.

 

[kivnul]

yes there are failures but there is not enough data to be able to point at a set HP and say that is the max it will handle. My transmission has always had weird clunks and behavior that my sons fiesta does not. So far it is holding up to some increased HP.

Of the folks with blown up transmissions, has there been a common failure part? (I do not recall reading about one but I have by far not read everything)

As to Axles, MFactory needed 10 preorders if I recall correctly. They were never able to get enough interest.

 

[jeffreylyon]

There have been a number of Fiesta ST transmission failures ranging from stock power levels all the way up to 400WHP. The transmission in these cars is definitely a weak point but unfortunately there are not any solutions to the problem. @MFactory came out awhile back saying they were going to make upgraded axles for our platform but that never happened.

There was a pre-order thread for uprated axles by @MFactory but I think that it went dark after @ron@whoosh stepped in and said that he'd order the first batch. I heard a rumor that Quaife was going to offer a sequential gearset/selector kit for the IB6 similar to their offering for the IB5. Google doesn't seem to know anything about that.

 

[kivnul]

That Quaife gearset looks nice! Spendy though. Quaife

 

[jeffreylyon]

That Quaife gearset looks nice! Spendy though. Quaife

But it's a straight-cut dog box - horrible for street use!

 

[Se7eN]

As someone with an MRX that broke some transmission parts I can say that it should hold really well. Just make your you have no wheel hop and that your engine mounts are all up to par. You should have no issues, in the future you can go ahead and change to an upgrade clutch.

Also make your you have some good trans fluid in it.

 

[Kevin8433]

As someone with an MRX that broke some transmission parts I can say that it should hold really well. Just make your you have no wheel hop and that your engine mounts are all up to par. You should have no issues, in the future you can go ahead and change to an upgrade clutch.

Also make your you have some good trans fluid in it.

What clutch are you running and what kind of transmission fluid. I was going to change all these with the turbo swap.


Sent from my iPhone using Tapatalk

 

[kivnul]

You didn't ask me, but I've replaced my OEM clutch & flywheel with OEM, and am using:

Ravenol J1C1002 SAE 75W-80 Manual Transmission Fluid - MTF-2 Full Synthetic API GL-4

 

[Se7eN]

^^ that same fluid kivnul posted is the one I use now.

The Clutch is a Spec Stage 3, with a new OEM Slave Cylinder and the stock flywheel which was in really good shape.