My (hopefully not a project) Z4M

[Benji]

That post should have had a bit more detail...I have undeservingly not driven or spent as much time on this car as I'd have liked. I "fixed" the sunglasses holder with 2 magnets, it now normally stays closed unless you are going sideways on a skidpan where shades will go flying into thankfully closed windows...



I have half-heartedly been chasing the stumble off idle issue. Replaced the rear TPS with a new one (the store only had stock of one) and gave the ICV and throttles a quick clean while I was in there. It did not solve the stumble issue, but I will replace the second TPS before giving up. I have noticed a few other S54s doing the same thing, so maybe I need my mental TPS reset.

Grubby:


Clean (-ish, could not get those stains off the brass). Bonus side effect: I need to buy a new crank vent hose as mine broke in twain 😠


Figured I'd update the ECU, this definetely made the car feel more responsive, but that may be due to the adaptations being reset and the ECU learning all taking place on the skidpan. Break them in hard, I say! It still stumbles tho 🤷‍♂️

Was slightly scary, took about 3 beers to update, started worrying if I had maybe bricked the car. Deffos have the car plugged into a beefy charger as the fuel pump remains running through the whole process!

 

[Benji]

I covered my door handles with a brushed aluminium wrap to match the dashboard. Nicely lifted the interior vibe a bit



Also replaced my second TPS so I have a new matching pair, checked valve clearances (thank you @Blue Shirt for lending me your shim kit, absolute legend as always) 3 valves were a bit tight, and checked cam timing for peace of mind (it was a little out). I will do the upcoming 170k km oil change shortly, but otherwise all is good in Z4 land, that S54 still puts a smile on my face

But...due to other opportunities, Ive decided to put this car up for sale at 320k...not a desperate or forced sale at all, but opportunity is opportunity.

 

[Venom23]

Stunning ride

 

[Benji]

Z4 got its 170k km oil change with a bottle of Ceratec and injector cleaner thrown in for good measure. Replaced the crankcase breather hose which was R700 for a plastic hose! M-tax is real. A set of H&R springs with Bilstein B6 dampers found their way onto the car.


Looks a bit more shhporty with no noticeable sacrifice in comfort, corners like it is on rails now. I had to reuse the original rear bump stops since BMW is on back order.

Z4M bump stops:

"Normal" Z4 M-sport bump stops:

I ordered them both, but will install the shorter M-sport bumps stops since the car is sitting a bit lower now, will be interesting to see if it softens the ride somewhat. Interestingly, the H&R rear springs are made of noticeably thinner steel than the original springs but with the same number of coils. This should translate to a lower spring rate and softer ride. The stock Z4 rear springs are a lot beefier than the E46 touring springs...weird since it weighs 200kg less and cant carry passengers or doggos in the back. An example of an obvious design fuckup, BMW?

Finally got around to repairing the collapsed drivers seat cushion with some straps. Kinda weird not sitting on the floor now 🤷‍♂️ Used the opportunity to clean up under the seat and in the boot area where there seemed to have been a chemical spill of sorts. The jury is still out on if it was molasses or some cheap coffee that spilled and got wet, soaking into and under the carpet. Yuck. Car smells noticeably better now


With all the other projects on the go and the E39 back in commission, the Z4 has been a bit neglected lately, finding itself in the darker corners of the garage...

 

[Benji]

Some feedback on my suspension upgrade after dailying the Z4 the last 2 weeks. I replaced my stock suspension (I suspect untouched from factory...) with the H&Rs and B6s. My initial thought was that the car felt a bit harder on the road, but the more I drive it, the more convinced I am that it is significantly more comfortable compared to the stock (shot) suspension. It feels much more controlled with much less roll/bucking/diving. I would find myself irritated with the stock suspension, but I have never found myself irritated with this setup. For example, previously when driving thru bumpy intersections in 1st, the car would buck so much that your foot would "jiggle" the hyper sensitive throttle, leading to more irritating bucking. This has never happened to me since fitting the new suspension. Overall, Im not saying it is perfect, but I would say the ride height and ride quality is what it should have been from factory.

Oh, and the Z4 is a hilarious riot in the wet on cheap Chinese tyres! 3rd gear at 3000rpm and she it breaking traction, every 2nd gear corner is a lazy sideways affair with the revs at 2000rpm 😅 good fun especially with the approving hoots from the Karens for the beautiful sideways view of the approaching Z4

 

[Benji]

Finally received and installed the M-sport Z4 rear bump stops. Wow! It no longer feels like going for a ride in a wheelbarrow. I have said it before, but I'll say it again, this is how the Z4 should have come from factory, slightly lower ride height, softer springs, better dampers, shorter bump stops. While still a stiff ride (sport car - duh), the suspension now has fluidity to it, absorbing bumps instead of bouncing off them. The stock Z4 suspension was the single biggest thorn in the side when it came to Z4 ownership, how BMW got it so wrong when the solution is so straightforward, even a nincompoop like me can figure it out, remains a mystery.

Comparison of M vs M-sport bump stops, M-sport is 17mm shorter. Now, 17mm might not sound like much, but it makes all the difference. At least, thats what she said. From precision use of my eyeballs, I estimate that I now have about 35mm of rear suspension travel before hitting the bump stops. Lovely


All this suspension talk requires an antidote; cue the wash mitt making it's first appearance for the year Post wash clarity:

 

[gavsadler]

Nice,

Yes it seems the E-Series cars were almost designed to run on the bump stops, probably also fast-tracking their degradation.

Glad to hear you are winning the niggle battles, I'm sure the car will be all the more enjoyable going forward.

 

[Benji]

Some pics from the waterless skidpans, still the best fun you can have with your pants on. Great group of people who attend. Thank you to the BMW Car Club for arranging these, long may they continue. Myself and @gavsadler seem to have a close battle for "top honors" here, with each of us having clinched a first and second place with suitably sideways M-Power antics

February event:



May event:



Note how much flatter the car is in the May event with the lowered suspension, also seemed much easier to control, but that may just be right-foot calibrations.

My best run:

Play time:

 

[KARMash]

Happy to say I subscribed to your YT channel , looking forward to more content

 

[Greenz]

That sounds glorious!!!!

 

[Clint@MMS AUTO]

Nice one! thats how a Z4m should be enjoyed.

 

[Alex/M5]

Nice job on the drifting! Seems easier to drift than the M5?

 

[Benji]

Not too much to report in Z4 land, car has seen much less use lately...maybe something to do with my daily actually being a daily.

She seems to be making a lot of friends lately




Participated in another skid pan event in June. Nice to see there were in total four Z4s participating, including a Sepang Bronze Roadster. For some reason I was really struggling to string the course together. Car felt like it had no rear grip or too little opposite lock - not something Ive noticed before. Maybe I should be more hungover at these events as that is when I seem to drive a bit slower...

Culprit found...?



Rear tyres successfully and deservedly killed. Front tyres are putting up a strong resistance. MUST. TRY. HARDER. Got my wheels refurbished and, perhaps stupidly, threw on a new set of Easgle F1s on the rear only... Love how "bulbous" the Eagle F1s are compared to the Chinesium that was on there.



Maybe less oversteer and more understeer will kill the fronts...off to Redstar on a mission...



Z4 was surprisingly good on the track except for the brakes, which, lets be honest, are rubbish. She can just about muster up 2 fast laps before needing a cooldown lap. The front tyres also, are hilariously inadequate. ABS getting involved at speeds over 160 and understeer here, there and everywhere else. I think I hit maybe one apex during the course of the day But it was a lot of fun, I really enjoyed myself.

You might notice the 350Z which I also got to drive as part of a training session. I cannot recommend Infinite Drive enough, they provide all sorts of training; ranging from boring things like defensive driving to skid pan and track coaching. My mate knocked 6 seconds off his PB after just 4 sessions on the track! Impressive. I managed a PB of 2.31 in the Z4 - insert appropriate racecar driver excuses like failing brakes and bad front tyres. For reference, the E34 M5 (which is a proper track car) does 2.17s around Red Star.

Next job on the list is to do a brake fluid flush and throw in a more track focused set of front brake pads in the quest to inflict more damage on the surprisingly resistant front tyres.

Lastly, a nice piece of history, here is the car at @Clint@MMS AUTO back in September 2022, nice to see she was getting the love and attention she deserves.

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More to come...

 

[Benji]

Thank you Mike for taking this awesome footage at the recent skid pan event This is just the coolest thing ever 🍿

In my continued quest to find the off-idle stumble that afflicts so many S54s, I have so far replaced both TPS's, cleaned the ICV, checked for vacuum leaks and updated the ECU software with no luck. I have some intermittent voltage errors and also noticed sporadic light brightness changing with revs, so decided to replace the voltage regulator. Found some aftermarket junk in there - straight to the bin it went - replaced with OEM Valeo. To be fair, this alternator was refurbished pre-covid days, however the date stamp (maybe) says it was changed in the future, so this regulator has probably done all right. It can time travel, so, who am I to judge.



Car still seems to be the same, the revs still seem to drop quite low after blipping the throttle which brings a momentary stumble and accompanying dimming of the lights. Maybe it is normal for the voltage to drop when the revs dip to 500rpm still, revs shouldn't be dipping that low...the quest continues, I shall continue to throw money at the car to get rid of the non OEM parts.

Or maybe I must lower my standards...Ha!

 

[Benji]

After frankly disappointing brake performance at Redstar, @Clint@MMS AUTO got in touch with me regarding his experience with his Z4 brakes and referred me to @FiRi@Rennzport who had a slightly used set of Ferodo DS3000 brake pads. After no haggling at all, Firi agreed on a price and sent the brake pads over. Clint very kindly offered to fit the brake pads for me and perform a brake flush with Motul 5.1 fluid at no charge to me. What a legend, thank you Clint! Highly recommend him to anyone who needs proper work done to their car.

Beers (and chick-beers) in hand, we did the brake fluid flush and found an alarming amount of bubbles from only the right/rear brake caliper. Very weird as the brakes were perfect before - no pulling and a firm pedal...Maybe the air was stuck in the ABS pump which also worked perfectly before the flush. Weird 🤷‍♂️ Again, my deepest gratitude to Clint

E86 Z4M Coupe – Ferodo DS3000 & Motul DOT 5.1

A few days ago, @Benji reached out and we got chatting about tracking the E86 Z4M Coupe 🏁. He’s heading to Kyalami at the end of the month and wanted some advice on track prep. He mentioned that on his last track day he experienced brake fade 😬, so he was looking at upgrading to Ferodo DS3000...

www.bmwfanatics.co.za

New MAF finally arrived. According to Bosch, I need to wear a hardhat when fitting a MAF...fair enough, I need new bonnet shocks


Old Bremi MAF went directly to the bin. It did not pass begin. I used this opportunity to clean out the air filter, I think I found where my rear tyre tread ended up! Last filter clean was about 3000km ago.


Thought the Rennzport breakfast run would be a good opportunity to bed in the "new" brake pads. Good fun and great to catch up with a few Fanatics. Firi's Z4 sounds amazing, was a highlight chasing him through the M1 underpass!



I am happy to report that the car feels much better with the new MAF, more responsive at low revs, the power delivery is more linear and predictable. I feel it pulls a bit harder now and the revs also dont drop below idle anymore, however, the slight stumble off-idle is still there. But, after hearing Gavs roadster stumble, I figure mine is very acceptable. The last potential culprit could be the throttle actuator, but I figure I shall put this saga to bed and be happy with my lot.

Oh and the brakes feel good, they probably need to bed in a bit more, but initial bite feels stronger, they are not as noisy as I was expecting but do seem to make a much louder humming noise once they are hot. The real test shall be on track at the end of the month. Cannot wait!

 

[Benji]

I had the amazing opportunity to attend the Festival Of Motoring at Kylami this past weekend to provide guests with experience laps in the Z4. I nervously arrived early on Friday morning for the 30min "warm up" to get my eye in. I had only ever managed one successful lap of Kylami on a race simulator After removing my jaw from the floor seeing the serious machinery I was sharing the track with, my humble little Z4 did its damndest not be a mobile chicane. I eventually had the whole track to myself where I could push a little harder and flirt with the limits, all the while pinching myself; here I am on Kylami with the track all to myself, how did this happen!



Is the hype around Kylami really warranted? I would say to a certain degree, yes, this is a "big boy" track. Heavy braking zones, high speed corners and technical, slower corners, it has it all. Personal favorites are The Esses and Mineshaft with Cheetah having a particular tendency to spike the heart rate. The first few corners are very technical and immensely satisfying when you string them together well. My balls have not yet dropped low enough to extract the most out of the blind "Leeukop" corner.

Onto my steed for the weekend: After purchasing the Z4, I was initially a bit underwhelmed by it (mostly blamed on the rubbish OEM suspension) but she has really wormed her way into my heart. She handled the whole weekend like a champ without a single hiccup! Even in 32C heat, the oil temperature would never go above 110C with the AC on. What luxury! I had literal squeals of joy from passengers with the general reaction to the Z4 being one of surprise at how capable it was. The Z4 really is unknown, underestimated and underappreciated. It was a real pleasure to see and share the joy of the passengers The minor flies in the admittedly fantastic ointment were the brakes which would overheat and start shuddering after 4 hard laps and my bloody useless Vitour front tyres which are made from an indestructible material and should be investigated for science. They have no grip when cold then will immidiately overheat and have even less grip. I learnt to drive around the brakes, applying pressure gently and putting less heat into them. The lack of front grip made the car a bit of an understeering mess, especially in turn 6 (Sunset) but it did provide me with the opportunity to experiment with the weight balance and allowed me to use Formula 1 terms like "manage the tyres" to sound like I knew what I was talking about.

In a desperate attempt to provide more cooling air to the brakes, I cut the smallest little slot into the front "tyre cooling" ducts to direct more air to the brakes. Not very effective I'd say


Front tyres after about 100 laps...I am out of ideas on destroying these. Short of installing them on the rear and doing burnouts, does anyone have any pointers on how to punish front tyres? Asking for a friend...


Anyway, on to the good stuff. Z4 after a hard weekend of work. What a fantastic little machine, punching well above her weight


Spot the imposter




Overall, one of the better weekends I've had, I met some great people, had a lot of fun and quite enjoyed the challenge of making small talk with passengers while managing tyres and brakes and keeping out of the way of much faster machinery on a foreign track. Who said men cant multitask?

I am eternally grateful to everyone who arranged this and their hard work to make this a memorable weekend for everyone and who provided me with this amazing opportunity. If I were a Gen Z, I'd insert a hashtagblessed in here

 

[TBP88]

I had the amazing opportunity to attend the Festival Of Motoring at Kylami this past weekend to provide guests with experience laps in the Z4. I nervously arrived early on Friday morning for the 30min "warm up" to get my eye in. I had only ever managed one successful lap of Kylami on a race simulator After removing my law from the floor seeing the serious machinery I was sharing the track with, my humble little Z4 did its damndest not be a mobile chicane. I eventually had the whole track to myself where I could push a little harder and flirt with the limits, all the while pinching myself; here I am on Kylami with the track all to myself, how did this happen!

View attachment 30424

Is the hype around Kylami really warranted? I would say to a certain degree, yes, this is a "big boy" track. Heavy braking zones, high speed corners and technical, slower corners, it has it all. Personal favorites are The Esses and Mineshaft with Cheetah having a particular tendency to spike the heart rate. The first few corners are very technical and immensely satisfying when you string them together well. My balls have not yet dropped low enough to extract the most out of the blind "Leeukop" corner.

Onto my steed for the weekend: After purchasing the Z4, I was initially a bit underwhelmed by it (mostly blamed on the rubbish OEM suspension) but she has really wormed her way into my heart. She handled the whole weekend like a champ without a single hiccup! Even in 32C heat, the oil temperature would never go above 110C with the AC on. What luxury! I had literal squeals of joy from passengers with the general reaction to the Z4 being one of surprise at how capable it was. The Z4 really is unknown, underestimated and underappreciated. It was a real pleasure to see and share the joy of the passengers The minor flies in the admittedly fantastic ointment were the brakes which would overheat and start shuddering after 4 hard laps and my bloody useless Vitour front tyres which are made from an indestructible material and should be investigated for science. They have no grip when cold then will immidiately overheat and have even less grip. I learnt to drive around the brakes, applying pressure gently and putting less heat into them. The lack of front grip made the car a bit of an understeering mess, especially in turn 6 (Sunset) but it did provide me with the opportunity to experiment with the weight balance and allowed me to use Formula 1 terms like "manage the tyres" to sound like I knew what I was talking about.

In a desperate attempt to provide more cooling air to the brakes, I cut the smallest little slot into the front "tyre cooling" ducts to direct more air to the brakes. Not very effective I'd say
View attachment 30422

Front tyres after about 100 laps...I am out of ideas on destroying these. Short of installing them on the rear and doing burnouts, does anyone have any pointers on how to punish front tyres? Asking for a friend...
View attachment 30420

Anyway, on to the good stuff. Z4 after a hard weekend of work. What a fantastic little machine, punching well above her weight
View attachment 30423

Spot the imposter
View attachment 30425
View attachment 30426
View attachment 30427

Overall, one of the better weekends I've had, I met some great people, had a lot of fun and quite enjoyed the challenge of making small talk with passengers while managing tyres and brakes and keeping out of the way of much faster machinery on a foreign track. Who said men cant multitask?

I am eternally grateful to everyone who arranged this and their hard work to make this a memorable weekend for everyone and who provided me with this amazing opportunity. If I were a Gen Z, I'd insert a hashtagblessed in here

Even in pretty hefty company it doesn't stand out as an impostor at all - still looks absurdly cool.

BBK imminent???

 

[Spanky]

Awesome, Benji!

Seems like you've got the correct pad, perhaps time to upgrade those rotors? Even the basic Vari heat-treated & slotted discs are very resilient. For added aesthetic, the two-piece units might be more suited to an M though. Some RBF600/660 probably wouldn't hurt either.

 

[Nishcat_M140i]

Even in pretty hefty company it doesn't stand out as an impostor at all - still looks absurdly cool.

BBK imminent???

I agree, the mustang is the imposter there.

Tree huggers don't sit well with track focused cars

 

[Benji]

Awesome, Benji!

Seems like you've got the correct pad, perhaps time to upgrade those rotors? Even the basic Vari heat-treated & slotted discs are very resilient. For added aesthetic, the two-piece units might be more suited to an M though. Some RBF600/660 probably wouldn't hurt either.

I have been giving this some thought but the Z4 is not my track car, and the current brakes are "acceptable" for road use. I dont really see the value in throwing money at a BBK for something I will (hopefully) do once a year. Having said that, the Z4 really does deserve better brakes!

My issue was not a soft pedal, I think the Motul 5.1 helped there, the issue was overheating discs that would start shuddering. I guess some proper brake cooling ducts would go a long way in improving matters.

I agree, the mustang is the imposter there.

Tree huggers don't sit well with track focused cars

Agreed! From my experience this weekend with cars in a similar performance level to the Z4, with the proviso that we were all driving at "six tenths" (we were not) and my really rather quite rubbish front tyres:

Mustang: they pulled away from me on the straights but I caught them under braking and in the corners
Golf GTi: I pulled away from them everywhere, but surprisingly close
Golf R: Pretty even on the straights, but they rocketed out of corners
BMW Race Series E36 and race taxi - fully race prepped cars, I had them on the straights, but they made me look a bit silly in the corners

I had a ride in the Golf R - the driver was giving it twelve tenths, really quite aggressive, but I was very impressed with how the cars electronics tidied everything up and translated sledge hammer inputs into forward progress