So I got a new boost controller that I haven't used before. started turning it up without a boost gauge (lol). I knew the valves would float at some point, I just wanted to experience it for myself. I've only heard about it, never had an engine actually do it.
So bit by bit turning it up but didn't realize the "high" knob was actually starting off higher than "low". So what I thought was 1 click higher on "high" turned out to be around 3 whole marks (about 30% higher) putting the engine from 7~psi to around 15+ psi. Me not having a boost gauge didn't let off, even though I felt it fall on its face I was interested in the log of "valve float" having never done it before.
So This was extremely interesting to compare with all the 7psi runs I had made before. I took a picture and made it easy for you to see:
lolboost.jpg
Question is
I thought the ECU used the VEmap, and air in lbs/hr to determine torque production. I thought that by using larger number in the VE table for example would increase 'torque' the computer thinks the engine is making.
This must be incorrect. If you look carefully at the picture you can see that at almost double the airflow, literally WAYYY higher VE from the VE map (which is fairly accurate) nearly DOUBLE the amount of fuel injected (engine didn't even hiccup just felt a little slower), yet the computer accurately determines that there is LESS TORQUE somehow? I thought it was a coincidence at first, but after attempting other boost levels and opening/closing the cutout (which reduces exhaust gas pressure thus reducing valve float allowing higher boost) I see the same trend over and over for it to be a mistake.
Buggles my mind. It must have some kind of rate of change algorithm? But it would need to know vehicle weight for that. How on Earth does it know I made less power with twice the airflow and fuel from the model??!
Setup is
all stock 5.3 turbo + 4l80e in a 3000lbs 240sx, 'test engine'
93 octane only
Actual A/F is very close to Commanded A/F. I command 12.7 I see 12.4~ for example. I leave it a bit richer in the base map because I dont have an IAT yet and other reasons.
And one other question as an aside. Why when the valves float don't the pushrods jump out of the rocker arms and send the whole engine into a bent up twisted pile of rubbish? I was kinda hoping for a catastrophic failure so I can swap in this gen4 4.8 I have lol. But it seems pretty indestructible... Not even a hint of oil flow from the crankcase vent at 16~ psi makes me really happy.