RomRaider

I made quick and dirty E85-setup, 0.7mm Cometic head gasket, 1.5mm shaved B20 head with 2mm shrank valves and reshaped combustion chamber for pressure recovery - about 14:1 compression ratio. Cams are reground, I don't have cam card near but duration was about 234 degree @ 1mm lift for both intake and exhaust. B28 injectors but everything else stock - performance is pretty good thanks to high compression, strong torq from idle and engine load stays above 500mg/stroke from about 3000rpm to 6900 rpm, peaking about 540mg/stroke 4000-6000 rpm.

B20 head flows enough for 2.5 liter engine up to about 8000rpm - with smaller valve head and more aggressive cams can do broader power band than with bigger valves and milder cam - my cams are actually very mild hydraulic profile, actually I planned to use more aggressive solid profile but became lazy and stick with hydraulic profile which did't need lifter tray modifications.

@naukkis79 thanks for sharing sounds very interesting! I like the not conventional builds

edit: i noticed iam missing quite some load @3000 rpm compared to before the cams, and your engine. i may have to look at cam timing again...

I also lost about 100mg/stroke @3000rpm when I changed original Y-pipe and cat to bigger diameter collector setup(with equal performance in upper rpm range) - exhaust is critical in those mid-range rpm range. And BMW original exhaust system is pretty good.

Here is some Intake testing with stock B28 Airbox vs BMC CDA.
Even with the open system of the BMC the IATs were pretty much identical. I was planning to 3D-print a 90 degree trumpet for it to get the air from the fog light area.

But looking at the results even a trumpet cant regain the measured losses imho.

Baseline and Control are identical, BMC is way down.

how about the airflow is the same but MAF readings are different because of air path being different on each setup affecting the readings?

I dont think that is the reason. I have the airguide in front of the maf to provide smooth laminar flow. The BMC box has a curved transition into the maf with a nice radius. So i expected better or same results.
Stock has a longer straight section after the trumpet inside the airbox. Another test with a similar straight section (6-10 cm) could provide more evidence that the bmc is worse.
Maybe i will try an open trumpet just for the fun of it when my 3d printer is up and running.

Did some testing for fun with a printed velocity stack. This pretty much concludes that the openness to the enginebay is a way bigger factor (who would have thought )
Also went back to the tests with the CDA and what i thought were practically the same IATs, were actually 5 °C difference on average. It got therefore an unfair test, maybe i test it with a cold air tube again, but i dont think it will be better than the stock box.

In the end it was worth trying the printed stack just for the sound alone. I dont get why they muffle the intake sound of NA engines that much. It is the best noise. People putting artificial sound through the speakers nowadays should be punched in the nuts

nice work !

whats about bigger intake manifold (M50B20) and throttlebody (M50B25) ?

i heard that the M52B20 intake manifold are not perfect for high RPMs
they build them too gain more torque between ~ 2500 - 4500 rpm

only an idea

Yes i read that also. I even had a M50b20 manifold but decided against doing it.
Thinking the S52 has the same manifold i got and makes way more hp than me. That was before i got cams. At the start of this i was expecting to get an eta motor

Has anyone done some actual testing back to back on a smallport/b20 head?

Hello! You have an email or instagram/facebook where i can ask you few questions about the build?

Do u really think someone will publish their private email or other accounts in a public forum that anyone on the internet can view? That is why there is a PM or email function in this forum for contacting members directly..

Or how about asking on the forum publicly that everybody benefits from it?

I tried pm him but i think the pm function doesn't work. Anyway, I got the car running and i don't have questions anymore about the engine.

Thinking of trying E85 (Found a somewhat close station over the border...)
I assume the fuel pump is sufficient, s50b32 should have the same pump. I am at ca. 75% duty on my B20 injectors already but have a set of B28/M3 ones to use.
Have you actually gained anything (Power?) beyond paying less for fuel?
I am not shure if my setup is really knock limited, mainly looking at the € savings.
Looking forward to your input =)

No you are not going to pick up anything.
If you go on a dyno and tune it, maybe you will get 2% more than gas if the engine was already tuned correctly