How Good is the BMW S58?
It’s no secret we’re not fans of the new front-end of the G80 M3 and G82 M4. However, we’ve always been excited to see just what the new S58 3.0L twin turbo inline-6 is capable of doing. As BMW enthusiasts it’s easy to appreciate the S58. It likely won’t end with BMW fans, though. In its early days, the S58 is already shaping up to be one of the most capable production engines the world has ever seen. In this article, we discuss the BMW S58 engine specs, tuning, and aftermarket potential.
BMW S58 Specs
The S58 is based on the basic design of the B58. However, the engines share very few common parts. Over 80% of the parts within the S58 are different than the B58. Just about all of those parts have been re-designed to be stronger, beefier, and/or more capable. Here’s a quick overview of the BMW S58 engine specs:
Engine: BMW S58
Displacement: 2993cc (3.0L)
Aspiration: Twin mono-scroll turbochargers
Bore x Stroke: 84mm x 90mm (3.31″ x 3.54″)
Engine Block: Aluminum, closed-deck
Engine Head: Aluminum, 3D printed core
Rotating Assembly: Forged crank, rods, and pistons
Redline: 7,200 RPM’s
S58 Engine Specs Comments
BMW really took things to the next level with the S58. Displacement is ever so slightly smaller than the B58 engine. BMW increased the bore and reduced the stroke. This helps fit in larger valves for improved cylinder head flow. Compression is down to 9.3, which is awesome to see on a turbo engine. These specs will reduce low-end potential a little bit in favor of top-end power. Lower compression is also ideal for higher boost and overall engine strength.
A closed-deck block will deliver excellent strength while the aluminum material helps keep weight down. The cylinder head is 3D printed to optimize coolant and oil flow. S58 crankshafts are forged chrome molybdenum heat-treated steel. Its crankpins are spherically ground which helps the bearings run smoother; this process is often used for race-spec cranks. Crack steel forged connecting rods are pulled over from the S63TU4 engine. Pistons are MAHLE forged with their proprietary anti-friction coating.
These specs alone don’t even paint the full picture. Diving into some of the specifics shows this is a true race-spec engine that meets emissions standards. Liter for liter the BMW S58 might very well be among the strongest production motors ever.
S58 Tuning & Aftermarket Potential
Specs on paper are impressive, but real world results are where the S58 looks even more insane. The S58 tuning and aftermarket scene is just starting. It takes time for testing, development, and dialing things in. Despite this, the BMW S58 is already putting out incredible numbers.
If you check out the video you’ll see RK Tunes was able to get this G80 M3 to 670whp already. Here’s the long list of mods:
- Port injection (100% E85)
The S55 M3/M4 are able to make plenty of power on 100% E85 without port injection. S58 fuel systems should be even more capable, so these numbers might even be possible without port injection. As with the S55 this engine uses dual HPFP’s. However, the S58 receives pumps capable of 350 bar versus 200 bar on the S55. Anyways, we’re talking about higher quality fueling (E85) and an early stage tune for the S58 to make 670whp.
BMW S58 Bolt-On Mods
We’re talking purely speculation here. The S58 engine can make 670whp on E85 with a brand-new still perfectly dialed in tune. What will the BMW S58 pump out with the other basic bolt-ons?
This isn’t always a perfect way to tell, but if you look at the RK Tunes dyno you’ll see the power curve is pretty darn flat up-top. To us that indicates the S58’s stock turbo probably have a bit left in them. Then there’s dialing in the tunes. Downpipes, intakes, methanol injection, etc.
With full bolt-ons (FBO) E85 and some methanol injection we find it hard to believe anything under 700whp is the limit. 750whp on stock S58 turbos might be pushing things and a little too optimistic. However, it’s certainly a possibility.
S58 Engine Limits
We talked about internal strength a little bit above. Most of this will be speculation, too. However, we can make some educated guesses based on the improved S58 specs compared to what previous inline-6 BMW engines are capable of. First, here’s a somewhat lengthy video:
These guys have already pushed a nearly bone stock S58 engine to over 1,000hp on an engine dyno. They did drop the compression ratio a tad along with a little head work to optimize flow. The main reason to drop the compression is due to the pump gas fuel quality. With E85 there should be no need to lower the compression to blow straight past these numbers.
Yes, there’s a difference between a team of professionals setting up a drift/race car than your typical guy on the streets trying to make 1,000+ horsepower. Regardless, we’re talking stock rotating assembly and a stock block making that power. The exact number was right around 1,040 horsepower, which likely translates to 900-950whp on a chassis dyno. They also seem to believe the S58 has more left in it, and they still haven’t found its limits.
Is 900+whp Really Possible?
Again, they made these numbers on pump grade fuels. Race gas and especially 100% E85 are totally different ball games. If anything those fuels would help support significantly MORE power.
The specs on paper look excellent, and this early testing shows massive potential. BMW S58 engines really are very close to true race-spec, and without question the most capable modern inline-6 from BMW. N54’s and B58’s hold up at 600-650+whp and S55’s crank out 700-750+whp on stock internals. S58 engines are significantly stronger and more advanced on paper.
Long story short – yes. It does seem possible that the BMW S58 will hold up at 900+whp, and 1,000+whp might even be possible. The S58 still has a long way to go before any true limits are known. Holding up for a few dyno or glory runs is a lot different than holding up for a season of racing or years and years of street abuse. S58 engines are impressive powerplants, though.
BMW S58 Tuning Potential Summary
A lot of this is purely speculation as the S58 is nearly a brand new engine. It will take time for aftermarket testing, development, and advancements. However, BMW put a lot of effort into crafting a truly insane, strong engine. RK Tunes already made 670whp with a JB4 and E85. A future drift car already made 1,040hp with the stock rotating assembly.
The S58 certainly has a lot of positive things going already. Time will tell what these engines are truly capable of, but as of now they’re looking to blow all former BMW inline-6 engines out of the water.
With the future of internal combustion engines (ICE) not looking great the S58 might be one of BMW’s farewells. It sure seems like BMW put it all on the table with the S58 engine. 700-750whp on stock turbos is a real possibility. 1,000+whp on an un-opened motor isn’t out of the question. It’s likely the S58 goes down as one of, if not, the best production engines if these numbers hold true.