Warning: This will be a long post. If you don't like reading, or are not into the subject id skip this thread..
Intro:
I have trough many years gotten some experience with RWD cars.
I have found out that there is a huge difference from car to car. Especially the cars with open-differentials. The biggest differences has to do with how easy they end up being 1-wheel drive, and how «drift/slide friendly» they are.
I have rated several cars from 1-10.
10=very drift friendly diff.
1= not drift friendly diff.
Rating of 3 is usually pretty good on snow, but have a tendency to easily spin one tire on wet surface.
Rating - Car
1- BMW E87 318D with M-package (short test drive, so rating might not be deserved)
3 – Mercedes CLK 230 Kompressor (lowered)
3- BMW E36 318TI (97 model, M-tech everything with open diff)
4 -BMW E36 318I Sedan (91 model ,40mm lowering springs and open diff)
4,5 BMW F20 116I (Stock Open E-diff. Rating based on short test drive)
6 -Toyota MR2 Roadster (stock 2001 model, open diff)
7 -BMW 325I (E34 with stock LSD, 25%?)
9,5 -Toyota GT86 (based on short trip, stock torsen LSD)
Open-diffs
There is a huge difference between open diffs. I have rated cars with "same type of diff" from 1-6.
-Am I the only one with that experience?
-Why is it that some cars have a tendency to easy spin one tire compared to others when they all have an open diff?
Open-diffs vs BMW E87 E-Diff
About a year ago I owned a Toyota MR2 Roadster. That car would usually spin both tires easily at the same time and the need for LSD was basically none.
I needed a new car and test drove a used E87 (I was looking for a petrol engine, but ended up test driving 318D with M-package and suspension)
I have never experienced a car wanting to spin one tire as bad as that car. It was one wheel drive no matter what I did. If I remember correctly that car had E-diff in DTC mode. But that mode had way too much electric interference to be fun so I was not able to notice that E-diff was useful on my test drive.
All electronics off, and it was just annoying with the 1-wheel drive.
I bought my Cooper S instead of the old 1-series due to the E87s tendency to only have one wheel drive. I was not planning a long term ownership and therefore it was not an option to buy LSD for the E87.
BMW F20 E-diff vs LSD
So, my Mini was on service, and I got to test drive a F20 116I about 2 months ago. Pavement was luckily very wet, and it was raining. The F20 handled well, felt pretty neutral and was very comfortable. With all electronics off it was much better than the E87 I had tested. Thanks to the E-diff I'm guessing. I could go sideways without one wheel drive, but due to E-diff braking (?) it seemed to lack momentum and power to get the car sliding out of corners. I know it is not that powerful, but it was really slippery that day.
-Do you guys have some of the same experience?
-Does E-diff also make handbrake (u-)turns way harder? Or was the car just strange in that way? (GT86 and Mini Cooper S are pretty easy to "flick around" with the handbrake when electronics are off)
Right after driving the F20 116I I got to test drive the Toyota GT86 on the same twisty mountain road. (A car I had been waiting for a long time to drive)
Here are sidenotes on the GT86, skip if not interested in that car:
Car really lacks torque, and automatic transmission is not approved by me (Im not into Automatic transmissions in general). Overall the engine feels much lazier compared to my Mini. Atleast combined with the automatic transmission I test drove it with. Manual has more sporty gearing. When comparing dynoes with the 86 you can easily see why the 86 did not feel that great when I am used to the Cooper S.Dyno link, scroll down for picture) Cooper S engine is also underrated like many BMW engines. Im guessing a BMW 170hp 118I would feel more powerful than the GT86 with its 200HP NA engine under normal everyday driving. I would probably prefer the 116I engine too. But when the 116I runs out of juice the 86 starts to get fun.
Steering feel is good, for an electric system. But could not compare to the MR2 I owned where you felt the road really good.
The power in the 86 is only good 5000+ rpm. And it is not as powerful as you might expect. Backseats are also very small and basically not suited for grown ups.
Anyway, handling in the GT86 was great. And it is a real sports car in terms of driving position and handling
The torsen LSD was fantastic. Way, way better than the E-diff in the 116I!
Most of you have probably seen the Chris harris review of the M135I and the Audi RS3. Im guessing if the M135I had a proper mechanical diff he would have gone more sideways like he usually does.
This review (press CC for subtitles) shows the car sliding and talks about the E-diff from 3.10-4.05. I have some of the same experience with the lower powered 116I on really wet roads.
LSD in the F20 1-series?
I see
birdsauto is one place with a good amount of Quaife LSDs for BMW.
They have have one diff that fits All F20s with « 215LW Final drives».
-Which current F20 cars have a diff with that finaldrive?
-Is there a way to 100% disable the E-diff in the F20? Im thinking that would be a must if investing i a LSD for that car.
It would be brilliant to have an on/off button on the E-diff in combination with a Quaife Torsen Diff...
Epilogue
Thanks for reading! Hope to get some input from you guys!
I am really considering the F20 1-series or the GT86 as my next car. (not sure when that time will come) But how the car behaves on and beyond the grip limit is crucial for how fun a car is for me. Especially if im going to us a lot of money on a new RWD car.