I think SSpdDmon is teasing us.
My car had a dip in TQ/HP right around 4k (a lot of LSX's do). Since I had a copy of his tune from several years back..I think that was his way of teasing us about 'copying' his tune.
In all honesty, I did utilize his Idle and Learning Airflows almost verbatim. Since then I have done my own Desired Airflow, Spark, and TC. I still use most of his TF settings.
That 4K dip is fairly normal...
Post pics of dyno sheets.
Last edited by joecar; July 10th, 2010 at 06:02 PM.
My 'dip' was very subtle. Shows up a little better when I plot it on Excel..
i'll try to post mine up tomorrow. i hope to be able to get some logging in also.Originally Posted by joecar
That dip is very consistant with long tube 4 into 1 headers & appears anywhere between 3-4000 rpm. I have only seen the one sheet with try Y's (4 into2 into1)and the dip doesnt appear as noticable.
The Tremor at AIR
$5 says the dip is timing related. I took a peak at his tune and the high spark table dropped right where I asked about the dip. Bump up the timing to 27* flat @ WOT from 3k on up and the dip magicly disappears. Seen it with mine on the dyno...
Graph is my '01, which was ported 241's and a 232/238 cam.
Could be Jeff.
I have read in some articles about the nature of exhaust pulses and how the intake and exhaust flow 'equalizes' in those RPM's. You could probably address it with timing.
Looking at a recent log, 3000-4000 Rpm's at WOT will take anywhere from .8 -2.2 sec depending on gear and traction. Hopefully the real-life effect is minimal.
Interesting phenomena though.
i did some more logging today & wanted to share it with you guys to check out. i have to apply it to my tune yet though. i did set the fans to come on earlier now & i copied the B4307 table from the dynotune i had done this spring, which idled great, but kept going lean in the lower rpms. that tuner spent a fair amount of time getting the idle sorted out, but i don't know how he overlooked the lean condition when he had the car for 4 days to "street tune" it after we did the dyno pulls. the change i made to B4307 seemingly had no change on the idle, so back to the stock parameters i go.
Bad:
It must all be in the Injector(s) and method of tuning.
I copied a log I did this morning. Stock Injectors Closed-Loop. It must be hard to control Idle fueling with those Injectors. Look at the IBPW1 differences.
So what are your conclusions?
that i really don't know what i'm looking at. lol i do like how your IBPW is smooth all the way across that screenshot, but i really dont understand what the numbers mean yet. what do i do about how my IBPW is all jagged & the numbers being so much different?
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