[StanDiego]

Originally Posted by BEAR-AvHistory

Guess I don't see buying the Z4 as a "rational" decision in the first place. A 2 seat car is want not a need.

True, but the OP has already made the "irrational" decision to join our motley crew and is trying to rationalize the choice between the s30i and M40i. Given that a Z4 is a want not a need, he's trying to decide between the two and has done some research. Asking us for a rational opinion may be a stretch but that's what he's looking for.

[spbonzo]

I test drove all three models in 2019 (20i, 30i and M40) and decided to go with the 30i.

The M40 definitely sounded better but the 30i felt nicer to drive and didn't feel a great deal slower - especially with the top down.

The M40 wasn't 'special enough' to warrant the price difference and the heavier fuel consumption.

[LoneStar]

Originally Posted by spbonzo

I test drove all three models in 2019 (20i, 30i and M40) and decided to go with the 30i.

The M40 definitely sounded better but the 30i felt nicer to drive and didn't feel a great deal slower - especially with the top down.

The M40 wasn't 'special enough' to warrant the price difference and the heavier fuel consumption.

which suspension did you chose?

[Amadeo]

Originally Posted by spbonzo

I test drove all three models in 2019 (20i, 30i and M40) and decided to go with the 30i.

The M40 definitely sounded better but the 30i felt nicer to drive and didn't feel a great deal slower - especially with the top down.

The M40 wasn't 'special enough' to warrant the price difference and the heavier fuel consumption.

Totally agree with you.
Plus since the 30i is much better weight balanced to take curbs with more grip, I got the 30(75 to 90 kg on top of front axle for the 40 and 75 to 90 kg less and placed behind and lower to the front axle for the 30)
Of course the 40 will accelerate faster on strait lines but on a curvy track, I think the 30 will be faster.
I drove the 40 and the 30 in a curvy track and it did feel like the 40 was losing grip in the back first like most rear wheel drives and the 30 was losing grip on both back and front wheels at the same time. The 30 felt more like a 4 wheel drive.

[ebirotedu]

Per FastestLaps.com:

G29 Z4 M40i (euro spec):
Autozeitung test track lap time: 1:39:00

G29 Z4 M40i (US spec):
Motortrend Figure-8 lap time: 00:24:00

G29 Z4 30i
Autozeitung test track lap time: 1:40:30
Motortrend Figure-8 lap time: 00:24:50

Originally Posted by Amadeo

Totally agree with you.
Plus since the 30i is much better weight balanced to take curbs with more grip, I got the 30(75 to 90 kg on top of front axle for the 40 and 75 to 90 kg less and placed behind and lower to the front axle for the 30)
Of course the 40 will accelerate faster on strait lines but on a curvy track, I think the 30 will be faster.
I drove the 40 and the 30 in a curvy track and it did feel like the 40 was losing grip in the back first like most rear wheel drives and the 30 was losing grip on both back and front wheels at the same time. The 30 felt more like a 4 wheel drive.

[spbonzo]

Originally Posted by Amadeo

Totally agree with you.
Plus since the 30i is much better weight balanced to take curbs with more grip, I got the 30(75 to 90 kg on top of front axle for the 40 and 75 to 90 kg less and placed behind and lower to the front axle for the 30)
Of course the 40 will accelerate faster on strait lines but on a curvy track, I think the 30 will be faster.
I drove the 40 and the 30 in a curvy track and it did feel like the 40 was losing grip in the back first like most rear wheel drives and the 30 was losing grip on both back and front wheels at the same time. The 30 felt more like a 4 wheel drive.

I can safely say that on the one occasion I drove my 30i in an inch of snow it definitely didn't feel like a 4WD

[DPelletier]

Originally Posted by ebirotedu

Per FastestLaps.com:

G29 Z4 M40i (euro spec):
Autozeitung test track lap time: 1:39:00

G29 Z4 M40i (US spec):
Motortrend Figure-8 lap time: 00:24:00

G29 Z4 30i
Autozeitung test track lap time: 1:40:30
Motortrend Figure-8 lap time: 00:24:50

Yep; if you want the 30i because it's cheaper, gets better gas mileage, helps save the planet, etc. etc. then fine but if it's performance you are looking at the 30i doesn't have a "much" better weight distribution and it isn't enough to make up the difference in power in any speed contest; straight lines or curvy ones.

Dave

[BEAR-AvHistory]

Think this is a good example of how well the M40i runs compared to other cars. Christian Gebhardt has driven many of the cars listed to their best lap times

https://youtu.be/v-vKs-T0Oa0

Thing to remember is is the Euro version with 335BHP not the 382BHP US Spec car.

List shows its in pretty fast company

190. Caterham R500 1.8L K Series Robert Nearn 7:55.00

191. Mercedes-Benz E 63 AMG S Horst von Saurma 7:55.00

192. Renault Megane RS Trophy R Christian Gebhardt 7:55.00

193. Ferrari F430 unknown 7:55.00 490 / 1498

194. BMW M5 (F10) unknown 7:55.00 560 / 1905

195. BMW Z4 M40i (G29) Christian Gebhardt 7:55.41 340 / 1582

196. Porsche 911 Turbo (996) unknown 7:56.00 420 / 1573

197. Porsche Panamera Turbo Walter Rohrl 7:56.00 500 / 1

198. Chevrolet Corvette C5 Z06 Dave Hill 7:56.00 411 / 1418

199. Ferrari California GT unknown 7:56.00 460 / 1787

200. Panamera Sport Chrono Turbo Walter Rohrl 7:56.00 5

[LoneStar]

it's not the performance in daily use, it's the feeling. Track times? This is out of my scope.

The one is more settled and feels heavier, just more solid. My A6 Quattro also feels very solid.

Do I want it in a roadster?

The other, especially with the smaller 18" 225/255 and M suspension, drives more agile with better feedback. Comparing side by side this 30i was a more involving driving experience.

So my impressions from the last run.

[LoneStar]

ok, the decision is getting closer, arguments for the 30i are in front at this time.

The availability of the lsd and the thinner wheels makes sense at all, as long you are not on the track. You get more lateral movement and more feedback from the road.

After the M40i I drive a 220i and M240i side by side, and the R6 feels far heavier than only 140 lbs. The M240i makes really fun, but I am missing a light and nimble car, it is the same like the M40i, it felt too heavy and settled for my driving profile. If I would drive more highways the decision would be easy, but looking forward what kind of driving I expect the next years, I would choose the 30i.

At least today;-)

[_icarus]

Just go try to test drive one, we can't decide for you whether the weight loss is relevant enough. I personally couldn't imagine the Z4 without the B58, but that's just me.

A few corrections about weight and weight distribution though:
1. the M40i's engine is still behind the front axle, not on it. It barely touches the front axle, and they deliberately moved components such as the timing chain and related hardware to the back of the engine for weight distribution purposes. As a result the engine's gonna be heavier at the back.
2. there's absolutely no way that 60-70kg difference between the M40i and 30i is happening at the front of the car. The 3.0 variant gets much more than just a larger engine - you have bigger alloys, bigger brakes, adaptive suspension and an eLSD to worry about. I haven't managed to find the weight of the B48 engine, but I'd be surprised if it were more than maybe 30 kg lighter than the B58.

I personally think you'd miss the power and the sound, but hey I don't know your priorities.

[BEAR-AvHistory]

Originally Posted by LoneStar

ok, the decision is getting closer, arguments for the 30i are in front at this time.

The availability of the lsd and the thinner wheels makes sense at all, as long you are not on the track. You get more lateral movement and more feedback from the road.

After the M40i I drive a 220i and M240i side by side, and the R6 feels far heavier than only 140 lbs. The M240i makes really fun, but I am missing a light and nimble car, it is the same like the M40i, it felt too heavy and settled for my driving profile. If I would drive more highways the decision would be easy, but looking forward what kind of driving I expect the next years, I would choose the 30i.

At least today;-)

Think you should drive what you want, like and can afford. Its your money not ours.

Personally I think "feel" is way over rated in these conversations & a blindfold test could prove that. Its real racy talk but then there is the reality of the clock.

Another thing on feel if you want to understand what feel really is & not an engineering departments take through electronics & hydraulics take a ride in a car like my Cobra.

The steering wheel is connected directly to the wheels, the brake pedal directly to the calipers & the transmission gears directly to the shift lever. The "feel" is nothing like any thing I have driven since my 67 Stingray which was also totally manual.

One group is talking "feel" another is talking actual performance. If a M40i with the lower powered B58 @ 340BHP can out run on the very difficult Nurburgring cars like the Ferrari, Porsche, Corvette etc there is not much more to say about its ability to carry its weight & handle.

Compared to smaller cars I have owned 718S Boxster PGK, 911 Carrera 4S 6MT and a number of Corvettes the Z4 stands up very well. Personally have no issues at all about the Z4 M40i driving experience outside of a loss of traction during a standing start at WOT.

Also think obsessing over some minor 170lb weight differential in what is a street car is a joke. A full tank of gas is about 78lb by itself. A fat guy with a full tank in a 30 will weigh about as much as a lighter guy with 1/8 tank in a 40. Put a passenger in the 30 & it will weigh more.

These are not class or challenge series race cars.

Since the 2 series came up though this was interesting

BMW Z4 M40i (G29) 7:55.41 - BMW M2 (F87) 7:58.00 - BMW M240i XDrive 7:58.59

[R3R]

For 2023, the weight difference between the M40i and 30i is 229 pds or 104 kg, according to bmwusa.com. Ouch

I have a Z4 on order and have also been torn between the M40i and 30i. Unfortunately I don't have the opportunity to test drive these cars (they're rarer than unicorns in VT), so I have to lean on Z4 or Supra reviews and opinions. It sounds like the choice is between better power and sound with the M40i and better handling with the 30i.

The reviews where the handling of the 30i or 2.0 Supra shined, were based on cars with magnetic dampers and eLSD, which fortunately can be optioned on the 30i here in the USA.

I have ended up ordering the M40i as I've been impressed by the B58-ZF8 combo on an X3 and am afraid I might miss it more than better handling with the B48. That and the fact that lumbar support on Sensatec seats is not tied to parking sensors/assistant on the M40i. Those clean bumpers do look nicer.

[LoneStar]

Nürburgring is not my daily driving profile and amazing tracktimes on one hand could also mean less involving driving on common roads because the limits are so far. The setup is just too „good“ for it.

The limits of the M240i are far closer but you know what? It is really fun to drive. But with 1750 kg real weigth just to heavy for a tiny fun car.

So I had already a M40i and was not convinced. One big complaint was the heavy and unresponsive steering out of the center the other one the too settled drive feeling. Unfortunately the 30i steering is not better at all, miles away from the variable steering of the M240i but coding it ligther may enhance it significantly (I did the same with an E60 once and it was very well).

But the car feels ligther, put 70kg of concrete in the front of an 30i and you know what I mean. It is definitly not less, with the same equippment it is around that, with standard it is far more than 100kg. The turbo R6 is a heavy one, not comparable to the light N52 3.0 engine which I liked very much.

So I was happy owning a M40i and know let‘s try anything else;-)

[_icarus]

Originally Posted by LoneStar

But the car feels ligther, put 70kg of concrete in the front of an 30i and you know what I mean.

Like I said before, there's no way the B58 engine is 70kg heavier than the B48. Since the B58 is 139 kg that would mean the B48 is 69 kg, which is impossible.

For reference, VAG's 2.0 TSI engine weighs 130kg while the 1.2 TSI is 97kg. Ford's 1.0 Ecoboost is 97kg as well.
69kg for a turbocharged 2.0 engine is unrealistic.

[LoneStar]

Originally Posted by _icarus

Like I said before, there's no way the B58 engine is 70kg heavier than the B48. Since the B58 is 139 kg that would mean the B48 is 69 kg, which is impossible.

For reference, VAG's 2.0 TSI engine weighs 130kg while the 1.2 TSI is 97kg. Ford's 1.0 Ecoboost is 97kg as well.
69kg for a turbocharged 2.0 engine is unrealistic.

base engine + aggregates and other components intake/outtake and so on. 2 cylinders more needs larger and heavier components.

As I said, I drive a 220i and M240i convertible side by side and measured weight is around 80kg more (M240i has sport brakes).

Just checked it:

220i convertible, 2019, M exterieur: 1681 kg
M240i convertible, 2021: 1754 kg, further extras: comfort access, foldable mirrors, Harman Kardon, that's it

From a driving perspective, the car feels far heavier than only this difference, especially in the front, without any doubt. Handling is not comparable.

While accelerating, this truth is the other way around;-)

[DavesZupra4]

Originally Posted by spbonzo

I test drove all three models in 2019 (20i, 30i and M40) and decided to go with the 30i.

The M40 definitely sounded better but the 30i felt nicer to drive and didn't feel a great deal slower - especially with the top down.

The M40 wasn't 'special enough' to warrant the price difference and the heavier fuel consumption.

How old are you?

Do you ever go on curvy canyon roads/back roads if no canyon or track it?

I had a 2015 m235i for 3 years and then got rid of it and just stopped following or knowing about any bmw models or any car for 3 years while I had some life issues to fix


When I finally decided to get one I wanted to try out taking over someone's lease of a 2020-21 m240i. I was scrolling the page skipping F80 M4s as I know how they drive and randomly found a z4 M40i. Didn't even know about it but I was stunned at how it looked in black and red interior. Went to the guy to take a look and told him I want it without test driving but he insisted. Holy sheet I knew the previous z4s just didn't drive that well, but the sound and handling of the new m40i and the premium looks and interior blew me away. It obviously handled far better to me than the last gen m4 did, and it even did a better lap than the M2 comp.(At this point I didn't even know this fact nor the fact the z4 and supra were a joint Toyota bmw collab meaning Toyota would help make it better handling/feeling).

So I took it over and gave over the least to someone and bought a alpine white magma red z4.

IT is far far superior to my m235i, the i8(in power and handling), and the f80/82 m3/4 and the m2.

The supra sets awesome lap times beating out all the m cars except the new gen. But I prefer the classic and gorgeous look of the z4 vs supras aggressive look. They both drive and handle the same yet feel different which confuses some into thinking one is better than the other but they're the same.

A simple tune on US spec m40i pushes it to 420whp on stage 1. I think I'm around 430whp and 470ish torque from butt dyno and statistics on similar tunes that I'm some percentages up and down by

[LoneStar]

I have a lot of curvy canyon roads here, but outside laptimes (need still my license). That is the point. Just "normally" driven, well fitted sports cars tend to unerchallenge.

[_icarus]

Originally Posted by LoneStar

base engine + aggregates and other components intake/outtake and so on. 2 cylinders more needs larger and heavier components.

As I said, I drive a 220i and M240i convertible side by side and measured weight is around 80kg more (M240i has sport brakes).

Just checked it:

220i convertible, 2019, M exterieur: 1681 kg
M240i convertible, 2021: 1754 kg, further extras: comfort access, foldable mirrors, Harman Kardon, that's it

From a driving perspective, the car feels far heavier than only this difference, especially in the front, without any doubt. Handling is not comparable.

While accelerating, this truth is the other way around;-)

There absolutely will be a difference in handling, I'm not contradicting the difference you feel.
I'm only saying you're incorrectly assuming that the entire weight difference is going straight to the front of the car. Out of that 73kg difference you have between the 220i and 240i the engine maybe accounts for 30kg, the rest likely has to do with the other M Performance goodies the car gets plus the options you mentioned.
You're not feeling a 73 kg deficit on the front of the car, you're feeling less.


Also, about aggregates and other components - it's the other way around. A larger engine (given the same piston arrangement) will be proportionally more weight-efficient per unit of CC because while some components like the block may be proportionally heavier (not a given though), other components will be the same (for example the alternator doesn't have to be bigger) or maybe even slightly lighter (engine may have a smaller turbo).
That's why in the example I gave earlier I mentioned the VAG 2.0 TSI engine weighing in at 130kg while the much smaller 1.2 TSI is 97kg. The 2.0 engine is 66% larger but only 34% heavier.

[BEAR-AvHistory]

Originally Posted by LoneStar

I have a lot of curvy canyon roads here, but outside laptimes (need still my license). That is the point. Just "normally" driven, well fitted sports cars tend to unerchallenge.

Reality is even at normal speeds the car that will corner better at high speeds will be easier to drive quickly as the entire package will not be working as hard Additionally the total spread of weight & weight distribution is not like plumping a 154lbs on the front of the M30 to show it would handle differently as you can't get one that way.

FWIW we have loads of two lane Moonshine roads along with the The Dragon (a.k.a Tail of the Dragon ®) is famous for it's 318 curves in 11 miles; it's America's number one motorcycle and sports car road. The Cherohala Skyway, designated a National Scenic Byway, is essentially a supersized version of the Dragon. Together they make a loop through the Great Smokey Mountains.

Weights by track scales as tested by Car & Driver.

BMW Z4 30i

Brakes 0-70 146ft (-2ft)
Skidpad 1.00G (+02G)
Weight 3470lbs (-65lbs)
Front 50.9 Rear 49.5 (-47lbs)

BMW Z4 M40i

Brakes 0-70 148ft
Skidpad 1.02G
Weight 3535lbs
Front 51.3 Rear 48.7

Using the 2323 numbers off the BMW web site for the cars M40 spec sheet the spread of 229lbs would be suspect as the S30 lost weight from the C&D test car while the M40 gained weight.

We don't know specifically how these weights are generated so its best to use a common test that weighs all the cars the same way.

Bring it to the track & put them on a scale as tested to get an apples to apples comparison.

NOTE: SavageGeese put an S30 on a corner weight scale & got 3392lbs for it along with different F/R weight ratios. Think this proves the point about common testing for weigh comparisons.

[LoneStar]

the weight difference of the complete engine is is around 50-60 kg and most of it is in the front, even before the axle (additional cooler and so on). There is no doubt about it, it is the same like the 3 or 5series with 4 or 6 pot, you feel it always - I had every variation of it.

And yes, you don't need to compare apples with apples, because it can't be, I do the maths:

30i
smaller brakes -15 kg unsprung mass -> 105 kg less sprung mass
smaller wheels (225/255 instead of 255/275) - 12 kg unsprung mass -> 85 kg less sprung mass
with this equippment you get curb weight -70 to 80 kg -> I checked a lot of tested 30i and 40i on scales (AMS in Germany and the CoC paper in EU states the real weight with specific equippment).

You feel the difference in curvy roads very well (though I had only 2 hours for comparison). One had sport brakes and 18" small alloys, the other one standard brakes and 19" wide alloys. I would even go for 18" small wheels and standard brakes. Best of both worlds, because sport brakes with small tyres makes no sense at all other than blue calipers.

The comparision is apples and pears and that's just OK, just because you don't get fitted the M40i like a 30i and it would make no sense to fit the R6 with 225 tyres in the front. That is what I try to point out.

The question is what you want and I know for sure I would miss the incredible engine and sound in a convertible. But how long? After the first or second curve?

It depends on the driving profile. I'm still unsure, taking the dying R6 and hit the silly greens in their stupid mind before buying a BEV made with coal power and charged with coal power?

HAHA, that is really insane and a big pro for the marvelous 3l at all

I think about it

[Horseman]

I think this has been stated before, but I really doubt your decision between the two trims is going to be the weight difference, tire difference or anything else that we're getting into crazy amounts of detail.

Really comes down to... if you can afford the extra on an M40i, why wouldn't you? Is the 30i enough? YES. Get the looks, good amount of power, for less. If you want to save 10-20k, go with the 30i.

If you want the ///M badge, more power, better exhaust and more options go with the M40i. I just don't think that you'll feel an incredible amount of difference between the two trims in terms of weight distribution and handling until you put it on the track.