MSefi.com read only forum (Jan.15,2018)

I have an aircooled flat 4 vw engine with dual throttle bodies and a cam with a bit of an overlap. This results in some high map readings at idle and throughout much of the operating range. I have been tuning speed density and have had some success although, there is more to go. Just wondering at what point are my efforts better spent with alpha-n or blended alpha-n? The idle results in around 67kpa and at rpms below 4000 some small throttle openings result in map readings in the 85 to 95 range. Lightly loaded cruise speeds result in 85kpa readings at 3000 rpms or so. The problem is that it gets difficult to get granular enough between small throttle opening cruise speeds and wide open throttle loads since the map is starting out at 85 kPa already. I have a decent ve map now (that runs better than it ever did with carbs) but it requires a very steep slope moving rich rapidly on the top 3 map bins to get from a lean cruise to a rich WOT in a short distance. I have moved the map bins a little and I guess I could sacrifice more bins in the low map range to create more up top but, just wondering if there is value in this approach or, should I be scrapping this for another method?
Any opinion are welcome as this is my first squirt and I am still a neophyte.
Thanks,
Paul

Hi,

Have you had any joy in fixing this? I've also got a vw flat4 with a pretty wild cam Engle 125 and it idles at 80 kPa, I've never been able to get it lower than this and in much as I've looked on here can't find anything to say whether this is ok or not.

I'm guessing that this is the case regardless and either I live with it or get a less wild cam..

Lance,
Thanks for the great information. I guess what I have is perhaps a step below what you describe in your first paragraph. There is a difference in MAP between part throttle and full throttle at low RPMs - just not much. What I end up with is the difference between say 95kpa and 99kpa. It just seems that with this small difference, I end up with so little resolution that there is this very steep slope at the highest map bin. I will keep at it to see how far I can take the speed density approach and I suppose, it is only time spent if I decide to toy with alpha -n or a blend.
Thanks,
Paul