BMW N20 BM3 Tuning Guide – Info & Horsepower Gains

Bootmod3 (bm3) is one of the most popular tuning options for F and G chassis BMW models. Pro Tuning Freaks bm3 offers a simple web and mobile interface for easy flash tuning. Bootmod3 also offers plenty of OTS flash maps with tons of extra features and options. If you're in the market for a BMW N20 or N26 tune then bm3 should definitely be a consideration. In this article, we discuss N20 bm3 tunes, maps, supporting mods, horsepower gains, and other helpful information.

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N20 bm3 Flash Tunes Basics

Standard bootmod3 tunes are off-the-shelf (OTS) flash tunes for the BMW N20 engine. These tunes are highly tested and proven on the F and G chassis BMW's, including the N20 engine. They're also easy to install and relatively affordable. A quick breakdown of costs for the N20 bm3 tune is as follows:

  • $595 software license
  • $50 map pack

The first step is purchasing the flash license which allows you to use the bm3 software to flash tunes to the vehicle. For $595 you also receive 1 OTS flash tune of your choice. An extra $50 unlocks all off-the-shelf tunes that bm3 offers for the N20/N26 engine. This isn't a necessary purchase upfront. However, most will appreciate the flexibility of having multiple tuning options.

Bootmod3 N20 Flash Maps:

OTS maps available from Pro Tuning Freak's bm3 tune include:

  • Stage 1 (91 octane, 93 octane, E30)
  • Stage 2 (91 octane, 93 octane, E30)

Some different engines also have bm3 stage 2+ tunes. However, the N20 engine only has options for stage 1 and stage 2. We'll discuss these N20 bm3 tune stages and supporting mods. We'll also provide rough power estimates for each tune depending on fueling.

*It's a good idea to replace your N20 spark plugs prior to tuning. This is especially true if you haven't changed your spark plugs in 40,000+ miles. A tune will quickly expose old, weak spark plugs. We recommend sticking with the OEM NGK 97506 spark plugs.

N20 OEM NGK 97506 Spark Plugs

N20 OEM Ignition Coils

**All N20 horsepower numbers are rough estimates. We're also basing the numbers on the supporting mods we recommend. Extra mods may offer more power while fewer mods may result in less. Additionally, power can vary significantly from dyno to dyno and many other factors.

N20 Low & High Compression

Alright. Two more important topics before diving into the actual tunes, power gains, etc. First up are the low-compression 28i models versus the higher compression 20i models. The N20 models with 20i badging use an 11:1 compression ratio and have 181hp and 199 lb-ft. Next are the 28i models with a 10:1 compression ratio and 241hp / 258 lb-ft.

The 28i models have a higher starting point for horsepower. They're basically the same N20 engine less the compression difference. As such, horsepower gains will appear greater on the 20i models with the lower horsepower starting point. Some 20i models can even make similar total power to the 28i models with the same mods. That leads us to the next topic.

BMW N20 EWG vs PWG

High compression BMW 20i models are either PWG or EWG depending on the year of the vehicle. Most switched to EWG around model year 2013. We wrote an article about the N55 PWG vs EWG here. The same basic concept applies to the N20 engine. Electronic waste-gate (EWG) models are more capable than PWG, so gains will be quite a bit higher.

The 28i models are also EWG or PWG depending on year. However, the difference in power gains is less drastic than that of the lower output 20i models.

We're going to ignore the PWG 20i models for the sake of this post. You can find helpful info about N20 horsepower gains on the bm3 site, too.

1) N20 BM3 Stage 1 HP Gains & Mods

Mods Recommended: Intake

There aren't any necessary mods to run these conservative N20 bm3 stage 1 tunes. Simply flash and go. The N20 stock intake is also pretty efficient on modest tunes like this one. However, we still like the overall idea of an intake upgrade. If not for the small horsepower gain we think an intake is worth it for the sounds alone.

That said, these bootmod3 stage 1 tunes are the least aggressive option. Power gains are still pretty good and you should notice a pretty big difference in feel. Anyways, if you just want a bit more power without going too far the stage 1 bm3 tunes are a good choice.

Bm3 Stage 1 Horsepower

91 octane: 250-260whp

93 octane: 250-260whp

E30: 260-270whp

Most stock N20 28i engines will dyno around 225-235whp on a dynojet. Power gains with these modest N20 bm3 stage 1 tunes are in the 25-40whp ballpark depending on fueling. Again, total gains for the 20i EWG models will be higher due to the lower starting point (around 170whp stock).

Anyways, these are pretty respectable gains for a modest tune. It's a good option to stay on the safe side and keep the engine healthy for the long-term. Those wanting more power will want to consider the stage 2 flash tunes, though.

2) BMW N20 Stage 2 HP Gains & Mods

Mods Recommended: Intake + VRSF Downpipe

BM3 stage 2 N20 tunes provide a solid horsepower bump over the modest stage 1 tunes. We're recommending a downpipe here, which is responsible for a good amount of the extra power. Not only does an N20 VRSF downpipe offer plenty of power, but it's also healthier for the turbo and engine. Reducing back-pressure helps improve turbo spool, too.

Regardless of stage we think a downpipe is an excellent mod for the N20 engine (or any turbo engine for that matter). You may also consider a FMIC upgrade at this point to keep IAT's down. It will help offer more consistent performance.

BM3 N20 Stage 2 HP

91 octane: 265-275whp

93 octane: 270-280whp

E30: 280-290whp

The 28i and EWG 20i models will end up roughly in the 265-290whp ballpark with stage 2 tunes. These tunes are starting to get aggressive enough that fueling becomes more important. Most N20's shouldn't have an issue with an E30 blend, but pay attention to AFR's. If you have access to E85 we highly recommend running E30.

Again, a bit more power may be possible with extra mods like a FMIC. Roughly 290-300whp is probably the limit on these bm3 stage 2 tunes, though. Those looking to go further should consider a back-end flash stack or custom tuning.

3) N20 bm3 BEF + Custom Tuning

Mods Recommended: Intake + VRSF Downpipe + FMIC + Methanol Injection

While this can be fun to think about we don't fully recommend going this route. The N20 isn't the most durable engine with higher boost. 22psi is generally the safe limit for the N20 engine. Sure, you can make more power at that boost by running more aggressive ignition timing. That can also be a risky move, though.

Anyways, those looking to push too far beyond 300-325whp and 350wtq should consider internal upgrades. We wrote a post here about the N20's engine limits. Nonetheless, for those looking to push the limits look no further than a JB4 + bm3 back-end flash or custom flash tuning. Both are capable of maxing the N20 on the stock turbo.

Most N20 bm3 custom tunes can max the stock turbo, which will likely fall in the 310-330whp ballpark. Again, this is assuming all the above mods are at work. You'll definitely need quality fueling and likely methanol injection.

BMW N20 Bootmod3 Summary

The BMW N20 2.0 inline-4 certainly isn't the most capable BMW engine around. However, it does leave plenty of power on the table. BM3 flash tunes have the ability to boost the N20 to the next level.

Stage 1 tunes are the less aggressive option, but still offer solid horsepower gains. Expect the N20 to fall roughly in the 250-270whp ballpark with bm3 stage 1 tunes. Next are the stage 2 tunes, which can take the N20 as far as about 270-290whp with a downpipe upgrade. Those wanting more should consider custom bm3 flash tunes or stacking a JB4 + bm3 BEF.

Ultimately, if you're in the market for an N20 tune then the bootmod3 flash tunes are a solid choice. We still prefer the JB4 for its simplicity and on-the-fly map changes, but some prefer flash tuning options. Either way, a tune and simple bolt-ons can turn the N20 into a totally new experience.

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