[itsnotanova]

Originally Posted by Ciao

The first file shows the HP (about 250) of a Boxster S without mods.

The first graph is my friend's modified boxster. It has 249 at the wheels which is about 285-295 at the crank

Originally Posted by The Radium King

interesting. any corrections entered for drivetrain loss (ie, this is actual wheel hp and not wheel hp adjusted to flywheel hp)?

otherwise, i would not worry about the afr readings - from what i've read, if they did the sniffer up the tailpipe approach the readings are not accurate; here's a quick search result:

tailpipe vs. wideband?

finally, looking at that 5500 rpm dip you have. i am trying to get my head around it. truegearhead had something similar. you see it on occasional dyno results. it may be an effect of scaling, as it shows up on the factory dynos also - ie, it just looks worse on a dyno that has an exaggerated 'y' scale. what is happening at 5500 rpm? the resonance tube closes again (opens at 3000 rpm, closes at 5000 rpm) and the variocam returns timing (advances timing at 1500 rpm, returns at 5500 rpm).

https://www.6speedonline.com/forums/996/205309-how-variocam-variocamplus-works-primer.html

Originally Posted by The Radium King

so, perhaps i am overthinking, but with engine conversions, and with plenum changes, often the resonance tube has to be rotated/moved for clearance; operation may have been impacted? oil can pool in the resonance tube - if positioned other than oem, it may start to not operate properly. or perhaps they get weak over time and can't return properly when faced with 5000 rpm airflows.

the other thing i am thinking is perhaps the turn-over points are not optimal for modified engines - ie, perhaps the flap should close sooner? not close at all? i presume this is not something you can change with a tune, as jfro's result w softronic tune indicates (he's got the dip too):

Dyno results!!

it would be interesting to dyno with the flap always open, and/or always closed, and see what happens with the dip.

Thanks. I'll look into the flap valve. I'm stuck on the AFR as mine gets leaner as the RPM's get higher and his gets lower. I kind of trust the readings as I've heard of a few 3.4 swaps having that issue. I plan on investigating that closer. As in another way of sampling and then what's causing it. I don't think a vacuum leak as it seems to rise with rpm. That really seems like a fuel delivery problem to me. I believe I changed the filter already. If I get confirmation from another source that I'm running lean then I might replace the fuel pump or jump up on the injectors. I'll have to see what's my best option