This is going to be a quick, nerdy post, but I just want to get this out of the way first. No dyno numbers in this one. But I finally pulled a log on the car with the current setup. To keep it simple, I will refer to the original setup as “ND1” and the new setup as “Hybrid”.
So…
“ND1” will refer to the car before I did the ND2 head swap.
“Hybrid” will refer to the engine as it is now: ND2 head, intake manifold, throttle body and ND1 cams.
I’ve been running the Hybrid setup for several months now on the same tune I ran in the normal ND1 configuration. Overall, it ran well and I could feel it pull harder. But the car wasn’t setup to run that hardware. While the ND1 tune, by Fab9, did an admirable job with the new hardware the top end felt like it had more to give. So I took a log with the Hybrid engine and sent it off to Fab9 to get a tune made for my current hardware.
Because I waited to get a new tune on it, I found myself in the perfect situation to see how the ECU reacted to ND2 hardware when it’s expecting the airflow of the ND1. Even with retaining the ND1 cams, the results were very interesting to me.
To keep it simple I had AI (Co-Pilot) analyze the log files and create a breakdown. I also manually looked at the files to “fact-check” Co-Pilot but since this was a simple “Look at the numbers and give me the data” kind of thing it did a good job.
Here is what the logs told me, again both setups are running the same tune:
There is a lot to looks at there, but I had a few pretty telling takeaways from comparing the logs. Again, same tune but ND2 head and intake vs ND1 running the same cams. The peak airflow for the ND1 was 135-140 g/s at 6700RPM. The Hybrid engine would flow that same amount of air lower at 6100RPM up to a peak of 150-155g/s.
Peak airflow went up and shifted 600RPM higher. Up to a 12% higher flow rate. I am still leaving a little power on the table with the ND1 cam as the engine can’t expel the spent gases as efficiently as ND2 cam, but overall I’m pleased with this result.
Co-Pilot estimated a 15-20HP gain under the curve, obviously that is impossible to tell without a dyno, it’s just estimating that based on the log numbers. So don’t read that as fact, just speculation.
What surprised me the most was the Hybrid setup showed 0 knock instances. As of the time of this writing the jury is still out on how this setup impacts the compression ratio. The most likely scenario is the compression stays 13:1 or just over at 13:1 or 2. But no one has published any hard data on it. This is all speculation. But I can say that on my setup even if the compression ratio increased it is not to a degree that invited detonation with a tune that was not made for it. AI analyzed the log and indicates there may be improved scavenging which would make sense with the slightly larger valves and port. But I’m not an expert on this, just reporting what I saw, and AI likes to make stuff up. But for analyzing and comparing raw data it does the job. And I thought this was interesting enough to share.
