LSA Swap Question - Help!

[mrnorm_hemicide]

Hi all,

For those who have done the LSA supercharger swap, what idle MAP do you guys see? I'm seeing 50 kPa on mine, and can go as high as 60 kPa when in drive and foot on brake... desired idle at 725 rpm (which is holding fine), but the long terms peg at -25... I checked for vacuum leaks in all the usual places, but have found none. I have the boost bypass valve set up to take vacuum reference from the port at ~5 o'clock, with the 6 o'clock port uncapped. I am measuring MAP via the rear sensor on the lid (compressor, not SCIAP). I'm also seeing my throttle blade being held at 13% during idle, which seems a bit high.

I'm suspicious of the bypass valve... if it is not opening the bypass throttle plate all the way (or not at all), would this cause the s/c to make enough airflow/pressure that the ECU would see it as unexpected at the O2 sensors and thus pull fueling out?

From the standpoint of the cal, I adjusted the MAF frequency curve to reflect the change over to the LS7 card-style MAF, and the addition of the blower, but I left the idle airflow parameters alone (ie - still factory G8 settings).

If anyone has any insight, or experienced a similar problem on their build, please chime in. Help is greatly appreciated!

Thanks,

Alex

[Phil@PnP Tech]

Long term trim pegging at -25% means it is pulling fuel and maxed out. A vacuum leak would typically show a positive fuel trim (it has to add fuel to make up for the entering unmetered air). 50-60kpa at idle for a mild cam is normal, 13% TPS idle is normal. Bypass valve settings wont cause a closed loop fueling issue.

You can't just copy/paste values from another calibration. My guess is you have way too large of values for the MAF curve and/or you don't have the correct MAP voltage offset.

Post your tune.

[mrnorm_hemicide]

Long term trim pegging at -25% means it is pulling fuel and maxed out. A vacuum leak would typically show a positive fuel trim (it has to add fuel to make up for the entering unmetered air). 50-60kpa at idle for a mild cam is normal, 13% TPS idle is normal. Bypass valve settings wont cause a closed loop fueling issue.

You can't just copy/paste values from another calibration. My guess is you have way too large of values for the MAF curve and/or you don't have the correct MAP voltage offset.

Post your tune.

Thanks for the reply. The forum won't let me post the tune here. I PM'ed you.

[gatorayde]

Is it still in blend mode or MAF-only? Are you changing the VVE table with the MAF? Put the MAF curve back to stock and start from there, I only had to bump mine a few percent from the stock MAF to the LS7.

Upload the tune/logs to a site like dropbox.

Is your wideband also reading pig rich? Could just be an issue on one bank or a bad O2 sensor, but it definitely sounds like the tune.

[Phil@PnP Tech]

Ok I took a quick look. MAF curve doesnt look too far off, MAP offset is correct... You do need to disable Dynamic Air flow (ENGINE>AIRFLOW>DYNAMIC>DYNAMIC AIRFLOW)... set the Disable and Re-Enable to 300 and 200 respectively. This will keep the VE table from skewing the MAF.

What injectors are you running?

[mrnorm_hemicide]

Ok I took a quick look. MAF curve doesnt look too far off, MAP offset is correct... You do need to disable Dynamic Air flow (ENGINE>AIRFLOW>DYNAMIC>DYNAMIC AIRFLOW)... set the Disable and Re-Enable to 300 and 200 respectively. This will keep the VE table from skewing the MAF.

What injectors are you running?

Factory LSA/LS9.

[Phil@PnP Tech]

What about fuel pump? How is the pressure controlled?

[mrnorm_hemicide]

What about fuel pump? How is the pressure controlled?

Factory ZL1 pump, no booster. Pressure regulated by an F-body mechanical regulator on the pump.

[Phil@PnP Tech]

Factory ZL1 pump, no booster. Pressure regulated by an F-body mechanical regulator on the pump.

Disable Dynamic Airflow for starters. The fuel injector data is incorrect for the LSA injector. 09-10 GM changed the architecture of the E38. The early version has a 63lb/hr limit were the later models have a 127lb/hr. The columns header values do not line up so you have to interpolate the data to get it to work correctly. Same thing goes for the offset data. You can not simply copy paste when comparing lsa/ls9 tune. Also change the max/min fuel pressure to 400kpa... idk if it does anything but that's the correct value for your setup.

Get the injector data correct, turn off dynamic airflow, then tune the maf within 1-2% correction.

[mrnorm_hemicide]

Disable Dynamic Airflow for starters. The fuel injector data is incorrect for the LSA injector. 09-10 GM changed the architecture of the E38. The early version has a 63lb/hr limit were the later models have a 127lb/hr. The columns header values do not line up so you have to interpolate the data to get it to work correctly. Same thing goes for the offset data. You can not simply copy paste when comparing lsa/ls9 tune. Also change the max/min fuel pressure to 400kpa... idk if it does anything but that's the correct value for your setup.

Get the injector data correct, turn off dynamic airflow, then tune the maf within 1-2% correction.

Thanks again for all the help Phil!