LSD Install Check-List & Recommendations

[ztrahan]

So I am working on putting together the final list of parts to order for a LSD install, and wanted to make sure I had all the parts I would need, plus see if there are any general recommendations for parts to replace while I am in there (i.e. clutch). Planning to do it myself with a buddy who used to be a Subaru tech and has done transmission/diff work on his personal cars as well, hoping it's not getting into deep haha...

1. Mfactory LSD
2. Ford Performance diff install kit (I believe I can also purchase these items separately to save $$)
   1. or put it together from this list https://www.fiestastforum.com/threads/lsd-installation-thread.2390/page-8#post-455551
3. OEM Fiesta St clutch kit
4. Syncho shift synthetic lube

I have nearly 50k miles on my 2019, including track days, so I figured the clutch was a smart replacement at the same time (it feels fine at the moment). At most, I'll go a hybrid or S280 turbo in the not-so-near future, so I assume the OEM clutch is a fine replacement. Open to suggestions on that.

Currently on the car:

• Mountune radiator
• CPE intercooler
• Hot/cold charge pipes
• Mountune optimized stage 1
• -3 camber up front, and camber plates on the rear

There was this list created by a forum member I believe, and there are additional parts not listed above that I wasn't sure if were needed, or you could reuse from stock assembly. https://docs.google.com/spreadsheets/d/1adAcwv1-jLLsVmsJ_p3f63JBfCDnGxfHwhcZooGjUUw/edit?usp=sharing

If there is another thread similar to this, please let me know so I'm not duplicating efforts. Thanks in advance!

 

[Jabbit]

Always do the slave cylinder

 

[Cdnmr2v6]

Always do the slave cylinder

I was going to say the same thing.

 

[foodtruck]

You may also need the flywheel. The inner mass eventually gets loose and results in a nice rattle. AFAIK there are deflection angle tolerances when you try turning it side to side & moving it in/out past which it's considered to be out of spec.

 

[Jabbit]

Honestly all that trouble I'd do an Uprated clutch and flywheel.

 

[Cdnmr2v6]

One thing we've forgotten about is shims. Unfortunately it's impossible to know what shims you might need until you get the diff in. They are relatively cheap though, so if you are under a time crunch it might be worth buying a couple and returning what you don't use.

 

[TyphoonFiST]

There are a couple of members and a builder who have done the LSD and all have said no reason to shim when it was already done at fomoco. I'm sure they will chime in.

Sent from my SM-N975U1 using Tapatalk

 

[Cdnmr2v6]

I've installed several differentials in other cars and the shimming is not a one and done thing. It should be checked when a new differential is installed. It has to do with manufacturing tolerances, so for example, if the original differential is 7.002" wide and the aftermarket diff is 7.004 or maybe 6.997" you will need to shim accordingly. You may get lucky and not need to make any changes, but you can't just say it was done once and is never needed again.

 

[ztrahan]

Always do the slave cylinder

Perfect, thank you!

My main concern with an uprated clutch/flywheel would be the clutch pedal weight. I have patellar tendinitis from years of competing, and a heavier clutch kills me (previously drove a WRX). The lightness of the stock clutch is a blessing in Bay Area traffic. Has anyone reported on pedal feel compared to stock with what's out there?

You may also need the flywheel. The inner mass eventually gets loose and results in a nice rattle. AFAIK there are deflection angle tolerances when you try turning it side to side & moving it in/out past which it's considered to be out of spec.

That makes sense, I appreciate the recommendation.

I've installed several differentials in other cars and the shimming is not a one and done thing. It should be checked when a new differential is installed. It has to do with manufacturing tolerances, so for example, if the original differential is 7.002" wide and the aftermarket diff is 7.004 or maybe 6.997" you will need to shim accordingly. You may get lucky and not need to make any changes, but you can't just say it was done once and is never needed again.

Yeah, I saw mixed threads on if people had to shim or not. So I was going into assuming we'd need to check tolerances and just go from there. This is where I'd be relying on my mechanic buddy.

 

[haste]

I had to go one step up thicker on the shim when installing the quaife LSD, just fyi.

 

[SST]

is there a list in this forum on the specs & part number of diff shims? i follow Worthams Garage spreadsheet, very helpful, but he only has 1 shim, and has a "8" on it

 

[Cdnmr2v6]

Yeah, I've been saving this hoping that one day I can do an LSD on my car too. I pulled this from another lsd thread here somewhere. There's one p/n that comes up as a bolt though.


Part NumberPart DescriptionSIZE

YS4Z4067KASHIM-TRANSAXLE DIFF0.1
91WZ4067LASHIM-TRANSAXLE DIFF0.2
YS4Z4067AASHIM-TRANSAXLE DIFF0.3
YS4Z4067BASHIM-TRANSAXLE DIFF0.4
91WZ4548CASHIM-TRANSAXLE DIFF0.5
YS4Z4067DASHIM-TRANSAXLE DIFF0.6
YS4Z4067EASHIM-TRANSAXLE DIFF0.7
YS4Z4067FASHIM-TRANSAXLE DIFF0.8
YS4Z4067GASHIM-TRANSAXLE DIFF0.9
YS4Z4067HASHIM-TRANSAXLE DIFF1
YS4Z4067JASHIM-TRANSAXLE DIFF1.1

 

[SST]

wow, perfect, thanks so much. this is very useful info

 

[Freefallin16]

I’m looking into having. Local trans shop install either the Mfactory or Wavetrac in my ‘16. I just looked up an oem flywheel and Tasca wants nearly $500 for this piece. Is the consensus factory is best if An oem clutch is chosen or can an aftermarket unit such as the ones Ron sells be used in an oem clutch?

Fyi, looks like $1160 and change shipped with the “Fist5” discount from Ron for:
-Mfactory diff
-Ford clutch kit/Slave cylinder
-BG trans fluid w/magnetic drain plug
-Ford install kit

I was quoted $1300 for install from a local trans shop who’s done 4 of them. So the $2500 question is: is it worth it?

Sean

 

[our guile]

So the $2500 question is: is it worth it?

Sean

I don't have an LSD in my car yet, but hell yeah it's worth it. In general it'll give more traction in basically every scenario and help put power down. If you track your car you'll notice a significant difference, and even if you only drive on the street you'll see big improvements as well.

Several members here have installed them and have nothing but good things to say.

 

[Cdnmr2v6]

If you are a casual car fan then the cost/benefit might not be there for you, it all depends. However, as someone that often drives agressively and autox' regularly it's a huge benefit, especially in a car with so much torque available. The factory lsd in my old civic was a godsend and that car had a lot less torque.

 

[Freefallin16]

If you are a casual car fan then the cost/benefit might not be there for you, it all depends. However, as someone that often drives agressively and autox' regularly it's a huge benefit, especially in a car with so much torque available. The factory lsd in my old civic was a godsend and that car had a lot less torque.

I haven’t autocrossed the car yet but I do plan to. I just really like zipping around down (within the speed limit) and some occasional country roads/twisties. I am the guy that wants to make the car as “perfect” and efficient as possible, and an LSD is, IMO, absolutely necessary for that to happen from what I understand.

Sean

 

[haste]

I honestly love the starting from a stop and turning at the same time traction that is available with an LSD. Other wise it's kind of a disappointment at high speed cornering. I have the Quaife LSD and am not sure if the wavetrac would make that much of a difference or not with wheel lift...

 

[Freefallin16]

I honestly love the starting from a stop and turning at the same time traction that is available with an LSD. Other wise it's kind of a disappointment at high speed cornering. I have the Quaife LSD and am not sure if the wavetrac would make that much of a difference or not with wheel lift...

I keep hearing mixed reviews about the LSD. A lot of folks love it but others say they can’t really tell a difference.

Sean

 

[haste]

I keep hearing mixed reviews about the LSD. A lot of folks love it but others say they can’t really tell a difference.

Sean

There is definitely a difference but I don't know about $3K out of pocket difference. I was able to buy a used trans AND all the tools(including a press) to do it myself, including a final drive conversion for roughly that same amount, but I think I would be disappointed If I had paid someone else to do it...

I think the final drive conversion made more of a difference than anything. The car is so much more drivable now in all of the gears. Much more streetable, imo.