TP as a benchmark for tuning?

[modulation]

Ignoring weather and similar factors, and obviously K constant can't change because it affects everything.

If I log for months and notice that my max Theoretical pulsewidth is X, and then do some mods and notice that my TP has maxed out higher, does that mean I'm producing more power? (Assuming more air = more power)

For example, if I can get a higher max TP with 12.5:1 AFR's then 12.9:1 AFR's, does that mean that the 12.5:1AFR produces more power?

[chris2712au]

If you are at the edge of the map further increases in TP just lean it out..

you will have to adjust the load scales again.. I think.. and leaner mixtures make more power.. however the injectors should follow the TP if your load scales are ok.. I would not make your max TP the max you do get I would allow some head room.. sometimes your car just goes a little better on some occasions.. and you dont want to be maxxing things out when it does..

[Matt]

I would guess to say that you are making more power. Because if the mapping is the same (ie untouched over the period of logging done) then really TP is representative of airflow (that is where it comes from) ... or you are reving is more

If your TP is now reading higher than before and your have improved your airflow (less restrictive exhaust or simlar) then that capability has improved and your MAF will measure a higher reading, so then your TP would be higher too

One way to check is compare your MAF readings also and see if they are higher voltage on peaks than previously

[Legionnaire]

I guess it does mean more airflow (not necessarily more hp, because you also need to effectively burn all that mixture) if the only variable in the TP calculation formula is maf lookup table value. Is there a known correct formula for TP calculation?

[Matt]

there is a TP calcuation formula. Eric from DTA motorsport worked it out for the Z32 (using disassembly) and load maptracing was originally calculated using this before TP was used over consult based on MAF input voltage

However it does change between various ECUs since there are different code bases

Definitely an indicator of airflow change

[Legionnaire]

That's nice, because from what i remember, there is some [old] info on ztechz.net that actual TP calculation is dependant (inversely proportional?) on revs as well as on airflow. Is this correct?

[Matt]

thats correct. if you look at TP on a bench setup, changing RPMs will also affect it because TP feeds back on the AFR value in the fuel map also. confusing huh?!

[Legionnaire]

Hmmm, it is - at first glance, but actually it makes sense - if your engine consumes say 1kg/sec of air, its load at 600rpm definitely differs from load at 6000rpm. I guess it depends on how you (or nissan engineers) define "load".

[raddy]

in my experience TP really follow engine load and more precisely engine VE very close and Im using it as tuning benchmark in sense of value and as torque curve parameter in sense of its trend.

[modulation]

in my experience TP really follow engine load and more precisely engine VE very close and Im using it as tuning benchmark in sense of value and as torque curve parameter in sense of its trend.

I've definitely seen that in adding stuff like less restrictive MAF, and removing the swirl control valves from the intake I've moved the max TP from occurring at lower rpm's to higher ones. This would be consistent with your experience that VE and TP are closely related.

[RomChip200]

Purpose is to get the highest TP value at the highest rpm, that would mean more power.
Accross my tunes, max TP was reached @3500 at the beginning and now it's about 4500. But the TP value is a bit lower than before, I suppose I increased the power, but decreased a bit the torque at low rev.
You will get the highest TP in 5th gear, but it's more a peak value.
You will get a more relevant value (a bit lower) in 3rd gear.