Poor idle help

[Jason W]

Hi.

I am about at my limits on tuning the idle on my car! No matter what I try I can't get it nice and smooth and even at 900rpm it still has a shudder when both in gear and in neutral or park.
When scanning I can get it a bit better by raising the timing to high 30's as well as commanding about a 13:1 AFR, but obviously the computer tries to maintain 14.63AFR as set in stoich.

My car was originally a 5.7L LS1 (2002 holden statesman, Auto) but now has a 6L block with a stroker crank taking this engine up to about 402CI/6.6L. I have drilled out the idle bleed hole in the throttle butterfly a bit and it has made it a lot better than it was, but still not ideal. I am thinking of drilling it out some more but obviously don't want to go too far! The IAC motor count is around 30-40 at 700RPM, so I am thinking it probably can't hurt to drill it out some more unless someone advises against it? It's the same throttle body from the 5.7L engine, so it makes sense this engine would need more air at idle.

The cam is a 224/224 (Or 224/229 if you use a calculator from the other values!), so I would have thought I should have been able to get a fairly nice idle down to at least 800RPM.

Anyway, with that said it would be great if people can give me some suggestions for making this a lot better than it is. I have it around 850 at the moment and it really wants to push forward as soon as my foot is lifted off the brake, so this isn't ideal. I can probably play with reducing the timing a bit more in this high idle state, but I think this may cause other issues!
I have been scanning and changing the idle airflow values based on both the LTIT and STIT for quite a while as well and this doesn't seem to help much in getting this smoother.

Thanks in advance,

Jason.

14.10.2016 tune 2.hpt
Jason Engine VE config.cfg
14.10.2016 9.hpl

[Jason W]

I have started to sort this out after all this time. I ended up setting all my end of injection timing to 8 and it seems to have smoothed this out heaps! Previously I had increased it slightly but didn't want it too late for fear of cylinder wall wash. I am worried I may have this happening now, but in the meantime it has sorted out the really bad idle!

Now back to re-tuning my VE table again!

If anyone has any suggestions to reduce this End of Injection timing to a safer level if it needs to be then it would be great to hear from you!

Thanks,

Jason.