bastarddsm
20+ Year Contributor
- 5,620
- 1,458
- Aug 26, 2003
-
Mendota,
Illinois
So end of last month I was fortunate enough to get to spend an entire day playing on an engine dyno. Ended up making about 15pulls. I have been experimenting with a new engine control system that I wrote the software for, so it was nice to proof that it actually works as expected.
I've been street tuning for years, and I thought I had a pretty good handle on getting a good tune without using the dyno. Turns out I was right, and my street tune was just about perfect. I actually use a MAF on this system so I had very little tuning to do on the fuel side. I often get chastised for my view on speed density being obsolete, and a maf being better. My dyno session ended up being a perfect example of why this was true. Over multiple cam timing settings, 3 different intake manifolds, and multiple boost settings, didn't have to touch anything on the fuel side to maintain my target AFR.
As for the dyno testing I went in search of testing a few intake manifolds, and what they do to the power curve as well as cam timing and it's effects. I was also looking to find where ignition timing wanted to be. Turns out it's a lot lower than I expected. At 34psi it seems my street tune was 2* and 20hp shy of MBT timing, which was a shocker. I figured it was at least 5* low.
I ended up making 725hp at 34psi, and picking up almost 100HP at 5500RPM by an intake swap and intake cam timing adjustment, while loosing only 19hp at 8200.
The amount of data I received was overwhelming. I will be able to calculate turbine and compressor efficiency's. I am running a Garret custom GT3788 AVNT turbo that I built. I modified the cold side to use a TO4S cover instead of the weird diesel truck one, as well as fitted a larger turbine, and reshaped the vgt vanes for better flow. As such it is invaluable to be able to calculate the efficiencies of the turbine and compressor.
Anyway here's a video of a 700+ 4g63 on an engine dyno. Pull from 4600-8200
I've been street tuning for years, and I thought I had a pretty good handle on getting a good tune without using the dyno. Turns out I was right, and my street tune was just about perfect. I actually use a MAF on this system so I had very little tuning to do on the fuel side. I often get chastised for my view on speed density being obsolete, and a maf being better. My dyno session ended up being a perfect example of why this was true. Over multiple cam timing settings, 3 different intake manifolds, and multiple boost settings, didn't have to touch anything on the fuel side to maintain my target AFR.
As for the dyno testing I went in search of testing a few intake manifolds, and what they do to the power curve as well as cam timing and it's effects. I was also looking to find where ignition timing wanted to be. Turns out it's a lot lower than I expected. At 34psi it seems my street tune was 2* and 20hp shy of MBT timing, which was a shocker. I figured it was at least 5* low.
I ended up making 725hp at 34psi, and picking up almost 100HP at 5500RPM by an intake swap and intake cam timing adjustment, while loosing only 19hp at 8200.
The amount of data I received was overwhelming. I will be able to calculate turbine and compressor efficiency's. I am running a Garret custom GT3788 AVNT turbo that I built. I modified the cold side to use a TO4S cover instead of the weird diesel truck one, as well as fitted a larger turbine, and reshaped the vgt vanes for better flow. As such it is invaluable to be able to calculate the efficiencies of the turbine and compressor.
Anyway here's a video of a 700+ 4g63 on an engine dyno. Pull from 4600-8200
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