LS1 Calc airflow vs rpm vs tps (i.e. turbo tuning)

[SSBerserker]

Anyone know what the equivalent table in HPT is to LS1 Edit's Calculated airflow vs rpm vs tps?

I added a turbo and have been told I need to scale this table based on:

:-X bad formula :-X

any idea how to translate that to HPT??

[Chris@HPTuners]

Engine -> Diagnostics -> General

It's the P1514 DTC your trying to fix yeah?

[SSBerserker]

That's the table ;D

I had the formula incorrect above (but its correct here). In other words, if boost is 10 psi,

24.7/14.7 = 1.68,

so put 168 in the value box and multiply, replacing any value less than 500 with 500.

In this case, every value is less than 500...

I am trying to adjust for the turbo in eliminating KR at WOT. I was told that by scaling the values of this table in LS1 Edit by the formula above will help the computer to deal with the turbo at WOT. The table in HP has values clustering around 1, however, so I am not sure how to translate to the new scale.

[Chris@HPTuners]

the value in the table is a predicted cylinder airmass (g/cyl) based on the current TPS and RPM for the Electronic throttle. The PCM compares this to the actual value it is measuring (log via the Engine->Airflow->Dynamic Cylinder Air PID). If the measured value is out by too much (usually greater than 0.15 g/cyl over the predicted value) for a period of time then it raises P1514.

you can try putting 1.68 in the multiply box and see how you go... either way you need to raise the value up.

[mustbbrent]

Mr. Berserker. This is the table I multiplied .1.6 1.68 should do it. I have thrown no codes so far. There are 2 other tables. Allen can tell you which ones. I forget. It's early in the morning for me.

[SSBerserker]

Awesome, thanks, Brent! As soon as you 'member those other tables ...

[SSBerserker]

BTW, Brent, I've been told this is the part of the answer to the KR problem we've both been seeing at WOT...

The sticking part is the mapping from the value of 500 in LS1 Edits version of this table to the correct value in HPT.

[SSBerserker]

OK. This is a solved issue.

LS1 Edit uses mg/cyl as units for this table. Since HPT uses g/cyl the conversion is easy

Here is the algorithm for forced induction (and I am just testing this now -- I do not make any claims that it is correct).

1) calculate your PR

PR = (14.7 - boost psi) / 14.7

2) In HPT, scale your calculated airflow vs rpm vs tps table by your PR [In LS1 Edit, take the PR X 100 and use mult %]

3) In HPT, apply a floor of .5 to all values (i.e. replace any value < .5 with .5) [In LS1 Edit, apply a floor of 500]

Voila. Done.


My first pass of testing left me very negative in LTFTs, but I had already adjusted the MAF table to shift the LTFT range into the -2 to -8 range. I feel from the testing (but haven't analyzed the data, yet) that I will have to scale the MAF table back 2% or so.