It's no secret that the S55 platform is bursting with potential. In this article we show you exactly how we took an F80 M3 to 900hp(721whp) all done on the stock block and transmission. Will it last? Read below to find out.
S55 ORIGINS
The S55 engine is roughly an evolution of the infamous N54 engine produced by BMW. This engine has been responsible for converting countless USDM and JDM fans over to the DSM platforms, due to it's ability to produce upwards of 700whp on the stock block. The N54 however came with some less than desirable maintenance and repair items, none of which are a concern for the S55.
Everything we love about the N54, the S55 does even better. The S55 engine comes with larger MHI turbos good for roughly 700HP (approximately 580whp)with supporting modifications. A number only achievable with upgraded turbos on the N54. Equipped with BMW's Dual Clutch Transmission, which is not only durable, but fast, the S55 is able to handle these high power/torque numbers, and put down some very impressive 1/4 mile and 60-130mph times. So, how do we unleash that power?
FROM STOCK TO STAGE 2
You will see the largest initial gains from your S55 with a tune. In order to make the most of the highest level of tuning, we needed to prep our S55 for the increased boost. Here is a list of the upgrades we installed on our S55 to prepare it for Stage 2.
High-flow downpipes, such as the ARM S55 Resonated Downpipes are listed as a required upgrade by BM3. The ARM downpipes not only check the box for decreased backpressure on the turbos, but they also sound incredible.
S55 INTAKE DEVLOPMENT
With a desire to increase the intake air volume we began development of our ARM S55 Intake. While power gains from S55 intakes in general aren't very impressive on the stock turbos with OEM tuning, we wanted to future-proof our build by creating one of the best flowing intake systems for the S55. One built with upgraded turbo setups in mind. Upgrading the intake on our S55 to a massive 3.5" Intake System would allow our future upgraded turbos to ingest more air. The result is the ARM 3.5" S55 Intake System, perfect for stock turbos, and ideal for upgraded turbos.
For our project F80, we started off by giving it the ARM FBO treatment and a Stage 2 tune from bootmod3 which yielded a very respectable 543whp and 547wtq. Not bad at all for an total upgrade cost of only $2k. Overall power was increased across the powerband, and low end torque jumped massively. Obtaining traction below 40 requires ideal conditions, hot and dry, but if you can get traction you'll see low 11 second 1/4 mile times, and 60-130mph in the low 9 second range.
FBO + 100% E85
Now that we've maxed out the power output on the stock turbos with 93 octane, the next logical step was to tune the car for E85. To handle the tuning for the E85 map, we joined up with world-class tuner Cary Jordan. We knew he would be able to safely and precisely custom tailor a 100% E85 tune for our S55.
In preparation for this we needed to upgrade the spark plugs to the NGK 97506 gapped to .020. We decided to save time and reduce the possibility of misfires by gapping them to .020 from the start. These worked perfectly gapped at this spec. With the spark plugs properly gapped and installed we were ready to flash our baseline E85 tune.
At this stage we highly recommend upgrading the crank hub to avoid the notorious crank hub failure. Once this upgrade is performed you will be ready to safely max out the stock turbos.
After getting the tune dialed in we were able to scratch more than a full second off of the 60-130mph time, down to high 7's. Same hardware, only with better fuel and great tune, not bad. For the full results of our E85 testing CLICK HERE.
FULL E85 STOCK TURBOS 60-130mph TESTING
With full E85 fueling the S55 equipped with the OEM turbos the best 60-130mph time we were able to achieve was 7.92 seconds. The times ranged between 7.92 - 8.15 seconds.
STAGE 2+ HF TURBOS
With the car equipped with full bolt ons, upgraded spark plugs, and a crank hub upgrade, we were ready for the next significant jump in power. Upgraded turbos. When it comes to turbo options for the S55, there are several to choose from. We went with Pure Turbos for their history of reliability, and we opted for the Stage 2+ HF turbo option. As you can see from the photo below, they are significantly larger than the OEM S55 turbos, but with OEM housings they are a direct replacement.
To support the fueling with these turbos, we needed to add port injection, controlled with the split second controller. This additional fueling allowed us to run 100% E85 with the upgraded turbos. Cary and his team dialed in the tune itself and the mapping for the port injection. As is typical with remote tuning, there were multiple datalogging sessions and tune revisions which necessitated road testing, where is where we ran into our next unexpected roadblock.
TRACTION ISSUES
There comes a point during the build where datalogging in 3rd gear is no longer possible on "max performance summer tires". At this point you have two options. Either you start datalogging in 4th gear which requires a considerable stretch of road as 4th gear peaks at 125mph, or you upgrade to R compound tires. We chose the latter, and went with the Toyo R888R. This would give us more datalogging options, and it would help us with putting the power down in general.
Upgrading to R compound tires will give you a significant improvement in traction. Traction with R-compound tires is so much better that we were able to not only get datalogs in 3rd gear again, but we could actually launch the car using the factory launch control as well. For comparison, using the factory launch control with the max summer tires would spin the tires through 3rd gear without reaching even 60mph. This is a whole lot of fun, but it's not very good for putting down good 1/4 mile times.
With our traction issues sorted out we were able to get accurate datalogs and Cary and his team were able to teak the tune to produce the finalized version of the tune for 100% E85 on the Stage 2 HF turbos.
The final result was a massive 721whp and 618wtq. 251whp and 199wtq over stock 165whp and 94wtq over 100% E85 on the stock turbos.
100% E85 STOCK TURBOS vs 100% E85 STAGE 2 TURBOS
The S55 with 100% E85 on upgraded turbos is completely different than 100% E85 on the OEM S55 turbos. With an extra 165whp that's to be expected. But aside from the overall increase in power, the way in which the power comes on is very different also.
Unlike many other turbo BMW's, the OEM S55 turbos hold strong to redline, whereas many other engines (N54, N55 specifically) power dies higher in the rpm range due to the turbos in these cars running out of steam. That is not the case with the S55. The S55 OEM turbos hold steady all the way to redline.
While an extra 165whp up top is an insane increase over the OEM S55 turbos, what made the upgraded turbos so drastically different than the stock turbos was how the power comes on. On the S55 stock turbo setup, the limiting factor in low-end torque is the turbos ability to spool quickly. Whereas with the upgraded S55 turbos the limiting factor is the engine's ability to handle low-end torque. With the upgraded turbos on the stock S55 block, you don't want torque to come in too strong lower in the rpm range, this is a great way to make some things bend inside your S55 that shouldn't. Therefore, boost is programmed to come on around 5,200rpm, with peak torque hitting at that engine speed. Having the tune dialed in this way is necessary for engine longevity, but it requires a different style of driving. To have power at the ready, you need to keep the rpms higher, similarly to the V8 E90 M3. This is in contrast to the stock turbos where you have torque virtually everywhere in the rpm range.
STAGE 2 TURBOS PERFORMANCE TESTING
With the upgraded turbos on the F80 dialed in, we took to getting some new performance numbers. All of this was performed on the street setup with no special prep for the track. 0-60mph remained approximately the same, hovering between 3.9 and 4.1 seconds. But that is where the similarities end. The best 60-130mph ranged between 5.98 seconds and 6.3 seconds. The best being 5.98 seconds, making it almost a full 2 seconds faster than maxed out OEM turbos. In the 1/4 mile it was consistently hitting mid 10's with the best being 10.7 @ 137mph. To put that in perspective, here are some cars that this F80 is as fast or faster than in trap speed.
This is just to name a few. Granted we are comparing a heavily upgraded F80 to stock supercars, but considering that the all-in cost of this build was under $60k, those are some very impressive numbers, wrapped in the quality of fit and finish of a BMW.
The journey of this F80 M3 from its baseline to a staggering 900hp showcases the potential of the S55 platform. We've seen that with the right modifications, and precise tuning, it's possible to extract monumental gains from the S55, all while maintaining the stock block and transmission. As for longevity? As of the writing of this article, our F80 has close to 10k miles of hard driving and is still holding up strong. We did need to swap the injectors due to leaving E85 in the fuel system while in storage for 4 months, but we can't blame it for our negligence.
If you're looking to take your S55 to the next level, whether that be Stage 2, or built motor, let us know and we'll be happy to assist you in your S55's journey.
