Pink snowstorm in the shop:
Actually....I was cutting down the AKG "Turbo" mount to fit next to the GTX40 compressor inlet:
And of course the 210mm LSD arrived from Wanganstyle:
It now lives in an E46M3 rear subframe with AKG poly mounts in all locations:
I learned there are a few things you need to do in sequence when installing this diff in a non-M chassis....the hard way:
Some people will know what I'm talking about....
Next, I found that the driveshaft was about 1.25"-1.5" too long for the new diff, so I sent the front section off to be shortened and balanced:
One thing that absolutely shocked me was how little effort was required to turn the input (or output) flange(s) on the diff from Wanganstyle. About midway through the build process, I requested that the ring and pinion, as well as bearing races had WPC treatment. ( http://www.wpctreatment.com ) This, along with use of quality bearings and precise assembly, has resulted in a "feel" by hand from the diff that I have never experienced before. Everything simply glides like it has zero friction.
I've had a number of previous 188mm diffs with REM polishing, and nothing compares to what this 210mm feels like.
The specs on the diff:
- 3.62 Ring and pinion
- Cusco LSD with custom 1 way ramps for drag racing
- New OEM rear cover, with upgraded Wanganstyle fastener package
- WPC treated bearing races, ring and pinion.
- Custom output stub shafts to mate with non-M half shafts (I have custom DSS half shafts)
After having the 188mm and 210mm sitting side by side....I think my rear end is not likely to be a problem for a very long time.
Which Cusco diff did you go with, the RS or MZ? The 1 way is actually pretty nice for even track driving, as it will have a higher preload than a stock type diff and way more friction plates.
Slowly...slowly coming back together.
The shortened driveshaft:
And modified center bearing:
Any particular reason you shortened the front DS and not the rear DS? The rear DS being shorter would allow the stock center bearing to maintain position, and it'd raise the lower critical frequency of the longer rear DS.
I'm sure you've got your reasons, just curious what they are.
On the aluminum welding, don't forget the three C's - Clean, Clean, Clean!
This was part of a mad dash to get the car to the race track on Sunday, and it was Wednesday morning. I took the part that I thought would be easiest to ship and work on, so that in theory I could get the driveshaft back on Friday. After I had shipped the shaft, and started bolting in the rear segment of the shaft, I realized that I had sent the wrong shaft....but I just went with it.
So my reason is: I'm a putz.
Not yet, for now I'm using Redline.
The diff was dry when I was doing my "spin" testing....so this isn't a function of oil.
Being a putz or too much beer dictated a lot of custom fab decisions on my S13. Feel you there
I twisted my front in 2. Have not seen a rear twisted in 2. Don't know why. Maybe some physics thing. But if that is the norm in breakage, maybe shortening the front will make it stronger. But I twisted the splines connecting the 2 halves on the replacement shaft . . .
I've never claimed to do professional work, I just try to have a professional mindset, but it's most often applied to awkward timelines.
#PutzIndustries
As you can see in one of the pictures, I still have the driveshaft from the automatic transmission nightmare. That gives me a spare back section with a center bearing, and a front section that's too short. My plan is to send the front section over to the same shop to see if they can replace all of the OEM tubing with something stronger. That would give me a spare driveshaft to add to the pile:
- Spare clutch friction plates
- Spare transmissions
- *Spare driveshaft
- Don't need a spare diff now.
- Spare stock half shafts
I'm interested in the math behind this calculator:
http://www.22rpd.com/boostcalc.php
Can anyone point me to the answers?
Some kind of goobermath - because it doesn't make any sense. E70 has roughly the same detonation resistance as E85, but it clearly puts them in different categories. E85 should also equal 116 leaded octane, but it gives the clear advantage to the 116.
Basically, it's garbage as far as I've seen when tuning...
High Preload is not desirable for circuit use. High preload = understeer for low speed hairpins.
1 way is ideal for many many things, one of them is tight circuits.
The specifications I use are have internal spring settings of either hybrid or RS style but not avail off the shelf;
In regards to aftermarket differentials one can't just order one and throw it in and expect it to be ideal; customization is even more important;
Cusco units have are mutiple ramps avail with 1, 1.5 and 2 way settings, mild (A), medium (b), and aggressive (c) all avail.
preload springs are avail outer (hybrid type) or inner (rs type) of the center cluster stack and between 0-12 inner and 0-12 outer can be fitted;
The combinations are pretty wide; MZ type is really ideal only for drifting.
The benefits of aftermarket differentials are mainly in smoothness of engagement/disengagement and the fact that they are new 2017 products vs a legacy unit.
One does have to properly setup either but the modern aftermarket units have much more adjustability.
The number of plates and style of plates does not really matter if set properly to the application; cusco units have a LOT of plates and well designed oiling as well as WPC internal gears standard for durability and cooling.
coated plates of a ZF style does not translate to plates of an OS/cusco type with steel plates.
Last edited by wanganstyle; 10-12-2017 at 01:14 PM.
Wanganstyle Powertrain
http://www.wanganstyle.com/
S54B32 E36 M3 DTA S100 Sedan Street car full swap:
http://forums.bimmerforums.com/forum....php?t=1437471
A much higher preload than stock makes the car much more stable under braking and especially trail braking. You do need to setup the car with how the diff is setup, so I don't agree that a blanket "high preload is bad for circuit driving." I found the opposite to be true, as my car going from a helical (Quaife type) diff to a Cusco RS 1.5 way with 80% lockup became much more predictable under threshold braking and trail braking. It did pick up a tad of entry understeer, but a little setup change and driving style change helped alleviate a lot of that. The car gained about 1.5 sec/lap on a 1:55 lap with that diff, mainly in braking/trail braking areas and higher speed corners.
Wanganstyle Powertrain
http://www.wanganstyle.com/
S54B32 E36 M3 DTA S100 Sedan Street car full swap:
http://forums.bimmerforums.com/forum....php?t=1437471
I was given a really wide range of options when spec'ing the diff for my application. The input I provided that had the most influence on the setup was: Street car, drag race focused.
If I had asked for circuit racing, the diff hardware and setup would be different.
My choices might not suit other people, but if I'm happy with the result, that's all that counts in my book.
The fact that Wanganstyle took the time to visit my thread and provide even more background on my diff is a nice bonus!
I must be the only one who loves the OE M-Diff...
1000+RWHP, Lab22 Built Turbo S54 - BMW Half Mile Record Holder
1000+RWHP, Lab22 Built Turbo S54 - BMW Half Mile Record Holder
Considering putting in 11:1 pistons I have on the shelf....instead of running the 8.5:1 setup currently in the block. Would require a race fuel mix with pump fuel all the time....and 100% race fuel with nitrous at the track.
Thoughts?
I find the engine a little soggy off-boost, and it takes a bit to get it to spool. Looking for more response on the street....
And no, I don't have access to E85.
Last edited by PEI330Ci; 10-26-2017 at 12:50 AM.
Bookmarks