Stupid question - E8x x-drive swap

[xQx]

Now here's a stupid question.

Has anyone tried swapping an xdrive AWD system into an E8x?

If so, how much would you need to transplant?

[captain slowly]

Not that I've heard of. Not worth the effort, IMO. If you want AWD just go buy a 3 series and be done with it.

[Yeineken]

Any things possible... http://instagram.com/sheff140

[doublevanosrc]

It's possible of course but for the money you're better off with preowned M235xi.

[tock172]

Definitely possible - I'm pretty almost all of the componentry bolts right up. The big question is why. AWD is great to have when you need it, but I don't think the 1-series gains any benefit from it.

[swagon]

Ridiculous and stupid idea.

Get an F22.

[xQx]

Well, it does look like a M240i xdrive Convertible is coming out this year, so I guess that's the (best) answer.
Edit: and it existed last year as the M235i xdrive Convertible.

Everyone I've seen swap in xdrive has done the whole engine too - probably because it's all controlled by the DME.

To answer the question of why:
1) Because the E92 M3 and F82 M4 Convertibles are too big.
2) My 0-60 times and spirited straight-line street driving is limited by one thing: rear wheel grip.

What's the point of having a 450rwhp street car if all you get is wheel-spin whenever you try to use more than about 300hp at street-legal speeds?

I know most people love RWD for the handling, and in a Mustang you have beer-barrel tires and tonnes of dead-weight to stop the back wheels from spinning. In a small, light car you reach a point where you either need drag-racing slicks up the back or AWD.

I'm not trying to convince you it's a 'good' idea, or even that AWD is a good thing. Just explaining why I was considering it.

But yeah, for the money and effort - better to just trade up to a M240i xDrive `vert.

[captain slowly]

Originally Posted by xQx

Well, it does look like a M240i xdrive Convertible is coming out this year, so I guess that's the (best) answer.
Edit: and it existed last year as the M235i xdrive Convertible.

Everyone I've seen swap in xdrive has done the whole engine too - probably because it's all controlled by the DME.

To answer the question of why:
1) Because the E92 M3 and F82 M4 Convertibles are too big.
2) My 0-60 times and spirited straight-line street driving is limited by one thing: rear wheel grip.

What's the point of having a 450rwhp street car if all you get is wheel-spin whenever you try to use more than about 300hp at street-legal speeds?

I know most people love RWD for the handling, and in a Mustang you have beer-barrel tires and tonnes of dead-weight to stop the back wheels from spinning. In a small, light car you reach a point where you either need drag-racing slicks up the back or AWD.

I'm not trying to convince you it's a 'good' idea, or even that AWD is a good thing. Just explaining why I was considering it.

But yeah, for the money and effort - better to just trade up to a M240i xDrive `vert.

I can assure you that in a 1 series, you are not even close to reaching the limits of what RWD has to offer., to justify needing AWD.

[desertman123]

Hilarious and I'd love to see it, but financially stupid.

[xQx]

Originally Posted by captain slowly

I can assure you that in a 1 series, you are not even close to reaching the limits of what RWD has to offer., to justify needing AWD.

Okay, I'll hijack my own thread, maybe save making another one.

What are the best ways to increase rear-wheel grip in the 1er for street use.

I can't get my 0-100km/h time under 4.75 sec due to wheel-spin.

Obviously, MPSS tires and a LSD are a good start, but from what I've read a LSD doesn't help straight-line dry performance (both wheels spin equally).

Classic physics says wider tires shouldn't help much (the contact patch gets wider and shorter, not larger) - but I'm open to people's experiences.

What have you done (or what's on your list) that makes the biggest difference to rear-wheel grip?

[captain slowly]

Originally Posted by xQx

Okay, I'll hijack my own thread, maybe save making another one.

What are the best ways to increase rear-wheel grip in the 1er for street use.

I can't get my 0-100km/h time under 4.75 sec due to wheel-spin.

Obviously, MPSS tires and a LSD are a good start, but from what I've read a LSD doesn't help straight-line dry performance (both wheels spin equally).

Classic physics says wider tires shouldn't help much (the contact patch gets wider and shorter, not larger) - but I'm open to people's experiences.

What have you done (or what's on your list) that makes the biggest difference to rear-wheel grip?

Not sure who told you LSD doesn't help straight line dry performance, but be sure to never take their advice on anything again Without getting too deep into it, do a LSD, get drag radials (if you live your life 1/4 mile at a time) and you will have your traction issues fixed.

[swagon]

Originally Posted by xQx

What's the point of having a 450rwhp street car if all you get is wheel-spin whenever you try to use more than about 300hp at street-legal speeds?

Jesus, I can barely use 50% of the 300hp on public roads! On back roads, sure, I can floor it in second and third but that's usually followed by hard braking lol. Isn't the Australian police & driving law one of the most strict in the world?

Originally Posted by xQx

What are the best ways to increase rear-wheel grip in the 1er for street use?

I can't get my 0-100km/h time under 4.75 sec due to wheel-spin.

But why do you care about straight line performance in a street car? I don't get it, please enlighten me.

Seems like your car is on stock suspension, which is mistake #1 IMHO. For that amount power, you need LSD, subframe bushings, better dampers, and tires. I've driven a ca. 400hp 135 once and even that thing was way too hairy at WOT.

[xQx]

Originally Posted by captain slowly

Not sure who told you LSD doesn't help straight line dry performance, but be sure to never take their advice on anything again Without getting too deep into it, do a LSD, get drag radials (if you live your life 1/4 mile at a time) and you will have your traction issues fixed.

Thanks!

I'm not interested in drag radials - I'll get into it below, but I'd like the car to be able to turn corners too

Anyway, I'm going to STFU until I've upgraded the rear guide rods, toe arms, subframe mounts and diff.
It sounds like doing all that should make a massive difference.

Originally Posted by swagon

Jesus, I can barely use 50% of the 300hp on public roads! On back roads, sure, I can floor it in second and third but that's usually followed by hard braking lol. Isn't the Australian police & driving law one of the most strict in the world?

But why do you care about straight line performance in a street car? I don't get it, please enlighten me.

Sure

Having never driven abroad, I can't compare our police to the rest of the world, but yes, they're pretty onto you. Driving 30kph above the limit (which is maximum 110kph) is instant suspension of your license, and general anti-hooning laws mean you don't have to specifically be breaking the law to have your car impounded - just doing anything that meets the broad criteria of 'hooning'. In all but one state radar detectors are illegal and our police are "anywhere, anytime" in unmarked camera cars. Also, after your third offence of hooning your car gets crushed. ... That said, you get a lot more latitude in a BMW 1er than you do in a Nissan Skyline, and we've got plenty of tight windy 100km/h back-roads so you can be pushing your car to the limit without necessarily breaking the law.

I'm now beginning to understand the idea that different people have different goals with a car, and it's not all about kw on a dyno, speed around a track or 1/4 mile times. I had/have aspirations of taking the car to the track, but I've come to the realisation that I actually can't afford the risk. If something goes wrong on the roads, the car is covered by insurance, so I can get paid out and can buy another one. If I'm on a track and the person in front spills coolant on a corner - without insurance - I can't afford $30,000 for a replacement car.

I had an x5 4.8is before the 1er, and chose to upgrade to n E88 rather than an X5M was because I really like small cars. Also, the climate in QLD is like that of florida, so you can drive a convertible with the roof off year-round. The E88 I have is the most fun car I've had since I first started driving in a `76 honda civic. It's small and open enough that you can throw it around and fit through gaps in traffic with joy. While the X5 was a behemouth, there's one thing it could do very, very well - which I'm working to replicate as best I can in this 1er.

It's this:

On the track or on windy backroads, you're anticipating what's coming up and working the gears, throttle and brakes to give yourself the best setup for what's ahead. It doesn't matter (much) how long it takes the turbos to spin up, or if you start making power from 3500RPM compared with 2500RPM. In traffic it is totally different. You'll be driving along in a convoy and someone will suddenly stop - there's a gap in the lane beside you, and a car coming 30km/h faster than you with a 4 second delay. In the X5, you could confidently plant your foot, swing the wheel and be in the next lane roaring and screaming and up to speed before the car is up your clacker. In a stock 1er, you're in the wrong gear and have a 3 second delay just to get into the correct gear and up to spool before you can think about swinging into the next lane. In mine - (FBO with XHP TCU) - you've got all the power you need, and you can gingerly jump into the next lane then plant the foot (RWD steer then accelerate not both at the same time like you can with xdrive ) - but you look like a real arsehole if you then light up the back wheels and don't get up to speed quick enough as a result. I know the E88 will never behave like an AWD 5 litre V8, but it *should* be able to confidently and consistently beat one in a straight line from an 'unprepared start'.

That's my obsession with straight-line performance in 2nd gear (and trying to make the car as forgiving as possible to ham-fisted input) - it's a metric that makes a very big difference to your overall speed in suburban traffic (which is where I spend most of my time).

There's a common criticism when I mention this and that's "why don't you just buy yourself an AWD v8 if you love them so much" - which is valid. But I love small cars and since nobody sells small cars with big v8's - unless you're going to do what that Russian did (and swap a S63 xdrive into a 135i) - the next best option is a torquey twin turbo six.

[ShocknAwe]

Smaller wheels and taller tires are key for straight line traction. Get a tune that allows you to set max boost by gear, helps a lot. With MPSS and fully modified rear suspension (no LSD yet) I can hold about 11 psi without breaking totally free in first gear off the line on the street. 2nd I have to limit it to 16 or 17, and third I can let it rip all the way out to 20 before I have issues with grip. On a prepped track, things are peachy.

With DR tires and a proper differential I could probably forget about traction issues at all with my current power levels.

Advice: Change one component at a time and se how it suits you. It will help you know what needs to be switched next, and how aggressive you want to go. Dont forget about the front, keep things somewhat balanced. Some rear suspension parts can introduce a lot of NVH, so go cautiously and have fun.

[Matt@EuroJerks]

Originally Posted by xQx

Thanks!

It's this:

On the track or on windy backroads, you're anticipating what's coming up and working the gears, throttle and brakes to give yourself the best setup for what's ahead. It doesn't matter (much) how long it takes the turbos to spin up, or if you start making power from 3500RPM compared with 2500RPM. In traffic it is totally different. You'll be driving along in a convoy and someone will suddenly stop - there's a gap in the lane beside you, and a car coming 30km/h faster than you with a 4 second delay. In the X5, you could confidently plant your foot, swing the wheel and be in the next lane roaring and screaming and up to speed before the car is up your clacker. In a stock 1er, you're in the wrong gear and have a 3 second delay just to get into the correct gear and up to spool before you can think about swinging into the next lane. In mine - (FBO with XHP TCU) - you've got all the power you need, and you can gingerly jump into the next lane then plant the foot (RWD steer then accelerate not both at the same time like you can with xdrive ) - but you look like a real arsehole if you then light up the back wheels and don't get up to speed quick enough as a result. I know the E88 will never behave like an AWD 5 litre V8, but it *should* be able to confidently and consistently beat one in a straight line from an 'unprepared start'.
.

Stop granny shifting and drive. 3 seconds....wtf are you doing? Putting makeup on?

[xQx]

Originally Posted by Matt@EuroJerks

Stop granny shifting and drive. 3 seconds....wtf are you doing? Putting makeup on?

Hahaha. That's not nice

Obviously you haven't had the pleasure of driving a stock standard 1 series 6AT in traffic.

Here's what happens if you foolishly tell the car you'd like to gain as much forward momentum as quickly as possible by mashing the throttle to the floor while cruising along at 50km/h:

1. The gearbox immediately disengages you from your current gear (third or forth) regardless of what (D/S/M) mode you're in and automatically selects the lowest possible gear - which is first.
2. The engine revs up nicely while the car's basically in neutral and the TCU eventually engages first and you find yourself doing 50km/h at about 6,000RPM in first.
3. You gain about 3km/h before the gearbox realises first is a stupid gear to be in, and it nice and casually upshifts you to second.
4. Now, (about 3 seconds after your initial reaction) you've got the power to the wheels and the car lurches forward with great gusto, and with the drivetrain properly engaged you start to build boost.

Driving in 'M' mode all the time and disabling kickdown eliminates this behaviour, replacing it with an almost instant boot of power, generally more than enough to light up the rear tires.

ShocknAwe Thanks for your suggestion, I had originally played with the 1st/2nd gear boost limiter on my previous set of tires but they were so crap I lost traction with 6psi in 2nd. I've got some half descent summer tires on now so I set 2nd gear to 11psi which didn't break traction (0-100kph in 4.8sec), so I'll incrementally increase & test. That'll tide me over until I get the LSD installed. Thanks!

[Matt@EuroJerks]

Originally Posted by xQx

Hahaha. That's not nice

Obviously you haven't had the pleasure of driving a stock standard 1 series 6AT in traffic.

Totally missed this part of the equation.