05-03-2015, 09:48 PM | #1 |
Captain
450
Rep 845
Posts |
Differential Review
My track weekend is over and I have been able to (at least a little) assess the difference that an LSD makes in an M235i on the track compared to stock.
In a word -- huge. (Just a reminder, the differential is custom with 35/60 ramps, about 90(ish) pounds of preload, and a 3.46 ratio.) It's honestly like driving a different car, for the better. Every corner is confidence inspiring (unless you blow the turn). You're never really afraid of losing your tail. It's very hard to upset the car with the differential in. In some limited circumstances (when you blow a turn and try to correct), you feel the back step out a little, but it is so progressive and predictable that it feels like the chassis is feeding the movement into your brain telepathically. You just kind of go "oh . . . . back's going out . . . okay, fixed" and you're good to go. I've never driven an "M" car, but I suspect that this is what some people refer to when they mean that the car feels more "connected" to the road. At all times this weekend I felt 1. stable and 2. confident. It's really pretty amazing. Comparing this weekend to the previous dozen or so days I've had on track with an open differential, I understand what all the fuss is about (at least for track applications). It's just a totally different experience. As far as handling characteristics, I cant really tell if my car is tight or loose right now. Sometimes it feels tight, but I keep turning the wheel and the car keeps turning in, so I'm not plowing in too hard. On the other hand, I've had a few minor situations when my tail got loose, but they were extremely controllable and not frightening. I suppose my car is just about neutral? I think I need some more seat time to figure it out. As far as the street . . . I'm not convinced it's worth the several thousand dollar (at least 2.5k for the M Performance diff) premium. Yeah, you do feel it, but if you're driving like a sane human being, it's kind of rare. I suppose it makes you feel more like this is a true performance car with the limited slip carrier, but you honestly don't need it. It's just nice to have. On the track however, if you plan to do it often, this is a very important upgrade. Also, the shortened ratio (3.46) is pretty cool. That extra torque is crazy -- very useful and fun on both the track and the street. I think it fits the car's personality a little better than the 3.08 (revs faster), but I can understand why BMW went with the 3.08 (fuel econ and all). It's really a personal preference thing, but holy shit does this car launch now. I'll post the video after I am done editing. I was running in the low 2:20's pretty consistently driving at about 7/10ths (around 2:22). I'd never been to this track before, so it was a learning weekend. Tons of fun though, especially turn 13 -- heavily banked, so you can pull some serious g's going through it. Would recommend going to this track (if you're West Coast). EDIT: No video this time. Camera is shaking too much (for some odd reason) and the audio is terrible (tried a different setup this time -- too much wind noise). Last edited by Liquidpaper; 05-04-2015 at 05:31 PM.. Reason: Video sucks. |
05-03-2015, 10:39 PM | #2 |
Private First Class
31
Rep 199
Posts |
What tires are you using pre/post LSD upgrade? Just curious if you've used some good high performance tires (not PSS) prior to the upgrade. I'd love to bite the bullet on it, but until it becomes legal for F-Street class in autox I sadly will remain in the open diff world.
|
Appreciate
0
|
05-03-2015, 10:40 PM | #3 |
Captain
127
Rep 765
Posts |
Sounds like a heck of a good time, glad I got the LSD as well Now for a proper track weekend, harder to find up here though.
__________________
"Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity." MLK Jr.
|
Appreciate
0
|
05-03-2015, 10:40 PM | #4 |
Captain
450
Rep 845
Posts |
Using Direzza IIs pre and post.
|
Appreciate
1
|
05-04-2015, 12:09 AM | #7 |
Private First Class
64
Rep 177
Posts |
I believe it's custom from DiffsOnline (http://diffsonline.com/). I could be incorrect, but that's what I'm remembering.
What track were you at? |
Appreciate
0
|
05-04-2015, 12:29 PM | #8 | |
Captain
450
Rep 845
Posts |
I did get the diff from Diffsonline.com
Quote:
|
|
Appreciate
0
|
05-04-2015, 01:38 PM | #9 | ||
Captain
215
Rep 661
Posts |
Quote:
|
||
Appreciate
0
|
10-17-2016, 05:24 PM | #10 |
Colonel
1475
Rep 2,672
Posts |
Liquidpaper curious how the diff did on subsequent track days and if you would have done anything different if you did it again? Considering getting a similar setup for my e92 m3. Also, this car is still my DD so any thoughts with that in mind?
__________________
2021 Alfa Romeo Stelvio Quadrifoglio | 2.9L | Trofeo White Tri-Coat | 8-spd
|
Appreciate
0
|
10-17-2016, 05:34 PM | #11 | |
Captain
450
Rep 845
Posts |
Quote:
Looking back, my only regret is that I think it was a bit overkill to do the custom ramp/clutch carrier. I think for a more experienced driver it would have been great, but for me, all I needed was some limited slip capability -- the one I got was overkill. I could have gone with the wavetrac core (or quaife for that matter) and have been fine and saved some money (like $1,200). That being said, I do not regret my decision, but I think I could have been smarter about where my money went. I would definitely do it again (but maybe with a torsen core rather than the custom clutch job). Dan does a great job with these differentials and are totally appropriate for street driving. Only recommendation is just stay current with your oil changes -- I get my diff oil changed with the recommended redline oil every third engine oil change (I do my engine oil changes about every 5,000 miles, so the diff is every 15,000 miles). I will say that after a year and a half of having the differential, it was the most transformative modification -- I think it was what the m235i was "missing" in my opinion (additional camber to the front tires not withstanding).
__________________
|
|
10-17-2016, 09:31 PM | #12 | |
Colonel
1475
Rep 2,672
Posts |
Quote:
__________________
2021 Alfa Romeo Stelvio Quadrifoglio | 2.9L | Trofeo White Tri-Coat | 8-spd
|
|
Appreciate
0
|
10-19-2016, 05:55 PM | #13 | |
Captain
450
Rep 845
Posts |
Quote:
If you are an intermediate driver, you would probably appreciate the advantages of a clutch type differential with custom ramps. That being said, how much is it worth to you? Also, since you are running an e92 M3, you might be interested in changing the final drive ratio for some more torque. I had mine changed from a 3.08 to the 3.46, same ratio as in the M2. It makes a significant difference, seeing as the gear ratios are the same in both cars (for the 6 speed).
__________________
|
|
Appreciate
1
///Mobbin1474.50 |
10-20-2016, 08:14 AM | #14 | ||
Colonel
1475
Rep 2,672
Posts |
Quote:
Then I hear you on the final drive ratio. My DCT car started out with a 3.15 ratio and was upgraded by the previous owner to a Dinan (BMW Motorsports) 3.45, which is the max recommended for a DCT e92 m3 w/o some remapping of the engine/transmission software and I've only heard of folks in Germany doing this, no one in the US has this knowledge that I'm aware of. Enjoying the 3.45 so far!
__________________
2021 Alfa Romeo Stelvio Quadrifoglio | 2.9L | Trofeo White Tri-Coat | 8-spd
|
||
Appreciate
0
|
03-21-2017, 01:18 PM | #15 |
Private
21
Rep 80
Posts |
Fantastic. Thank you for providing us with your insight.
A have a few questions prior to purchasing the M Diff, especially for track duty. With your custom diff. do you notice a difference with a reduction in the cars nature to understeer? Easier to power oversteer? Do you run the car with traction and slip control disabled? What tyre pressures do you run? |
Appreciate
0
|
03-21-2017, 01:23 PM | #16 | |
Captain
450
Rep 845
Posts |
Quote:
The car is easier to power oversteer as it is more predictable. Without the diff, once you lose the back end, it is very hard to predict where it will go. With the diff, the back steps out very progressively and is easy to correct. I usually run the car with everything disabled when on track. I try to run 36 psi front and rear while hot. Keep in mind I am running -2.3 camber front and -2.25 camber rear though, so I don't have any sidewall rollover. Also I am running Hankook RS3 tires.
__________________
|
|
Appreciate
0
|
03-21-2017, 01:24 PM | #17 |
Lieutenant Colonel
743
Rep 1,700
Posts |
I have the M Performance LSD in mine and the upside is that its great all around.....it doesnt make any noise and is very "driveable" every day
The downside is that its only a 30% lockup iirc and there have been times when accellerating in a more spirited manner I can feel one wheel spin and the other get SOME power.....and I find myself wondering if I would have been better off (happier) with something more agressive |
Appreciate
0
|
03-21-2017, 01:26 PM | #18 | |
Captain
450
Rep 845
Posts |
Quote:
If I could do it all over again, I would probably have gotten a torsen diff or the MP LSD. I love my diff, but it was really expensive, and considering I am a rank amateur, I probably wouldn't know the difference. However, moving the ratio up to 3.46 from 3.08 was the best thing I've done to the car.
__________________
|
|
Appreciate
1
BM235iW97.00 |
03-21-2017, 01:31 PM | #19 | |
Lieutenant Colonel
743
Rep 1,700
Posts |
Quote:
I wonder if I would notice it ENOUGH to make a difference......I probably wont track the car more than 1-2x/year and thats only for recreational purposes.......I'm no wanna be racer (yet?) I do however want to upgrade to a dinan stage 1/2 option and add an exhaust to it and felt that SOME sort of upgrade over the open differential was a prerequisite for any of this,..... I can always upgrade to a qualife (sp) or something else more agressive down the road if the want/need is there I suppose |
|
Appreciate
0
|
03-21-2017, 01:37 PM | #20 | |
Captain
450
Rep 845
Posts |
Quote:
Honestly, the car should have come from the factor with some sort of LSD (maybe not the crazy M division trick LSD, but something). However, I wouldn't recommend going my route necessarily due to cost. If I could do it again, I would still use diffsonline and get he 3.46 gears, but with a Wavetrac carrier probably. Would save a lot of money.
__________________
|
|
Appreciate
1
BM235iW97.00 |
03-21-2017, 01:43 PM | #21 | |
Lieutenant Colonel
743
Rep 1,700
Posts |
Quote:
But the 2 series is soooooo driveable all the time with the adjustable suspension And the B58 has soooo much potential for making power....... I cant complain at all about the gearing in my 240 and am wondering what issue you encountered that pushed you from 3.46 from 3.08? Obviously you have more torque now....... |
|
Appreciate
0
|
03-21-2017, 01:48 PM | #22 | |
Captain
450
Rep 845
Posts |
Quote:
Here is the thing, is the M2 better? Yeah. Is it different enough to warrant getting rid of a perfectly good M240i (in your case) and getting that car? I don't really think so, but your mileage may vary.
__________________
|
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|