Questions about reliability.

[Sirmario]

Greetings all, I am in the market for a z4 2009+, i really find these cars attractive and need a fun car to drive. I currently own a CLS550. Love it, but I want a two seater manual. The more I research the Z the more I am starting to love it.

I would drive it alot, 300 miles per week probably.
I am set on the 6 cylinder engine. Which one is more reliable?
S30i? Or s35i?
If you have any other suggestions or tips please let me know. Looking forward to being a long time member.

Regards
M.

[tranquility]

Ok, so you're set on the 2nd gen. I dunno about the reliability part of the 30i but the 35i had HPFP and fuel injector prbs, but they should've been sorted (replaced) out a long time ago but something to look out for.

You come from that MB and a quick google says it has >400 in hp and tq. Even though it's close to 2 tons, I dunno if you'd be satisfied w the power of the 30i. When I tested all the trims available to me, I thought that the 35i was just right and the 30i was a bit underpowered and 35is overpriced for what one was getting.

GL.

[Sirmario]

Originally Posted by tranquility

Ok, so you're set on the 2nd gen. I dunno about the reliability part of the 30i but the 35i had HPFP and fuel injector prbs, but they should've been sorted (replaced) out a long time ago but something to look out for.

You come from that MB and a quick google says it has >400 in hp and tq. Even though it's close to 2 tons, I dunno if you'd be satisfied w the power of the 30i. When I tested all the trims available to me, I thought that the 35i was just right and the 30i was a bit underpowered and 35is overpriced for what one was getting.

GL.

Well that's good to know that I may have to go with the 35i. Which one do you have and do you know when they made those corrections? Which years I should try to avoid. My CLS is beastly close to 500hp, but I want something nimble to drive.

[tranquility]

Originally Posted by Sirmario

Well that's good to know that I may have to go with the 35i. Which one do you have and do you know when they made those corrections? Which years I should try to avoid. My CLS is beastly close to 500hp, but I want something nimble to drive.

Nimble is relative so while it definitely is compared to your beast, one can still feel the weight when cornering. I have the 35i and I assume that those prbs have been sorted out, i.e. replaced, so best to get their service records.

[Ichiro]

Originally Posted by tranquility

Nimble is relative so while it definitely is compared to your beast, one can still feel the weight when cornering. I have the 35i and I assume that those prbs have been sorted out, i.e. replaced, so best to get their service records.

I concur

I have a 28i (2L 4cyl turbo) and I thought it was nimble till I drove a Mini Cooper JCW....then my car felt....not so nimble.

OP, if you're used to 500+ Hp then 35i will satisfy you whereas the 30i will leave you wanting more (if you like a bit of shove-into-the-seat feeling). I was ok with the power and torque of the 28i at first but eventually succumbed to some mods to turn up the spiciness.

[Sirmario]

Great thank you for the replies the market is kinda crappy for manuals at the moment. I will be on the look out.

[Sirmario]

Moving this thread to the general discussion.

[proboner]

The 30i will definitely be more reliable, but I personally wouldn't buy anything other than the 35i. There are still plenty of issues with HPFP, injectors, etc, so know that you'll have to replace them more frequently than you probably imagine and that it will be EXPENSIVE.

If you do go with a 35 and want a manual trans it's only available on the 35i (not 35is) and they're VERY rare compared to the auto. Will probably take a while to find one.

[Sirmario]

Originally Posted by proboner

The 30i will definitely be more reliable, but I personally wouldn't buy anything other than the 35i. There are still plenty of issues with HPFP, injectors, etc, so know that you'll have to replace them more frequently than you probably imagine and that it will be EXPENSIVE.

If you do go with a 35 and want a manual trans it's only available on the 35i (not 35is) and they're VERY rare compared to the auto. Will probably take a while to find one.

I see, is yours manual and did you have to do any of those repairs. If so how diy are they? I am a mechanical individual and would do most of the repairs myself, I would consider this my toy car and would do most of the things myself.

[B21]

I’d echo the comments on the 35i / 35is…

If you are planning to average 300 miles per week then you will probably sooner rather than later hit most of the specific faults relating the the 35i / 35is..

Having had a quite heavily tuned 20i version which is essentially the same car as the 28i I’d say that a tuned 28i maybe an option to consider..

A re-mapped / tuned 28i would have the same power n torque as a stock 35i..not a 35is plus it’s a lighter more nimble car than the 35i/35is.

Of course a few people get excited about the 4 cylinder vs 6 cylinder argument.

A re-mapped 28i would eat a 30i which has little room for tweaking.

The other point reference 30i is that production was halted in 2011 so they tend to be older and certainly in the UK tend to less well optioned.

[Sirmario]

Originally Posted by B21

I’d echo the comments on the 35i / 35is…

If you are planning to average 300 miles per week then you will probably sooner rather than later hit most of the specific faults relating the the 35i / 35is..

Having had a quite heavily tuned 20i version which is essentially the same car as the 28i I’d say that a tuned 28i maybe an option to consider..

A re-mapped / tuned 28i would have the same power n torque as a stock 35i..not a 35is plus it’s a lighter more nimble car than the 35i/35is.

Of course a few people get excited about the 4 cylinder vs 6 cylinder argument.

A re-mapped 28i would eat a 30i which has little room for tweaking.

The other point reference 30i is that production was halted in 2011 so they tend to be older and certainly in the UK tend to less well optioned.

THANKS for the reply, any issues it being a 4 cylinder pushing the numbers of a six? Displacement and pressure could cause issues 50k to 100k down the road? Curious what the major issues are with the 28i.

[B21]

The N20 engine used in the 28i has one Achilles heel, pre 2015 had a poorer quality cam chain and associated plastic tensioner..

A percentage of cars typically between 50k and 80k will suffer from failure for this part…

It can be replaced preemptively with the later better quality cam chain sub system..cars with lots of use of the stop start and extended oil changes seem to be causal factors..

Apart from that they are good motors..technically being both shorter and lighter they sit behind the front axle making the handling sweeter than the older 6 pot engines.

Pep wise, especially with a simple ECU map they are a much more capable engine with more and broader torque and if married to the 8 speed auto a fine combination.

Unless you want the ultimate in straight line acceleration with a 35is or ‘need’ to hear 6 pots firing they are a better car than the earlier 6 pots.

For sure the N52 engine is a great engine and has shown great reliability.

I miss my N20 version, it offered a lot of fine handling and good performance for a fraction of the running costs of a 35i/35is.

[Sirmario]

Thank you for the input. I appreciate it.

[geez4]

I am looking at the 2009-10 35i version in Australia. It is rare to see 23i without either high kms or extensively modified. Plus my wife wants the fancy interior.

I currently have my eye on an Orion Silver 35i with about 65,000km on the clock. Just in time to put the next 60,000 and pay for all the problems