Question about my just installed intake
Thread Starter
Racer
Joined: Aug 2007
Posts: 397
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From: Charleston SC
Question about my just installed intake
Good evening... I just installed the Airaid intake for my LS2. Step one said disconnect the battery, but I didn't. Never have for any of my other cars when I installed intakes. Question... is this a big deal? What is the point of disconnecting the battery? Thanks.
Nick
Nick
Thread Starter
Racer
Joined: Aug 2007
Posts: 397
Likes: 0
From: Charleston SC
Ahhh makes sense... So, no biggie? I wanna get the most power outta the intake. If disconnecting my neg terminal will cause the PCM to some how relearn something I'm all for it I suppose.
Safety Car
Joined: Jun 1999
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Its not a bad procedure in any case and resetting the LTFT to zero is also a good idea when doing this kind of mod to start the relearn process.
Safety Car
Joined: Nov 2010
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From: Woodlands (houston) TX
mine is a dd so every few weeks or so friday before i leave work i disconnect my batt so it resets my ltft so sat when i drive outta town to have fub drivin in country i get the most i can but a tune is best i picked up more from tune then i did intake
Safety Car
Joined: Jun 1999
Posts: 3,570
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Programmed fuel and timing tables are used in open loop mode so disconnecting the battery does nothing to these.
The PCM has a table to establish under what conditions it switches over to open loop once coolant temp is over a certain level. The switch to open loop conditions is based on throttle position and RPM. The higher the RPM, the less throttle and visa versa.
One more thing....the last LTFT % correction when you are in closed loop is used when you go into open loop. That may help or hurt performance depending on how much and if it makes it too rich or too lean.
My advices is leave your battery connected. Its your friend.
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Safety Car
Joined: Nov 2010
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From: Woodlands (houston) TX
it dosnt 'learn' your driving conditions and kinda tune to that? it sure seems to make a difference. not much but a lil snappier. durring the week its all city driving hardly ever above half throttle and nothing over 60. so on weekends i dont want it to "remember' how i drive during the week. am i just wasting my time?
Safety Car
Joined: Jun 1999
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
it dosnt 'learn' your driving conditions and kinda tune to that? it sure seems to make a difference. not much but a lil snappier. durring the week its all city driving hardly ever above half throttle and nothing over 60. so on weekends i dont want it to "remember' how i drive during the week. am i just wasting my time?
The PCM is very sophisticated. It will adjust ignition advance and fuel for a long list of changing conditions. Now if you call that adjusting to your particular driving style, well go ahead.
The GM PCM must be programmed conservatively. I highly recommend you have a well qualified tuner do a dyno tune. You will pick up power and torque.
Safety Car
Joined: Nov 2010
Posts: 3,725
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From: Woodlands (houston) TX
its been dyno tuned at fastlane in houston they did not suggest to disconnect batt. cant really recall where i heard, but i know i heard it more than once. i guess thats one of the old wivestales. good to know. no more resetting all my stereo stuff
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The ECU will relearn its self over time. It just takes a little longer. Its VERY difficult to properly tune a car without LTFT resets in between data logs and tuning adjustments.
Its very difficult to properly tune a car if you don't tune the car, data log, insert corrections, reset the LTFT, data log,, insert corrections, reset LTFTs, data log, insert corrections, reset LTFT, data log etc. It all takes time and time is $$$$$$
BC
Safety Car
Joined: Jun 1999
Posts: 3,570
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Any TUNER worth salt will know that you can reset the LTFTs right in the Turing software without a battery disconnect.
The ECU will relearn its self over time. It just takes a little longer. Its VERY difficult to properly tune a car without LTFT resets in between data logs and tuning adjustments.
Its very difficult to properly tune a car if you don't tune the car, data log, insert corrections, reset the LTFT, data log,, insert corrections, reset LTFTs, data log, insert corrections, reset LTFT, data log etc. It all takes time and time is $$$$$$
BC
The ECU will relearn its self over time. It just takes a little longer. Its VERY difficult to properly tune a car without LTFT resets in between data logs and tuning adjustments.
Its very difficult to properly tune a car if you don't tune the car, data log, insert corrections, reset the LTFT, data log,, insert corrections, reset LTFTs, data log, insert corrections, reset LTFT, data log etc. It all takes time and time is $$$$$$
BC
One additional point is the PCM is continuously adjusting the LTFT in the feedback process I outlined earlier. This is the fuel only. The ignition advance is managed by various fixed tables that a tuner can only change. These tables have degrees of advance/retard based on engine load and RPM. There are other tables that will add/subtract advance based on coolant temp and air temp. Knock retard also have an impact on the final advance. Again, they are all fixed and disconnecting the battery does not change them.
Only the fueling correction factors when in closed loop are erased when you disconnect the battery. Open loop (or Wide Open Throttle) won't change either.
Pulling the negative terminal on weekly is a waste of time. I won't hurt anything if you do, however.
