S54 Stroker build

[M/Anthony]

To be completely honest with you, my car isn't that much fun around town lol. It's almost a chore to rev it out so I'm mostly driving the M5.

Head has a full Supertech Titanium valvetrain. Ported and polished, 5 angle valve job etc. Valves are not oversized. Basically everything that Supertech makes for the S54, it has in the head. Inconel would have been nice but not noticeable and this setup is OVERKILL to the Nth degree lol .

With proper tuning you can get to 288 numbers with 280's and have a beefier midrange. Peak torque on my car was at like 4500 rpm.

I'm only missing stepped headers and a CSL airbox. With E85 I'd be over the 400 whp mark but I don't want to run E85. It gums up cars since it has a lot of sugar in it. I feel like if you're gonna run E85 only, that motor is on borrowed time haha.

thats good to hear that about your valve train lol. This is good information since you've done this. Thank you for sharing your build btw. Your car does look stunning
So gong big duration camshafts aren't the best option and idea basically, don't go higher duration because you lose lower end power. How much of a difference with 288/280 in the top range compared to 280/272?
Are those the Supertech valves that people had issues with? and since they're titanium how often do you have to replace/do valve adjustments?
I will most likely run inconel because there doesn't seem to be a negative to it beside a few more bucks.
What do you mean by a chore to rev it out?
Who did your port and polish?

[Sharocks]

It will barely be daily driven, and its going t be a fun weekend and track car.

May I ask what components do u have in your head ex valves springs, valves etc.

any certain reason for the 280/272, is it for the power band?

This will have E85

To be completely honest with you, my car isn't that much fun around town lol. It's almost a chore to rev it out so I'm mostly driving the M5.

Head has a full Supertech Titanium valvetrain. Ported and polished, 5 angle valve job etc. Valves are not oversized. Basically everything that Supertech makes for the S54, it has in the head. Inconel would have been nice but not noticeable and this setup is OVERKILL to the Nth degree lol .

With proper tuning you can get to 288 numbers with 280's and have a beefier midrange. Peak torque on my car was at like 4500 rpm.

I'm only missing stepped headers and a CSL airbox. With E85 I'd be over the 400 whp mark but I don't want to run E85. It gums up cars since it has a lot of sugar in it. I feel like if you're gonna run E85 only, that motor is on borrowed time haha.

[M/Anthony]

Other than it's mildly possible with enough money, OP where do you plan on driving this thing? I have 288/280s with a built/ported head for 9k rpm. I have my redline set at 8500. I'm short shifting usually around town at like 8k.

If this is going into a street car, understand these are PEAK numbers.

If it's gonna be a street car, grab some 280/272's, mildly build your head, run E85 and you should be good for at least very close to 400 rwhp at a useable rpm.

If I was gonna do it over again, I'd go that route.

It will barely be daily driven, and its going t be a fun weekend and track car.

May I ask what components do u have in your head ex valves springs, valves etc.

any certain reason for the 280/272, is it for the power band?

This will have E85

[Sharocks]

Other than it's mildly possible with enough money, OP where do you plan on driving this thing? I have 288/280s with a built/ported head for 9k rpm. I have my redline set at 8500. I'm short shifting usually around town at like 8k.

If this is going into a street car, understand these are PEAK numbers.

If it's gonna be a street car, grab some 280/272's, mildly build your head, run E85 and you should be good for at least very close to 400 rwhp at a useable rpm.

If I was gonna do it over again, I'd go that route.

[M/Anthony]

Using forged rods (CP-Carrillo: 491 grams) and pistons (JE: 330 grams) takes approximately 1,686 grams, a reduction of 34%, of rotating mass out of the engine. That's the equivalent weight of 2.66 stock pistons or 3.5 stock rods. You can spin that a little faster.

Feff

Yes that is one part of this build I wanted to do, since the s54 feels slow to rev in my opinion. But that also adds strength. Also why I want a billet crank, lighter and stronger. Thank you for the detailed information. I didn’t even think it was that much until now.
Anthony

[Feffman]

Using forged rods (CP-Carrillo: 491 grams) and pistons (JE: 330 grams) takes approximately 1,686 grams (3.717 pounds), a reduction of 34%, of rotating mass out of the engine. That's the equivalent weight of 2.66 stock pistons or 3.5 stock rods. You can spin that a little faster.

Feff

[M/Anthony]

And Id like to apologize to seeming a bit crazy, I didn't even know much until this forum about building s54s, lots of good s54, and overall engine building knowledge being shared. I also feel like I started the most interesting and highly debated thread on this forum so far lol.

[M/Anthony]

Lots of good advice & recommendations in here, and I’ll add something else as well...I’ve seen you mention sleeving the block twice now. I’m not sure if someone suggested this to you, but it’s an added machining step/expense that’s totally unnecessary for an NA S54.

Since we'll be down there already there really isn't a negative to sleeving it, in case anything goes wrong we can just remove the sleeves instead of worrying about replacing the block. If it comes down to cost at that point, then we won't be sleeving the engine.

[M/Anthony]

Lets semi-start over,
I hear what everyone is saying and I also thank you for your input.
can we shift the build to scrapping 9000rpms as it will be impossible and dangerous
What if we switch to running a higher compression, but also increasing torque.
Going off what Carbahn and Mike run, increasing compression in displacement can be doable, his engine maxes his hp at 8100.
So then, I'm not saying stuff won't be custom and this and that. Making this engine reliable with higher compression and higher torque.
I still believe we can get a pretty aggressive build matched with a high diff ratio.

[stash1]

I'm awaiting a response from Lang Racing. Will sleeve and bore the engine while we're there, what about bumping compression up a slight bit to run 12:5/13:1, and run E85, since I have a pump 5 miles away. Would that harm mid-range power and increase the top end? And to clarify, I want the valve train to be able to hold 9000rpm and as stout and well built as I can get.

Lots of good advice & recommendations in here, and I’ll add something else as well...I’ve seen you mention sleeving the block twice now. I’m not sure if someone suggested this to you, but it’s an added machining step/expense that’s totally unnecessary for an NA S54.

[ethan]

It's not logic - it's fact. If you want a streetable 9000rpm 6 cylinder that can run on pump gas, what other options are there?

I totally agree with you. I'm just poking fun at your statement that we should:

prioritize the midrange and have a motor that is 'faster' in the real world and MUCH more reliable

Reminds me of the "torque wins races"/"BMW engines suck, swap in an LS" crowd m3forum used to have to educate in matters of taste not that long ago. "You just don't appreciate the high revving nature of BMW's glorious S54." And don't get me wrong - I'm a major proponent of this engine's character as justification for its expensive maintenance and lack of power relative to turbos and big displacement alternatives. Funny for me to be on the conservative side of a moar NA RPM debate for once.

[digger]

the mean piston speed is too high with even the stock stroke to have good reliability at 9000 rpm

9000 rpm and 91 mm stroke MPS = 27.3 m/s
9000 rpm and 95 mm stroke MPS = 28.5 m/s
9000 rpm and 97 mm stroke MPS = 29.1 m/s

Even pro race teams that develop endurance engines don't go that high 25-26 is normally upper limit. that is big cubic inch drag motor territory which get rebuild often. it can be done but it is just not going to be reliable if you spend a significant amount of time at those rpm especially since you arent designing the engine around that from a blank sheet

the main point is a big stroker doesn't need the rpm it makes the power at a proportionally lower rpm so 97 mm would peak at 94% earlier so instead of 8200 its 7700 rpm and so on

for those that dont know mean piston speed is also tied to mean port speed not just reliability. above certain mean port speeds the VE starts to drop off rapidly anyway making turning those kind of rpm often a waste of time and engine life.

[jvit27]

Is there really a way to get midrange power out of the S54 besides slapping a turbo on it? I could run stroker kit but that really isn't the best way to in terms of reliability.

A lower-revving stroked S54 will be more reliable than what you're asking for and hit most of your targets. You're stuck on this arbitrary 9000rpm redline that is sabotaging all of your goals. Given what you're asking, it's wildly optimistic and dare I say greedy. I'm glad Anri explained it so well because at the end of the day, you're expecting WAY too much out of what is basically an evolution of a 30 year old engine design. Forced induction even would be more reliable than what you're asking for. The most successful race-built S54's would not even meet these criteria.

Or a Corvette or LS-swapped-anything by your logic. Still, agreed 9000rpm on an S54 in an HPDE context isn't pragmatic in the slightest.

It's not logic - it's fact. If you want a streetable 9000rpm 6 cylinder that can run on pump gas, what other options are there?

[jbfrancis3]

Many times we have seen that the 280/272s have more mid range and the same top end as the 288/280s.

What about with increase in displacement? No longer as definitive I am guessing

[ethan]

Many times we have seen that the 280/272s have more mid range and the same top end as the 288/280s.

Yep.