Header Tuning?
Thread Starter
Launching!
Joined: Aug 2002
Posts: 231
Likes: 0
From: Ontario, Canada
Header Tuning? Hey all! 
So I spent some cash this year and picked up a set of Pacesetter longtubes and a TSP 3" Catted Y. Threw these on my WS6 and am loving it.
However a friend of mine (Mark99Hawk) just got done tuning and recal'ing his VE tables and using redhardsupra's sheet to fix his car up. Seems to run better now for sure.
Can I tune mine the same way even though my O2's have been moved further back? I've heard that headers also screw up the MAF cal a bit? Any specifics to tuning a car with longtubes? I've done some searching and seen little bits of what I need, but I figured I'd throw up a post just to see if anyone can provide some advice!
Mods:
- Lid
- FRA
- Home-made Borla-Style exhaust (muffler bypass of the stock 98 WS6 single exhaust to make it a dual outlet)
- Pacesetter Longtube headers
- TSP 3" Catted Y (Carsound Cats)
I'm not sure if it's just my imagination or not, but when I first had the headers done, the car really hauled *** for a couple days afterwards.. out on the highway tonight though it seemed a bit sluggish.. would the car get slower as the PCM interpretted the screwing the headers do to the stock tune? I hear the PCM thinks there is a lean condition (even though it's false) and then dumps fuel?
My Scan data shows the LTFT's all between +11 and +20 so that seems to be in line with my theory above.. the PCM thinks everything is WAY lean so it's dumping fuel... also the exhaust smells much more pungent then it did before.
Any and all help is greatly appreciated!!
So I spent some cash this year and picked up a set of Pacesetter longtubes and a TSP 3" Catted Y. Threw these on my WS6 and am loving it.
However a friend of mine (Mark99Hawk) just got done tuning and recal'ing his VE tables and using redhardsupra's sheet to fix his car up. Seems to run better now for sure.
Can I tune mine the same way even though my O2's have been moved further back? I've heard that headers also screw up the MAF cal a bit? Any specifics to tuning a car with longtubes? I've done some searching and seen little bits of what I need, but I figured I'd throw up a post just to see if anyone can provide some advice!
Mods:
- Lid
- FRA
- Home-made Borla-Style exhaust (muffler bypass of the stock 98 WS6 single exhaust to make it a dual outlet)
- Pacesetter Longtube headers
- TSP 3" Catted Y (Carsound Cats)
I'm not sure if it's just my imagination or not, but when I first had the headers done, the car really hauled *** for a couple days afterwards.. out on the highway tonight though it seemed a bit sluggish.. would the car get slower as the PCM interpretted the screwing the headers do to the stock tune? I hear the PCM thinks there is a lean condition (even though it's false) and then dumps fuel?
My Scan data shows the LTFT's all between +11 and +20 so that seems to be in line with my theory above.. the PCM thinks everything is WAY lean so it's dumping fuel... also the exhaust smells much more pungent then it did before.
Any and all help is greatly appreciated!!
Last edited by Mat; May 23, 2005 at 11:13 AM.
You could do like your friend did and tune the ve and then recal the maf table using the sd calculations in redhardsupra's sheet. That would be the best way. If you want the easiest way you can just scale the maf table to get the trims negative. Once that is in line you can mess with the pe table to lean it back out some.
Thread Starter
Launching!
Joined: Aug 2002
Posts: 231
Likes: 0
From: Ontario, Canada
Ahh perfect! Thanks for the response man! I've had horrible luck getting anyone to give me some advice until just now! 
I'm going to do just what you mentioned for sure. I'll do the VE tuning and see where I end up. I'll get my buddy to help me out with it as well as he's been through it all once before. One quick question for yah.. he used the "Last Value" measurement on the histogram LTFT tab whereas I've seen people recommending the "Average" measurement as the best to use. I tend to agree with an average value being more accurate over time instead of a last value since you have a better idea all across the board of what value it's returning over a given period of time. Am I correct in assuming this?
Thanks big time for the response man!
I'm going to do just what you mentioned for sure. I'll do the VE tuning and see where I end up. I'll get my buddy to help me out with it as well as he's been through it all once before. One quick question for yah.. he used the "Last Value" measurement on the histogram LTFT tab whereas I've seen people recommending the "Average" measurement as the best to use. I tend to agree with an average value being more accurate over time instead of a last value since you have a better idea all across the board of what value it's returning over a given period of time. Am I correct in assuming this?
Thanks big time for the response man!
Yeah. I would say you'll have much better results using the average values. Just remember that the ltfts take awhile to "learn" so make sure you drive awhile before deciding to make more changes.
I'm the guy Mat is refering to
My thought was to use the "last value" mostly because I wanted to watch it while driving. While watching what was happening I could see where it was hovering around and that way I didn't get any weird values included in the average - I could just discount them right away. I just did this 4 or 5 times adjusting the VE table where I figured it needed adjusting based on the values the scanner was reporting.
Eventually (after about 5 tunes) I got the LTFT's close to 0 (on the negative side of 0). I started with everything at +10 to +17. Only intake mod is an SLP lid and I only have the SLP catback that came with the Firehawk. No idea why my car was so far out but part throttle response is definitely better now after the VE tuning.
Mark
My thought was to use the "last value" mostly because I wanted to watch it while driving. While watching what was happening I could see where it was hovering around and that way I didn't get any weird values included in the average - I could just discount them right away. I just did this 4 or 5 times adjusting the VE table where I figured it needed adjusting based on the values the scanner was reporting.
Eventually (after about 5 tunes) I got the LTFT's close to 0 (on the negative side of 0). I started with everything at +10 to +17. Only intake mod is an SLP lid and I only have the SLP catback that came with the Firehawk. No idea why my car was so far out but part throttle response is definitely better now after the VE tuning.
Mark
I had the same thing happen with feeling power after the header install then it felt sluggish 2 days later. Was due to running really rich. Once I took away some PE the car felt great again. Was so rich at first the car would get a bog sometimes when going WOT. My A/f was high 10:1 , brought it up to 12.8:1 and seen a 25+ h.p gain. But I have a Predator and can't do anything but adjust WOT without a custom tune.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
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 you really can't lean it out too much unless you have turned off your cat converter protection. I have efi live v7.2.2 and I just turned that off and set my air to fuel up to 3400 to 13.6:1 and above that to 13.0 :1 just to be safe
I can paste the table up here or email what i have used if you would like. my email is sm1218@aol.com All that i have done is taken my hypertech tune...smoothed out the spark tables..high and low (the hypertech sometimes came up with some funky numbers) the hypertech already leaned out my car some in the PE based on RPM and i leaned it out further using an excel sheet that i have created using what efi live detected my car as having a stoich mix of 14.63 so i used that value and found out what values would give me certain AFR mixes...let me know if you want any of this..it was very helpful to me...we are also installing an Autometer fuel to air gauge this weekend so we will have that to help us.
do you have efi live?
I can paste the table up here or email what i have used if you would like. my email is sm1218@aol.com All that i have done is taken my hypertech tune...smoothed out the spark tables..high and low (the hypertech sometimes came up with some funky numbers) the hypertech already leaned out my car some in the PE based on RPM and i leaned it out further using an excel sheet that i have created using what efi live detected my car as having a stoich mix of 14.63 so i used that value and found out what values would give me certain AFR mixes...let me know if you want any of this..it was very helpful to me...we are also installing an Autometer fuel to air gauge this weekend so we will have that to help us.
do you have efi live?
I would be interested in seeing your table.
supercharged_z2000@yahoo.com
Are you adjusting that to get your Ltrims down? How do you just set your A/F to 13.6? Isn't that a little lean?
Someone earlier in the thread suggested adjusting the MAF table up(I think) to adjust Ltrims...I was told by Ed Wright to never adjust MAF table.
Thanks,
Jason
supercharged_z2000@yahoo.com
Are you adjusting that to get your Ltrims down? How do you just set your A/F to 13.6? Isn't that a little lean?
Someone earlier in the thread suggested adjusting the MAF table up(I think) to adjust Ltrims...I was told by Ed Wright to never adjust MAF table.
Thanks,
Jason
Suspended Sponsor
Joined: Oct 2004
Posts: 371
Likes: 0
From: Just outside of Palm Springs Ca.
Guys,
Also just a little tidbit you all may or may not know is make sure you don't have ANY exhaust leaks before the o2's as they will throw off the readings and cause an overly rich condition by making the computer think it has more oxygen left after the burn and is therefore lean. Just something I see some overlooking sometimes when tuning their cars.
-Bryan
Also just a little tidbit you all may or may not know is make sure you don't have ANY exhaust leaks before the o2's as they will throw off the readings and cause an overly rich condition by making the computer think it has more oxygen left after the burn and is therefore lean. Just something I see some overlooking sometimes when tuning their cars.
-Bryan