N20 vs N52 vs N54 Engine

[GoSteve]

I just watched the entire series of SimpleCarGuy on YouTube changing his timing change on his N20 engine 28i Z4. However, only after changing the timing chain did he discover it wasn't just a knackered timing chain. He calmly said 'I threw a wrench'. So, then he sets about changing it a new engine. All in his garage at home. It was at this point, I thought, I might have called someone. Actually, I might have called someone much much earlier. So that leads me to ask a good question. What engine should I get?

Ultimately, I want more power. A 3.0 running 254 bhp is okay, but 280 bhp or a little more would be better.
If I thought the N54 engine was reliable, then it would be a 35i, 35is. I am not a great fan of sequential manual gearboxes. However, some advice and experience would be welcomed. That brings us to the N52 2.5 or 3.0. I have a 23i so, given I am looking for more power, it would have to be the N52 3.0. An auto would be preferrable, but I wonder if the ZF 6HP19 auto box is a little ponderous in the 3.0. So that brings me to the 2.0 N20 engine. Ideally, if I thought I am going to start a YouTube comedy channel of me changing timing chains and engines for you all to enjoy, that would be my first choice. A 2.0 8 speed auto remapped to 280 bhp.

My 23i has been utterly faultless and superbly smooth. My previous 3.0's were the same. Smooth and reliable.

So, N20, N52 or N54. What are the risks, issues, reliability and possible costs to fix.
I think we could safely say the N52 is fairly bullet proof. But what about the N20 and N54 both can have issues. What are those issues and which engine is the best balance against risk and performance.

 

[Anonymous]

This addresses the N20..

https://z4-forum.com/forum/viewtopic.php?f=23&t=121232&p=1734136&hilit=pbondar#p1734136

 

[GoSteve]

This addresses the N20..

Yes, fantastic read, and should be a sticky.
It was that article and SimpleCarGuy that led me to pose the question (plus, way too much time on my hands). Clearly, and maybe I am wrong, the N52 seems to be a safe choice, but a little limited by being naturally aspirated. Celtic Tuning can take the N52 3.0 to 272 bhp. Not too bad.

Your article demonstrates the N20 is safe to 280 bhp, what are the unrelated and underlying risks, unrelated to tuning. Is the DNA of the N20 engine such that it is 'likely to fail' at 50-75k miles, and does the N54 come with a different set of problems and risks.

I am trying to weigh up my choices for changing my Zed for a little more power.
N20 280 bhp, N52 272 bhp, N54 more than enough.

 

[Smartbear]

This addresses the N20..

Yes, fantastic read, and should be a sticky.
It was that article and SimpleCarGuy that led me to pose the question (plus, way too much time on my hands). Clearly, and maybe I am wrong, the N52 seems to be a safe choice, but a little limited by being naturally aspirated. Celtic Tuning can take the N52 3.0 to 272 bhp. Not too bad.

Your article demonstrates the N20 is safe to 280 bhp, what are the unrelated and underlying risks, unrelated to tuning. Is the DNA of the N20 engine such that it is 'likely to fail' at 50-75k miles, and does the N54 come with a different set of problems and risks.

I am trying to weigh up my choices for changing my Zed for a little more power.
N20 280 bhp, N52 272 bhp, N54 more than enough.

It’s the torque difference that sets a remapped n20 apart from the normally aspirated n52, it’s 220 odd lbft compared to almost 300lbft. That’s a fair amount of difference in pulling power available over a wider rpm range as well.
Rob

 

[GoSteve]

How many people of experienced problems with the N20 engine, despite good maintenance?
I have been looking for an N20 2.0 auto, with the objective of getting a remap to 280 bhp.

I wondered what the likelyhood of timing chain failure on an N20 vs alternative issues with an N54 35is.
Or are the issues rare and not worth worrying about?

Despite lots of reading, I am finding it hard to quantify the overall risks. N20 clearly seems the best choice on paper, but are the risks of engine issues something I should be considering.

 

[Busterboo]

Mmm ... all this makes me want to use Celtic's 'Emotion2' to take my 35iS to 392bhp.

https://www.emotion-tuning.co.uk/

 

[sunnydays]

Mmm ... all this makes me want to use Celtic's 'Emotion2' to take my 35iS to 392bhp.

https://www.emotion-tuning.co.uk/

Don't use a generic celtic map. Use MHD and choose a map from a proper source.

 

[Mr Tidy]

Interesting question OP!

Of the engines you mention I've only had any experience of the N52 in my first 2 Coupes, but I liked it so much I've now got one in my 3 Series daily. And you've been running one in your 23i, so you know what they are like.

A remapped N20 does sound like it would be fun, but from what you've mentioned my concern would be that a cam-chin issue could prove to be terminal.

Whereas the issues I've read about with the N54 engine seem to relate more to peripheral components, so while there will always be some cost involved hopefully none of them are going require a replacement engine.

In your position I suspect you'd soon get used to a 30i and want more power, so maybe a 35i or 35iS would be the way to go?

Unless you go back a generation and get an S54. :lol:

 

[sunnydays]

So, N20, N52 or N54. What are the risks, issues, reliability and possible costs to fix.
I think we could safely say the N52 is fairly bullet proof. But what about the N20 and N54 both can have issues. What are those issues and which engine is the best balance against risk and performance.

N54 is generally pretty reliable, just the ancillaries around it that can have issues. Prices depend on if you are DIYing or getting bent over by a dealer.

Common Faults
Injectors
High Pressure Fuel Pump
Oil Filter Housing Gasket
Valve Cover Gasket
Valve Cover (Cracking)
Turbo Wastegates
AC Pulley
Engine Mounts

Other than the above it is a solid engine.

Edit: They will also make circa 450bhp with a custom remap and have a great tuning platform and community.

 

[GoSteve]

Other than the above it is a solid engine.

A remapped N20 does sound like it would be fun, but from what you've mentioned my concern would be that a cam-chin issue could prove to be terminal.

Those are really helpful responses.
It's the risk of totalling an engine that concerns me most. I can handle failed ancillaries (within reason).
My annual mileage is really low, so fuel economy really isn't an issue.

 

[Anonymous]

The whole 4 pot vs 6 pot debate gets hot under the collar...

The massive generalisation is IMHO..

20i/28i with remap...great performance...great handling..pretty reliable for most people most of the time
30i adequate performance ...slightly more ponderous handling.. very reliable with the odd lifter issue
35i/is best performance..a bit more ponderous handling..chassis tends to get overwhelmed...predictable failures in turbos/injectors/coils

All share common issues like oil/water exchange , cam box covers/gaskets , oil filter gasket/housing

That should upset someone somewhere...

 

[sunnydays]

The whole 4 pot vs 6 pot debate gets hot under the collar...

The massive generalisation is IMHO..

20i/28i with remap...great performance...great handling..pretty reliable for most people most of the time
30i adequate performance ...slightly more ponderous handling.. very reliable with the odd lifter issue
35i/is best performance..a bit more ponderous handling..chassis tends to get overwhelmed...predictable failures in turbos/injectors/coils

All share common issues like oil/water exchange , cam box covers/gaskets , oil filter gasket/housing

That should upset someone somewhere...

20i/28i with remap...great performance...great handling.

35i/is best performance..a bit more ponderous handling..chassis tends to get overwhelmed

LOL this shill again hyping up his 4 pot with its mythical handling abilities

 

[R.E92]

I just don't think you'd be happy with the relatively low output of the N20. 280hp isn't much these days, even a boring Golf comes with over 300hp from the factory.

With the 35i and 35is you are above 400hp with a remap and around 440hp with downpipes added and a custom tune. If you ever want more then you can go to around 600hp with upgraded turbos without needing any transmission or engine work.

 

[Mr Tidy]

I sort of did something similar to the 23i to 30i change last year when I swapped my 325i with 218PS for a 330i with 258PS, both with the N52 engine.

The 330i is definitely quicker, but it isn't night and day different.

But when I swapped my 3.0Si (265PS) for my M (343PS) in December it was just WOW!

So if you want a significant performance gain the N54 has to be the way to go, especially as others have pointed out that can also be remapped for more if you decide you need it.

And a 6 does fill the engine bay so much better! :lol:

 

[mcbutler]

Mmm ... all this makes me want to use Celtic's 'Emotion2' to take my 35iS to 392bhp.

https://www.emotion-tuning.co.uk/

Don't use a generic celtic map. Use MHD and choose a map from a proper source.

Celtic maps are not generic, they are developed in house and tweaked individually for each car if done on site. I think the guys at Celtic would be quite unhappy to hear people calling them 'generic'.
My 35i was done in house at their facility in Cornwall, it took around 2.5 hours with the ecu being removed and retweaked upstairs over and over again. My particular engine at its individual 'best tune' was at 365BHP and 400lb/ft torque. Not too bothered about BHP as its torgue that gives the accelaration, drivability.
AND its done on a rolling road so I know what I am getting, not what it says on a box.
After fitting catless downpipes Celtic remapped it for me to 395 BHP and 415lb/ft and I LOVE IT

 

[RobbiZ4]

20i/28i with remap...great performance...great handling..pretty reliable for most people most of the time
30i adequate performance ...slightly more ponderous handling.. very reliable with the odd lifter issue
35i/is best performance..a bit more ponderous handling..chassis tends to get overwhelmed...predictable failures in turbos/injectors/coils

All share common issues like oil/water exchange , cam box covers/gaskets , oil filter gasket/housing

Fully agreed!

 

[mcbutler]

My previous Zed was a 23i, I loved it, so smooth and driveable, especially after Celtic mapped it and modified the torque curve.
Anyhow, I bought a 35i with only 24K on it.
So many people go on about the engine being unreliable whilst mapping the hell out of their smaller engines. You dont have to be an engineer to realise that higher performance = higher stress and wear = higher chance of failure.
The N54 engine is extremely strong and is well known as probably one of the most tuneable engines ever made. An N54 with stock INTERNALS is good for 700BHP!!!!!! bigger turbos, port injection, stage 2 HPFP.
Without any its good for nearly 500!!!
If you are worried just get a warranty direct full warranty - I paid £1100 for 3 years complete cover, even covers MOT fail items (not tyres and the like of course)... It also covers items that are wearing, not just items that fail.
The handling issues are simply what suits you, I love being able to slide my car round a corner, kicking the tail out with a blip of the throttle. You can easily tune up the suspension thanks to EIBACH, apart from that a limited slip diff is also a good idea.

Go N54 and live it LIVE IT :evil: :evil: :evil: :evil: :evil:

 

[Deepseaskateboard]

I very much doubt anyone could realistically use anything over 280bhp to it’s full potential on public roads. Perhaps a trained professional driver
BHP figures have just become a marketing statistic and ‘who has the biggest pair’ but come on, if you are putting down 400bhp to it’s full potential around Wales, or on the M1, you won’t last long. Financially or otherwise!

Even 280 is enough to get into some serious trouble.

A z4 20i stock probably is quicker than 90% of cars on the road.

 

[ronk]

There are very few “driving gods “ out there. Most of us with big Bhp numbers are kept away from the ditches by the electronics.

 

[Silverstar]

If you really want more power forget the N20 and just go for the N54 35i or 35is, just make sure you keep a grand or two aside for the inevitable repairs it will need. Sorry but 6 pots will always be better than 4, that is why the current B58 is such a gem! As for handling you aren't buying a track car, if handling is your main objective get a Boxster be it one with a 6 pot! For most people most of the time I doubt they will notice any difference in the handling between the N20 and N54. :stir: