Why is rear end so squirrelly in straight line acceleration?

[maul3d]

I tried launch control with fresh new tires.. car peeled out for aboit 10 ft, then the vehicle went into a slow drift sideways, almst landing me in a ditch. Lol

This was at the lowest rpm available...

Would have thought the vehicle would shoot straight forward with an active diff.

[Sedan_Clan]

Originally Posted by maul3d

I tried launch control with fresh new tires.. car peeled out for aboit 10 ft, then the vehicle went into a slow drift sideways, almst landing me in a ditch. Lol

This was at the lowest rpm available...

Would have thought the vehicle would shoot straight forward with an active diff.

#drivererror

[hellokitty]

Originally Posted by maul3d

I tried launch control with fresh new tires.. car peeled out for aboit 10 ft, then the vehicle went into a slow drift sideways, almst landing me in a ditch. Lol

This was at the lowest rpm available...

Would have thought the vehicle would shoot straight forward with an active diff.

Gotta wear it down a bit before driving like that on fresh tires. Maybe do a burnout first then send it lol

[dezzracer]

Originally Posted by Sedan_Clan

#drivererror

Other than not scrubbing in new tires I would disagree. I would challenge anybody to do a full on "by the book" launch control take off in this car without going sideways.

[maul3d]

Tires had approx 300 miles on them! New, yes. But should have had that new layer off by then.

This wasnt a one time thing. It was constant, numerous times guys

Iv dragged race cars since i was a kid! Ownimg 500HP Subarus and Evos.

One can say modulate the throttle.. but im losing precious time!!

Out of control i tell ya.. either that, or our roads here in town are ice.

[Andrae26]

I have zero issues with launching my M3CS.

[Sedan_Clan]

Originally Posted by dezzracer

Other than not scrubbing in new tires I would disagree. I would challenge anybody to do a full on "by the book" launch control take off in this car without going sideways.

I have an MT. My launch control is modulated by my feet.

[Sedan_Clan]

Originally Posted by maul3d

Tires had approx 300 miles on them! New, yes. But should have had that new layer off by then.

This wasnt a one time thing. It was constant, numerous times guys

Iv dragged race cars since i was a kid! Ownimg 500HP Subarus and Evos.

One can say modulate the throttle.. but im losing precious time!!

Out of control i tell ya.. either that, or our roads here in town are ice.

AWD cars are easier to launch; they require less finesse to get a good launch.

[dezzracer]

Originally Posted by Sedan_Clan

AWD cars are easier to launch.

Really? Your kidding? Lol.

[Sedan_Clan]

Originally Posted by dezzracer

Really? Your kidding? Lol.

I sense sarcasm, but I was referring to him seemingly attempting to qualify launching AWD's cars as if that has anything to do with the complexity of launching RWD cars.

[dezzracer]

Originally Posted by Sedan_Clan

I sense sarcasm, but I was referring to him qualifying launching AWD's cars as if that has anything to do with the complexity of launching RWD cars.

Yea I know. No offense meant but I believe the proper technique for launching an AWD car is floor it and hang on. Lol. At least that's been my experience.

Edit. Oh I see. The cars he was referring to are all wheel drive. Sorry about that.. missed that part.

[CanAutM3]

Originally Posted by dezzracer

Other than not scrubbing in new tires I would disagree. I would challenge anybody to do a full on "by the book" launch control take off in this car without going sideways.

I've already done it more tha once. With warm and clean tires on a good surface, the car grips and launches hard.

[maul3d]

Well, ill own it then. Must have been me.

Great thing with the new vehicle, I drive it harder, and faster, then I did with mt M4.. my wife doesnt pipe up anymore telling me to slow down , or yell at me. Its amazing. Lol

I asked her what changed? You havent screamed, or told me im driving like an asshole!

Her reply ; "This car feels much more stable, and isnt' allover the place. I thought i was going to die in the yellow car."

Not knocking the m4. I miss it and some its good qualities.

[TideMD]

Originally Posted by dezzracer

Other than not scrubbing in new tires I would disagree. I would challenge anybody to do a full on "by the book" launch control take off in this car without going sideways.

I launch my '16 M4 fairly regular and keep it straight, with minimal rear drift or tire slip. And that's "by the book" all the way into 3rd or 4th gear.

Also, the side to side slipping you describe with MDM sounds exactly like what MDM is supposed to do - the car gets loose and lets you push the edge, but compensates to keeps you out of the ditch until the tires finally hook up.
Turn off MDM and you likely won't get that squirreliness (or it will be mitigated to a large degree).
Turn off TC completely and that side to side slip becomes a full-on spin into a ditch or a hard tank slap.

[dezzracer]

Originally Posted by TideMD

I launch my '16 M4 fairly regular and keep it straight, with minimal rear drift or tire slip. And that's "by the book" all the way into 3rd or 4th gear.

Also, the side to side slipping you describe with MDM sounds exactly like what MDM is supposed to do - the car gets loose and lets you push the edge, but compensates to keeps you out of the ditch until the tires finally hook up.
Turn off MDM and you likely won't get that squirreliness (or it will be mitigated to a large degree).
Turn off TC completely and that side to side slip becomes a full-on spin into a ditch or a hard tank slap.

You are correct., virtually no side to side action with TC fully activated as the program cuts power and mitigates slip which causes "Fishtailing". Thought I would throw that old school term in there in reference to another old-school term you just used. "tank slapper". Lol.

The term "tank slapper" was originally coined by motorcyclists racing at high speeds (usually off road) when they hit a rock or a ditch causing the handlebars to go into a violent uncontrollable wobble slapping them against the gas tank and almost always ejecting the rider. The term was eventually picked up by car enthusiasts. Fortunately, I've yet to experience that phenomenon in a car, however I have experienced it on a motorcycle and it's not fun.

[AO08BAS]

This is one of my biggest grips with the F8X as a whole. Living in the UK and 8/12 months being not "perfect" M driving conditions the fact that I cant floor my car in 1st or 2nd without having to worry about ending up in a ditch is slightly annoying.

I believe its 60/40 problem 60 driver 40 the car and once I and many others learn how to push the car properly then this will remain a sore point for us! But as long as we can learn in a safe way then it should turn out to be a fun and fruitful experience.

[dsmclark]

I've found limiting the torque 20% in 1st and 2nd has helped keep the rear in check on my car. And mine always goes sideways even with traction control fully on! but then it kicks in mid drift and then makes me look like a dick!

[Formermercowner]

Originally Posted by dezzracer

Car is stock with MPSS.

Mpss on a cs? In my region the cs has the cup2s as stock tire. I have an early m4, a 15 with the first map where the torque is high even at low rpm and it grips fine with 4s tire when they get to optimal temperature.

[AlterZgo]

Originally Posted by dezzracer

I get it but not more than a supercharged V-8 4 cammer pushing 13lbs of boost :

Supercharged engines are much more linear with boost building as RPMs rise. Higher RPMs spins supercharger faster generating more boost. OTOH, modern turbo motors, while still having a bit of lag off the line, will build full boost by 2000 RPMs and give it to you in one big wallop causing tires to easily break traction when safety nannies are disabled or muted with MDM.

[CanAutM3]

Originally Posted by Formermercowner

Mpss on a cs? In my region the cs has the cup2s as stock tire. I have an early m4, a 15 with the first map where the torque is high even at low rpm and it grips fine with 4s tire when they get to optimal temperature.

For some odd reason (probably some fear of liability), BMW USA decided to fit all the CS sold in the US with the PSS tires instead of the PSC2.

[Beemerm3]

I had a Mercedes with a V8 turbo n it wasn't this swirly. I think because the car needs wider tires to grip and more weight. With wider tires it hooks when u floor it. The m3 is tail happy n a drift machine with the lsd.

[tropicalypso]

Try adding a tune to your car. My 2nd to 3rd shift sends me fish tailing at full throttle.

Damn Continentals...