What do you NOT like about the 1 series?

[Happy Jose]

Originally Posted by chris_flies

I'm just highlighting to you some other people's misfortune with the DCT, not even trying to say the manual is bulletproof...

Maybe having a bit of fun here

I would describe your post as a stream of unconsciousness, unconnected & inaccurate information.

I don't need you to compare or contrast a DCT to other automatic transmissions. I knew exactly what I was buying and its principles of operation.

I also made a mistake going against my instincts to never trust BMW's new ideas. While other companies can successfully execute innovations, BMW falls short.

And you truly sound like a high school student!

[Esteban]

Originally Posted by Happy Jose

Obviously, you are insensitive to other people's feeling and their reactions to your remarks. Also you are the asshole thinking your observations are obvious to a general audience.

Also you should learn to substitute the word "I" for "we". There are plenty of assholes here either incognito or covert!

You're the one who is incognito. Figured out who you are. Your posts give you away. You were banned from here last year for being a jerk, weren't you? And you have a post in this thread under your banned name, right? Let's see if anyone else can figure out who you really are.

Hint:

[PA135ii]

Originally Posted by Esteban

You're the one who is incognito. Figured out who you are. Your posts give you away. You were banned from here last year for being a jerk, weren't you? And you have a post in this thread under your banned name, right? Let's see if anyone else can figure out who you really are.

Hint:

I know I know....

[asiflicious]

Originally Posted by xQx

For me, the worst thing after 2 years of ownership of my FBO 135i is the realisation that I'm never going to be happy with one sports car.

Regrettably I can't afford a stable full of luxury cars, nor the risk of doing $30k of damage to a car on a track where you're not covered by insurance, so my fun is had in my daily driver.

Since I'm currently limited to 4 seats due to a young family, I often pine for a M3 vert... but I've driven them, they've got the "M" badge, the response and handling is in a different class from the 135i (even though my car has more power on paper), they're fun and all, but compared to a 135i, they're a boat.

I love having a small, throwable car with no roof. I get annoyed by the aggressiveness of the aftermarket LSD I've got in my 135i at slow speeds, and the nasty things it's done to the balance and handling - but the ability it gives me to rotate the back around a left-hand turn is absolutely intoxicating. It'd be nice to have the growl of a V8 rather than the injector tick of a N54; but it's rather nice being able to drive past cop cars without attracting attention.

If I weren't limited to 4 seats, I'd be considering a Porsche Boxter S (which I'd get sick of because it's not powerful enough) a Z4M (as above) or an aftermarket turbo/supercharged MX5 (but then I'd be in exactly the same position as I am now - a small fun modified car with plenty of power - at the expense of prestige, balanced handling and grip) or if money was no object a 911 GTS... but from what I've read, a 911 actually isn't much fun on the street, because it's so eminently capable of taking a 90 degree corner at 60kph - the fun only starts at about 100MPH.

Leaving me with one 'breed' of car which I expect will be my next car following the 135i - A Caterham, Westfield or Ariel Atom. Small, light, throwable in traffic and with blistering performance. A true, raw driving experience at the expense of safety and practicality (no roof, no aircon, no heater, no radio, no back seats, no central locking, no power steering,no power breaks, no airbags ... you get the point).

Driving around in a steptronic FBO 135i convertible with comfort access and 425rwhp means you're in a car that is more prestigious, more comfortable, more practical, more powerful and more fun than 90% of the cars on the road. But it's all about compromise. ... and looking at the alternatives, they're all compromises in some way too.

So if I'm not happy with this car, I'm never going to be happy.

I'm not unhappy with the 135i... but after a few years of ownership, don't we all just yearn for 'something more'?

Could you elaborate on your thoughts on the LSD? I want to get a helical diff this summer but I don't know much about locking diffs (other than that they apply power to both wheels and give better grip through corners and allow you to be a hooligan) so I don't really understand what people mean when they say it effects daily driving

[BimmerAg]

Originally Posted by asiflicious

Could you elaborate on your thoughts on the LSD? I want to get a helical diff this summer but I don't know much about locking diffs (other than that they apply power to both wheels and give better grip through corners and allow you to be a hooligan) so I don't really understand what people mean when they say it effects daily driving

Here's a good video explaining how a Torsen (helical gear) defferential works:

Basically, they allow for normal differential wheels speeds during turning and daily driving, but when there is a difference in traction between the two wheels (wet vs dry, hard cornering, ice, etc) the wheels become locked together and torque is transmitted to the wheel with more traction.

A clutch type LSD operates based on a ramp and wedge that applies pressure to a clutch pack as the speed difference between the wheels changes. These types of diffs are the ones that people occasionally complain about for daily driving, because for very tight turns the wheel speed differential can be enough to start locking the diff and then one wheel will drag.

Clutch type diffs are usually preferred for racing and drifting for a couple of reasons. One, the engagement is more gradual and less likely to upset the balance of the car. Two, the ramp rates and amount of lockup can be changed to tune the handling characteristics of the car. Three, most torsen diffs can only transmit torque up to an 80/20 difference in available traction. That means that if you lift or almost lift a wheel during cornering that a torsen diff basically becomes an open diff. And finally, clutch type diffs can be arranged in a 2-way configuration that allows for lockup during deceleration as well. This is good for drifting because even when you let off the throttle the wheels can remain locked and give you a more predictable and controllable slide than if they are constantly locking and unlocking as you modulate the throttle.

[chris_flies]

Originally Posted by Happy Jose

I would describe your post as a stream of unconsciousness, unconnected & inaccurate information.

I don't need you to compare or contrast a DCT to other automatic transmissions. I knew exactly what I was buying and its principles of operation.

I also made a mistake going against my instincts to never trust BMW's new ideas. While other companies can successfully execute innovations, BMW falls short.

And you truly sound like a high school student!

At least I can speak with correct grammar.

And, I was simply clearing up someone else's (apparent) confusion, maybe it was redundant and not totally relevant information, but I felt it was useful at the moment I typed 'er up.

Yup, your mistake. Too bad it didn't blow up...we'd all be much happier right about now.

Lastly, what the hell is that supposed to mean?

[chris_flies]

Originally Posted by rowsdower

This is true of most automatics, but in fact there are some autos that are basically manual transmissions with a torque converter instead of a clutch. In these transmissions, there are no planetary gearsets, but rather meshed gears like you would find in a typical "manual" transmission. Most automatic Hondas since the 70s have this type of transmission.

https://en.wikipedia.org/wiki/Hondamatic

So I would disagree with the idea that the word 'automatic' can only apply to a transmission with a torque converter and a planetary gearset. We've been calling automatic Civics 'automatic' for decades, despite 'automated manual' being arguably a better term for them. DCT is clearly a new generation of automated manual, but I would still tend to say they are automatics.

I didn't know that, thanks for the info! That's actually kinda cool. Maybe explains why they were/are looking into having a DCT transmission with a torque converter.

[asiflicious]

Originally Posted by BimmerAg

Here's a good video explaining how a Torsen (helical gear) defferential works:

Basically, they allow for normal differential wheels speeds during turning and daily driving, but when there is a difference in traction between the two wheels (wet vs dry, hard cornering, ice, etc) the wheels become locked together and torque is transmitted to the wheel with more traction.

A clutch type LSD operates based on a ramp and wedge that applies pressure to a clutch pack as the speed difference between the wheels changes. These types of diffs are the ones that people occasionally complain about for daily driving, because for very tight turns the wheel speed differential can be enough to start locking the diff and then one wheel will drag.

Clutch type diffs are usually preferred for racing and drifting for a couple of reasons. One, the engagement is more gradual and less likely to upset the balance of the car. Two, the ramp rates and amount of lockup can be changed to tune the handling characteristics of the car. Three, most torsen diffs can only transmit torque up to an 80/20 difference in available traction. That means that if you lift or almost lift a wheel during cornering that a torsen diff basically becomes an open diff. And finally, clutch type diffs can be arranged in a 2-way configuration that allows for lockup during deceleration as well. This is good for drifting because even when you let off the throttle the wheels can remain locked and give you a more predictable and controllable slide than if they are constantly locking and unlocking as you modulate the throttle.

So is a helical basically a half measure? Clutch type>torsen>open diff?

[xQx]

Originally Posted by asiflicious

Could you elaborate on your thoughts on the LSD? I want to get a helical diff this summer but I don't know much about locking diffs (other than that they apply power to both wheels and give better grip through corners and allow you to be a hooligan) so I don't really understand what people mean when they say it effects daily driving

I'm always happy to elaborate about the LSD, because I did all the research I could, was well warned, but still had no idea what effect it would have on the car - I'm passionate about it because it's both the best mod I made to this car, and the worst

The tl;dr version is: Putting a LSD in our cars is the single best thing you will do to the car. It's expensive and can have negative consequences (depending on your choice), but is hands-down the best value-for-money modification I've done to my 1er.

I also welcome feedback, argument or agreement by other LSD owners, because I've never driven a car with a helical LSD, or a welded diff.

Now, when you go to get a diff in our cars, you have 3 options:

1. Aftermarket clutch diff
2. Aftermarket Helical Diff
3. OEM M3 Diff

For street use and light track use the OEM M3 diff is hands-down the way to go. If you can get one from a smashed M3 and swap it over, it'll give the best driving experience. It's great value if you can pick up the subframe and suspension bits from the doner car too... But from what I've read there's some welding involved in getting it on a 1er, and in Australia it's basically not an option ($3,000USD in parts then another $3,000USD in labour to get the thing fitted and working).

Now, I'm going to spread a little FUD about the Helical which I haven't found anyone talking about first-hand online. The Helical puts the power to the wheel with the most grip; not evenly between the two. It also allows your two back wheels to rotate at different speeds, and can instantaneously transfer power to the wheel which 'needs' it. This is good on the street, because it takes the power away from the spinning wheel and puts it on the grippy wheel without 'tying your back two wheels together'. But, you will find online that helicals aren't great for drifting - and nobody really elaborates on why.

When I was going to pull the trigger on a helical, the local diff-builder told me why I should think twice about a clutch. The fact that the helical can rapidly transfer torque from the wheel that's slipping to the wheel that's gripping means that it can be very unpredictable if you're driving it at the limit. Once you have two wheels slipping, it'll move power to the one with most grip, and can very instantly transfer 70% of the power from the left-hand to the right-hand corner... or worse - oscillate.

What that means is the car can be just as squirrely with a helical LSD as it is with the eDiff - and getting rid of that 'squirrely' behaviour was half the reason I wanted to get a LSD in the first place. (the other reason was outright grip.)

So, onto clutch diffs - basically they work by locking the back two wheels together. Unlike an intelligent 4wd diff (like xDrive) or a helical diff there's no torque proportioning - it's like the clutch in a manual gearbox - It's either open, slipping the clutch to give some friction but not too much, or it's locked - like a welded diff.

The M3 diffs allow a lot of differential in wheel spin before they engage, allowing M3 drivers to take tight corners without diff shudder (which feels the same as if you ride the clutch out very slowly in first gear like a Learner driver in their first manual car), then allows more slip than an aftermarket diff (or so I'm told).

A 1.5way aftermarket diff will be far more aggressive, since when you race a car you should never be on the power driving into or around the apex of a corner. Mine basically welds the two back wheels together whenever I'm accelerating above 60kph, or at anything more than 1/2 throttle at slow speeds. That has some very noticeable effects on handling:

• By welding the back tires together, they can't spin at unequal rates. In unison they push the car hard in a straight line
• It overcomes many of the 'soft subframe', 'soft suspension' issues in our cars, since it puts symmetrical forces onto the rear subframe
• In a 'u turn' or tight 90 degree turn situation, something's gotta give. Under low acceleration it's the clutches in the diff (diff shudder as described above), under high acceleration it's the wheel with the least grip

Diff shudder is something you ignore. It's completely normal, it's not harmful, and it's only disconcerting if you don't know what it is. You also get used to and ignore the odd 'clunk' from the drivetrain as the diff harshly engages or disengages; but both factors would worry the hell out of a buyer if you ever try to sell the car.

The soft subframe issue is a real hidden bonus. I was ready to do rear guide rods and Rear subframe bushes before I did the diff, but now they seem totally unnecessary because the 'twisting forces' across the back wheels no longer exist under acceleration.

But it's the straight-line rear-wheel push that's most noticeable and ... interesting ... to deal with.

On the street you generally don't reach corners at terminal velocity and have the luxury of trail-breaking into to the apex then powering out of the corner. It's very common to be powering in to the apex or coming off the power before you fully exit the corner.

Because the diff welds the back wheels together under power, the steering is much heavier under power (thanks to our cars being one of the last with hydraulic steering) and the track the car takes through a corner is pushed outwards by the extra force of the back wheels. The car feels like it's going to plough understeer (since that's what the back wheels are trying to get it to do).

If you come off the power in a corner, the diff lets go (releasing the inside wheel), the weight goes to the front of the car, the back wheels stop pushing the car outwards, and you need much less force on the steering wheel to maintain the same turn. In other words - it tries to snap oversteer.

Conversely, If you jab the throttle mid-corner (when it feels like it's about to understeer), you overwhelm the grip at the back and predictably drop into a powerslide. (ie. oversteer)

So this is the quality you really want to be aware of and practice, practice, practice - It's not really a _good_ quality that the car feels like it's about to understeer but is actually about to oversteer if you either increase or decrease your power

Also, DTC in our cars once you have a diff is a real dream. On the 'short-press' setting, it'll let you loose grip almost entirely then cut power momentarily, catching the back just after it lets go. With DCT on it's very easy to powerslide around street corners in traffic without ending up spinning out of control.


Lastly, when you've got a passenger in the car and you're about to take a tight turn into traffic from a standing start, you need to decide:

1. Do I take it extremely slowly around the corner for occupant comfort and so as not to make a scene
2. Do I power into the corner normally and hope my passengers don't notice the clutch-shuddering in the drivetrain
3. Do I go on the power hard and let the inside wheel squeal as I take the corner

But the car was a pig before I put the diff in. Any time I got on the power it'd spin one wheel and make heaps of noise then DCT would kick in and take all my power away. For all its negative consequences, the diff is extremely predictable. I can put 400hp onto a dry road in 2nd gear in a straight line without wheel spin. In the wet, I can take off quickly and not loose all forward momentum if the wheels spin a little. Around roundabouts in normal traffic I use the throttle to steer the car just as much as I use the steering wheel. The car now has a tendency to oversteer in most situations, and if you're driving next to a cop car or with your mother in the car, all you have to do to avoid any attention is drive sedately.

I don't know how many of these negative effects can be removed with properly setup suspension (my car is stock, except for good non-RFT tires), nor how many are common to a helical diff; but I'd thoroughly recommend getting a LSD, even with these shortcomings.

Originally Posted by asiflicious

So is a helical basically a half measure? Clutch type>torsen>open diff?

I doubt many torsen owners would agree with you, especially owners of Wavetrac diffs which are supposed to be the best of both worlds.

Torsen is nicer to drive with, fixes the 'one wheel drive' problem, but doesn't have the same predictability at the limit as a clutch does. It's also supposed to be maintenance free.
Clutch diffs have downsides. (see above ) But they're the best choice for racing and drifting because they're predictable, no matter the circumstances.
Open diffs are a scourge on the earth, eDiffs are a half measure.

[Esteban]

WTF, you guys! And I've been happy all this time with my measly little e-diff! Shows what I know. lol

[chris_flies]

Originally Posted by Esteban

WTF, you guys! And I've been happy all this time with my measly little e-diff! Shows what I know. lol

I did some mad skids just fine in the rain with my “measly” eDiff. Though, my tiny 225 section tires probably helped a good deal...

[BimmerAg]

Originally Posted by asiflicious

So is a helical basically a half measure? Clutch type>torsen>open diff?

It depends what you want to do...For racing/drifting, the helical isn't usually the best choice, but it's a good compromise for something that's a daily driver and occasional weekend track toy. Helical diffs don't require any tuning, any special fluid, and the clutches don't wear out (because there aren't any)

[chris_flies]

Originally Posted by BimmerAg

It depends what you want to do...For racing/drifting, the helical isn't usually the best choice, but it's a good compromise for something that's a daily driver and occasional weekend track toy. Helical diffs don't require any tuning, any special fluid, and the clutches don't wear out (because there aren't any)

I heard that they can't do anything once one wheel gets off the ground...

[BimmerAg]

Originally Posted by chris_flies

I heard that they can't do anything once one wheel gets off the ground...

Except for wavetrac, that's true. They actually can't do anything if there's more than an 80/20 split (IIRC) of available traction between the drive wheels. So if one tire is on dry ground and the other is on ice, it may not work as expected. Or, if at the time you try to apply power coming out of a hard turn there is more than 80% of the weight on the outside tire, the diff won't transfer torque to it. This situation is probably unlikely with street tires, but could happen if you're running slicks at the track. A stiffer rear sway bar also increases weight transfer and makes this situation more likely.

[chris_flies]

Originally Posted by BimmerAg

Except for wavetrac, that's true. They actually can't do anything if there's more than an 80/20 split (IIRC) of available traction between the drive wheels. So if one tire is on dry ground and the other is on ice, it may not work as expected. Or, if at the time you try to apply power coming out of a hard turn there is more than 80% of the weight on the outside tire, the diff won't transfer torque to it. This situation is probably unlikely with street tires, but could happen if you're running slicks at the track. A stiffer rear sway bar also increases weight transfer and makes this situation more likely.

Interesting...thanks for the info!

[asiflicious]

Originally Posted by xQx

I'm always happy to elaborate about the LSD, because I did all the research I could, was well warned, but still had no idea what effect it would have on the car - I'm passionate about it because it's both the best mod I made to this car, and the worst

The tl;dr version is: Putting a LSD in our cars is the single best thing you will do to the car. It's expensive and can have negative consequences (depending on your choice), but is hands-down the best value-for-money modification I've done to my 1er.

I also welcome feedback, argument or agreement by other LSD owners, because I've never driven a car with a helical LSD, or a welded diff.

Now, when you go to get a diff in our cars, you have 3 options:

1. Aftermarket clutch diff
2. Aftermarket Helical Diff
3. OEM M3 Diff

For street use and light track use the OEM M3 diff is hands-down the way to go. If you can get one from a smashed M3 and swap it over, it'll give the best driving experience. It's great value if you can pick up the subframe and suspension bits from the doner car too... But from what I've read there's some welding involved in getting it on a 1er, and in Australia it's basically not an option ($3,000USD in parts then another $3,000USD in labour to get the thing fitted and working).

Now, I'm going to spread a little FUD about the Helical which I haven't found anyone talking about first-hand online. The Helical puts the power to the wheel with the most grip; not evenly between the two. It also allows your two back wheels to rotate at different speeds, and can instantaneously transfer power to the wheel which 'needs' it. This is good on the street, because it takes the power away from the spinning wheel and puts it on the grippy wheel without 'tying your back two wheels together'. But, you will find online that helicals aren't great for drifting - and nobody really elaborates on why.

When I was going to pull the trigger on a helical, the local diff-builder told me why I should think twice about a clutch. The fact that the helical can rapidly transfer torque from the wheel that's slipping to the wheel that's gripping means that it can be very unpredictable if you're driving it at the limit. Once you have two wheels slipping, it'll move power to the one with most grip, and can very instantly transfer 70% of the power from the left-hand to the right-hand corner... or worse - oscillate.

What that means is the car can be just as squirrely with a helical LSD as it is with the eDiff - and getting rid of that 'squirrely' behaviour was half the reason I wanted to get a LSD in the first place. (the other reason was outright grip.)

So, onto clutch diffs - basically they work by locking the back two wheels together. Unlike an intelligent 4wd diff (like xDrive) or a helical diff there's no torque proportioning - it's like the clutch in a manual gearbox - It's either open, slipping the clutch to give some friction but not too much, or it's locked - like a welded diff.

The M3 diffs allow a lot of differential in wheel spin before they engage, allowing M3 drivers to take tight corners without diff shudder (which feels the same as if you ride the clutch out very slowly in first gear like a Learner driver in their first manual car), then allows more slip than an aftermarket diff (or so I'm told).

A 1.5way aftermarket diff will be far more aggressive, since when you race a car you should never be on the power driving into or around the apex of a corner. Mine basically welds the two back wheels together whenever I'm accelerating above 60kph, or at anything more than 1/2 throttle at slow speeds. That has some very noticeable effects on handling:

• By welding the back tires together, they can't spin at unequal rates. In unison they push the car hard in a straight line
• It overcomes many of the 'soft subframe', 'soft suspension' issues in our cars, since it puts symmetrical forces onto the rear subframe
• In a 'u turn' or tight 90 degree turn situation, something's gotta give. Under low acceleration it's the clutches in the diff (diff shudder as described above), under high acceleration it's the wheel with the least grip

Diff shudder is something you ignore. It's completely normal, it's not harmful, and it's only disconcerting if you don't know what it is. You also get used to and ignore the odd 'clunk' from the drivetrain as the diff harshly engages or disengages; but both factors would worry the hell out of a buyer if you ever try to sell the car.

The soft subframe issue is a real hidden bonus. I was ready to do rear guide rods and Rear subframe bushes before I did the diff, but now they seem totally unnecessary because the 'twisting forces' across the back wheels no longer exist under acceleration.

But it's the straight-line rear-wheel push that's most noticeable and ... interesting ... to deal with.

On the street you generally don't reach corners at terminal velocity and have the luxury of trail-breaking into to the apex then powering out of the corner. It's very common to be powering in to the apex or coming off the power before you fully exit the corner.

Because the diff welds the back wheels together under power, the steering is much heavier under power (thanks to our cars being one of the last with hydraulic steering) and the track the car takes through a corner is pushed outwards by the extra force of the back wheels. The car feels like it's going to plough understeer (since that's what the back wheels are trying to get it to do).

If you come off the power in a corner, the diff lets go (releasing the inside wheel), the weight goes to the front of the car, the back wheels stop pushing the car outwards, and you need much less force on the steering wheel to maintain the same turn. In other words - it tries to snap oversteer.

Conversely, If you jab the throttle mid-corner (when it feels like it's about to understeer), you overwhelm the grip at the back and predictably drop into a powerslide. (ie. oversteer)

So this is the quality you really want to be aware of and practice, practice, practice - It's not really a _good_ quality that the car feels like it's about to understeer but is actually about to oversteer if you either increase or decrease your power

Also, DCT in our cars once you have a diff is a real dream. On the 'short-press' setting, it'll let you loose grip almost entirely then cut power momentarily, catching the back just after it lets go. With DCT on it's very easy to powerslide around street corners in traffic without ending up spinning out of control.


Lastly, when you've got a passenger in the car and you're about to take a tight turn into traffic from a standing start, you need to decide:

1. Do I take it extremely slowly around the corner for occupant comfort and so as not to make a scene
2. Do I power into the corner normally and hope my passengers don't notice the clutch-shuddering in the drivetrain
3. Do I go on the power hard and let the inside wheel squeal as I take the corner

But the car was a pig before I put the diff in. Any time I got on the power it'd spin one wheel and make heaps of noise then DCT would kick in and take all my power away. For all its negative consequences, the diff is extremely predictable. I can put 400hp onto a dry road in 2nd gear in a straight line without wheel spin. In the wet, I can take off quickly and not loose all forward momentum if the wheels spin a little. Around roundabouts in normal traffic I use the throttle to steer the car just as much as I use the steering wheel. The car now has a tendency to oversteer in most situations, and if you're driving next to a cop car or with your mother in the car, all you have to do to avoid any attention is drive sedately.

I don't know how many of these negative effects can be removed with properly setup suspension (my car is stock, except for good non-RFT tires), nor how many are common to a helical diff; but I'd thoroughly recommend getting a LSD, even with these shortcomings.

I doubt many torsen owners would agree with you, especially owners of Wavetrac diffs which are supposed to be the best of both worlds.

Torsen is nicer to drive with, fixes the 'one wheel drive' problem, but doesn't have the same predictability at the limit as a clutch does. It's also supposed to be maintenance free.
Clutch diffs have downsides. (see above ) But they're the best choice for racing and drifting because they're predictable, no matter the circumstances.
Open diffs are a scourge on the earth, eDiffs are a half measure.

So the car is easier to lose if you're not careful? I don't want to end up sliding into a ditch or off a canyon if the car allows excessive slip with DTC on haha. I'm not looking to make my car into a race car or drift car, I want it to feel and handle like the E46 M3 I drive a couple years ago

[Gangplank]

[xQx]

Originally Posted by asiflicious

So the car is easier to lose if you're not careful?

I found stock standard the 135i was very easy to lose. Coming into a corner hard I didn't know which end was going to let go first. With DTC off I'd start spinning a back wheel anywhere from 1/2 to 2/3 throttle. With DTC on I wouldn't know when it was going to kick in and take all my power away. Cornering, the car would loose grip differently each day in the same corner driven in the same way.
Basically, I have nothing nice to say about the stock handling of the 135i, even with non-RFT tires.

Now, the car is easier to predict, easier to drive near the limit and easier to recover when you go over the limit; but it's lethal in the hands of an experienced driver who's not got practice in this particular car because it tells you it's going to do one thing, then what it actually does is the exact opposite. It's cool if you know the car, but deadly if you don't.

For an uncompromising sports car that you want to have fun in, I'd certainly go a clutch-based diff again; but if you just want to improve the rear-grip without substantially changing the balance and handling, I'd go a helical or wavetrac.

EDIT: the big reason I didn't go a helical or wavetrac was because it doesn't fix the bad behaviour our cars have when you do exceed the limit. Essentially what these diffs will do for you is move the limit further away, so you can go faster than you used to and get more power down; but you'll still have to drive at 80% or less, because the characteristics are rather unforgiving when you do start sliding. My view is the best fun in a car is when you're nudging the limits - at 60pkh I'm going to have much more fun in a MX5 than in a 911. To use an analogy with tires - I'd prefer to be driving on less grippy tires that give you warning before they let go and time to recover if one breaks loose, than racing slicks which have tonnes of grip until they let go, but go from total grip to nothing in a heartbeat.

Originally Posted by asiflicious

I'm not looking to make my car into a race car or drift car, I want it to feel and handle like the E46 M3 I drive a couple years ago

Don't we all. I ran out of money before I got close. Hopefully you can succeed where I've failed.

I'd start with something like this:
https://www.ebay.com/itm/2012-BMW-M3...0AAOSwhcdalC~H