[tke743]

Sweet, one of my friends from autoX just let me know that he installed a quaife in his 2014 m235i. He is comming over Sunday so we can test the m performance piece vs the quaife. This will speed up the reviews by at least a month. We will be able to do the tests back to back.

[abp689]

Anticipation bumb...

[tke743]

We finished at 6. Dealing with a work issue, then will post a writeup ( Give a day or so, big work issue). Interesting as to how diferent they are and how the e-diff interacts with them.

[tke743]

Alright, after an afternoon of the true drudgery of sliding 2 m235i’s around with LSD’s, here is our result.
E-Diff – Already reviewed in OP

M-PERFORMANCE LSD
Eco-pro – STILL boring, hate it, nuf said.

Comfort - soft, smooth, cruising mode. Nanny heaven. Minimal discernible difference from the e-diff. Nannys kick in too soon. No discernible difference between the 2 LSD’s.

Sport - it is just comfort mode with firmer suspension along with exaggerated inputs on throttle and steering, plus the slightest lag in the nannys taking the fun away. With the M-Performance LSD, the LSD will actually kick in before the nannys, so you can push a bit harder then without it. Adds a little more fun, but there is not enough difference to justify the cost. No discernible difference between the 2 LSD’s.

Sport+ - It is sport, nanny lag is increased to approximately .5 sec of stupidity, then it kicks in hard with the nanny regimen. And this is where the LSD starts to earn it’s keep. The LSD kicks in before the nannys get a chance, if you are driving at or near (or slightly over) the limits of grip the nannys will stay in the back seat unlike with the stock diff. If you are trying to drift it, then the nannys are still there to take over. Little difference between the 2 LSD’s (this will be discussed in the summary).

DSC OFF - My favorite mode (not for day to day driving where the nannys have their place, especially on these roads.) No nanny kick in, just the e-diff. Does not have the exaggerated throttle and steering but keeps the suspension tight. I prefer the lack of the exaggeration, I don't need fake enhancements, and I tell the car when to shift. This is where the 2 LSD’s show their stuff and show the difference from the e-diff (which is definitely still there.) The M-Performance LSD is just quicker than the e-diff and keeps the rear end stable in all situations. On heavy power it does its job. Very well sorted, but different from the Quaife (this will be discussed in the summary).

Pre Corner off throttle (DSC OFF) – This is a major improvement on deceleration. Wow, the 9% lock is felt, and the chassis is much more stable on the off throttle event then the stock pumpkin. (Note that the e-diff is adding to the 9%, because this is in no way a simple 9% locker.)

Starting on ice – Works as you would expect. You just pull away. Slight advantage from the e-diff, but it is a $50 improvement, not a $3k improvement.

QUAIFE

Eco-pro -STILL boring, hate it, nuf said.

Comfort - soft, smooth, cruising mode. Nanny heaven. Minimal discernible difference from the e-diff. Nannys kick in too soon.

Sport - it is just comfort mode with firmer suspension along with exaggerated inputs on throttle and steering, plus the slightest lag in the nannys taking the fun away. With the Quaife LSD, the LSD will actually kick in before the nannys, so you can push a bit harder then without it. Adds a little more fun, but there is not enough difference to justify the cost.

Sport+ - It is sport, nanny lag is increased to approximately .5 sec of stupidity, then it kicks in hard with the nanny regimen. And this is where the LSD starts to earn it’s keep. The LSD kicks in before the nannys get a chance, if you are driving at or near (or slightly over) the limits of grip the nannys will stay in the back seat unlike with the stock diff. If you are trying to drift it, then the nannys are still there to take over. Little difference between the 2 LSD’s (this will be discussed in the summary).

DSC OFF - My favorite mode (not for day to day driving where the nannys have their place, especially on these roads.) No nanny kick in, just the e-diff. Does not have the exaggerated throttle and steering but keeps the suspension tight. I prefer the lack of the exaggeration, I don't need fake enhancements, and I tell the car when to shift. This is where the 2 LSD’s show their stuff and show the difference from the e-diff (which is definitely still there.) The Quaife LSD is just quicker than the e-diff (And the M-performance LSD) and keeps the rear end stable in all power on situations. On heavy power it does its job. Great pumpkin, but different from the M-Performance (this will be discussed in the summary).

Pre Corner off throttle (DSC OFF) – This thing is an open diff on deceleration. The chassis gets skittish on the off throttle event just like the stock open diff.

Starting on ice – Slight advantage from the e-diff, but it is a $50 improvement, not a $3k improvement. (Note: We tested the infamous 0 traction on one wheel start too, the e-diff kicks in and this slight hypothetical limitation of the Quaife disappears. Even when there is 0% traction on a single wheel the e-diff adds resistance and off you go.)

Summary.
If you are looking for an LSD for bad weather traction or for hard driving up to, and including, a single track day per year, don’t bother. The E-diff is actually quite good.

If you are still fretting about that 1/10 th of a second you left in corner 5 during your third track day last summer (I am) then LSD is for you. Then it comes down to which one.

Here is the summary of the breakdown between the LSD’s

M-Performance – This is a mechanical (clutch type) 30% locker on acceleration, but the electronics on the M235i were obviously designed to work with this specific pumpkin. There is no way that in the real world that this is a 30% lock, the electronics are assisting it and my guess is that it is over 40% in practice. On power it is very good as a combination, but the Quaife is better on throttle.
Then there is off throttle. The M-Performance LSD is a 9% locker, but the electronics help it here too. There is no way this is just 9% in real world situations. What it does on the hard into a corner off throttle stabilization is amazing. It changes the car. There is a reason that road racers use 1.5 way LSD’s. (And 2.0 way LSD’s if not streeting the car.)

Quaife – This is a gear type LSD and has almost 100% transfer available on acceleration. Flat out it is quicker to adjust than the M-performance LSD on throttle and it is so quick that it adjusts before the car tries to help further.
The issue is that off throttle it does nothing. It is just like the stock open pumpkin when you lift the right pedal.

Final Summary-
Again, for basic street driving, aggressive street driving, track day novice and bad weather, don’t bother. The e-diff is quite good.

Now for the fun summary
Buy the M-performance if you are road racing, autoX, anything where the chassis dynamics needs to be at its best entering the corner. It is 95% as good as the Quaife on throttle, but MUCH better in other situations.

Buy the Quaife if you are drifting, drag racing, want massive (but amazingly controllable) oversteer or you are a hooligan. It is just flat out better on throttle. But if you are looking for 0.1ths of a second on a track, the M-performance will be better.

We both tested without sharing notes until done, we both fully agreed on these assessments. Incidentally, he likes drifting, and dragging and I race, so we are happy with our choices even though we acknowledge the other LSD’s strengths and realize there is no perfect choice.

Alright my $0.02 given.

p.s. I did not consider maintenance as part of this, only performance. I know that the M-Performance will need maintenance at or before 50k miles. I know the Quaife will be bulletproof and still in existence when the sun explodes. That is not what I was testing.

[chaswyck1]

I don't drift, drag or race so this thread was of limited interest to me, but I just want to say what a great job you did with your comparison and explaining the benefits and drawbacks of each option so even novices like me could understand it. This was an outstanding posting and one that is worthy of being published in an enthusiast magazine. It's not often that you find a posting that is this informative and objective on here.

[JustChris]

I haven't read all this but can appreciate the effort that went into this, well done guys, great help too potential buyers!

[ocN55]

OP is the man!

[nike001]

I was hoping this thread would help me decide whether or not I want the Perf diff, and I'm still on the fence.

My hooning is pretty limited, but still occurs. My main concern here is whether or not the Perf diff will help in the winter.

I hear that you can't really tell the difference between the stock diff & the Perf diff until you get in Sport+ or have DSC off, is that correct?

[tke743]

Originally Posted by nike001

I was hoping this thread would help me decide whether or not I want the Perf diff, and I'm still on the fence.

My hooning is pretty limited, but still occurs. My main concern here is whether or not the Perf diff will help in the winter.

I hear that you can't really tell the difference between the stock diff & the Perf diff until you get in Sport+ or have DSC off, is that correct?

I specifically addressed your question in the post. Bad weather/Winter don't bother.

You can tell that you have an LSD in Sport, but only barely. It is Sport+ and DSC OFF where it is in your face that it's there (Especially DSC OFF).

[nike001]

Originally Posted by tke743

I specifically addressed your question in the post. Bad weather/Winter don't bother.

You can tell that you have an LSD in Sport, but only barely. It is Sport+ and DSC OFF where it is in your face that it's there (Especially DSC OFF).

tke, my comment wasn't meant to take anything away from your review. I was more-so hoping for a "you're an idiot if you don't get this " or a "don't waste your money" type of deal. You gave a good review that will probably help people deciphering between what to do, it just so happens to be that my driving style leaves me between the two.

[tke743]

Originally Posted by nike001

tke, my comment wasn't meant to take anything away from your review. I was more-so hoping for a "you're an idiot if you don't get this " or a "don't waste your money" type of deal. You gave a good review that will probably help people deciphering between what to do, it just so happens to be that my driving style leaves me between the two.

No worries, it wasn't taken that way. Net is that if you don't race at least twice a year, save your money. A noob or true novice racer will get little from this. If it is just the weather/winter that is making you consider it then let me just say "don't waste your money".

If you are someone who races and is REALLY looking for 1/10ths, then "you're an idiot if you don't get one of these". It is the "which one" that you must ponder.

[hoppy6698]

Thanks to the OP on this endeavor. I wish there were reviews of this nature before my own purchase - I may have put the MP LSD $$ elsewhere. Having not driven a M235i with the e-diff to compare first, I was worried about traction and track ability - so I went with the LSD. Tracking 4-5 times a year, I'm still not sure it was worth the $$ spent (don't tell the Mrs.). I guess I will find out at the first HPDE this summer

[tke743]

Originally Posted by hoppy6698

Thanks to the OP on this endeavor. I wish there were reviews of this nature before my own purchase - I may have put the MP LSD $$ elsewhere. Having not driven a M235i with the e-diff to compare first, I was worried about traction and track ability - so I went with the LSD. Tracking 4-5 times a year, I'm still not sure it was worth the $$ spent (don't tell the Mrs.). I guess I will find out at the first HPDE this summer

If you track 4-5 times a year you will be using it. So it was a good idea. FYI, our cars are clones. EBII/Black, moonroof delete, etc.

[ketema]

Great write up. Makes me glad I got the MPerf Diff. Question: do you guys have the auto tranny or manual? I have a manual. Been to two events so far this year and the one thing I have noticed is that the car's rear end wiggles under heavy high speed breaking (140 to 80). Is this more a function of the suspension or the diff?

[tke743]

Originally Posted by ketema

Great write up. Makes me glad I got the MPerf Diff. Question: do you guys have the auto tranny or manual? I have a manual. Been to two events so far this year and the one thing I have noticed is that the car's rear end wiggles under heavy high speed breaking (140 to 80). Is this more a function of the suspension or the diff?

Both were automatic. If you think it wiggles under braking with the LSD, you should have tried it without. The LSD helps settle the chassis on braking.That is what I was referring to in the tests.

[Supernaut]

Thanks for putting the effort into sharing your experience. I canceled the LSD in my build about a week ago after your earlier comments on tracking the e-diff. With just a couple track weekends a year, I don't think I'd have gotten my money's worth from M Performance diff. Your writeup confirms that, though it might be an option down the road if I get more serious on the track. So, basically, you saved me $2500. I owe you a beer!

[tke743]

Originally Posted by Supernaut

Thanks for putting the effort into sharing your experience. I canceled the LSD in my build about a week ago after your earlier comments on tracking the e-diff. With just a couple track weekends a year, I don't think I'd have gotten my money's worth from M Performance diff. Your writeup confirms that, though it might be an option down the road if I get more serious on the track. So, basically, you saved me $2500. I owe you a beer!

Glad I could be of assistance. The fact that you can add it later should weigh heavily in this. If you get serious then do it.

[abp689]

Originally Posted by tke743

No worries, it wasn't taken that way. Net is that if you don't race at least twice a year, save your money. A noob or true novice racer will get little from this. If it is just the weather/winter that is making you consider it then let me just say "don't waste your money".

If you are someone who races and is REALLY looking for 1/10ths, then "you're an idiot if you don't get one of these". It is the "which one" that you must ponder.

This was great, one of the better reviews, saved me $3000, and I also owe you a beer! As a result, I am sticking with the e-diff.

Now, can anyone talk me out of an aftermarket exhaust?

[wjones14]

Awesome write-up. I echo chaswyck's comments about this being as good or better than what you'd read from the major automotive magazine writer/testers. I fall in the category of 1 track per year (since 2007), so according to your conclusion I don't need the LSD. And I didn't order one. But I am skeptical of driving a car without one, since this would be my first.

I just hope I am able to have a little fun with it in a low-speed 2nd gear 90 degree corner, where every car I have ever owned would easily swing the rear out with a moderate amount of throttle. My Mustang will break loose without really trying, even with the traction control on. If I can no longer do that, I'm going to be disappointed...

[tke743]

Originally Posted by wjones14

Awesome write-up. I echo chaswyck's comments about this being as good or better than what you'd read from the major automotive magazine writer/testers. I fall in the category of 1 track per year (since 2007), so according to your conclusion I don't need the LSD. And I didn't order one. But I am skeptical of driving a car without one, since this would be my first.

I just hope I am able to have a little fun with it in a low-speed 2nd gear 90 degree corner, where every car I have ever owned would easily swing the rear out with a moderate amount of throttle. My Mustang will break loose without really trying, even with the traction control on. If I can no longer do that, I'm going to be disappointed...

DSC OFF, you will have no issues. You can drift it and draw 11's all day. Sport+ is almost there, but depends on how much user control you want. Try it in Sport and you will be disappointed as the nannys will clamp down faster then you would belive. Try this in Comfort and I'll be laughing at you...

[hoppy6698]

Originally Posted by tke743

If you track 4-5 times a year you will be using it. So it was a good idea. FYI, our cars are clones. EBII/Black, moonroof delete, etc.

A lot to be said for good taste

[tke743]

I've been asked to further refine the line between the need for the LSD on the track vs not. I had stated up to one track time a year and no you don't need one. I stated that as it usually is the defining line between the novice and the non-novice. Let me refine that.

If you are tracking the car and know how to heal-toe AND left foot brake then get the LSD. If either of the above are no, then it's not needed (yet). If you add these skills and track more you can always add it later.