Doing some desk research

E

Ed.Straker

Member
 Hertfordshire
Hello, I’m a newbie looking to buy a Z4, my plans to test drive some have been put on hold courtesy of the current developments.

My background is in part in data analysis so thought I’d do some desk research until I can go and do some test drives.

I have a few questions having read this forum for a couple of weeks and looking at Honest John, Evo, TG, various back US magazines etc

Reliability

Seems from what I can see that the first Z4s with the N52 type engine seem to be very reliable, there seems to be several issues mostly engine related on the 35 with the N54 engine?

I guess the better N55 engine arrived too late for the initial Z4s?

There doesn’t seem to be many comments here about the 20 and 28 which use the N55’s little sister?

Popularity

What I find slightly strange but maybe only the faithful buy the biggest engine versions is that there seems to be many 35 owners here but as a percentage of cars sold they represent only a small fraction of all Z4s made according to the websites on how many cars were sold by model by year?

So is the answer that only the faithful buy the 35 and all the problems are collated here?

Reviews

Reading press articles the general commentary seems to be from journos that the 35 was overpowered or too heavy for the chassis.

Given that the 30 seems to be a similar engine those comments don’t seem to materialise about that version? So is it the weight or the power or both?
 
Well my car 11 year old 23i N52 engine approaching 90k miles, not a single problem with the engine. No cracked plastics or funny noises.
But i now do 5k oil changes, not wait for 15k which the computer might tell me to do.
And of course loads more variety of options 2nd hand with 23i.
 
Good morning,
Well you are lifting the lid off a huge can of worms discussing engine weights, balance etc.
I am not qualified to comment but many will tell you the weight distribution, and slightly less of it, makes the 4-cylinder turbo car handle better on the twisty bits, but then the 35iS boys just wait until a straight and blast up behind you again. So on a standard British road I'd suspect the swings and roundabouts would balance out and A to B would be about the same. If that is true then I guess it would come down to whether you prefer smooth progress with satisfaction of a job well done, or the outright push in the back of all that torque when the road straightens out.
It would be interesting to find out (no idea how) what percentage of the available performance the owner of a 35iS is able to use, compared with a 20iS for example.
This all of course applies to standard cars. Once you start messing about with suspension, different tyres etc then everything changes.
And of course, a quick search on here will then bring up the question of remapping the 4-pot turbo.
My wife runs an early 2.5i auto. I have to say, whilst I much prefer driving my E89 remapped 4-pot, the noise her straight 6 makes is far superior.
With your budget the Z4 world is your lobster, so in your shoes I'd be trying out as many different models as possible to see which you fit, which you like, which you could live with etc.
Good luck with it. The bonus you have is that there is not likely to be a huge amount of depreciation on any of the older models right now, so if after 6 months you're not gelling with it, you could probably move it on at no great loss.
 
Thanks for the comments...

I wondered whether the 4 pot Z4s were regarded as the elephant in the room.

When I did consider a Boxster or contrary to what I said about coupes a Cayman the 4 pot engines were regarded as worse than Beetle engines by the guys in the Porsche forums. Mind you if you didn’t have carbon ceramic steering wheels with self levelling ash trays and PDK music player you were regarded as the lowest of the low. I worked with various Porsche owning chaps and I suspect that was part of the reason I excluded them for my choice as a toy.

Never having been a BMW fan..a Bavarian I worked with described BMW ownership being only fit for gypsies..I’ve not yet been assimilated by the Borg.

So the 4 pot 6 pot issue doesn’t bother me..the only decent engines are V5/V6/V8!-:)

What I do know is that on Audis the longer 5 cylinder engined cars handled worse than the 4 pot or V6s as the weight moved forward and in the case of the 90 well past the front axle and they were heavier too..

When I drove a 90 when my then 80 Quattro went in for body repairs I was surprised how wallow-ey the front wheel drive 90 was.

Similar on the A4 the front wheel drive version just didn’t feel as nice as the Quattro variant but I suspect that was 4 wheel drive plus weight shift rear with the drive train and rear diffs.

The BMW adverts that banged on about perfect balance aka 50/50 I think were directed at Audi with their nose weight biased front wheel drive cars, especially in the 90s.

So intrigued about the 4 pot versions..I remapped my Audi A5 and released another 60+ bhp plus more torque..amazing what those turbo engines can do.

I’ll try and drive a 35 and 28 back to back when I can and see how they compare with the 30 I drove.

I plan to keep whatever car as my toy for some time, I can’t see many new IC cars coming out..so keen not to rush into it despite my normal impetuous behaviour when buying toys.

Again thanks for the feedback on that and the N52 engined cars!
 
T
enuff_zed said:
I am not qualified to comment but many will tell you the weight distribution, and slightly less of it, makes the 4-cylinder turbo car handle better on the twisty bits, but then the 35iS boys just wait until a straight and blast up behind you again.
Click to expand...

Pretty sure the same conversations were had in the 80s about E30 325i vs E30 318is. :D The cars change, the story doesn't :D
For me it's got to be a straight six every time for driving enjoyment.
 
Ed.Straker said:
So intrigued about the 4 pot versions..I remapped my Audi A5 and released another 60+ bhp plus more torque..amazing what those turbo engines can do.

I’ll try and drive a 35 and 28 back to back when I can and see how they compare with the 30 I drove.
Click to expand...

Driving a 28 will give you a fair idea of the differences to a straight 6, but of course all three 4-pots can be tuned to the same output. A lot of 18 and 20 owners have an easy 280bhp, which is seen as well within safe limits. From my perspective that gave me 100 more ponies on my 20i, with the associated hike in torque, plus a wider spread across the rev range too.
 
The 4Cyl engines can indeed be re mapped to give some quite impressive outputs - but I chose my 6cyl not only for its decent standard output but its basic relaxed smoothness and inherent balance - That feature is often ignored when engine outputs are discussed.
Ive attached a YouTube video which explains the science behind it -

https://www.youtube.com/watch?v=82rxavW0A3c&t=921s
 
I found the heavier 6 pot cars handle better than the 4 pot 28i I tried, in fact it was quite noticeable. I put it down to the 100kg or so less weight of the 4 pot, meaning the heavy roof mech isn’t counterweighted by the engine. So perversely more weight up front improves the E89. Thats just imho. :thumbsup:
 
I don't really get the importance people apply to the weight figure when comparing the models. I drove a 20i before buying my 35i and I wouldn't have been able to tell you which weighed more. I suppose from a top trumps point of view it's the only area where a 4cylinder is going to score points, that and mpg.

On the scales the 35i weights 100kg more but that isn't all engine and it's not all added in a single place. Half of the weight increase may be the engine block and the additional turbo but the rest is going to be as a result of the larger brakes, beefier suspension and thicker driveshaft, diff and axles. The transmission will also be heavier.
 
If you're really wanting to reduce the weight then the lumps of meat sat in it along with their paraphernalia probably don't help much either :D
I just get in and drive it for the pleasure.
I also prefer the sound of the 6 over the 4
 
M340 said:
Pretty sure the same conversations were had in the 80s about E30 325i vs E30 318is. The cars change, the story doesn't
For me it's got to be a straight six every time for driving enjoyment.
Click to expand...

I have had both E30s the 325i and the 318is both very enjoyable cars and drove great in different ways, sure the 318is felt lighter and more dartier but you can't get away from the creamy smooth inline 6 of the 325i. I think the same applies to the E89 Z4.

I remember reading a test article or video on the Z4 where they said that the handling was slightly better with the 4 pot but they said the difference isn't that great and most people in everyday driving probably wouldn't notice much difference, the difference would only be noticeable if you are really going at it like on a track.

Personally I would take the 6 pot any day over the 4 pot the difference in MPG isn't that great unless you are doing mega miles nor is the handling but the difference with the creamy smooth 6 pot and the sound especially with the top down is mega. After all this is supposed to be a fun car right? BMW only put the N20 in the E89 to comply with ever stricter emissions set out by Brussels.
 
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