F80 M3 S55 Single Turbo Build

[bokchoi]

Dang, I saw some guy at a meet a while back who had this in an F82 but he sold for '20 TT RS

[McBobby Jr]

Originally Posted by thesashachoi

Dang, I saw some guy at a meet a while back who had this in an F82 but he sold for '20 TT RS

I think you're referring to @kleaperm4 on Instagram.

[Clevocapri]

Do you limit peak torque as you tune or will the rods live at whatever torque it can make at 900rwhp?

[chetrickerman]

Originally Posted by Clevocapri

Do you limit peak torque as you tune or will the rods live at whatever torque it can make at 900rwhp?

I ramp the torque up, so im not trying to make a ton of peak torque in the midrange. This helps reduce the stress on the rods because they are able to transmit the torque better when the engine is rotating faster.

[McBobby Jr]

At 900whp, that should take the record for highest horsepower on a stock block S55. It's cool to see this platform keep developing.

[Wanted_M]

Any updates??

[chetrickerman]

Originally Posted by Wanted_M

Any updates??

Yep, I installed the head, just have to put the rest of the parts on, then I will fire it up.

[M3ZCPNYC]

Fire that bad boy up

[chetrickerman]

Originally Posted by M3ZCPNYC

Fire that bad boy up

Its running well now. Im going to put some miles on the new parts to let them get broken in.

I also installed a turbo speed gauge so I can see if I have any headroom with my turbo to push the boost even higher.

[Solo_G]

I love well documented threads like this, I wish they were more common! Keep posting updates, this is an epic build!

[WhatM4]

Wow awesome build

[chetrickerman]

No big updates yet, the car is driving well and is pulling hard. Im going to wait until the winter to hit the dyno because I want to make another downpipe. This one will use a concentric expansion going from 3" to 4" which the small angle of expansion should increase turbine efficiency allowing faster spool up and easier breathing of the engine.

Here is how the engine bay looks as of September 2022.

As another project, I also picked up another S55 block. This one had part of the connecting rod impaled into the oil galley, so I got out my Makita die grinder with some carbide bits and removed enough aluminum to get the piece out and leave a fresh surface that I can weld and repair. The block will be getting sleeved.

[Wanted_M]

Looking good. Yikes, that rod definetly left its mark!!

[chetrickerman]

Originally Posted by Wanted_M

Looking good. Yikes, that rod definetly left its mark!!

Here is how it looked before I got the piece out

[chetrickerman]

The downpipe is done and it is glorious. I was able to use the long concentric expansion to maintain attached laminar flow uniformity better to further improve turbine efficiency. The first almost 3 feet of the downpipe is 4 inch stainless tube, which then necks down smoothly to 3.5 inch to accelerate the exhaust flow and reduce pressure drop. I then went through the rest of the downpipe and exhaust and cut out the tight radius bends and replaced them with smoother more gradual bends to help keep exhaust velocity as high as possible.

You can see in the side by sides how much smoother the new downpipe is. I took it for a test drive after finishing it and could immediately tell a difference in spool up and response. I will update later how much faster the turbo gets to full boost compared to the old 3.5 inch downpipe. If you have a single turbo setup, definitely get the 4 inch downpipe if there is the option!

I also added an external wideband so I can see the true AFR average of both banks so I can be absolutely certain the AFR is within a safe range. I chose to use the Zeitronix ZT-3 which has the CAN Bus option so I will be able to see the ZT-3 AFR in my datalogs through the ECU.

[DaiLyCS]

Always loved Chet build, you always put a lot of effort into the build, I followed you since the evox build and got it tuned by you also.
Im excited to see where this go

[chetrickerman]

Originally Posted by DaiLyG80

Always loved Chet build, you always put a lot of effort into the build, I followed you since the evox build and got it tuned by you also.
Im excited to see where this go

Thank you!

[cmcintosh339]

Question. As a non engineer, slightly ignorant individual, why go from a dual turbo system down to one? More turbos = more boost, yes? With your knowledge and availability with parts, why not just change the current twin turbo system, try for better airflow and move from there.

OR, was this a passion project to test your own limits? All very impressive stuff, great work.

[chetrickerman]

Originally Posted by cmcintosh339

Question. As a non engineer, slightly ignorant individual, why go from a dual turbo system down to one? More turbos = more boost, yes? With your knowledge and availability with parts, why not just change the current twin turbo system, try for better airflow and move from there.

OR, was this a passion project to test your own limits? All very impressive stuff, great work.

Good question. Usually OEM or aftermarket companies will use twin turbos since two turbos usually have a lower polar moment of inertia than one larger turbo, which means the two smaller turbos should have faster transient response and spool up quicker while having the same power potential as a single large turbo.

With the advent of the Borg Warner EFR turbos, they utilize a Gamma-Ti turbine wheel which has half of the inertia compared the exact same size turbine wheel made out of Inconel or Mar-M. This dramatically affects transient response, and with their redesigned compressor wheel that flows a lot more, I chose to go this route.

The sound, response, power and simplicity this setup produces is found no where else on the market, hence why I decided to make it myself.

[F30_320D_UK]

Those pipes look great and will flow so much better than before.

Interesting about the Gamma-Ti turbine wheel!

[DaiLyCS]

Originally Posted by chetrickerman

Good question. So usually OEM or aftermarket companies will use twin turbos since two turbos usually have a lower polar moment of inertia than one larger turbo, which means the two smaller turbos should have faster transient response and spool up quicker while having the same power potential as a single large turbo.

With the advent of the Borg Warner EFR turbos, they utilize a Gamma-Ti turbine wheel which has half of the inertia compared the exact same size turbine wheel made out of Inconel or Mar-M. This dramatically affects transient response, and with their redesigned compressor wheel that flows a lot more, I chose to go this route.

The sound, response, power and simplicity this setup produces is found no where else on the market, hence why I decided to make it myself.

Single big turbo always have good sound, good intakes sound, turbo spools sound and most important exhaust note on it

[DaiLyCS]

Also weights saving, I wonder how much did you shave the weights from going single turbo?