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 the car in action

https://www.youtube.com/watch?v=rAef3HpD7oI&feature=youtu.be

[IND-Distribution]

Awesome! We're big fans of the S65 in both NA and FI forms, but NA Stroked is special, especially with the carbon airbox. 👍

[tdott]

Awesome build!

[IamFODI]

Yes, excellent build.

SYT, out of curiosity, how much do the new internals weigh vs. stock?

[SYT_Shadow]

Yes, excellent build.

SYT, out of curiosity, how much do the new internals weigh vs. stock?

if i remember correctly, the rods/pistons are lighter but the crank is heavier due to the increased stroke.

In the next month I should be able to get a proper dynojet reading and I'll post it up here

[Obioban]

if i remember correctly, the rods/pistons are lighter but the crank is heavier due to the increased stroke.

In the next month I should be able to get a proper dynojet reading and I'll post it up here

I'm looking forward to that!

Please try to get an SAE plot.

[ultimatemj]

SYT_Shadow, I'm curious to know A) did this require engine removal and B) would you mind guestimating the cost over a road bearing job...would it be 5k, 10k, 15k, more?

In for the Dynojet results!

[IamFODI]

SYT_Shadow, I'm curious to know A) did this require engine removal and B) would you mind guestimating the cost over a road bearing job...would it be 5k, 10k, 15k, more?

This is basically a full engine rebuild with custom parts. Crankshaft, rods, pistons, and cams are all new, which means so are the piston rings, all the related bearings, anything else that might be considered a wear part or sensible while-you're-in-there upgrade, and a shitload of incidentals (gaskets, one-time-use bolts, etc.). Can't imagine doing something like this with the engine in the car, and the cost will make a rod bearing job look like an oil change.

[tdott]

A 4.6L stroker requires an over bore, it's and engine out job for sure.

[SYT_Shadow]

SYT_Shadow, I'm curious to know A) did this require engine removal and B) would you mind guestimating the cost over a road bearing job...would it be 5k, 10k, 15k, more?

In for the Dynojet results!

Sorry I missed this post

A rod bearing job should be around 3k including proper BE bearings, BE-ARP bolts and new engine mounts.

A stroker engine is at least $30k. Think that just to remove the engine and put the stroker back in plus gaskets/oil/etc is 5k.

Supporting mods are also hugely expensive, like cams/headers/intake