Thirsty Discovery and Z4 thread
Discussion
All quiet on the car ownership front, which is a nice change after a flurry of activity in recent months.
I took the Z4 to a Drive Limits tuition day last week, which was absolutely fantastic. I've shared more detail in the Trackday forum, but needless to say I'm feeling a lot more confident in the way the car behaves than I did after Snetterton.
I treated the Z4 to an oil change over the weekend, which was the first in my ownership. What came out was as black as midnight, so I've ordered an analysis kit from Miller's Oils to see where I stand in terms of bearing material etc. What went in was ~7 litres of Mobil's finest 5w40 fully synthetic.
On the tuition day it did suffer with a slightly sticky tappet, which isn't uncommon for these engines and is potentially a result of using the OEM spec 5w30 when giving it a kicking. The 30 just doesn't flow enough when the engine is really warm, so accepted wisdom is to move to 5w40 for harder use.
I'm at Cadwell on Thursday, on what will unfortunately be yet another wet trackday. I'm hopeful I can still learn a bit about the car, but that isn't a track where you want to push hard in the rain. Annoying.
More positively, I've decided to hold onto the Z4 for a little while. I'm of the view that they are really underappreciated little cars, and every time I did the man maths on upgrading I couldn't reconcile how much performance the Z4 offers for such comparatively small outlay and running costs. I'd feel much better learning how to drive a rwd car on track in something that can hustle as fast as many modern hatches (tested at 8.25 around the Ring), but can be replaced for less than five grand if it all goes wrong.
I've never been one for owning cars as a symbol of status, and I'm not really interested in having people fawn over my car at owners meets etc. The Z4 is the right tool for this particular job.
Next steps (after a potential Ring trip later this year) are to gently titivate it, trying hard not to lose its usability on the lovely B Roads around where I live. Starting points are seats and suspension.
Seats: the Z4 Sport seats go for ridiculous money, far beyond what they are worth. If I can find a cheap car with electric heated seats fitted over the winter, I'll buy it, swap the seats with mine, and sell it on. Otherwise, it's going to be either something from another BMW model (E46 M3 seats drop right in) or aftermarket.
Suspension: I'm trying really hard to avoid going to coilovers here, but the options aren't brilliant. A set of Bilstein B6 or Koni adjustables is running to almost the same price as damping adjustable coilovers like HSDs. Need to find some cars with them fitted to understand the trade-off.
Lots of thinking to be done. For now, it needs a wash after it got dive-bombed by the pigeon Luftwaffe. Let's see what Thursday holds...
I took the Z4 to a Drive Limits tuition day last week, which was absolutely fantastic. I've shared more detail in the Trackday forum, but needless to say I'm feeling a lot more confident in the way the car behaves than I did after Snetterton.
I treated the Z4 to an oil change over the weekend, which was the first in my ownership. What came out was as black as midnight, so I've ordered an analysis kit from Miller's Oils to see where I stand in terms of bearing material etc. What went in was ~7 litres of Mobil's finest 5w40 fully synthetic.
On the tuition day it did suffer with a slightly sticky tappet, which isn't uncommon for these engines and is potentially a result of using the OEM spec 5w30 when giving it a kicking. The 30 just doesn't flow enough when the engine is really warm, so accepted wisdom is to move to 5w40 for harder use.
I'm at Cadwell on Thursday, on what will unfortunately be yet another wet trackday. I'm hopeful I can still learn a bit about the car, but that isn't a track where you want to push hard in the rain. Annoying.
More positively, I've decided to hold onto the Z4 for a little while. I'm of the view that they are really underappreciated little cars, and every time I did the man maths on upgrading I couldn't reconcile how much performance the Z4 offers for such comparatively small outlay and running costs. I'd feel much better learning how to drive a rwd car on track in something that can hustle as fast as many modern hatches (tested at 8.25 around the Ring), but can be replaced for less than five grand if it all goes wrong.
I've never been one for owning cars as a symbol of status, and I'm not really interested in having people fawn over my car at owners meets etc. The Z4 is the right tool for this particular job.
Next steps (after a potential Ring trip later this year) are to gently titivate it, trying hard not to lose its usability on the lovely B Roads around where I live. Starting points are seats and suspension.
Seats: the Z4 Sport seats go for ridiculous money, far beyond what they are worth. If I can find a cheap car with electric heated seats fitted over the winter, I'll buy it, swap the seats with mine, and sell it on. Otherwise, it's going to be either something from another BMW model (E46 M3 seats drop right in) or aftermarket.
Suspension: I'm trying really hard to avoid going to coilovers here, but the options aren't brilliant. A set of Bilstein B6 or Koni adjustables is running to almost the same price as damping adjustable coilovers like HSDs. Need to find some cars with them fitted to understand the trade-off.
Lots of thinking to be done. For now, it needs a wash after it got dive-bombed by the pigeon Luftwaffe. Let's see what Thursday holds...
Z4s do seem to offer plenty of RWD fun for relatively low cost.
I know what you mean about the standard "Sport" seats. The M-Sport ones are just so much better but that's why they are so desirable, and therefore expensive!
I think the M-Sport seats out of other E46 Sport models are fairly easy to fit - I had a 325ti Sport and its seats were great.
But with a bit of messing other Z4 owners have managed to put other seats in, like this owner who put Mazda RX8 seats in his:- https://z4-forum.com/forum/viewtopic.php?p=1971057...
I know what you mean about the standard "Sport" seats. The M-Sport ones are just so much better but that's why they are so desirable, and therefore expensive!
I think the M-Sport seats out of other E46 Sport models are fairly easy to fit - I had a 325ti Sport and its seats were great.
But with a bit of messing other Z4 owners have managed to put other seats in, like this owner who put Mazda RX8 seats in his:- https://z4-forum.com/forum/viewtopic.php?p=1971057...
Agreed on the point about bang for buck. It will lap most tracks quicker than a stock S2000 for between half and a third of the cost. I kept asking myself why I was upgrading, and more often than not it came down to itchy feet. Everything I looked at came with significantly higher running costs, which made it tough to reconcile for a car that gets used hard. The Z4 is ultimately still lots more capable than I am, so it will stay until I get bored or competent. Whichever comes first.
The seats thing is a bit of a head-scratcher. I need lateral support, and many of the seats that people have fitted (like S2000, E46 and RX8) aren't a massive step up. I really want Recaro Sportsters, and may yet still cave in and buy them, but it seems odd to fit such expensive seats to such a cheap car. I'd like to retain the electric and heated bits, so finding an OEM-ish solution appeals. I'm desperately trying to remember what E92 M3 seats felt like, because I suspect they will drop in with minimal fuss. There's a holy grail of Z4 Sport seats with electric adjustment and heating, but in half-leather with a cloth centre. If I spot a set of those for sale, it's game over.
The overall plan is to continue gently improving it and replacing worn parts over the next 12 months, before doing a trackday at the Nurburgring this time next year. I need to get a few more laps under my belt between now and then, which unfortunately means more trips and braving TF sessions.
The seats thing is a bit of a head-scratcher. I need lateral support, and many of the seats that people have fitted (like S2000, E46 and RX8) aren't a massive step up. I really want Recaro Sportsters, and may yet still cave in and buy them, but it seems odd to fit such expensive seats to such a cheap car. I'd like to retain the electric and heated bits, so finding an OEM-ish solution appeals. I'm desperately trying to remember what E92 M3 seats felt like, because I suspect they will drop in with minimal fuss. There's a holy grail of Z4 Sport seats with electric adjustment and heating, but in half-leather with a cloth centre. If I spot a set of those for sale, it's game over.
The overall plan is to continue gently improving it and replacing worn parts over the next 12 months, before doing a trackday at the Nurburgring this time next year. I need to get a few more laps under my belt between now and then, which unfortunately means more trips and braving TF sessions.
After initially fearing another wet day at Cadwell, Michael Fish came through for me and it ended up being dry and sunny (enough for me to burn my bloody neck) all day!
I love Cadwell, and I'm lucky enough to have a group of friends who also have track cars. Combining this with the good weather and minimal track closures (the highlight being an Atom losing a wheel!) meant that this was probably the most fun trackday I've done in a long time.
We spent the day jumping in and out of each other's cars, taking passenger rides to learn lines and braking points, and going out in groups of 2-3 similar cars to follow each other. Gaps between sessions were passed fiddling with cars and talking car bore stuff, and thankfully there were no incidents or breakdowns for the group. Utter bliss.
After a wet Snetterton these were my first track laps with the roof down, which heightened the sensory experience somewhat over tintop track cars. I'm sold. Obviously the Z4 remains a luxury limousine next to something like the MV Exocet that one of the chaps in our group tracks, but it was still a really rewarding drive.
I got progressively faster and more confident as the day wore on, learning where I could lean on the brakes and deciding that second was only really necessary for Hairpin thanks to the torque of the M54 engine. All of that being said, I'm still not brave enough to take Coppice without a dab of the brakes (I'm typically approaching it at 100mph+), which really harms momentum into Charlies and onto the straight.
Gone was the driveline shunt I'd noticed on the way back from Germany, and gone was the vagueness in the front end after having the alignment tweaked prior to the trackday. However, as is always the way with the first few trackdays in a new car, it did highlight some issues.
Brakes: The DS2500 pads stood up really impressively to 5-6 lap stints of fast driving, but I think the front discs (of indeterminate brand) have warped a little due to the heat. Time to chuck some plain Brembo discs on to see if that's the cause of the issue.
Alignment: This headscratcher has happened a few times when I've been using the car hard. I get the alignment done, the guys doing it lock the topmounts and track rods, and it's perfect when I leave the garage. After a hard day on track, I found that the steering wheel was a few degrees out of straight on the drive home. It's really quite confusing, and I think I'm going to chuck a new set of inner and outer tie/track rods on to see if this solves it.
I was also lucky enough to run into another Z4 on track, who had coilovers fitted. The lovely chap who owned it tossed me the keys to drive it up and down the potholed circuit access road, and they are really no worse than my tired OEM kit in terms of ride quality. I think this might be a winter project for me.
Seating continued to be an issue, and I think I've settled on the Corbeau RRB recliner as my solution. They are shaped a bit like 911 GT3 seats (if you squint a bit), in that they have lots of hip support but low thigh bolsters, meaning that it's not too annoying to get in/out of. They also come with the option of heating, which was one of my big gripes with many aftermarket seats. Jury's out as to whether I can convince MrsC to sit in one for a sunny Sunday drive, so I might end up just doing the driver's seat. Again, a winter project beckons.
No trackdays in the diary for now, but eyeing up a Snetterton day in October with the same group. Otherwise, it's business as usual.
Oh, and the Disco is fine, for a change.
I love Cadwell, and I'm lucky enough to have a group of friends who also have track cars. Combining this with the good weather and minimal track closures (the highlight being an Atom losing a wheel!) meant that this was probably the most fun trackday I've done in a long time.
We spent the day jumping in and out of each other's cars, taking passenger rides to learn lines and braking points, and going out in groups of 2-3 similar cars to follow each other. Gaps between sessions were passed fiddling with cars and talking car bore stuff, and thankfully there were no incidents or breakdowns for the group. Utter bliss.
After a wet Snetterton these were my first track laps with the roof down, which heightened the sensory experience somewhat over tintop track cars. I'm sold. Obviously the Z4 remains a luxury limousine next to something like the MV Exocet that one of the chaps in our group tracks, but it was still a really rewarding drive.
I got progressively faster and more confident as the day wore on, learning where I could lean on the brakes and deciding that second was only really necessary for Hairpin thanks to the torque of the M54 engine. All of that being said, I'm still not brave enough to take Coppice without a dab of the brakes (I'm typically approaching it at 100mph+), which really harms momentum into Charlies and onto the straight.
Gone was the driveline shunt I'd noticed on the way back from Germany, and gone was the vagueness in the front end after having the alignment tweaked prior to the trackday. However, as is always the way with the first few trackdays in a new car, it did highlight some issues.
Brakes: The DS2500 pads stood up really impressively to 5-6 lap stints of fast driving, but I think the front discs (of indeterminate brand) have warped a little due to the heat. Time to chuck some plain Brembo discs on to see if that's the cause of the issue.
Alignment: This headscratcher has happened a few times when I've been using the car hard. I get the alignment done, the guys doing it lock the topmounts and track rods, and it's perfect when I leave the garage. After a hard day on track, I found that the steering wheel was a few degrees out of straight on the drive home. It's really quite confusing, and I think I'm going to chuck a new set of inner and outer tie/track rods on to see if this solves it.
I was also lucky enough to run into another Z4 on track, who had coilovers fitted. The lovely chap who owned it tossed me the keys to drive it up and down the potholed circuit access road, and they are really no worse than my tired OEM kit in terms of ride quality. I think this might be a winter project for me.
Seating continued to be an issue, and I think I've settled on the Corbeau RRB recliner as my solution. They are shaped a bit like 911 GT3 seats (if you squint a bit), in that they have lots of hip support but low thigh bolsters, meaning that it's not too annoying to get in/out of. They also come with the option of heating, which was one of my big gripes with many aftermarket seats. Jury's out as to whether I can convince MrsC to sit in one for a sunny Sunday drive, so I might end up just doing the driver's seat. Again, a winter project beckons.
No trackdays in the diary for now, but eyeing up a Snetterton day in October with the same group. Otherwise, it's business as usual.
Oh, and the Disco is fine, for a change.
Glad that Cadwell was dry for you, tracks like Cadwell and Oulton Park are incomparable to the majority of circuits we have - airfields which are mostly flat as a fart and provide little in the way of sense of speed.
I wouldn't give much weight to your worries about braking for Coppice, that corner in itself has little to do with speed down the back straight and trying to chase speed through Coppice can be a falsehood as it'll hurt your line through/exit from Charlie's 1/2 - quick corners where you probably wouldn't want to go off. Superb circuit though, the feeling of the car dancing in to the top of the Gooseneck and then having to get it all settled down and stopped for the lefthander at the bottom, lovely stuff
I wouldn't give much weight to your worries about braking for Coppice, that corner in itself has little to do with speed down the back straight and trying to chase speed through Coppice can be a falsehood as it'll hurt your line through/exit from Charlie's 1/2 - quick corners where you probably wouldn't want to go off. Superb circuit though, the feeling of the car dancing in to the top of the Gooseneck and then having to get it all settled down and stopped for the lefthander at the bottom, lovely stuff
Pleased to hear that you had a great day. 
I love Cadwell too(although I've never drove on a trackday myself though), and I occasionally pop across just to spectate because it isn't all the far for me. Plus the drive there is great, because it is pretty much all on quiet country roads as well.
I love Cadwell too(although I've never drove on a trackday myself though), and I occasionally pop across just to spectate because it isn't all the far for me. Plus the drive there is great, because it is pretty much all on quiet country roads as well.
As many car enthusiasts, I'm in a state of perpetual 'what next?' when it comes to my fun car. I recently started a thread here in fact, with a budget of up to £40k to replace the Z4. The best the thread could manage was to suggest a Boxster. Try as I might, I can't get excited about a Boxster (I've driven a few), so I felt a bit deflated.
Then I popped outside earlier and caught a glimpse of the Z4, where it's sat since I got home from Cadwell. It struck me that tying up £40k in a car that isn't going to move most weeks is just a bad idea, and I'm not in the habit of financing fun cars. So it looks like the Z4 is staying.
To muster up some enthusiasm and motivation, I started a list. Lists are always good for this kind of thing. Then it became two lists. Even better.
To fix
- Annoying rattle inside passenger door
- Less annoying rattle inside bootlid
- Really annoying rattle from passenger side of cabin
- Stop new floormats from sliding around (probably velcro)
- Get the 17s refurbished
- New track rods
- Get rid of headlight condensation
- Sort out some feature coding
- Replace driver's side tweeter cover
- New front discs
- Reattach seat backs (they all do that, sir)
To add
- Corbeau RRB driver's seat and heating pad
- Braided hoses
- Coilover (HSD MonoPro the current fave, because of the softer springrates)
- Smaller steering wheel
- Wheel spacers to stop the 17s looking lost in the arches
Looks like this has turned into a project thread. Nice.
Then I popped outside earlier and caught a glimpse of the Z4, where it's sat since I got home from Cadwell. It struck me that tying up £40k in a car that isn't going to move most weeks is just a bad idea, and I'm not in the habit of financing fun cars. So it looks like the Z4 is staying.
To muster up some enthusiasm and motivation, I started a list. Lists are always good for this kind of thing. Then it became two lists. Even better.
To fix
- Annoying rattle inside passenger door
- Less annoying rattle inside bootlid
- Really annoying rattle from passenger side of cabin
- Stop new floormats from sliding around (probably velcro)
- Get the 17s refurbished
- New track rods
- Get rid of headlight condensation
- Sort out some feature coding
- Replace driver's side tweeter cover
- New front discs
- Reattach seat backs (they all do that, sir)
To add
- Corbeau RRB driver's seat and heating pad
- Braided hoses
- Coilover (HSD MonoPro the current fave, because of the softer springrates)
- Smaller steering wheel
- Wheel spacers to stop the 17s looking lost in the arches
Looks like this has turned into a project thread. Nice.
If anyone's interested, the Discovery is fine. It's costing 50p a mile in fuel, but it's still fine.
The Volvo goes back soon, and I haven't got a clue what to replace it with. Lots of offers on Tesla Model Y leases at the moment, so that's potentially the favourite. Need something with ~300 mile range, because I can't rely on MrsC to bother to charge it if she drives to London and back.
The Volvo goes back soon, and I haven't got a clue what to replace it with. Lots of offers on Tesla Model Y leases at the moment, so that's potentially the favourite. Need something with ~300 mile range, because I can't rely on MrsC to bother to charge it if she drives to London and back.
C70R said:
Looks like this has turned into a project thread. Nice.
Great! I'm not a fan of spacers though, but E89 Z4 and E9* 3 Series wheels have much different offsets so getting wheels from one of those would push the wheels out to fill the arches. I ran a set of staggered 18" E89 wheels on my previous E86 and didn't have any issues with rubbing.
Mr Tidy said:
C70R said:
Looks like this has turned into a project thread. Nice.
Great! I'm not a fan of spacers though, but E89 Z4 and E9* 3 Series wheels have much different offsets so getting wheels from one of those would push the wheels out to fill the arches. I ran a set of staggered 18" E89 wheels on my previous E86 and didn't have any issues with rubbing.
I'm going to get the variety with longer bolts, because they make most sense for a car that gets used hard.
I much prefer the way the car looks on staggered wheels, but I hate the way it handles. 255s are just too big for a car with 230lbft, and it just seems to tip the balance too far towards understeer that alignment can't dial out.
Buying a car with a fairly slim folder of service history and then using it hard on track is always a gamble. So far I've gotten away with replacing a few bushes and the usual wear and tear stuff. As I'm about to embark on a mini-project of sorts, I thought it would make sense to give the engine a bit of a health check.
The M54 is an astonishing engine. Possibly BMW's peak, outside of the non-M engines. In M54B30 format (as this one is), it's a really unstressed lump too - 230bhp/torque from 3 litres isn't pushing any limits really.
Outside of cooling systems failing, the only thing that really kills these cars is bottom end bearing wear. Given that the oil in the car was of unknown provenance, I thought I'd take advantage of Millers Oils' testing service. Millers screen for the presence of various substances in your oil, and give you a breakdown and an overall health check.
The oil that came out was allegedly OEM-spec 5w30, and had apparently been changed 8k miles ago. Given that many of those 8k have been quite hard miles (track, training, roadtripping), it's hardly surprising that it came out of the car as black as midnight. I switched to 5w40 given the change in the car's use, and will see whether more track time merits switching up to 5w50 or similar.
This got me wondering how bad the results would be, but I needn't have worried. The health check came back exceptionally clean for a car that's done 106k miles. Bearing material presence was exceptionally low (nice), and fuel/coolant contamination was also very minimal.
I'm going to take that as a massive win, and a sign that I should reward it with some shiny goodies and a bit of TLC.
The M54 is an astonishing engine. Possibly BMW's peak, outside of the non-M engines. In M54B30 format (as this one is), it's a really unstressed lump too - 230bhp/torque from 3 litres isn't pushing any limits really.
Outside of cooling systems failing, the only thing that really kills these cars is bottom end bearing wear. Given that the oil in the car was of unknown provenance, I thought I'd take advantage of Millers Oils' testing service. Millers screen for the presence of various substances in your oil, and give you a breakdown and an overall health check.
The oil that came out was allegedly OEM-spec 5w30, and had apparently been changed 8k miles ago. Given that many of those 8k have been quite hard miles (track, training, roadtripping), it's hardly surprising that it came out of the car as black as midnight. I switched to 5w40 given the change in the car's use, and will see whether more track time merits switching up to 5w50 or similar.
This got me wondering how bad the results would be, but I needn't have worried. The health check came back exceptionally clean for a car that's done 106k miles. Bearing material presence was exceptionally low (nice), and fuel/coolant contamination was also very minimal.
I'm going to take that as a massive win, and a sign that I should reward it with some shiny goodies and a bit of TLC.
C70R said:
Outside of cooling systems failing, the only thing that really kills these cars is bottom end bearing wear.
Seen a few go 'pop' from the oil pumps failing under fast road or track use, something to be mindful of. Strange really as not something I was aware of until the M52/54 onwards, and not a problem I recall from my days of abusing M90/30 engines (probably from before your time if you're proclaiming the M54 as one of BMW's best).CKY said:
C70R said:
Outside of cooling systems failing, the only thing that really kills these cars is bottom end bearing wear.
Seen a few go 'pop' from the oil pumps failing under fast road or track use, something to be mindful of. Strange really as not something I was aware of until the M52/54 onwards, and not a problem I recall from my days of abusing M90/30 engines (probably from before your time if you're proclaiming the M54 as one of BMW's best).M
camel_landy said:
CKY said:
C70R said:
Outside of cooling systems failing, the only thing that really kills these cars is bottom end bearing wear.
Seen a few go 'pop' from the oil pumps failing under fast road or track use, something to be mindful of. Strange really as not something I was aware of until the M52/54 onwards, and not a problem I recall from my days of abusing M90/30 engines (probably from before your time if you're proclaiming the M54 as one of BMW's best).M
C70R said:
I wouldn't usually be either. However, the Z4 I ran into at Cadwell had fairly modest ones fitted (12/20), and I couldn't believe the difference it made, particularly in stopping the rears getting lost in the pronounced arches.
I'm going to get the variety with longer bolts, because they make most sense for a car that gets used hard.
I much prefer the way the car looks on staggered wheels, but I hate the way it handles. 255s are just too big for a car with 230lbft, and it just seems to tip the balance too far towards understeer that alignment can't dial out.
You have to use longer bolts with spacers as the OE bolts don't go in many turns with standard wheels! I'm going to get the variety with longer bolts, because they make most sense for a car that gets used hard.
I much prefer the way the car looks on staggered wheels, but I hate the way it handles. 255s are just too big for a car with 230lbft, and it just seems to tip the balance too far towards understeer that alignment can't dial out.
Personally I'd get longer studs put in and use wheel nuts - it's so much easier to swap wheels than with bolts.
You're right about the staggered 255 rears giving understeer too.
I didn't know about M54s suffering from worn shells though - I thought that was only an S54 issue.
But M54s and the facelift N52s do generally seem to be pretty bullet-proof and hopefully yours will be too.
Gassing Station | Readers' Cars | Top of Page | What's New | My Stuff