How Much Power Can the BMW N20 Handle
Since the initial release of the N54 in 2007, BMW has earned a reputation for building a line-up of turbocharged engines that are capable of significant power gains with a tune and basic bolt-ons. The N20 was BMW’s first turbocharged, direct-injected 4-cylinder engine. From the factory the strongest version of the N20, found in 28i variants, is rated at 241hp and 258tq. However, real world dyno testing suggests those numbers are slightly underrated with the engine producing similar numbers to the wheels. Depending on the assumed drive-train loss, this would put the N20 in the ballpark of 275hp and 290tq at the crank. A stout performance for a stock 4-cylinder, however, as we know with almost any turbocharged engine, there is a lot of untapped power that some basic mods can unleash. Though, the question is – can the stock components handle the newfound power?
Check out our N20 350whp for $1,500 guide here!
A Look Into the BMW N20
There seems to be quite a bit of information floating around forums that the BMW N20 is a relatively weak motor. Although, for some reason, it is challenging to find any solid evidence the N20 is truly as weak as some suggest, but that is not to say the engine is flawless. It has been plagued with a major issue involving the timing chain, which in some cases may lead to complete engine failure. BMW updated the timing chain in 2015, which seems to have solved the problem for the most part. We will write a more in-depth post regarding the timing chain issues in the future, but for now let’s examine the more exciting aspects of the N20.
As stated, the engine is underrated from the factory and already provides respectable performance for a fuel-efficient 2.0L engine. However, for some enthusiasts, a little extra power can go a long way. Like other turbocharged BMW engines, the aftermarket industry is littered with tunes and basic bolt-on modifications. Common mods include tunes, air intakes (CAI), catless downpipes (DP), and upgraded front mount intercoolers (FMIC). Typically, when all mods are combined the engine may be referred to as full bolt-on (FBO). An FBO N20 engine with a small E85 mixture is capable of producing upwards of 350hp and torque. However, the question remains – can the N20 really handle that much power?
As a disclaimer, it is important to note that putting a specific number on the upper limits of the stock internals and block is tough. The N20, as with any engine, may be capable of producing higher numbers than the engine can tolerate in the long-run during “glory runs” on the dyno. Additionally, every N20 is different. Some may be able to produce power and torque significantly above stock levels without issues, while other engines may let go much sooner. With that being said, lets dive into the generally accepted upper limits of the N20.
N20 Tuning Potential
The safe upper limits of the N20 appear to be somewhere in the lower-mid 300whp and wheel torque range. This is roughly where you will end up with full bolt-ons and some E85 in the N20, and the general consensus is not many owners are pushing their cars beyond this limit without upgraded rods at the least. You may be able to push the car a bit harder on the stock engine, but here are a few things to consider:
- Limit boost from stock turbos to 22psi
- Use data logging to your advantage – watch for lean conditions
- Oil starvation under hard braking or cornering
On a stock turbo N20 it is highly recommended to keep boost in the lower 20’s with 22psi being towards the higher end of the safety margin. Additionally, the N20 is known to have issues with running a bit too lean. This is concerning when pushing the engine towards it’s limits as lean conditions are more likely to cause engine knocks. Lastly, hard braking and cornering may cause the N20 to go through a period of oil starvation. Obviously, on a stock motor oil starvation is still a horrible thing, however, increased power may lead to more significant issues due to oil starvation.
The Importance of Having the Right Tune
I believe some consider the N20 a weak motor, because it is more finicky than the 6-cylinder N54 and N55 engines. There are many N54/N55 owners and tuners who have no idea what they’re doing. They toss a few mods on the car, turn up the boost, dump some E85 in the tank, and let it rip. In most cases, the engines hold up very well on stock turbos as they are simply not making enough power or torque to do significant damage without major abuse. In my opinion, the N20 is a relatively capable engine from the factory and performs well for a small 4-cylinder, however, they do require a bit more attention and knowledge than their counterparts.
It is highly important to ensure you are running the right tune on your N20. You cannot simply toss on some bolt-ons, E85, and crank up the tune to be as aggressive as possible. Ensure you have the right supporting and cooling mods, and your tune is properly accounting for the mods you are running. For example, running an upgraded FMIC will assist in keeping IAT’s to a minimum, thereby reducing the change of engine knock. Additionally, upgraded fueling components for heavy E85 mixtures will help the fuel flow and reduce the likelihood of the engine running too lean. In other words, keep the tune modest and do not push things too far. The extra 10hp from an aggressive tune is not worth the significantly increased risk of blowing the motor.
Overall Impressions
The N20 has earned a reputation for being a weak BMW engine, a reputation that I believe is falsely warranted. I am not saying it is as capable as the N54, N55, B48, S55, etc but is that what anyone would expect from the engine? It is a 4-cylinder 2 liter engine that was designed with entry level BMW models, not a 6-cylinder engine designed for mid-range or higher end models. If the N20 could really handle 500whp without breaking a sweat why would any enthusiast get excited about the 425hp M3 or 300hp N55?
The N20 does exactly what it was designed to do, and then some. A tune and simple bolt-ons can propel the engine into 300+hp and torque territory; respectable performance which remains fuel-efficient and enjoyable to daily drive with enough power on tap to have some good fun when called upon. However, the N20 does have its limits which may be a concern when looking to push things too hard. Equip your N20 with full bolt-ons and the appropriate supporting mods and a conservative tune. Do this and you will likely have a wonderful experience driving an engine that is powerful, reliable, responsive, fuel-efficient, and an all-around enjoyable driving experience. Treat the N20 like its BMW’s twin turbo S55 engine found in the M3/M4, then you may join the crowd of owners complaining the N20 is too weak.
Hi,
I’m driving a N20 engine here.
What is the difference between the 20i and 28i engines other than the compression rate?
And also, what could be done to counter the issue of engine oil starvation issue? I spoke to my local workshops, and all I got back was to top up more engine oil before heading to the track.
Is there a more conservative method? Or should I say, a more prudent method?
Hi Ballesteiro,
The compression and power are the biggest differences. The 20i engine is essentially de-tuned and runs less boost from the factory; I believe the exhaust is also a bit more restrictive. Otherwise, with a tune and bolt-ons they will produce pretty similar power with a slight advantage to the 28i models. Additionally, the higher compression limits strength a bit but not a considerable amount.
Regarding oiling, ensuring you’re topped off is probably about the best you can do. It really comes down to oil system design and that’s not cheap or easy to modify. The N20 (as with many other BMW models) uses a wet sump oiling system. Dry sump systems are best for track duty. I know the N54 has a few “upgraded” for the oil pan baffle. To be honest, I’m not sure if similar mods exist for the N20 and whether or not they even have any benefits. There is always risk associated with tracking a car that wasn’t designed for track use.
The N20 should be up for the task, just be cautious and aware of the risks. Long, high speed, high G corners, followed by hard braking, heavy acceleration, opposite turning etc can be dangerous. The oil sloshes around and oil starvation becomes possible. I don’t believe the oiling is all too different from the N54, N55 etc. They just have slightly stronger components that can better tolerate slight starvation.
Best Regards,
BMW Tuning
Really nice writing, good one. N20 with around 260 WHP is keeping it on the safe side and it’s a very nice alternative to a golf gti or so. That is why I bought 220i. I wanted an hot hatch with RWD and in my country, buying an m240i is like buying an M3 Competition in the US. Some engine tune, coilovers, upgraded steering parts and better brakes and I got myself a nice fun to drive car which it’s much more fun that any hot hatch FWD I have tried.
Very accurate description of the bmw n20 engine. I’ve driven three different f30 328i’s and currently own my second one… a 2013 328i m sport. As soon as I test drove this one I noticed it was the smoothest revving & most flexible n20 I’d driven. It was well maintained at dealer & I continue the same way. I’ve got a stage one jb4 tune on it & it’s a surprisingly strong engine. It feels like a 320 hp engine all day. I timed it on a dragy & got a best run of 4.6s to 100km/h (62 mph) & 13.0 sec flat 402m quarter… on a cool night it felt quick with non runflat new yokohama advans on rear. Unfortunately the highway pigs were hiding in bushes waiting for me at 11:00pm at night on a dead highway with no cars or houses anywhere nearby… 🤦♂️😏🤬 & they were in a 5 series bmw hwy patrol.!!.. It has been extremely reliable with around 110k kms (70k miles) on it with all servicing up to date. It’s a very comfortable daily with excellent performance. And it’s not a common golf fartbox which I love chopping to their amazement. If I was going to upgrade it would have to be something with the b58 engine.. very strong motor. And yes James the new generation of auto only front drive & awd hero drivers have no idea how to control a rwd car with any sort of power or how rewarding it feels.
Dyno results , 2015 320i xdrive is pushing 477whp and 501 tq with fbo including fmic and dinan turbo . 26lbs boost .
Hi Anthony,
Those are impressive numbers. Was that on a built engine? Please feel free to share a link or any additional information.
Thank you,
Zach
So there’s an important distinction to be made here in N20 engines: the pneumatic wastegate (pre 2014) versus the electronic wastegate (2014+) versions.
In short, according to Burger Motorsports (https://www.n54tech.com/forums/showthread.php?t=15536) the old pneumatic wastegate versions were more tuner friendly, allowing for freedom to control boost. Furthermore, “E85 mixtures are not suggested for the electronic wastegate x28i model as the high pressure pump may have a hard time keeping up with fuel volume demand.”
At some point later, Burger Motorsports cracked the code with the electronic waste gate and now provide a product that will handle EWGs better….but “For the N20 motor the wastegate harness is relatively easy to reach but there is little benefit to be had. The JB4 can control up to map 2 levels well and the N20 motor is not reliable at higher boost levels. For these reasons we’ve not done much N20 EWG development.”
Its true that a true BMW power aficionado would likely not be targeting the N20 for their vehicle purchase (so it’s no big loss to not have EWG support for N20 engines), but it is a bit disappointing for those of us who want to max FBO the EWG 320i or 328i we just so happen to own.
I’d love to know what you’ve done to achieve those numbers also. I have a Dinan boosted ’14 328i with electronic wastegate and I have no idea what kind of power it is making yet. I just know it feels like a completely different car.
Bolt-ons are as follows:
Dinan Big Turbo
VRSF 5″ stepped intercooler
VRSF charge pipe
Turner Motorsport Upgraded Silicone Turbo Inlets
Wagner downpipe with high-flow sport cat
Borla S-type cat back exhaust
GFB DV+ Diverter Valve upgrade
K&N Cold Air Intake
Dinantronics stage 4 software upgrade
I’ve also gone a couple of steps colder on plugs with the M4 part # and upgraded coil packs to high-performance Bavarian. Currently experiencing what I can’t tell is a spark issue or fuel delivery issue where maybe once very 3-4 pulls power cuts out between 4500rpm and WOT. Might try to reduce the plug gap and also thinking of doing the Dinan high pressure fuel pump upgrade.
I have a 328i x drive, and I was wondering if I could still do full bolt ons and e85 even though it’s awd, or would it cost more?
Not worthing puting any money in the n20. It’s a weak engine I owned 2014 bmw 528i rwd n20 and even after modifications you have major risks of engine failure later down the road and once it goes over 100k miles it’s. Risky engine to put all that money when you could just upgrade to the n55 car for half the price of mods and more power and more reliablity. Even after all mods you have to change the brakes to big brakes that will cost a lot without that all the power is too much for those tiny crappy brakes stock for the n20. My 528i was totaled due to complete brake failure after a brake fluid flush by bmw in okc did a botched job and it was too late to be addressed. I can assure you those BMWs are very heavy cars and braking is the key component to be upgraded. The n55 can have more power reliably for same price of all mods and bigger brakes stock that will be fine with power upgrades.