[Joeshin87]

Does anyone know if its possible to swap the B58 for a S58 engine with the G29?

[SpeedyATL]

I'd be interested to see this, but it'd be overkill IMO.

My M40 runs very strong with zero want for additional pace. I came very close to choosing a '22 M4CV but decided that the Z4 was just more fun and damn near as fast due to reduced weight.

And without 4WD, not sure you would get much more than a stronger pull above 60mph and I know my license would not appreciate that.

[jdhiro]

I'd love to see an S58 in the Z4, but I don't think I'd go out of my way to try that swap myself.

[Westside Guy]

If it isn't broke don't fix it!

[jcolman]

If more power is what you want a chip remap and down pipe swap will get you over 450hp. A bigger turbo will take you to 500-600 hp which at that point you're probably testing the limits of the drive train.

[BEAR-AvHistory]

No point. Without AWD & more tire it will all be wasted. The base M4 473BMP with RWD & heavier that the Z4 can't put the power to the ground.

An AWD M440 will give it a good in a 1/4 mile race.

M4 RWD

C/D TEST RESULTS
60 mph: 3.8 sec
100 mph: 8.3 sec
160 mph: 24.6 sec
1/4 mile: 12.0 sec @ 121 mph
Results above omit 1-ft rollout of 0.2 sec.
Rolling start, 5–60 mph: 4.7 sec
Top gear, 30–50 mph: 7.6 sec
Top gear, 50–70 mph: 6.4 sec
Top speed (mfr's claim): 180 mph
Braking, 70–0 mph: 146 ft
Braking, 100–0 mph: 291 ft
Roadholding, 300-ft-dia skidpad: 1.03 g

M440 AWD

C/D TEST RESULTS
60 mph: 3.9 sec
100 mph: 9.9 sec
1/4-Mile: 12.4 sec @ 111 mph
Results above omit 1-ft rollout of 0.3 sec.
Rolling Start, 5–60 mph: 4.8 sec
Top Gear, 30–50 mph: 2.5 sec
Top Gear, 50–70 mph: 3.2 sec
Top Speed (gov ltd): 128 mph
Braking, 70–0 mph: 148 ft
Braking, 100–0 mph: 295 ft
Roadholding, 300-ft Skidpad: 0.94 g

[jdhiro]

Originally Posted by BEAR-AvHistory

No point. Without AWD & more tire it will all be wasted. The base M4 473BMP with RWD & heavier that the Z4 can't put the power to the ground.

The Z4 is only about 250lb lighter than the M2 w/ S55. They could detune the S58 a bit or even put on some wider tires.

While more power is fun, the main reason I want an S engine is the way it delivers power. It's an engine that begs to be driven harder, at higher RPMs, and delivers a more direct feeling. It's just more appropriate for a drivers car IMO.

[BEAR-AvHistory]

Originally Posted by jdhiro

The Z4 is only about 250lb lighter than the M2 w/ S55. They could detune the S58 a bit or even put on some wider tires.

While more power is fun, the main reason I want an S engine is the way it delivers power. It's an engine that begs to be driven harder, at higher RPMs, and delivers a more direct feeling. It's just more appropriate for a drivers car IMO.

Agree on more power can be fun and the weight spread but the M2 is still hamstrung with RWD & small hard tires as delivered. Just believe an S58 even in base power mode is overkill for a RWD car. BMW pulls power by restricting 1st gear in the RWD 8ZF M4 applications. Also the M3/4 S58 traction/power management packages are quite a bit more elaborate than the B58 versions.

BMW says this in their configuration:

2023
M2 Coupe
3.0-liter BMW TwinPower Turbo inline 6-cylinder
Rear-wheel drive
453 HP
24 MPG
3.9 sec 0-60 MPH

2023
M240i xDrive Coupe
3.0-liter BMW TwinPower Turbo inline 6-cylinder
xDrive, intelligent all-wheel drive
382 HP
32 MPG
4.1 sec 0-60 MPH

The M2 is optimized for track day performance where rolling acceleration is important as opposed to street acceleration where bottom end is important.

Personal opinion formed by driving a car that can't go to WOT at less than half way through 3rd gear & maintain traction on 315's @ 100 treadware road course tires.

Also at the current power/tire/drive setup my stock Z4 will slip tires in first & 1/2 shift if its just punched. It will take more power, with a managed launch, but not a great deal before it becomes non effective.

Our Z4's pretty much hit the sweet spot for a RWD street package

2023
Z4 M40i
3.0-liter BMW M TwinPower Turbo inline 6-cylinder
Rear-Wheel Drive
382 HP
31 MPG
3.9 sec 0-60 MPH

Think a basic JB-4 package with softer 285 tires, if they fit, would be a good way to go compared to an M2 if you were not doing track days.

Have fresh PS4S tires added when the car was still on lease. Will possibly do a JB-4 type mod if I can fit better tires after the Michelins wear out. Will not go the full bolt on route.

[Bimmerfun82]

Originally Posted by BEAR-AvHistory

Our Z4's pretty much hit the sweet spot for a RWD street package

2023 Z4 M40i
3.0-liter BMW M TwinPower Turbo inline 6-cylinder
Rear-Wheel Drive
382 HP
31 MPG
3.9 sec 0-60 MPH

Thanks for doing this write up. I would add that my M3 competition x-drive was really a tough car to enjoy on the street at legal speeds... even in the mountains the car was so brutally fast at higher rpm's with the turbos just pulling so fast, almost not enjoyable (the weight is a real problem, as is the long wheelbase)... here's what I experienced and the data is from the M drive analyzer:

2023 M3 Comp X Drive, 3.0 liter S58 engine - 503 HP, 479 ft-lb Torque
22 MPG highway
15 MPG city
16.8 MPG average over 9000 miles
0-60 times:
3.1s with LC
3.7s without LC

The other observation I've had with the Z4 v M3 (B58 v S58) is the torque max comes much earlier in the band (1700 v 2750, I think?) ... so it's more responsive, less insane for the street...enjoyable throughout the rpm range....the B58 has a higher compression ratio, which makes it feel more NA

Originally Posted by jdhiro

The Z4 is only about 250lb lighter than the M2 w/ S55. They could detune the S58 a bit or even put on some wider tires.

While more power is fun, the main reason I want an S engine is the way it delivers power. It's an engine that begs to be driven harder, at higher RPMs, and delivers a more direct feeling. It's just more appropriate for a drivers car IMO.

Your best bet is going with the M2 because the chassis, brakes, and drivetrain can handle the additional power. But I really love the B58 in the Z4 - are you comparing this setup or X3M40i? I feel the X3 weight makes the car behave differently plus you have the additional weight of the battery which assists as a mild hybrid... I really enjoy the higher RPM range on the Z...

[BEAR-AvHistory]

Originally Posted by Bimmerfun82

Thanks for doing this write up. I would add that my M3 competition x-drive was really a tough car to enjoy on the street at legal speeds... here's what I experienced and the data is from the M drive analyzer:

2023 M3 Comp X Drive, 3.0 liter S58 engine - 503 HP, 479 ft-lb Torque
22 MPG highway
15 MPG city
16.8 MPG average over 9000 miles
0-60 times:
3.1s with LC
3.7s without LC

The other observation I've had with the Z4 v M3 (B58 v S58) is the torque max comes much earlier in the band (1700 v 2750, I think?) ... so it's more responsive, less insane for the street....

Yeah, Published BMW & C&D numbers as they are pretty consistent against each other.

Have done short some Dragy runs now that it warming up & they show pretty much the same thing.

Best with the Z4 so far is roll out 3.72 true 3.93. Have not gotten a clean run with the M4C yet & its back to cold/rain today. Expect it being a convertible it will be a bit off the published numbers.

With M4C you can feel a slight hesitation on launch then if you don't have your head back it can bounce you off the head rest. On the same section of pavement the Z4 M40 builds quicker & smoother for the first few feet, all most no lag, then gets over run by the M4C power.

[Bimmerfun82]

Originally Posted by BEAR-AvHistory

Best with the Z4 so far is roll out 3.72 true 3.93. Have not gotten a clean run with the M4C yet & its back to cold/rain today.

That's blisteringly fast for a roadster by any historical standard...

... the higher end of the range is super fun, too, imho

[BEAR-AvHistory]

Originally Posted by Bimmerfun82

That's blisteringly fast for a roadster by any historical standard...

... the higher end of the range is super fun, too, imho

Was a perfect run on the second of this month. NC sun heated the pavement while it was in the 60's ambient & had a bit of E85 in the mix.

Prior best was rollout 3.99 true 4.28 straight 93 octane

Was trying to see if you got any boost with E85 without a tune. Looks like there is a little bit of overhead in the factory tune for more octane.

First encountered this when Beta testing JB-4 tunes for the new 2011 335is 7DCT. The head room was about to 95 octane. After that nothing.

Was interesting the car on a DynoJet did 319/321WHP against an advertised 320BHP. Standard 335 coupe was advertised at 300BHP.

[Bimmerfun82]

Originally Posted by BEAR-AvHistory

Was a perfect run on the second of this month. NC sun heated the pavement while it was in the 60's ambient & had a bit of E85 in the mix.

Prior best was rollout 3.99 true 4.28 straight 93 octane

Was trying to see if you got any boost with E85 without a tune. Looks like there is a little bit of overhead in the factory tune for more octane.

First encountered this when Beta testing JB-4 tunes for the new 2011 335is 7DCT. The head room was about to 95 octane. After that nothing.

Was interesting the car on a DynoJet did 319/321WHP against an advertised 320BHP. Standard 335 coupe was advertised at 300BHP.

Well, 4 flat is great too. My car is broken in now, and I plan to stretch its legs a little... not so much in 0-60 or 1/4 mile times as throwing the go pro on for some mountain runs!

[mjposner]

You can easily tune the B58 for more power and a custom tuner can tweak the tune to more closely match the S58 power delivery. Only reason to do a swap is if you have a toast B58 and an S58 handy. Should fit with some mods.

Intake, tune, exhaust and the right tires and the G29 will beat the M2. Plus you can get a tan...

[BEAR-AvHistory]

Originally Posted by Bimmerfun82

Well, 4 flat is great too. My car is broken in now, and I plan to stretch its legs a little... not so much in 0-60 or 1/4 mile times as throwing the go pro on for some mountain runs!

Have a camara sitting in a box for a year. Bought it for a roll bar mount on the Cobra. Was doing a rebuild on the car & forgot about it. Your post reminded me of it. Will see about installing it this week.

Most of my fun driving is along local two lane former moonshine roads twisty, hilly but not mountainous.

For mountain driving we have to go to the NC/Tenn border. Some of our groups do the 120 mile Tail of the Dragon/Cherohala Loop twice a year. Usually early fall & late spring before the tourist season kicks off.