Understeer: 135 vs M3

[josh]

Why is it that BMW saw fit to dial in undesteer into the 135, and yet leave the M3 neutral? You'd think if they worried about liability of neutral handling and people swapping ends, they'd set up the M3 to understeer also?

[larryn]

I think this pretty powerful car is one of the most accessible cars they sell, especially compared to an M3. There certainly will be more high school grad 135i gifts than M3 gifts.

[Robert]

Is M3 neutral? I heard the e46 m3 understeers as well but quickly mitigated with the throttle.

[confusion]

Originally Posted by robert

Is M3 neutral? I heard the e46 m3 understeers as well but quickly mitigated with the throttle.

i think this statement is fairly accurate. at least for me there's a tiny bit of front-end push when hustling around a track but assuming you're in the right gear (i.e., in the power band) it's super easy to swing the tail around just right w/ a modest application of throttle. on that note, it's not hard to over do it, either. all in all, very tossable yet very easily controlled once you've got a little experience. i'm hoping the 135 will be very similar w/ the understeer dialed out.

[BForbes]

Originally Posted by josh

Why is it that BMW saw fit to dial in undesteer into the 135, and yet leave the M3 neutral? You'd think if they worried about liability of neutral handling and people swapping ends, they'd set up the M3 to understeer also?

Very simple my friend. BMW plans on selling many more 135i's than M3. That will exponentially increase the volume of unexperienced people with overpowered cars on the road.

[Garrett]

Originally Posted by josh

Why is it that BMW saw fit to dial in undesteer into the 135, and yet leave the M3 neutral? You'd think if they worried about liability of neutral handling and people swapping ends, they'd set up the M3 to understeer also?

The M3 is a perfect car! It's made by the M-Division of BMW and uses the best engineering found on the planet to derive at their outcome. They may look like a 3 series, but their not!

The premis for an //M is different, so the outcome is different. Why would assume or even compair a normal BMW to an //M?

Secondly, I'm lost as to your approach for correcting it. Swapping ends..? hunh? The 135i is a torque monster, thus it easy to throw the ass end out, so understeer is ONLY a problem when you want it to be. Everyone knows this!

[Doolab]

Originally Posted by josh

Why is it that BMW saw fit to dial in undesteer into the 135, and yet leave the M3 neutral? You'd think if they worried about liability of neutral handling and people swapping ends, they'd set up the M3 to understeer also?

Will this change your opinion of the car? www.youtube.com/watch?v=LFCB2GvKrVc

According to BMW here: http://www.bmwusa.com/Standard/Conte...fications.aspx
The 135i with manual tranny has 47.7% of it's weight up front, and 52.3% in the rear... This doesn't look to me like this chassis has an inherent predisposition to understeer. Am I right?

So, without driving the car for yourself (especially on a track), it's not fair to dismiss the car as though it's an understeering pig like so many of the nose-heavy fwd cars out there.

Now what seems obvious to a true car enthusiast is that BMW biased the car with skinnier tires up front to promote a more understeering character and help it stay within the driving means of your average Joe Leadfoot.

But this should be pretty easy to fix. Swap out the front 215 tires for 225 or even 235, and now you've improved traction up front... Or you can replace the small rear anti-roll bar for a slightly thicker one and again, you've counteracted the understeering condition...

The true beauty in this car lies in the short wheelbase & short overhangs, great weight distribution and yummy 6-piston brake calipers. Of course, the 300hp I6 & 6spd MT help it tremendously.... :biggrin:

The only concern I have about it so far are the reports of the engine's high oil temps (even for those with oil coolers according to owners' reports). I'm still trying to get additional information to answer this concern more definitively.

[Templedogg]

Originally Posted by Doolab

Will this change your opinion of the car? www.youtube.com/watch?v=LFCB2GvKrVc

According to BMW here: http://www.bmwusa.com/Standard/Conte...fications.aspx
The 135i with manual tranny has 47.7% of it's weight up front, and 52.3% in the rear... This doesn't look to me like this chassis has an inherent predisposition to understeer. Am I right?

So, without driving the car for yourself (especially on a track), it's not fair to dismiss the car as though it's an understeering pig like so many of the nose-heavy fwd cars out there.

Now what seems obvious to a true car enthusiast is that BMW biased the car with skinnier tires up front to promote a more understeering character and help it stay within the driving means of your average Joe Leadfoot.

But this should be pretty easy to fix. Swap out the front 215 tires for 225 or even 235, and now you've improved traction up front... Or you can replace the small rear anti-roll bar for a slightly thicker one and again, you've counteracted the understeering condition...

The true beauty in this car lies in the short wheelbase & short overhangs, great weight distribution and yummy 6-piston brake calipers. Of course, the 300hp I6 & 6spd MT help it tremendously.... :biggrin:

The only concern I have about it so far are the reports of the engine's high oil temps (even for those with oil coolers according to owners' reports). I'm still trying to get additional information to answer this concern more definitively.

Well said, great first post. Welcome to the forum.

[josh]

I hear you all. I just hate having to reverese-engineer a car that should have been set up right at the factory. True, I haven't driven a 135i, but reviews are unequivocaL about undesirable understeer, yet we don't hear anything remotely similar from M3 reviews. Nobody talks about having to mess with M3 swaybars.
I don't believe BMW didn't know how to set up the 135i neutral, or at least without this underseer that's been so objectionable to reviewers.
So the only thing that makes sense to me is they did it deliberately out of liability concerns. Somehow, the US public believes if you run off the reoad nose-first, it's your fault - if you swap ends and run off the road trunk first, it's because the car's defective.

The original question was really about why the M3 found a way around this (potential) liability problem, and the 135i didn't.

[Garrett]

Originally Posted by Doolab

Will this change your opinion of the car? www.youtube.com/watch?v=LFCB2GvKrVc

According to BMW here: http://www.bmwusa.com/Standard/Conte...fications.aspx
The 135i with manual tranny has 47.7% of it's weight up front, and 52.3% in the rear... This doesn't look to me like this chassis has an inherent predisposition to understeer. Am I right?

So, without driving the car for yourself (especially on a track), it's not fair to dismiss the car as though it's an understeering pig like so many of the nose-heavy fwd cars out there.

Now what seems obvious to a true car enthusiast is that BMW biased the car with skinnier tires up front to promote a more understeering character and help it stay within the driving means of your average Joe Leadfoot.

But this should be pretty easy to fix. Swap out the front 215 tires for 225 or even 235, and now you've improved traction up front... Or you can replace the small rear anti-roll bar for a slightly thicker one and again, you've counteracted the understeering condition...

The true beauty in this car lies in the short wheelbase & short overhangs, great weight distribution and yummy 6-piston brake calipers. Of course, the 300hp I6 & 6spd MT help it tremendously.... :biggrin:

The only concern I have about it so far are the reports of the engine's high oil temps (even for those with oil coolers according to owners' reports). I'm still trying to get additional information to answer this concern more definitively.

+10
:thumbup:

Now This^ guy gets it...!

[Garrett]

Originally Posted by Doolab

The only concern I have about it so far are the reports of the engine's high oil temps (even for those with oil coolers according to owners' reports). I'm still trying to get additional information to answer this concern more definitively.

BMW has already mentioned the higher engine temps in one of their BMW-TV video's they shoot several times a month. An engineer stated the engine DOES run hotter than previous BMWs because the engine runs more efficiently and cleaner. He mentioned BMW's Efficienct Dynamics as the leading force behind this.

Though even cars without an oil cooler run with no problems, there are several that have caused the car to go into "limp mode" protecting the engine before the oil gets too hot to cause dmg. Those cars would receive an Oil Cooler at dealer cost.

I have not heard a story yet envolving a car with an oil cooler going into "limp mode". As far as i can tell ALL 135i's come with an oil cooler!

So I fear... your fear is misplaced..!

[NOLEimit]

Originally Posted by Garrett

BMW has already mentioned the higher engine temps in one of their BMW-TV video's they shoot several times a month. An engineer stated the engine DOES run hotter than previous BMWs because the engine runs more efficiently and cleaner. He mentioned BMW's Efficienct Dynamics as the leading force behind this.

Though even cars without an oil cooler run with no problems, there are several that have caused the car to go into "limp mode" protecting the engine before the oil gets too hot to cause dmg. Those cars would receive an Oil Cooler at dealer cost.

I have not heard a story yet envolving a car with an oil cooler going into "limp mode". As far as i can tell ALL 135i's come with an oil cooler!

So I fear... your fear is misplaced..!

Great post! Also, there isn't a "standard" temperature range that all engines fall into. Some run hotter than others. The VW VR6 runs notoriously hot, from a normal engine perspective. However for the particular engine it is fine, and it is a very bullet proof engine.

[adc]

Originally Posted by Garrett

I have not heard a story yet envolving a car with an oil cooler going into "limp mode".

Where exactly were you listening? BMW Radio Channel 1?

Go to e90post and search, there have been documented instances. Last week at the DC auto show, I talked with the guys at Road Racing Technologies from VA. They are a highly respected race shop and they displayed a 335 all prepped for the One Lap of America.

The guy said they are taking a 2 prong approach to reducing oil temps in the 335: the use of an appropriate racing oil (Motul in their case, but I forgot to ask the weight - I'll call them up when the weather warms up again to find out) and a larger oil cooler.

Forgive me, but I'll trust an experienced hands-on racing shop a lot more than the BMW PR machine, or some soothing internet post. :iono:

[Doolab]

Originally Posted by Garrett

BMW has already mentioned the higher engine temps in one of their BMW-TV video's they shoot several times a month. An engineer stated the engine DOES run hotter than previous BMWs because the engine runs more efficiently and cleaner. He mentioned BMW's Efficienct Dynamics as the leading force behind this.

Though even cars without an oil cooler run with no problems, there are several that have caused the car to go into "limp mode" protecting the engine before the oil gets too hot to cause dmg. Those cars would receive an Oil Cooler at dealer cost.

I have not heard a story yet envolving a car with an oil cooler going into "limp mode". As far as i can tell ALL 135i's come with an oil cooler!

So I fear... your fear is misplaced..!

It's not fear, it's more like a concern... Especially since I'm seriously contemplating spending >40K on this car... And if you're like me, excited about this car, I invite you and everyone here to try to get some concrete evidence to dispell these concerns and not swallow the manufacturer's marketing / PR hype, hook, line, and sinker.

Now we know that higher temps = lower emissions. But also, higher temps = reduced durability/reliability and ultimately, shorter service life...

Plus, since I actually track race my cars, limp mode is not something I want to encounter while running around a race track...

So the other post about race shops preparing a 335i for race duty, and similar R&D by tuners/racers/owners and their upgrades/findings should be very telling and shed some light on this topic to either minimize our concerns or possibly offer viable solutions & upgrades...

[BMW135iCA]

think this pretty powerful car is one of the most accessible cars they sell, especially compared to an M3. There certainly will be more high school grad 135i gifts than M3 gifts.

High school grad gift, not bad if someone gets a 40k car for their high school grad gift. Personally I do not think you will see as many teenagers driving this car as you think. i definately think you will see alot of young guys in their 20's or 30's though.

Chris

[adc]

Originally Posted by BMW135iCA

High school grad gift, not bad if someone gets a 40k car for their high school grad gift. Personally I do not think you will see as many teenagers driving this car as you think. i definately think you will see alot of young guys in their 20's or 30's though.

Chris

There will be some, and you will see them all flock on these internet forums boasting about their highway races and cool 20" rims. Check e90post if you don't believe me...

[MrRoboto]

Originally Posted by josh

Why is it that BMW saw fit to dial in undesteer into the 135, and yet leave the M3 neutral? You'd think if they worried about liability of neutral handling and people swapping ends, they'd set up the M3 to understeer also?

Safety

[mdynamics]

So far what I have heard from people who driven the 135i they loved it but the common problems still exist no matter how much we deny them.

1- The handling:
The car handles great but with a tendency to understeer (you are right Doolab “it's NOT an understeering pig”) and avoid oversteer as much as possible and when it does oversteer it becomes unstable and more of a hassle to control rather than using oversteer to assist handling. But let’s face it, we are all or the majority of us are looking at the 135i as a performance car. I’m looking for the E30 M3 in the 135i (especially the 135tii!) since the e92 M3 has grew in size and cost.

As a response to the video you have showed of youtube for the 135i yes it was oversteering there but did you mension that it took “sweetnl” the driver of the car 3 attempts to get the car to oversteer as you saw, and one of the attempts the car almost skid of the road. Take in to consideration that this was in wet conditions.
Here is another driver trying to get the car to drift.

I’m not certain if the driver is skilled but an M3 will never perform like that even if the driver was that bad. The car gets unstable when you oversteer it which due to the 4” shorter wheelbase than the 3 series cope and narrower by 3” and is higher than the coupe which doesn’t help the center of gravity. And the ELSD doesn’t help either a true LSD would of made things a lot better. I know we are not looking at an “M” level car but it’s on the level of the 335i coupe which is .7s faster to 60 and handles much better without LSD.

335i beating the S5

2- The turbos:
The turbos will last beyond the warranty expiration date without doubt. But to what cost? Heating up the engine for over 50K miles under “efficient dynamics” is not going to make the engine last over 100K. That’s besides the fact the turbos will never last beyond 100K, and with 2 turbos in there that’s $10K just to replace for a $40K car, and turbos do fail its nature of high heat on materials.

3- The Airodynamics:
Although the car looks soo good, however, the semi boxy shape it adapted from the 2002 (which I love so much) isn’t a plus since its not helping with the drag that is caused by the car. I believe in the next 3 years bmw will have a face lift on the 1 series since it hasn’t changed from the European hatchback version, which has been out for a while.

4- The price:
Most of us want the 135i cuz it’s a smaller version 3 series and some of us want it cuz its cheaper, and both perhaps. But the majority of us idealize it as a performance car when it isn’t, so my question is it worth the 40k? I know it’s not an M3, but it is not as equal as a 3 series coupe either. And the difference is 5K between the 3 series coupe and the 1 series.

I may have came strongly opposing the 135i, but don’t get me wrong I want to buy one. I have always been a fan of the M3 and still am but the 135i open my eyes at smaller car than seemed to me like the younger M3s I adored. So my point is I’m trying to point out the only flaws that are in the 135i to justify buying it over the all mighty e92 M3 (more expensive), the e92 335i (5K more expensive), or the older but a beast e46 M3 (which one could get almost new for 40k and more power 333hp and much better handling than the 135i but older now)

[hellrotm]

Originally Posted by BMW135iCA

High school grad gift, not bad if someone gets a 40k car for their high school grad gift. Personally I do not think you will see as many teenagers driving this car as you think. i definately think you will see alot of young guys in their 20's or 30's though.

Chris

It depends were you live, here in Orange County kids getting a BMW at 16 yrs old is not rare at all, its common place.

[imported_merlot]

Originally Posted by josh

Somehow, the US public believes if you run off the reoad nose-first, it's your fault - if you swap ends and run off the road trunk first, it's because the car's defective.

The reason cars understeer from the factory is because most drivers will stab the brakes if the car looses control. If the car has a tendncy to be neutral or oversteer, braking will worsen the effect since it will unload the rear end even more. With understeer, braking will shift the weight to the front where traction is needed.

It's pretty simple. :wink:

[sethchan]

Originally Posted by merlot

The reason cars understeer from the factory is because most drivers will stab the brakes if the car looses control. If the car has a tendncy to be neutral or oversteer, braking will worsen the effect since it will unload the rear end even more. With understeer, braking will shift the weight to the front where traction is needed.

It's pretty simple. :wink:

I didn't realize that was the reasoning. Makes sense to me. And then drivers who know what they are doing can take out the understeer themselves pretty easily.

[pumaknight]

I know this post will probably draw a few reactions, but here goes!

A road car is specifically designed to understeer for one reason - because it is designed to drive on roads!! Key word there - roads - not tracks!

For 99.99% of the time, you should not be driving at anywhere near the speed that will tell you whether a car has under or over steer characteristics. for the remaining 0.01% of the time, you want the car to react predictably when you find yourself in a potentially out of contorl situation induced by circumstances outside your control - and for the nearly 100% of the population that is understeer.

Oversteer control requires skilled use of the steering, throttle an brake, a skill which nigh on 100% of the population do not poses. I think it is safe to say that if a car oversteers for most it is enough to make people panic and hit the brake, furhter exaberating the loss of control.

if you are lucky enough to poses these skills, you should still not be using them on the road - drive within the limits of the road and other road users, not you or your car I was once told. I can control a car at speed, and have competively raced, but i still prefer my road car to have slight understeer.

Manufacturers know this and deliberately design in understeer, because research shows that brakes are hit in 99.99% of out of contorl situations, so understeer is far easier to manage.

Over here in the UK in the 90's, M3s were known as the Death Car by police - most of the calls that were received by the police involving the M3 were fatalities - and for good reason - it over steered like a pig, wet or dry.

You cannot say that of the new breed of M3s and thank god for that.

Well, over to you: