S54 Stroker Kits - PRO/CON

[Obioban]

Vac gets cranks from arrow so shouldn’t have an issue as they didn’t develop it.

VAC is mostly overpriced and products “over sold”

Being local to they, I routinely get to see the "quality" of their work first hand. I'm written it out several times at this point, but it's just absurd stuff... like using too much sealent (in areas where none should be used), and their solution being to just drill out the oil passage and drive the car (not even an oil change after). It's just absurdly bad.

Lots of their products are horrendous, as well. E.g. Back when they made a CSL airbox, it couldn't take the vacuum of the engine running and would collapse in on itself.

The owner is also a bad person.

Certainly their least bad products are the ones where they have no part in the development and just resell it. But, so many things they sell are terrible, their ethics are terrible, and their quality of work is worse than pep boys... so I'd just avoid them completely.

[Feffman]

The wider bearing on the stroker crank is unique to Lang Racing, no?

Not exclusively. My friend kept the stroke stock but Engine Services suggested the wider bearings for better oil control.

Feff

[terra]

Equally exciting for me, this project also made my trunk bigger. On the left side BMW sold trunk liner for cars with nothing there:

I realize this is off topic in a stroker thread, but for what it's worth, you can make that left side of the trunk bigger without deleting the whole stereo. The key is eliminating the CD changer / nav. I still have my HK amp (though it did require a new bracket.. which can probably be 3d printed without much issue, but I didn't have one back then)

[mleveroni]

Why was supercharger ruled out? Any of the entry level supercharger kits on a stock motor (assuming the motor is healthy) will live much longer than a stroker. Also much cheaper, simpler, and keeps all of your stock comforts. A Just my thought, but I can't deny a stroker would be interesting if you can swing it. I have no experience with strokers but I have built my motor for a turbo. So similar process, minus the special crank and different specs for boost. Whether its my motor built for boost or a stroker, they are both going to have the same problem with durability. A built motor could need a rebuild possibly as soon as 10k miles on the low end and maybe 50k miles depending on circumstances. You are replacing OEM internals with aftermarket upgrades, so assume there are some drawbacks. The majority of aftermarket upgrade parts involved in a build will be stronger, lighter or have some advantage while lasting just as long as OEM. Stuff like the stroker crank, forged rods, headstuds, etc, assuming they are installed correctly.

The one part that limits the life of any built motor, is the pistons. I think they still sell OEM .02mm overbore pistons, but expensive and can't change compression. So most likely the only options are the aftermarket forged pistons. This is not to say any are bad quality, they will all probably be stronger, lighter, and in whatever bore size/compression ratio you want. I got a set of CP's from Lang Racing, I believe VAC, Lang, and Carbahn all use CP pistons as standard. CP, JE, Wiesco, Mahle all use the same 2618 forged aluminum, so decision comes down to which one offers the specs you need. If the correct spec piston is being used, I can't imagine much of a difference between them. So regardless of which one, this same following issue is going to happen. While the forged piston is stronger in terms of handling higher loads and higher temperatures, it will eventually cause damage to the cylinder walls. Forged pistons have a higher wear rate over cast in general, but the majority happens on cold start. Forged pistons expand significantly with heat compared to a cast piston. so they require larger clearance to the cylinder wall. When an engine is cold, the pistons are shrunken causing them to rattle around making a noise called piston slap. Once they are warm they expand to where they should be and will stop rattling. This piston slap when cold is what will simply wear out the cross hatching in the bores, slowly wearing away compression. So if you went with a stroker kit, probably wouldn't have any other failures, but this problem is inevitable. 4032 alloy pistons are much better in regards to wear but no company currently offers it. Would be good for an NA stroker if you could get a company to make you a set.

So that is my explanation why a built motor will simply wear itself regardless of the situation. So I think there are better options than building a stroker. but if this doesn't worry you, then go for it.

[digger]

Why was supercharger ruled out? Any of the entry level supercharger kits on a stock motor (assuming the motor is healthy) will live much longer than a stroker. Also much cheaper, simpler, and keeps all of your stock comforts. A Just my thought, but I can't deny a stroker would be interesting if you can swing it. I have no experience with strokers but I have built my motor for a turbo. So similar process, minus the special crank and different specs for boost. Whether its my motor built for boost or a stroker, they are both going to have the same problem with durability. A built motor could need a rebuild possibly as soon as 10k miles on the low end and maybe 50k miles depending on circumstances. You are replacing OEM internals with aftermarket upgrades, so assume there are some drawbacks. The majority of aftermarket upgrade parts involved in a build will be stronger, lighter or have some advantage while lasting just as long as OEM. Stuff like the stroker crank, forged rods, headstuds, etc, assuming they are installed correctly.

The one part that limits the life of any built motor, is the pistons. I think they still sell OEM .02mm overbore pistons, but expensive and can't change compression. So most likely the only options are the aftermarket forged pistons. This is not to say any are bad quality, they will all probably be stronger, lighter, and in whatever bore size/compression ratio you want. I got a set of CP's from Lang Racing, I believe VAC, Lang, and Carbahn all use CP pistons as standard. CP, JE, Wiesco, Mahle all use the same 2618 forged aluminum, so decision comes down to which one offers the specs you need. If the correct spec piston is being used, I can't imagine much of a difference between them. So regardless of which one, this same following issue is going to happen. While the forged piston is stronger in terms of handling higher loads and higher temperatures, it will eventually cause damage to the cylinder walls. Forged pistons have a higher wear rate over cast in general, but the majority happens on cold start. Forged pistons expand significantly with heat compared to a cast piston. so they require larger clearance to the cylinder wall. When an engine is cold, the pistons are shrunken causing them to rattle around making a noise called piston slap. Once they are warm they expand to where they should be and will stop rattling. This piston slap when cold is what will simply wear out the cross hatching in the bores, slowly wearing away compression. So if you went with a stroker kit, probably wouldn't have any other failures, but this problem is inevitable. 4032 alloy pistons are much better in regards to wear but no company currently offers it. Would be good for an NA stroker if you could get a company to make you a set.

So that is my explanation why a built motor will simply wear itself regardless of the situation. So I think there are better options than building a stroker. but if this doesn't worry you, then go for it.

A stroker won’t reduce longevity compared to stock anywhere near as much as people think if you build it right. Mahle MS can do 4032 just find a good dealer or contact them directly for a custom order.

[CrisSilberGrau]

Why was supercharger ruled out? Any of the entry level supercharger kits on a stock motor (assuming the motor is healthy) will live much longer than a stroker. Also much cheaper, simpler, and keeps all of your stock comforts. A Just my thought, but I can't deny a stroker would be interesting if you can swing it. I have no experience with strokers but I have built my motor for a turbo. So similar process, minus the special crank and different specs for boost. Whether its my motor built for boost or a stroker, they are both going to have the same problem with durability. A built motor could need a rebuild possibly as soon as 10k miles on the low end and maybe 50k miles depending on circumstances. You are replacing OEM internals with aftermarket upgrades, so assume there are some drawbacks. The majority of aftermarket upgrade parts involved in a build will be stronger, lighter or have some advantage while lasting just as long as OEM. Stuff like the stroker crank, forged rods, headstuds, etc, assuming they are installed correctly.

The one part that limits the life of any built motor, is the pistons. I think they still sell OEM .02mm overbore pistons, but expensive and can't change compression. So most likely the only options are the aftermarket forged pistons. This is not to say any are bad quality, they will all probably be stronger, lighter, and in whatever bore size/compression ratio you want. I got a set of CP's from Lang Racing, I believe VAC, Lang, and Carbahn all use CP pistons as standard. CP, JE, Wiesco, Mahle all use the same 2618 forged aluminum, so decision comes down to which one offers the specs you need. If the correct spec piston is being used, I can't imagine much of a difference between them. So regardless of which one, this same following issue is going to happen. While the forged piston is stronger in terms of handling higher loads and higher temperatures, it will eventually cause damage to the cylinder walls. Forged pistons have a higher wear rate over cast in general, but the majority happens on cold start. Forged pistons expand significantly with heat compared to a cast piston. so they require larger clearance to the cylinder wall. When an engine is cold, the pistons are shrunken causing them to rattle around making a noise called piston slap. Once they are warm they expand to where they should be and will stop rattling. This piston slap when cold is what will simply wear out the cross hatching in the bores, slowly wearing away compression. So if you went with a stroker kit, probably wouldn't have any other failures, but this problem is inevitable. 4032 alloy pistons are much better in regards to wear but no company currently offers it. Would be good for an NA stroker if you could get a company to make you a set.

So that is my explanation why a built motor will simply wear itself regardless of the situation. So I think there are better options than building a stroker. but if this doesn't worry you, then go for it.

This is the type of info im after. Thanks for the input, ill dig deeper.

[jet_dogg]

A cheaper alternative would simply be uprated pistons and head gasket to get the increased bore and compression. This would be a cheaper option but would make sense during a rebuild.

You can get CPs for $1200, arps for 1-200 and head gasket for a couple hundred if you want to bypass Steve's almost thousand dollar markup. I would wait until your motor needs this rather than just going at it now.

I thought about building a spare motor for fun but the massive investment for at most 20hp gain doesn't make sense. I'd go a little different route than carbahn but it's just personal preference at that point.

[JeremyJames]

People have been over (just) 390rwshp (SAE dynojet) without a stroker/with stock compression ratio. If that's really your power goal, you might be better served going full bolt on. Messing with the internals is when people start to have issues (though admittedly that's less likely going the Carbahn route).

Curious to know what bolt ons would achieve 390whp? I ask this because I once asked on another platform how to achieve around the 400whp ballpark running full NA and not cracking into the block or stroking it. Every single person told me I was insane lol.

[9kracing]

While the forged piston is stronger in terms of handling higher loads and higher temperatures, it will eventually cause damage to the cylinder walls. Forged pistons have a higher wear rate over cast in general, but the majority happens on cold start. Forged pistons expand significantly with heat compared to a cast piston. so they require larger clearance to the cylinder wall. When an engine is cold, the pistons are shrunken causing them to rattle around making a noise called piston slap. Once they are warm they expand to where they should be and will stop rattling. This piston slap when cold is what will simply wear out the cross hatching in the bores, slowly wearing away compression. So if you went with a stroker kit, probably wouldn't have any other failures, but this problem is inevitable.

This was true in the 60s, not really now in 2022.

I've personally run almost 13:1 on 91 octane for 10s of thousands of miles. You can run tight tolerances on today's modern piston designs.

That being said.... I 100% agree that a supercharger kit makes more sense in every way.

[Tbonem3]

Curious to know what bolt ons would achieve 390whp? I ask this because I once asked on another platform how to achieve around the 400whp ballpark running full NA and not cracking into the block or stroking it. Every single person told me I was insane lol.

Many are probably not aware of what the s54 can do now with full 2.5" exh piping and most modern dyno tuning with wideband.

Healthy motor (and healthy vanos!) That includes new precat o2s at a minimum.
stepped v1 headers, 2.5" sect 1 and 2. 3 is nice, but the least important of the 3 sections (proper X pipe [not Y] for sect 2 might yield higher peak for someone chasing max hp versus H pipe)
Cams (280s are better overall, but 288s for absolute peak iirc)
Dyno tune
CSL airbox
You can get a little more with dinan TBs, but better to pair them with a port/polish.
93 octane will help a little vs CA 91.

[oceansize]

Post 4 in the dyno database thread is Hassan's car. I think that pretty much sums it up. If you want more buy a SC kit (I think this is best), build something awesome yourself (I guess), or pay some shop a bazillion dollars.

[JeremyJames]

Many are probably not aware of what the s54 can do now with full 2.5" exh piping and most modern dyno tuning with wideband.

Healthy motor (and healthy vanos!) That includes new precat o2s at a minimum.
stepped v1 headers, 2.5" sect 1 and 2. 3 is nice, but the least important of the 3 sections (proper X pipe [not Y] for sect 2 might yield higher peak for someone chasing max hp versus H pipe)
Cams (280s are better overall, but 288s for absolute peak iirc)
Dyno tune
CSL airbox
You can get a little more with dinan TBs, but better to pair them with a port/polish.
93 octane will help a little vs CA 91.

That is a nice set of mods for sure. May do cams and a little bit of exhaust work next steady chasing that 400 lol. I feel like this car in the 375whp+ range would just be perfect platform no need for anymore than that. I know the SC 550whp M3s are fun but I have zero interest putting forced induction on the S54. If I can only get 350-360whp out of her I’d still be happy. A carbon airboxed S54 sings the most beautiful symphony. Im currently at 310whp/245tq and she’s a dream.

[EthanolTurbo]

Many are probably not aware of what the s54 can do now with full 2.5" exh piping and most modern dyno tuning with wideband.

Healthy motor (and healthy vanos!) That includes new precat o2s at a minimum.
stepped v1 headers, 2.5" sect 1 and 2. 3 is nice, but the least important of the 3 sections (proper X pipe [not Y] for sect 2 might yield higher peak for someone chasing max hp versus H pipe)
Cams (280s are better overall, but 288s for absolute peak iirc)
Dyno tune
CSL airbox
You can get a little more with dinan TBs, but better to pair them with a port/polish.
93 octane will help a little vs CA 91.

E85 will add 10-15 whp vs 91. Once you start making more power, the S54 really needs higher octane.

[Tbonem3]

Im currently at 310whp/245tq and she’s a dream.

Quit while you're ahead. Just enjoy the car imho.
___

Forgot to mention you'll want larger injectors when you do FBO esp with headwork.

[JeremyJames]

Quit while you're ahead. Just enjoy the car imho.
___

You are not wrong!