Bought an already turbo'd car - some Q's - bonus fuel table smoothing script included
 

Hi There,

I just joined here but I've been a lurking round for a bit. I bought a 1995 with a bunch of mods installed recently for a pretty good deal. The guy I got it from had his dad who is a professional mechanic do the turbo install and it seems well sorted. I have been pouring through info regarding it though and looking over how it was put together. I did want to bring up a few noted things I'm looking into better sorting out.

Usually the first time the engine catches on cranking it revs to about 15-1600 then dies out, the 2nd time it catches it has always stayed on.

It has a light weight flywheel and the engine nearly stalls when I turn the steering wheel at idle. I wonder would wiring the ps load switch to the hydra help fix this, the FMII kit steals the ps load wire for the IAT.

The Flyin Miata install of the IAT uses a chassis ground instead of a sensor ground. Won't this cause inaccuracy from common impedance paths? Shouldn't it be spliced to the ECU sensor ground?

The Flyin Miata Hydra instructions call for adding grounds "Your harness may have the following flying-lead ground wires that you'll need to crimp a ring terminal to & bolt to a chassis ground point." Wouldn't proper star point grounding require you to ground the ecu to the engine? Without that the body grounded sensors, knock, nbo2, etc will have a common impedance path problem.

The previous owner had the car running catless. He mentioned having been monitoring his boost gauge for boost creep. He had also lowered his redline by 500 rpm and the wastegate actuator has no washers for pretension and was running the ebc at 10 psi using open loop. I had a feeling he did all that to prevent boost creep at the top rpms. I have installed a different exhaust and put a cat in so at the moment I've turned off the ebc and the wastegate is making about 6.5 psi steady and I raised the redline back up to the standard Flyin Miata tune's values. I'm going to add on the washers/shims and then work back into using the ebc.

The previous owner didn't touch much on the tuning. I have zero'd the long term trims after putting the new exhaust on. I plan to merge the long term trims into the base fuel once I've run through a few tanks of fuel. I wrote a script to auto smooth the fuel table after using Flyin Miata's excel table instead of smoothing it by hand like their instructions say to.

https://github.com/natek83/csv-gauss-filter