S54 Stroker build

[digger]

Why not someone that offers stages

if youre paying upto a few grand for a ported head you want it done to suit the engine and its application not based on some prexisting shopping list. Honestly when shopping for a place to do porting id avoid the big name places that do alot of BMW stuff. you want a more specialized place that knows engines

[M/Anthony]

I briefly talked with Chris fletcher, and he will end up building and speccing my engine out and it will be paired with an epic tune. I will ask him about head poritng etc. But he is doing my labor and speccing out. It will end up being a 3.4l stroker. I will email him this week to discuss specs, and I will regularly upload information and specs and why on this thread. Is there any questions I need to ask him when building this engine like hamronic damper, x part y part etc, whats the best option for x etc. ? I let him know it has to be in a car by december, but he is backed up which isnt a problem as time is on our hands.

[M/Anthony]

if youre paying upto a few grand for a ported head you want it done to suit the engine and its application not based on some prexisting shopping list. Honestly when shopping for a place to do porting id avoid the big name places that do alot of BMW stuff. you want a more specialized place that knows engines

I never thought of that before, thats good to note, it does make sense why not to go with stageed head builders. Thank you Digger, I will take this into account. How do u get bench flow numbers? is it reasonable to ask for them?

[digger]

I never thought of that before, thats good to note, it does make sense why not to go with stageed head builders. Thank you Digger, I will take this into account. How do u get bench flow numbers? is it reasonable to ask for them?

Whoever does the port work usually calculates flow using a flow bench just ask for them if they didn’t use one then ask how they know they did a good job.
Some background as to the textbook way to port IMO. some will just grind away willy nilly and pray for a good result.

Normally the flow bench test is firstly done in stock form to determine the baseline numbers and after modifications to compare the difference.

They apply a depression across the head (pressure differential) and measure flow at each valve lift increment e.g. 1 mm, 2 mm, 3 mm or 0.050" 0.100", 0.200" ,0.300" etc up to slightly past max valve lift.

The measurements are usually corrected to CFM at 28" water pressure differential standard but they should be tested at that same pressure or higher (not tested at 10" and corrected to 28" which is 1980’s and 90’s methods).

Unfortunately, a flow bench can be misleading as normally if you make it bigger it flows more, what you want is efficiency (velocity or flow per square inch). A well ported head flows better but a head that flows better doesn’t mean it is ported well if that extra flow is achieved by making it huge but inefficient.

Normally what they should do is start with the goals and the application. What size engine, how many rpm, how much hp, what powerband is required, what cams, street or race or something etc

Then the valve size in relation to bore is determined using rules of thumb and inspection of valve placement and other considerations for what can fit and what’s appropriate for the application. Do you need oversized valves? If the port and valve is big enough already to meet power goals then bigger simply makes it less efficient during operation even though on the flow bench it looks great. no use a port that works well on a engine at 10,000rpm if you are only gonna turn 8500

Then they machine throat of the port in relation to valve size with the valve job blending the throat size to the combustion chamber. this again depends on the application e.g. say 88-92% is a common throat % based on valve diameter (say 35 mm valve would have approx. 31-32 mm throat diameter) depending on what is used by the factory and whether new seats are being installed. The seat angles have to transition the port angle to the valve and into the chamber to diffuse the air smoothly The valves might be back cut to compliment the multi angle valve seat.

Then they size the minimum cross area (might already be the throat but sometimes its near the guide at the short turn radius is smaller if the casting is like that) and also the port entry may need to be changed to provide a taper. again the actual size depends mostly on maximum hp. Lower hp means less area is needed to keep the velocity appropriate.

Then they shape all the ports, the short side is reshaped to help the air turn and keep the air attached and not too fast and blended to the seat, same with the bowl its blended to the seat and throat. Basically, streamlining things without unnecessary material removal. The good porters will probably use a pitot tube to check for velocity at various locations to make sure they aren’t too fast or too slow and shape accordingly.

Sometimes the valve and port is already too big so its just a job to improve flow with minimum material removal to optimize efficiency. Like an S52 head flows 240cfm at 28” at around 12 mm lift , the engine even for 300 hp needs maybe 200 CFM only so its not working efficiently in stock form and why without vanos its got no bottom end torque.

A ported S54 with stock valves should flow up to 7-10% more than stock (which is 10% more power potential) and a slightly bigger inlet valve will flow around 15% more if done correctly. You only realize the full power potential gains if the engine is built with parts that support the extra flow meaning, cams exhaust, inlet runner length and so on all done to work together as a system.

[Speed Monkey]

Symbolically - me dropping this info... 🤪

[Feffman]

Interesting article from Engine Labs about connecting rod design type.

https://www.enginelabs.com/engine-tech/cranks-rods/connect-the-rods-i-beam-and-h-beam-connecting-rods-explained/

Feff

[stash1]

^^^ Interestingly though, I don't believe that Callies has rods for the S54...at least not that I've heard? Also, for those not aware, Carillo came out w/a lighter weight rod (434g's) specifically designed for NA applications up to 400 whp.

Speaking of rods, anyone ever heard of these? https://www.hurricanerods.com/produc...139-53-21.html

[Speed Monkey]

Yup, those are some bootyful rods mang. 🤣 🤪

[digger]

Interesting article from Engine Labs about connecting rod design type.

https://www.enginelabs.com/engine-te...ods-explained/

Feff

I've done a fair bit of FEA on rods and don't agree with that article that H-beams are better for higher rpm NA engines. I-beams are better in extreme rpm applications that's why version of it were used in F1 high rpm era the load paths are better under tensile loads less likely to crack.
Also H-beams provide slightly better support for the pin and BE journals in compression that's why big cylinder pressure engines predominantly run them and then step up to aluminum if it’s not enough.

So observations don’t agree with the article, must have excess stock they are trying to flog off

I agree for most applications the beam doesn't matter at all just look at Pauter rods lol worst of the worst. Best of the best would be the Honda F1 rectangular hollow style rods.
A NA S54 falls into that category where the beam type is just not critical. It just needs to be good material, good bolts and to be well machined any of them will work. I like Molnar for an H-beam lightweight and slim profile

https://molnarrods.com/bmw-connecting-rods

sources of I-beams

https://www.zrp-rods.com/shop/bmw-m3...nnecting-rods/
https://www.hurricanerods.com/produc...l#.XrzqvWgzaUk
http://www.performancebyie.eu/index....roduct_id=1268
https://www.pureperformancemotorspor...ds-pleuel.html

[Feffman]

Guess I should have clarified the Engine Labs article wasn't a promo for one company's rods, but more toward the info of design ("I" versus "H" beam) and metallurgy with the two varieties of steel alloys mentioned. I know very little of the not-so-popular rod manufacturers so when the time comes, likely next year, I'll bite the bullet on CP-Carrillo.

[digger]

it was basically a promo for Callies as conveniently they offer both options so have all bases covered.

Many of these kinds of articles have agendas in the background that's how they get funded the aftermarket industry is full of this kind of thing. Some of these kinds of articles are good and are correct but others have hidden motives its a real shame. A good way to find out what works is find an independent long term engine builder who's god a really good reputation. Their reputation is dependent on the products they use as they have found out what works and ask them. Thats also problematic as some get more profit selling certain brand parts like tire salesmen who push tires they profit more from.

[M/Anthony]

Ok I don't know if people have forgotten about this thread but ill update it anyways

I have talked to chris fletcher and I will have him build and spec my engine out.

It will be a 3.4L stroker with FMH: valve springs, custom spec carillo rods, custom spec, cp pistons, PTG designed crank, custom rod bearings. Basically it is a PTG build without the 312/314 degree camshafts. I will be running close if not 400whp and very close to 300wtq
It will be run E85, and 12:5:1 compression, 8200 rpm redline. 288/280 12.5mm lift cams- chris advised against anything bigger so I can have reliability on the road. It will also be dynoed at FMH and most likely paired with an EPIC tune

I will be running a custom CSL airbox that routes air from the kidneys, Bimmerworld.
I still have to figure out the ideal exhaust and header setup
And learn how to do valve adjustments (every 10-15k miles)

Surprisingly this build isn't that much considering how indef, who is building it, and the parts being replaced.

[jbfrancis3]

Great update. Did he have any comments against boring it out (I'm assuming 3.4L comes from longer throw and stock bore)?

[M/Anthony]

Great update. Did he have any comments against boring it out (I'm assuming 3.4L comes from longer throw and stock bore)?

he mentioned he will not bore if he doesn't have to. 3.4L typically comes from a 95mm stroke and an increase of .5mm bore. I'm not too confident on the exact rod specs, but they off the shelf ones are stock length. (139mm) Hmay have differently specced rods, will ask.

Later on once I buy the parts I will aks for specific specs, or soon because I am urging to know where 16k is going.

[digger]

You’d be nuts not to bore and torque plate hone even if it was as little as 0.25 instead of 0.5mm. What pistons specifics ?