Turbo 3.1/3100 tuning

[Mars]

The info on the Z24 site will get you started but there is some debate regarding the BPC(base pulse constant) which some say to adjust down with larger injectors until the engine idles properly and some say leave it alone. I'm beginning to believe except for a small amount that you should leave it alone.

In the TGP code it starts out at about 105, I have 33 lb/hr injectors corrected for fuel pressure instead of the 22s used by the TGP code on the 3900. On the second test drive attempt after having lowered the BPC to about 48 to get a decent idle the car actually ran worse, leaning out by part throttle and backfiring suggesting that the fuel trim needs to be spread out over the BPC, Idle efficiency table and maybe the main efficiency table, so that an adequate BPC is available over the entire rpm range with necessary adjustments at other points.

In other words lowering the BPC can put you in a situation where although the combined parameters show adequate fueling the BPC winds up maxed out before you actually reach that point leaning out the engine. What I'm refering to is the formula used by the ecm to arrive at the appropriate amount of fuel for a given input.

There is an entry for the fuel injector size but it really doesn't appear to work all that well in my experience and another problem is potential bugs that have not quite been identified in Tunerpro. I had to use my backup program Tunercat to raise the rev limiter and noted that when it read over 6k rpm in Tunercat it read 4k rpm in TunerproRT however the reading in Tunercat was correct. If you changed it to above 6k in Tunerpro it would read 4k in Tunercat and would limit rpm to 4k. So it is also possible that bugs are contributing to the tuning problem. Since I have had Tunercat for a long time I'll upgrade to the TunercatRT and see how well it works with my emulator since I've had no real problems with it in the past.

Fuel calculating formula:

BPW = BPC * MAP * T * A/F * VE * BVC * BLM * DFCO * DE * CLT * TBM

I use that process, with the BPC and my car has 20 000 km's on in (4years) with a stock 3400 and 14-15 psi through an intercooled SC.

I am not sure why you are having such trouble. I have WB02 data and no lean spots anywhere really.

The only tables I tune with are the BPC vs. desired EGR, (I think it's around 57-58 from 105) the PE table, and the Accel Enrich table...

the rest is pretty much stock, besides the 3 dozen or so changes for a manual trans...

my car runs DAMN well, and powerful too. traps 115+ MPH, should run fast this year now that I have traction.