Quote:
Originally Posted by shivers
Do you know exactly what was changed and by how much?
While this is great news with nice results, I'm still a bit nervous about what the safe operating range is before the valves decide to meet in the middle and have a catastrophic party.
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There are max limit tables that prevent taking things too far, so no worries of damage so long as you leave that alone.
Based on evidence from other folks with the PPE headers that suggested adding a mechanical restriction to the PPE headers (e.g., a cat) minimized the small dip in torque down low (around 3.8-4.5K), we decreased cam overlap in that region, and made nice gains, with the exception of a very narrow band (about 4 - 4.2K -- seemingly a resonance issue) where it just didn't budge.
Experimenting with increasing overlap there reduced power, and confirmed that we were making changes in the right direction. I suppose we might play with it all more another time -- I'll keep everyone posted.
Anyway, in the mid range to up top, we increased overlap and made nice gains from about 5K to redline. A small touch up of fueling to help maintain target AFR's and we were done.
Generally speaking, the goal is to set cam overlap, duration, and lift to optimize cylinder filling and exhaust pulses at a given RPM so you achieve an optimal mixture for making peak torque -- it can take some trial and error, although we had a few clear ideas of what to change and where.
However, this is a protuner feature only -- email Martin at
rsenthalpy@gmail.com for more specific details on the tune or to arrange for a tune yourself.