Interesting day on the dyno
Rather than drive the GTV6 500+ miles to Al Mitchell's I took the GTV6 to Carolina Chassis Dyno in Lexington SC - about 45 minutes away. It is a Mustang Dyno.
The first run made 204 HP at the wheels at about 5400 rpm. It was running lean but only made it up to 206 when we added fuel. We then moved the max ignition advance from 32 to 33 and it made 212 HP and another degree (34 total) got us to 214 HP at 6000 rpm. Max torque was 207 ft-lb at 5300. The runs were in 3rd gear. Using the rule of thumb 15% transmission loss gives 252 HP and 243 ft-lb at the flywheel.
The starter quit after the penultimate run and we waited a little while for it to cool down but it only worked when I tapped it with a hammer and long socket extension. Then it refused to start again after the last run and it tried to start when we pushed it but it would not catch and I called for a tow. When the tow truck arrived I turned on the ignition and noticed that the fuel pressure was high (I have an electronic gauge). I loosened a clamp to vent the pressure, turned the key and it fired up so I drove it home. The car had a misfire up to about 5000 rpm when it was on the dyno and it acted up all the way home and the tachometer quit. I have some troubleshooting to do on the ignition system but it seems to be a good sign that it is fine at WOT above 5000 rpm!
You can see on the charts that the dyno was struggling to control the motor below 5000 rpm but it is clear that the power curve is flat from about 5400 to 6800. The junk at 6800 is the rev limiter cutting in.
The RW torque at 3500 appears to be about 170 which corresponds well with what we saw at Al's before we broke the driveshaft.
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Last edited by alfaparticle; 05-02-2017 at 10:39 AM.