Tune or not?
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TECH Senior Member
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Joined: Dec 2009
Posts: 9,728
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From: Jefferson City, MO
Tune or not? Will I need to get a tune after adding long tube headers and a true dual exhaust system? Making out my budget and whether or not I will need a tune right away or not will determine if I get the LPP headers or go with Pacesetter. Thanks for the help guys.
If you have an automatic transmission, I think getting a tune right away is more important. Here's why.
If your MAF sensor and O2 sensors work properly, they will for now, correct enough that your engine will be safe, so thats not really a concern.
If you have an automatic transmission, line pressure references calculated engine torque, which is derived from airflow, but it isn't perfect once the engine isn't stock. As you mod the engine to make more power, the torque calculations aren't necessarilly correct anymore, and you might not have enough line pressure, which can result in internal transmission slipping, and damage.
Also, shift points, are based entirely on throttle position, not airflow...mods to the engine generally mean more airflow for the same given throttle angle and other external conditions (incline of the road you're on and stuff like that)...so the shift points need some tweaking.
A good tune, will properly re-calibrate the engines sensors for it's new airflow mods which will do a lot to help correct the torque calculation, and thus the line pressure, and it will also give the tuner a chance to perfect that line pressure, and setup your part throttle and full throttle shift points in the PCM.
With a stick shift car...a lot of that isn't necessary as your left foot and right hand control the transmission, and the O2 sensors will correct the MAF "enough" that the engine won't be hurt if you hold off on the tune to save up some money to not stretch yourself too thin.
All that said...I think it's worth the wait for good stainless headers on a street car...I've never seen mild steel headers survive long in any car, coated or uncoated...granted I live in the rust belt of New England...but thats been my experience.
If your MAF sensor and O2 sensors work properly, they will for now, correct enough that your engine will be safe, so thats not really a concern.
If you have an automatic transmission, line pressure references calculated engine torque, which is derived from airflow, but it isn't perfect once the engine isn't stock. As you mod the engine to make more power, the torque calculations aren't necessarilly correct anymore, and you might not have enough line pressure, which can result in internal transmission slipping, and damage.
Also, shift points, are based entirely on throttle position, not airflow...mods to the engine generally mean more airflow for the same given throttle angle and other external conditions (incline of the road you're on and stuff like that)...so the shift points need some tweaking.
A good tune, will properly re-calibrate the engines sensors for it's new airflow mods which will do a lot to help correct the torque calculation, and thus the line pressure, and it will also give the tuner a chance to perfect that line pressure, and setup your part throttle and full throttle shift points in the PCM.
With a stick shift car...a lot of that isn't necessary as your left foot and right hand control the transmission, and the O2 sensors will correct the MAF "enough" that the engine won't be hurt if you hold off on the tune to save up some money to not stretch yourself too thin.
All that said...I think it's worth the wait for good stainless headers on a street car...I've never seen mild steel headers survive long in any car, coated or uncoated...granted I live in the rust belt of New England...but thats been my experience.
