Project Turbo Deathkart

**etravoda** · 06-20-2021

I flashed my initial tune and have gone for a few light drives while data logging to see how far off the closed loop VE tables are. For some reason it's running VERY lean across the whole table. Trimalyzer has been a handy tool for this! I'm still on the factory fuel system (not going into boost) and want to make sure I can get it to run well before changing another variable (understanding I will need to again go back through closed loop tuning). I've lowered the injector flowrate down to 20 lb/hr because it was so lean all the way across the map.

Is the barometric pressure reading (now at 47 kpa with the 2-bar) causing a massive compensation in leaning out the map? I'm at altitude so it might be even a little worse?

**steveo** · 06-21-2021

so you've ditched the maf?

there's no such thing as a closed loop ve table, just a ve table. it's used all the time except cranking with no maf

what method did you use when you scaled your 1 bar table into a 2 bar one? did you just copy and paste the columns or did you do some smoothing?

you could post a log but if you're sure your fuel pressure is good and it's firing on all cylinders you probably just need more damn fuel, crank 'er up!

**PJG1173** · 06-22-2021

just my $.02. not sure how this relates to the LT1 computer but when tuning $0D for boost I had to cut my injector size by almost 70% to get to where the VE table wasn't trying to go over 100 while in boost. I also zeroed any table referencing baro compensation for fuel and spark as I could not find a way to keep it from reading baro while in boost. start out very rich and conservative timing boosted engines don't like to go lean. I found with mine I couldn't run as much timing as I did NA while not in boost since the turbo acts as a ram air and increases VE. I ended up pulling almost 10 degrees in some areas due to KR. I didn't see any mention of a wideband if you don't have one I would highly recommend it especially for tuning PE. if you want to run more boost (who doesn't) and you think your engine can handle it, you should start looking at different fuel (E85) or water methanol. right now I am running E85 (actually tested as E70), 8 psi, 12* timing on a 9.73:1 compression (aftermarket hypertunetic pistons) 4.3L v6.

**steveo** · 06-23-2021

even when not "in boost" your turbo is moving and creating turbulence and altering airflow and pressure, and also heating your intake charge. none of your n/a tables will be correct.

**etravoda** · 05-29-2022

Update with the project: VE tables are pretty well dialed and I've gotten into a little boost. Landed at about 50% of the injector value to get the VE numbers in a reasonable spot. Trimalyzer has been a big help, but the car thinks it wants to keep pulling fuel around idle because of the cam reversion. I've just learned to dummy in a few extra % VE around this range and at least it helps in open loop. PJG, same as you I noticed a few cases of KR coming into just 1 psi. That was was already with a substantial amount less timing past the 55 kpa mark (which scaled nicely from the 100 kpa with the 2 bar map). I've got timing numbers falling off quick with more boost and I feel it will be pretty conservative. AFRs are sitting nicely around 11.7:1 so far as it touches boost.

The bad: I had "issues" with the clutch last year and put in a 2nd one almost immediately. Car sat for most of the winter and I finally just finished my "500 miles of city driving" for break-in on the new clutch. Spec Stage 2+. Spec's customer service has been essentially nonexistent and I think I've got slipping on this one too. I'm guessing it's maybe 450 BHP at the current 2.5 psi (absolute).

Car is fairly aggressive as it is. It needs new tires. 2nd gear has no traction so I've been doing WOT runs in 3rd for tuning.

The only issue I've been chasing is a surging behavior at 1500-2000 ever since I did the cam, a year before the 2-bar MAP re-scale. With very light throttle input at that rpm the car will begin to buck and datalogs will show a wildly jumping timing. I'm not sure if it's the cause or the byproduct. Some guys seem to think its just cam surge and to deal with it...