I disconnected my 2.5" dynomax super turbos and put 12" collector extensions on. I also made some other modifications:
ditched the platinum plugs as they were fouling badly with open exhaust
installed Autolite 45s gapped at .035 and rounded the side electrodes
Increased jetting from 73/82 to 77/86
The car runs very noticeably better than it did. It dyno'd at just below 360 RWHP a couple of years ago so I figured it would be up around 400 RWHP.
Surprisingly, peak HP was about 5 HP more...that's it, but below the peak, HP was as much as 20 HP more in some places. Torque peak was about 10 ft-lbs more, but in some places below the peak, it was also as much as 20 ft/lbs more.
The graphs were also much smoother than before so that was a plus. A/F is a bit rich as it was between 11.8 and 12.4. Probably need to decrease jetting by about 2 sizes.
The engine was cutting out some especially below 6000 so there is something still amiss. Maybe the richness is the culprit. I haven't noticed it cutting out when I drive it though...hummmm? There were gaps in the graph too as the dyno pickup wasn't getting a signal sometimes.
Given all this, I figure with 15% loss the engine is producing about 425 HP and 410 ft/lbs of torque.
The old boy and my ported 351w heads are probably just about maxed out in its current configuration.
Now it's time to quiet it down, but i'm going with Magnaflows this time.
Here is the graph:
ditched the platinum plugs as they were fouling badly with open exhaust
installed Autolite 45s gapped at .035 and rounded the side electrodes
Increased jetting from 73/82 to 77/86
The car runs very noticeably better than it did. It dyno'd at just below 360 RWHP a couple of years ago so I figured it would be up around 400 RWHP.
Surprisingly, peak HP was about 5 HP more...that's it, but below the peak, HP was as much as 20 HP more in some places. Torque peak was about 10 ft-lbs more, but in some places below the peak, it was also as much as 20 ft/lbs more.
The graphs were also much smoother than before so that was a plus. A/F is a bit rich as it was between 11.8 and 12.4. Probably need to decrease jetting by about 2 sizes.
The engine was cutting out some especially below 6000 so there is something still amiss. Maybe the richness is the culprit. I haven't noticed it cutting out when I drive it though...hummmm? There were gaps in the graph too as the dyno pickup wasn't getting a signal sometimes.
Given all this, I figure with 15% loss the engine is producing about 425 HP and 410 ft/lbs of torque.
The old boy and my ported 351w heads are probably just about maxed out in its current configuration.
Now it's time to quiet it down, but i'm going with Magnaflows this time.
Here is the graph:
