Tuning after header install .....
Thread Starter
TECH Apprentice
Joined: Jan 2002
Posts: 332
Likes: 0
From: Louisville, KY
Tuning after header install ..... I'll be soon installing PPC headers with the hi-flo cats and Y-pipe. What changes in scanning results can I expect and what will I likely need to tune???
Any help is appreciated.
Any help is appreciated.
Mine was the opposite of Tileman. Mine ran a little leaner LTrims and alot richer 02's (.940 compared to .90). I installed headers on car and Autotaped them and they are perfect. Good luck with the header install.
John
John
The thing that usually happens with headers on an LS1, is the headers improve the engine's airflow making it run leaner. The PCM responds to this by running up the LTFT's to compensate, so at part throttle the AFR is still the same as before. But at WOT, extra fuel gets dumped because the positve LTFT's. So to tune for headers, adjust the LTFT's negative first, then lean WOT AFR to 12.8 to 13 or so by scaling down the PE. Be sure to use a wide band to measure WOT AFR.
On The Tree
Joined: Dec 2001
Posts: 193
Likes: 0
From: Southwestern, PA
Originally Posted by Cal
The thing that usually happens with headers on an LS1, is the headers improve the engine's airflow making it run leaner. The PCM responds to this by running up the LTFT's to compensate, so at part throttle the AFR is still the same as before. But at WOT, extra fuel gets dumped because the positve LTFT's. So to tune for headers, adjust the LTFT's negative first, then lean WOT AFR to 12.8 to 13 or so by scaling down the PE. Be sure to use a wide band to measure WOT AFR.
Originally Posted by Cal
The thing that usually happens with headers on an LS1, is the headers improve the engine's airflow making it run leaner. The PCM responds to this by running up the LTFT's to compensate, so at part throttle the AFR is still the same as before. But at WOT, extra fuel gets dumped because the positve LTFT's. So to tune for headers, adjust the LTFT's negative first, then lean WOT AFR to 12.8 to 13 or so by scaling down the PE.
Be sure to use a wide band to measure WOT AFR.
BTW, with stock CR, it slowed down before it got into KR or showed detonation on the plugs.
Trending Topics
Thread Starter
TECH Apprentice
Joined: Jan 2002
Posts: 332
Likes: 0
From: Louisville, KY
Thanks everybody!!!
It seems all I really need to do is get the LTFT's back in line and then hit the dyno w/ wideband and iron out the AFR.
I currently have my LTFT's just negative and adjusted them with the MAF table since I had a lid and MAF ends added. Should I adjust the LTFT's using this method again or by a different method???
It seems all I really need to do is get the LTFT's back in line and then hit the dyno w/ wideband and iron out the AFR.
I currently have my LTFT's just negative and adjusted them with the MAF table since I had a lid and MAF ends added. Should I adjust the LTFT's using this method again or by a different method???
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0
Brett Foote
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever
Verdad Gallardo
TECH Regular
Joined: Aug 2002
Posts: 400
Likes: 0
From: New Hampshire
When I hit the dyno after the header install, to get the "after" numbers, with no tuning.....
Above about 4000 RPM it was very visibly rich.
Gordon
www.provenperformanceconcepts.com
Above about 4000 RPM it was very visibly rich.
Gordon
www.provenperformanceconcepts.com
after install pacesetter LT's and 3" y, my LTFT's changed from - 5 to +2 and o2's changed from .880 up to .940, these were checked with A-Tap ( only thing Ihad to scan with) will bring ltft down with Ls1edit useing IFR and bring o2's down useing ls1edit /pe/rpm ( Like to lower o2's untill I get a little KR, then rase a little )in cool weather about .880 with my stuff added
my o2's Johnny
my o2's Johnny
