Tune changes when adding long tubes?

[Sébast19X]

http://www.hptuners.com/forum/showth...tegrator-delay

[HoP]

Under your proportional section of ol/cl fuel you have airflow mode. This is read against lb/min. drive the car and scan your o2 sensors. usually with the headers around 15% throttle and light load the sensors will fall to the flow and will not oscillate. Take notice at what your maf is reading in lb.min. It should be at light load around 2-3 lb/min. increase the cells by 5% at a time. the first cell is 0 and the next is 8 so you would manipulate just those cells.

[u1arunit]

Under your proportional section of ol/cl fuel you have airflow mode. This is read against lb/min. drive the car and scan your o2 sensors. usually with the headers around 15% throttle and light load the sensors will fall to the flow and will not oscillate. Take notice at what your maf is reading in lb.min. It should be at light load around 2-3 lb/min. increase the cells by 5% at a time. the first cell is 0 and the next is 8 so you would manipulate just those cells.

Thanks for the reply. What results are we looking for though after making these changes?

[Niemer]

[o2] sensors will fall to the flow and will not oscillate.

This happens to me coasting to a stop, 7-10% ETC and 1-1.5 lb/min. airflow, the narrowbands just drop out and the mix goes really lean then it finally catches itself. Could this also be why my STFTs are minus 1-3% but my wideband reads lean?

What do the column numbers (0, 8, 16, 24, 32, etc...) represent?

[Pekka_Perkeles]

Airflow mode. I think there's another table which links the mode and how much air flows to the engine.

[monte4ever]

Anyone have any success with changing these tables?

[wetcoast]

Bump! The lack of a methodical way to tune this is driving me crazy. I'm not smart enough to figure it out myself and I don't have enough free time to trial and error.

[warriorpluto]

Is this the correct way to do this on an 1999 trans am? I've been driving on someone else's tune since last year and finally just now have time to sit down and tune it. I have full exhaust only. Also adding doorman ls2 intake next month when I get a chance to put it on

[BROWNSTONE]

I know this is kinda old, but....

You guys are really bringing out some great, hard to find info.. I'm kinda new also and amidst tuning my 2000 silverado p01. 2" primaries are giving me a challenge with CL running AFR (lean 16.00) due to I believe incorrect response time on the factory o2's. (Rears deleted, 231 cam).. I have pretty well dialed the maf and ve and these run well in OL eachb on their own, but now have one question... should I be adjusting swtchpoints to help compensate for the increased header volume compared to stock, or should I focus more in the milliseconds in the "proportional integrator" airflow table? Just looking for advice from anybody with more experience... I'm going fairly lean in CL at lower rpm.... thanks 😊

[Cringer]

I know this is kinda old, but....

You guys are really bringing out some great, hard to find info.. I'm kinda new also and amidst tuning my 2000 silverado p01. 2" primaries are giving me a challenge with CL running AFR (lean 16.00) due to I believe incorrect response time on the factory o2's. (Rears deleted, 231 cam).. I have pretty well dialed the maf and ve and these run well in OL eachb on their own, but now have one question... should I be adjusting swtchpoints to help compensate for the increased header volume compared to stock, or should I focus more in the milliseconds in the "proportional integrator" airflow table? Just looking for advice from anybody with more experience... I'm going fairly lean in CL at lower rpm.... thanks 😊

Here ya go bro
https://youtu.be/5hjzI8wSItk

[bran]

Here ya go bro
https://youtu.be/5hjzI8wSItk

Here I was thinking I wasn't gonna find any recent info on this ten year old thread, and y'all are still teaching the good stuff! I'm running into this issue with an LS3-swapped Grand National with long tubes with the O2s at the very end of the pipe. The tune is *close* but those silly lean spikes at part throttle and beyond reallyyyy bug me and make the car run like it has a vacuum leak. Gonna start from what's suggested here and hopefully get this fully dialed in.

Thanks to all.

[blindsquirrel]

with the O2s at the very end of the pipe.

If you described that right, there's no tuning that can make that work. Exhaust has pulses, and fresh air goes some distance back up the pipe with every pulse, worse at lower engine speeds. Sampling outside air is no good whether it comes from an O2 being too close to the end of a pipe or from an exhaust leak that pulls in fresh air upstream of a sensor.

[JayRolla]

If you described that right, there's no tuning that can make that work. Exhaust has pulses, and fresh air goes some distance back up the pipe with every pulse, worse at lower engine speeds. Sampling outside air is no good whether it comes from an O2 being too close to the end of a pipe or from an exhaust leak that pulls in fresh air upstream of a sensor.

I think he meant at the end of the header pipe, not exhaust pipe. At least I hope so.