Stroker build

[SYT_Shadow]

After much internal pondering, we’ve decided to post this for the betterment of humanity

There continues to be a lot of debate whether stroking an S65 is ‘worth it’.
For us, a NA engine’s response, intake sound and power delivery are always worth it, but it’s also clear that previous strokers were not really moving the envelope in terms of max power.
We absolutely know there are cheaper ways to get more hp, but not ones that sound quite as good (queue Karbonius intake) or (hopefully) can withstand 1h back-to-back sessions at the top 10% of the pace at the event.
Hopefully this is a constructive thread. Please note we’re not engine builders or involved at all in buying/selling of car stuff

Backstory:
We use our E90 as a streetable track car, it primarily sees double duty at HPDE’s. Last year the engine blew up (long story here), and after considering our options we decided to go for a stroker build. This is the pinnacle of M engines and making it better is a very attractive proposal!

Base – stock car (pulleys only): 371whp

After adding the following components, we got up to 412 whp:

Bimmerworld tri-y stepped headers
Bimmerworld Xpipe, fully catless
Karbonius intake, Dinan filter
284 Schrick cams
Rk dyno tune
93 octane



Finally we can get to the purpose of this thread: the stroker! Build and test details (adding onto 412 configuration):


Tuner:
Jordan @ RK Tunes

Fuel:
Regular 93 pump

Stock ECU - no standalones, thank you very much
292 Schrick cams (maintains full VANOS)
4.6L
stock compression ratio
93 octane
Same dyno as the 412whp result

Here are the results:










Here is the car and engine bay in all its glory







Many thanks to:

Izzy we would not have gone so deep into the dark end without your help. Incredible build!
Corry you are the Mozart of engine building
Jordan @ RKtunes, there is so much talk about tuner this and tuner that, but you are the real deal!
Phil @ Bimmerworld for his consistently great advice on building a streetable track car
David and Ana @ Karbonius for building this great intake (such glorious music!)
Robert for paving the way for all the cool S65 builds
Arne @ Schrick for the breakthrough info that 292 cams can mantain VANOS in the S65

[SYT_Shadow]

Updated the graph of the different states of tunes vs the Alekshop engine, here it is

Bear in mind all the dynos are in STD vs my stroker which is SAE. SAE which reads lower. The day I get a dynojet we can compare both of them on the same graph done properly, but this is interesting meanwhile





Conclusions:
From 5500 to +8000 this stroker makes way more whp than the Alekshop. It is clear that between the internals and the 292 cams/headers/Karbonius airbox the car has more hp pretty much everywhere.
If you look at whp average from 7000 to 8000 this is at least as powerful as a 595 supercharger kit

[SYT_Shadow]

Here's a video of it at the track

[BayE30]

WOW!!!!! that is some real power gain there, i would love to ride in this car!

Next time im visiting my family in CT, i hope i can drop in and hear this car in person!

[Icecreamfoo]

totally woke me up from my afternoon food coma

Would love to see/hear clips of this unicorn in real action

[VictorH]

Is this car coming to the Labor Day VIR event?

[SYT_Shadow]

Originally Posted by SFCM3

WOW!!!!! that is some real power gain there, i would love to ride in this car!

Next time im visiting my family in CT, i hope i can drop in and hear this car in person!

definitely, just don't make it in winter as the car will be hibernating

[SYT_Shadow]

Originally Posted by VictorH

Is this car coming to the Labor Day VIR event?

in theory yes! it'll be its first track day but still missing a lot to be able to track the car, alignment, tires, etc

[Dpc2u]

Very nicely done!

[Scharbag]

Well played. Those numbers are pretty great sir!!

Did you ever post about the details on how your old engine failed?

Well done.

[SYT_Shadow]

Originally Posted by Scharbag

Well played. Those numbers are pretty great sir!!

Did you ever post about the details on how your old engine failed?

Well done.

I have not disassembled it yet. As you see, I do things slowly but they eventually get done!

[VictorH]

That's a super nice power curve. Do you still have VANOS active with these cams or are they locked?

[SYT_Shadow]

Originally Posted by VictorH

That's a super nice power curve. Do you still have VANOS active with these cams or are they locked?

Vanos active. Schrick confirmed that was the case. I would not want to lose vanos on a NA high revving engine

[SYT_Shadow]

Originally Posted by Icecreamfoo

totally woke me up from my afternoon food coma

Would love to see/hear clips of this unicorn in real action

It's hard to post a video but I'll see what I can do

[VictorH]

Anything done to the heads? Valve springs or anything else?
What's the redline?

[SYT_Shadow]

Originally Posted by VictorH

Anything done to the heads? Valve springs or anything else?
What's the redline?

The 292 cams from schrick require the use of their retainers, shims and valve springs if you want to retain vanos. It comes as a kit

Redline is at 8600 iirc

Headwork was done. I don't have the details

[Richbot]

Holy moly and it looks very tractable below 3k also? Nice work guys

[SYT_Shadow]

Originally Posted by Richbot

Holy moly and it looks very tractable below 3k also? Nice work guys

That's the best part: you look for low rpm torque loss and it isn't really there

[ebisu8]

Incredible! Nice work Danny!

[amrazM]

Dope I saw Img post the car on their Instagram. Amazing

[pbonsalb]

500 rwhp and 370 lbs rwtq NA would make one of these cars very responsive and pretty quick. Unfortunately it’s often twice the cost of a supercharger kit, but if you need a motor anyway, you are halfway there.

[M3anest]

Geez those are some serious numbers. Knowing that it is safe power I really think this is the dream build.