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taylorp035 New Reader
11/10/19 8:43 p.m.

New Video!  



I did the fun science experiment to measure the volumetric efficiency of the rotary valve cylinder head and compare it to my 99 BMW M3 with the M50 manifold and K&N air filter.  These are both 2nd gear pulls down the road in the same place, with roughly the same air intake temperature.  I've moved the rotary valves +/-5 degrees from where this is plotted and this was the best result.

All of this was a result of me finding out my MAF that I had replaced turned out to be a down-grade from the 20 year old OEM sensor.  The replacement was a cheap Chinese unit and it was reading bad values and then would max out early, causing the fueling to be super confused.  I compared my 328iS sensor to the M3 sensor and they were very, very close when using my M3 as a test bed.


Here's the fueling.  At run 10, I swapped in my original sensor.


Some acceleration data.  I needs some help tuning at the top end.  We are working on getting the AFR gauge running again.


Here's the data comparing the two 20 year old BMW OEM MAF's.

Run 26 was when I put the Chinese MAF into my M3 vs 2 dozen runs with my OEM sensors.  As you can see, the commanded fuel was way off... explains why the rotary valve would die on the dyno at ~5k rpm

taylorp035 New Reader
5/10/20 9:30 a.m.

Some progress videos!   The rotary valve cylinder head now has 100 miles on it and completed it's fastest acceleration run ever and longest continuous drive without any issues.


We have been struggling with spark plugs that are too cold and they foul.  You can't buy hotter 8mm sparkplugs, so we just machined some 0.1" thick spacers to try and reduce the heat flow back in the water cooled bronze floating seals.

We also showed at one point a peak airflow of 184 g/s by the MAF, which is really good since it is only 2.8L versus my E36 M3 3.2L with the M50 manifold reving to 7k only does 200 g/s.  This means the volumetric efficiency is a few percent better in spots.  The 6500 rpm acceleration up the driveway proves it was making more power than it did on the dyno.


You really need to look at the photos of what this engine head is if you've never seen it on page 1.





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