Ownership Cost of Z4M vs 3.0si

[HEY32G]

Okay, I feel like I've asked way too many questions of you guys, but if I could ask just one more.

In reality, how much more expensive is an M to own? This will be my daily driver, but I work at home and there are days I don't even drive and I also live in a small town, so I'm never stuck in traffic. Also, I have my wife's car to drive at times. I'm not concerned about fuel costs over five years or that type expense. I'm more concerned about maintenance and repairs. Also, I plan to keep the car for a very long time.

My fear with the 3.0si is that I may eventually want more power. Although, I will never track or modify either car.

Plus, I have owned a lot of sports cars, and I like a fun car, but I'm not a wild man.

Thanks.

[SD ///M4]

Can you do your own maintenance? Things like more-frequent oil changes (at least every 5,000 miles or no more than 1 year) and brake pad and rotor replacement can add up. Valve adjustment every ~30,000 miles can cost > $1,000 if you can't do it yourself, a couple of hundred for parts if you can (not required on a non-M Z4).

People have had problems with the the rod bearings in the S54 engine and this job runs into the thousands. Other people have replaced engine and transmission bushings costing hundreds.

So yes, the real-world cost of maintaining a Z4 M will be more expensive than a Z4 3.0si. Other people with more experience than I do maintaining a Z4 M may have other things to consider.

[donoman]

I've had my Z4MC for about a year and have been driving Z4 2.5i's for about 2 years. I know it's not a 3.0si but I figured I'd chime in.

I think the general reliability of both cars is similar, with the main difference being the motor, brakes and suspension. Tires on the 2.5i were cheaper than the M's larger 18" tires. Brake rotors on the M are huge and will be much more expensive. But basically if nothing goes wrong then you aren't paying THAT much more to operate the M.

These are not unreliable BMW's (knock on wood) compared to some of the other shitboxes that BMW makes. E39 M5's are a headache and the guys on the E60 M5 forums literally advise new buyers to "budget $10K in the first year to iron out any gremlins."

One of the best features of the Z4M is that the S54 had been in production for a good 5-6 years before it ever saw the inside of a Z4. I like that.

Worst thing about the Z4M: Gas mileage. I'll regularly do 19MPG mixed driving (220 mile range). My 2.5i can regularly do 25MPG+ (300 mile range)

[Efthreeoh]

Since I've only had my 3.0si Coupe for only a month I can't comment on maintenance between it and the M Coupe, however I have a 2006 325i (N52) with 273,000 miles on it, so I can comment on the maintenance of the N52, which is the same engine in the 3.0si. The N52 is very reliable and doesn't break much; I've not yet needed to even replace a coil.

But my thoughts are this, the M Coupe is a performance car, with a performance engine (solid lifters tell you that), so why wouldn't you drive it hard the way the car was meant to be driven and the reason BMW built it? So if you drive it hard, then the maintenance costs will increase of course. If you are going to drive the M Coupe "soft" to lower maintenance costs then you are defeating the purpose of the M Copue and you would probably be better off driving the 3.0si Coupe since the level of performance you would experience would be about the same. Also, the N52 can take a lot of hard driving (I can attest to that), so you may find the 3.0si as fun (driven hard) as the M Coupe (if you drive the M softly).

My 2 cents...

[Huz-Z]

If you are not going to track the car, you won't be disappointed with an SI. Around town and most legal highway driving, I'm told it feels every bit as strong as an M. I recall one time in my just newly "imported from the US" SI that I was cruising along at what I thought was a Canadian legal 100 kph, marvelling at the willingness of the motor to pull, when I realized that my US speedometer was indicating 100 mph. Crikey! Even an SI can provide performance that is scary for a newbie.

But, an M does have that "M" thing going for it. It certainly looks that much more aggressive. Assuming you find a good example, I expect that the most annoying thing would be the gas mileage - but you are okay with that. The regular maintenance things with an M like more costly valve work and brakes are known things that you can budget for in advance.

Whatever you buy, make sure its optioned up the way you want, been properly maintained and in good shape. Good luck! And we WANTS pictures!!

[David70]

Roughly how many miles a year will you drive it? Big difference in costs at 8k miles a year compared to 15k.

[gas-can]

Just buy the M already! haha

If you are always going to be second guessing not buying the M, you will probably upgrade to it in a few years anyway - might as well just save the 2k you would spend in tax and registration 2x to buy the bloody thing out right...

That said my N52 hasn't asked for anything other than tires, brakes, and some fluids in 40k miles! More reliable than the honda I have... And it always puts a smile on me everytime I drive it. I think you'll probably be happy with either car...but of course the grass will always be greener on the other side if you get the 3.

-gc

[RADRACR]

Originally Posted by HEY32G

I have owned a lot of sports cars, and I like a fun car, but I'm not a wild man.

This tells me you'll be fine with the si and won't see much of a gain with the ///M. The ///M needs high revs through the gears to make it stand out. If all you're doing is zipping around town and the occasional twisty road, skip the wild man's ///M and its premium cost.

As far as maintenance cost, the difference is negligible considering how seldom you'll drive it. You can get away with a valve adjustment every 50k (///M).

[HEY32G]

Originally Posted by David70

Roughly how many miles a year will you drive it? Big difference in costs at 8k miles a year compared to 15k.

Closer to 8k than 15k.

And to answer another question on here. I will not do any of the work on it myself. Not in my bag of talents. But I have a great indie shop 10 miles from me.

[David70]

Originally Posted by HEY32G

Closer to 8k than 15k.

And to answer another question on here. I will not do any of the work on it myself. Not in my bag of talents. But I have a great indie shop 10 miles from me.

At 8k miles per year you are looking a 1.5 oil changes, tires every other year roughly?, valve adjustment every 3 years?, gas won't matter much. All of the items above are just the upcharges over the 3.0si as you still have most of them with it, just cheaper.

Double all of these these items at 15k miles per year and I wouldn't do it but with limited miles doesn't seem too bad to me.

[HEY32G]

Originally Posted by David70

At 8k miles per year you are looking a 1.5 oil changes, tires every other year roughly?, valve adjustment every 3 years?, gas won't matter much. All of the items above are just the upcharges over the 3.0si as you still have most of them with it, just cheaper.

Double all of these these items at 15k miles per year and I wouldn't do it but with limited miles doesn't seem too bad to me.

Interesting way to look at it. Thank you.

[cooticooti16]

I'm in the same boat now. I can afford either car, and have 2 SUV's that are used for family duties. So the Z I pick up will be my daily toy.

I will also drive < 10,000 miles a year without seeing any track time. I cruise 90% of the time, but the other 10% has now become the deciding factor. I'm sold on the ///M because of its looks and sound and the way the S54 sounds above 6000 RPM.

But then again, for the few times I will take the car close to redline, I might get better use out of the more flexible N52 engine and its wallet friendly behaviors.

R.

[GomboRombo]

Originally Posted by HEY32G

My fear with the 3.0si is that I may eventually want more power. Although, I will never track or modify either car.

Plus, I have owned a lot of sports cars, and I like a fun car, but I'm not a wild man.

I owned an Si for almost 2 years. Did everything I could to get more power out of it short of FAI, including installing an LSD from Performance Gearing with shorter gearing. All that I added to the car could have bought me an M, and it only satisfied me for a short while. I then consider forced air but from what I've research the N52 could only handle about 310 HP reliably, that compared to a stock normally aspirated M which has 330 HP.

Like you I'm in no way a wild man on wheels, but do like to feel the power when I want it.

[Shipkiller]

Originally Posted by RADRACR

As far as maintenance cost, the difference is negligible considering how seldom you'll drive it. You can get away with a valve adjustment every 50k (///M).

To go 50K between valve adjustments, you would have to get 75MPG.......

Not sure why this fallacy will not die but valve adjustments on the S54 are not conditioned or mileage based, but based on 'how much fuel is burned' in the engine. 660gallons is the magic number.

[GomboRombo]

Originally Posted by Shipkiller

To go 50K between valve adjustments, you would have to get 75MPG.......

Not sure why this fallacy will not die but valve adjustments on the S54 are not conditioned or mileage based, but based on 'how much fuel is burned' in the engine. 660gallons is the magic number.

So it should be done around 12.5k miles? Ouch! I better learn to do my own valve adjustments (which I planned on anyways)
I just bought my Z4M back in April with 29k and had the valves done for the very first time because the previous owner had never done it. My Indy shop said that only 4 pucks were out of spec and he has seen a lot worse (not sure what that means) I instructed them to replace all since it was going to cost me the same whether it be 4 pucks or all anyways.

To me I enjoy the car enough that I would shell out the $$ to maintain it. I try to do all the maintenance myself because for me thats part of the fun of owning this car.

If you can afford the maintenance I say go for the M. Done the Si, loved it, missed it when I sold it, but I love my M so much more.

[pokeybritches]

People would like the si a whole lot more if they didn't come down with ///M-vy... knowing that something else out there is faster and supposedly "better". It's not worth the cost of the M unless you actually use the performance. Even for the track, it's a much more expensive car to run - Vanos hubs, cam bolts, rod bearings, and now some follower / camshaft wear problems on certain cars. Unless the car is solely used for pleasure (a few thousand miles per year), and you have deep pockets should repairs surface, I say go for the 3.0si (or even 3.0i). If you're even asking this question, the 3.0si is probably a better choice.

If you want to go beyond stock, then it's a different story. The S54 can easily handle 500+ horsepower. The N52 is being pushed hard at much over 300 horsepower.

It's too bad BMW didn't offer an M package with everything from the M minus the S54.

[dc_wright]

I've had the 3.0si for about 18 months now and have run against Z4Ms for autocross and on the track. Unless you're doing something where you can be in the higher rpm range for a significant amount of time the M hasn't shown any real performance advantage. For autocross I haven't seen the M have any advantage. On the track on the longer straights the M is able to pull away pretty easily, but in tighter parts of the track we've been pretty even. I believe this is because the si version of the N52 and the S54 have pretty close performance specs up until you get to 4500 rpms or so where the S54 starts to breathe better. Attached is a dyno comparion between a si Coupe and an M Coupe for reference.
The main drawback I've seen for the si is the lack of performance bolt ons compared to what's available for the M. If you want to change to a performance exhaust, the Eisenmann axle back is about all that's available at $1,200 for the si, while there are at least half a dozen sources for the M.

[KevinM]

I'm not sure of the cost differences to run, but based on my experience driving a Z4M coupe since 2007 it will (barring bad luck or poor prior maintenance) likely come down to more expensive oil, worse gas mileage and more expensive tires. I'm sure overall maintenance costs are higher and the S54 needs a valve adjustment with Inspection II. If you are like most car guys it already over. If you don't get the M you will be thinking about it until you do. I drove 2 E39 six cylinder cars for 6 years because I didn't "need" the M5. Of course I didn't. After driving the E39'M5 during a BMW driving school, it was over (and the M5 is still my DD over a decade later).

[BruceJ]

Not trying to scare you out of an Z4M. I own a Z4Si and love it. I regularly drive with a friend who has a Z4M and have little to no problem keeping up on all the twistys we drive on. We don't track our cars. I'm looking at E46 M's (same engine). But.......

Couple corrective maintenance issues inherent to the S54 (M).
1. VANOS for this engine does occasionally experience failure - the exhaust sprocket tab(s) break. Scary thought if this tab drops into reciprocating components. Replacement if you DIY it (and nothing else) is approx. $1000 - $2500 depending on what you replace. There is an improved sprocket.
http://www.drvanos.com/index.php?opt...&id=5&Itemid=6

On the fluke side of things my buddy (Stihlbolts) had a VANOS intake bearing break up in his 2008 M roadster - cost: $3-4k.
http://www.zpost.com/forums/showthread.php?t=809470

The link below talks about several more failures in the S54 VANOS. I think the bulk of these are more associated with the early (2001-2003) S54 engines.
http://www.beisansystems.com/procedu..._procedure.htm

2.Connecting Rod bearings - premature wear. Although generally associated with tracking the vehicle there are some reports where it happens and the owner never tracked the car. Randy Forbes (on this forum and others) can replace without pulling the engine but this is still a $1000 - $1500 cost. If you DIY its probably approx. $600. How often? Depends on how you use the car.
http://www.bimmerforums.com/forum/sh...y-Randy-Forbes

http://www.zpost.com/forums/showthread.php?t=607732

These guys provide a much more expensive replacement option, but what really interesting is that they imply its a design flaw; generally speaking, bearings don't have enough surface area (not wide enough) for the load imposed by the engine. Oil gets squeezed out and thus excessive metal to metal contact. Course they would like you to buy their product(if money's no problem it does look sweet).
http://www.langracing.com/finding-a-...aring-failure/

If wrenching doesn't scare you I wouldn't look at any of these issues as show stoppers. Just keep them in mind and budget for them. Otherwise budget more money.

Good Luck
Bruce

[dekaliber]

Knock on wood, but no issues with my Z4M in the 5 years I've had it. Granted, I've only put about 20K miles on it (total 35K) in that time and I take very good care of it. As many have said the S54 is a pretty bulletproof engine that was already very proven by the time it made it to the Z4. Oil changes are expensive (about $100 for just the parts) and I'm sure brakes and other wear parts are going to cost you more than a 3.0si.

Frankly, though, the 3.0si is plenty of car and actually *feels* just as torquey at lower RPMs (what you'd usually use for normal driving). If I'm totally honest with myself, 95% of my day-to-day driving felt pretty much the same when I upgraded my 3.0si for the M. Stock, I actually thought the 3.0si sounded better but I know the metallic S54 sound is pretty polarizing.

That said, I have never once regretted my choice to go with the M.

What it offers though is the slightly greater exclusivity, subtle (but significant) cosmetic improvements, the obvious edge in top-end power, and the "street cred" that comes with owning an M car, so if those are important to you then definitely go for it.

[cooticooti16]

Originally Posted by dekaliber

Knock on wood, but no issues with my Z4M in the 5 years I've had it. Granted, I've only put about 20K miles on it (total 35K) in that time and I take very good care of it. As many have said the S54 is a pretty bulletproof engine that was already very proven by the time it made it to the Z4. Oil changes are expensive (about $100 for just the parts) and I'm sure brakes and other wear parts are going to cost you more than a 3.0si.

Frankly, though, the 3.0si is plenty of car and actually *feels* just as torquey at lower RPMs (what you'd usually use for normal driving). If I'm totally honest with myself, 95% of my day-to-day driving felt pretty much the same when I upgraded my 3.0si for the M. Stock, I actually thought the 3.0si sounded better but I know the metallic S54 sound is pretty polarizing.

That said, I have never once regretted my choice to go with the M.

What it offers though is the slightly greater exclusivity, subtle (but significant) cosmetic improvements, the obvious edge in top-end power, and the "street cred" that comes with owning an M car, so if those are important to you then definitely go for it.

There's also the whole EPS vs hydraulic steering imaging. I haven't had the chance to drive either yet (no MT cars in my area) but the BMW's I've driven with Electronic Power Steering have NOT been pleasant.

R.

[dekaliber]

Originally Posted by cooticooti16

There's also the whole EPS vs hydraulic steering imaging. I haven't had the chance to drive either yet (no MT cars in my area) but the BMW's I've driven with Electronic Power Steering have NOT been pleasant.

True that, although I don't remember ever finding the 3.0si steering lacking in day to day use (I never tracked that car as I did with the M). As a weekend car or a fun commuter, I doubt any flaws of the EPS system would really become a concern, and I suspect this will not be a significant differentiator for the OP as well.