drakec9

Hello all, I have been learning to tune megasquirt myself for awhile now, i installed an ms2pnp long before my turbo build to learn the ins and outs before putting my engine at risk with boost and no knowledge. I have since installed by turbo with all the supporting mods necessary and have began the journey of tuning my first turbo miata. Im in a 92 1.6L with a gt2554r, walbro 255 pump, flowforce 640cc injectors, turbosmart manual boost controller(turned all the way down) and turbosmart bov, intercooled setup running 7-9psi. The boost hits early most ive ever seen is 8.8psi and tapers down to 7.5psi or so as the rpm rises. While i have only been at this for a few days, i have ran into a couple of issues along the way. I have tuned only fuel so far for idle the way i want it, low rpm, some of cruise and i have been working on high rpm and load. i have accel enrichment off and timing fixed (not 'use table') and the fuel calculation does no include afr target table. The biggest problem i am battling right now is what seems to be a random, but probably isnt, boost cut. The first occurrence surprised me a bit but shouldnt have because i failed to replace my spark plugs before i started this process. I changed them to NGK heat range 7 plugs gaped at .30. The second occurrence really surprised me, 1st gear, WOT felt like i hit redline early, i did catch this one on a datalog which i will provide, i am not very good at reading datalogs, i cannot find any issue with anything except for imperfect afrs, range from 11.5-12.5 but a little inconsistent (still working on fuel table). The next time i experienced this boost cut was a few minutes ago on the way to pick up dinner. This time i was in 4th gear, close to WOT and seemed to be lower in rpm range around 4500-5500 but i was looking at the wideband and boost gauge not the tachometer. I also was not data logging because im stupid. i suspect this may be due to a too rich air fuel mixture i notice that sometimes i was getting down to he 10s in boost. I honestly do not know any other cause for boost cut other than spark blowing out or terrible afrs. I know my tune in probably terrible i am still learning and i have never driven a turbo car before so i did interpolate some on the fuel table and hit some boost. i probably jumped the gun and skipped some things but i do not want to damaged anything and i know hitting boost cut is not good for anything especially my engine and engine mounts. i have replaced every seal and gasket as well as the timing belt and water pump (twice now) i do not suspect this is a mechanical problem. My next step will be to check the base timing again and also pull the new plugs out and check them. Is there anything i am missing or any tips some of you gurus have for me to solve this boost cut? i will provide my tune and datalog mentioned above any input is greatly appreciated and criticism is welcome as long as it is constructive, i am trying to learn a much as i can.

drakec9

boost cut occured at 1549 of 4194 on the datalog

SpartanSV

You hit 150 kpa at that point. Your boost cut setting is 150 kpa. It's doing exactly what you're telling it to do.

drakec9

Oh jeez, I never even knew that was there thank you the help spartan I feel kind of stupid but at least the problem is fixed