We just installed an LSX90 w/TB on an 388 all bore motor that had an LS6 and stock TB. I was able to get the idle pretty decent by playing with the idle air flow and a few of the other parameters. I figure since it wanted to idle at 4K that too much air was entering around the large 90mm blade vs. the stock.
Tomorrow I am going to get the rest of the tuning cleaned up as it seems like it is running richer since the intake/tb change. Is this typically normal?? Besides A/F adjustments, is there any logic that the larger intake on this motor could favor more timing?
Finally I did notice that the idle seems to hang very slightly before returning to a solid idle. What table should I look at?
Thanks guys!
Howard