Installed headers, any tuning necessary?

[Shazbot]

Just finished installed my pacesetter headers, big increase in performance and I am satisfied with the results. Anyone know of any pertinent changes that should be made if any?

[BlackGS]

I'm pretty sure you will have to increase your MAF values to keep trims in line, but I would make sure first that you don't have any leaks. I had a really small leak right before the O2, and it gave me fits trying to keep the trims steady.

[Shazbot]

I'm pretty sure you will have to increase your MAF values to keep trims in line, but I would make sure first that you don't have any leaks. I had a really small leak right before the O2, and it gave me fits trying to keep the trims steady.

I verified the absence of leaks before I went out for a test drive, the only possible leak may exist at the reducer slip-joint but that is after the important O2 sensor. I definately have trims in mind but I have to wait until later, was 7*F outside today .

[JerryH]

What do your scans tell you?

[BlackGS]

I verified the absence of leaks before I went out for a test drive, the only possible leak may exist at the reducer slip-joint but that is after the important O2 sensor. I definately have trims in mind but I have to wait until later, was 7*F outside today .

I had that slip-joint welded, but I scraped my exhaust not that long ago, and I think it broke the weld loose.

I don't know what your KR was like before the headers, but if it was zero, you might be able to add some timing as well.

[JerryH]

Adding headers, if left untuned for usually increases KR more than takes away... for the simple reason that it increases breathing and that increases airflow and that makes things leaner a bit.

If compensated for, yes it should permit you to increase timing a little. Exhaust modifications are one of the few things that one can do that increase power and MPG at the same time.

[Shazbot]

What do your scans tell you?

I have not looked at the scan yet, the point of my question was to find out in general if any tuning needs to be or should be done -just so I knew. I am not making any changes to my tune until Spring. The scan I just took was at 7* F...

I did notice my KR was halved at WOT though, which is contrary to what you said Jerry. However, I was only able to accomplish 2 near WOT runs, was too icy and snowy.

I kind of got a little ahead of myself, I have a set of 1.9s and 105 springs to put on but do not want to until I have my tune in order... which.. guess what... wont happen until spring. ..lol

[Shazbot]

Adding headers, if left untuned for usually increases KR more than takes away... for the simple reason that it increases breathing and that increases airflow and that makes things leaner a bit.

If compensated for, yes it should permit you to increase timing a little. Exhaust modifications are one of the few things that one can do that increase power and MPG at the same time.

After looking through the scan I noticed my O2s at 940-965 during one of my quick runs, that corroborates what you were saying regarding more airflow. I never saw the O2s that high before the headers.

[Perforator]

After looking through the scan I noticed my O2s at 940-965 during one of my quick runs, that corroborates what you were saying regarding more airflow. I never saw the O2s that high before the headers.

Your O2's shouldn't have increased because of headers unless you increased your fueling or something. If anything it should cause your O2's to decrease. More air, same amount of fuel = lower O2's.

[JerryH]

Exactly. Should be leaner not richer. Outisde temps play a lot, though. Colder temps equal leaner O2s.

If you ar getting 960s now... you are well in the 980s or more when things warm up!

[louvered97gtp]

Adding headers, if left untuned for usually increases KR more than takes away.....

Can you explain this? I constantly see people advising about headers helping to reduce KR, and now you state the contrary.
Thanks.

[starks]

for the reason they said above. when i added headers, my car ran considerably leaner. air's getting out alot easier, so its also comming in easier (your engine is air pump, you have to think of it as a complete system from intake to exhaust) when you run leaner, you get more kr. once you compensate for it being leaner, it will overall reduce kr.

now if you were running pig rich, and you added headers and now your tune is actually closer, you wont have this issue...every cars different.

its possible to the original poster saying his 02's went up, that his LTFT's went from say +1 to +6, and they learned the +6 so now at WOT its adding +6 so overall its getting a little more fuel...you need about 30+ miles for it to learn LTFT's i believe. but overall the closer to 0 you are on your fuel trims, the more efficient the engine, the more power

[starks]

ALSO! i just remembered this

when i first installed pacesetters i had a bunch of tiny leaks, and my 02's went to 1000+ from the 950's they were at.

an exhaust leak WILL SCREW UP your narrowband 02 readings (dont know about wideband) once i buttoned up the little leaks, they went back down to 950.

on the pacesetters i had a leak on the ball flange connection connecting the front primary to the crossover. supposadly there is no gasket needed, but i could feel the leak around it. i rtv'd this, and all the slip connections.

[louvered97gtp]

Thanks so much for the response. So understood the more airflow running leaner concept. But doesn't the narrowband detect this and adjust fueling (seperate from the LTFT adjustments we do) . this is where i'm not understanding what the o2 reads exactly I guess. I know o2 readings get affected if there's an exhaust leak, so therefore more flow affects these readings as well and would affect the tune's fueling should it not?
Or is it that the headers (air pump concept) allows the better flow like mentioned, necessitating the MAF to be retuned for the new flow, hence, recurving the fuel as appropriate?

[Perforator]

But doesn't the narrowband detect this and adjust fueling

In closed loop yes but not in PE.

[Shazbot]

I had my MAF tune at 2 to -1 back in November and that was around 32* outside. The day I reported my findings, it was 7* outside.. At that time, my LTFT's were bouncing back and forth between 0 and -10. Also, my trims were learning since I had the battery disconnected during the header install.

I got the car back together(lights and upper mounts), when the roads clear I am going to get out there and take some extensive scans.

[GTPNoga]

My O2’s were in the 950’s before header install, after install they dropped down to an avg 0f 906. I then decided to do the VE, MAF, Fuel and Spark timing. I am still working on the PE fuel.

[JerryH]

Can you explain this?

I did, in the same post. Headers increased breathing, lean things out. Look at your O2 or WB before and after. There is your proof.

[louvered97gtp]

I did, in the same post. Headers increased breathing, lean things out. Look at your O2 or WB before and after. There is your proof.

Yes Jerry, I read your post. But that statement alone did not answer my question on how this equates to additional KR as evaluated by the PCM. This was something I still didn't quite comprehend the way you explained it, which is why I asked for further clarification. I am new to tunning after all and don't have all your experience to make sense of all this very quickly. My confusion however was already put to rest by others who had the patience to explain further. Thanks all for the extra help. Much appreciated. It's gonna be a fun year!