Quote:
Originally Posted by mfanatic325
Up to 9psi of boost, I got like just under 400rwhp and right at 300rwtq peaks with supposedly an older style supercharger core unit (they say it has to do with the impeller or something  ). So they think that until I swap the core unit out, I won't see the 470rwhp and 330rwtq that I should be at. They informed me there are zero changes to the VF570 tune, and so there are no improvements in drivability.
How's your drivability? Part-throttle? Any idle hunt? Do you have an AFR gauge? How do they look during driving?
Mine stutters during driving and has erratic idle hunt every now and then. I've just lived with it for the past few months, as I've been too busy with work to do anything about it anyhow. Looking to get everything ironed out this springtime. |
So if a core/impeller swap would bring you up to the full 470rwhp with the identical tune you have now, I would assume the setup you have now would be all kinds of inefficient or otherwise borked. Yes, the ECU is adaptive and can vary fuel trims and timing to reach it's targets... but we're also running w/o the MAF sensor, so it's gotta have some air volumes pre-programmed or something, right?
My drivability is actually pretty darn good. I haven't put it on a track nor dyno, though, so I'm just drivin' around town trying not to grab too much attention. I've still got my OEM resonators, so I'm not as loud as you
part-throttle is pretty stable... sensitive like the pre-install sport mode. I don't use sport mode now, it seems tooo twitchy. But I might try it again.
On startup, there IS about 10-15 seconds of idle hunt... it ping-pongs +/- maybe 600 rpm or so until it settles. If I blip the throttle, it does it again (albeit for a short time) when the rpm comes back down. I think it does this regardless of engine temp, but less in general once it warms up. I'll do a recording of it next week.
I have no external AFR gauge nor sensor. Since those SS cats have an extra bung, I'd like to install one. So all the AFR measurements I have are via TorquePro on my phone. In general, I think they look good, although I think it's a bit low on idle.
My logs are captured at one record/second. I'd like to increase the sample rate, add a few more sensors and make some more controlled runs to see what's going on. I just realized that while I'd been viewing ST/LT fuel trims, they haven't been logged. My logs do have speed, rpm, throttle position, AFR and voltages of the pre/post o2 sensors and a few other things. I'm attaching a couple of them to this post. I think the big file is when I went driving around late at night trying to complete a "drive cycle" for the OBD test.