I already have PHP custom tunes for my Edge, 87 perf and 93 perf tunes on the stock intake. Love them.

Anyway I have been tossing around the idea of adding OBX long tube headers with high flow cats.

Would adding the headers/cats mean I have to get new custom tunes written?

Thanks for helping.

 

You're pulling our chains, right? If not, I'm going to let MDGfan or shotgunz handle this one.

- Jack

 

Thanks.

 

Stealth, I don't believe you need new custom tunes. Certainly there are parameters that delay the response of the 02 sensors because their placement is a little further in the exhaust, but changing them is really splitting hairs and will not have a profound effect. If timing and the MAF transfer function is okay with your current tune, they will be fine with headers.

 

Thanks, Windsor.

 

long tubes it's advisable to re-tune, but with shorties it's not (because they don't do much)

 

More power with tunes... do it!

 

thisis exactly why I paid a lil' more for my tuning device thru my reputable tuner, I get lifetime adjustments for my truck no matter what I do to it

 

OK now, I have conflicting reports.

 

Let me try to clear up the confusion, as I have been dealing with a few tuners and this subject myself, plus have researched this problem.

According to the tuners I have talked to, and my research, shorties DO NOT NEED to have custom tunes as long as the O2 sensors are in the STOCK LOCATION. Long tube headers WILL need custom tunes, as the O2 sensors ARE NOT in the the stock location, and are further down the exhaust path from the combustion chamber. The reasons I heard for the need for custom tunes with long tubes are: better exhaust scavenging with long tubes causing a lean condition, lower exhaust gas temperatures at the O2 sensors, and the fact that the O2 sensor is further away from the combustion chamber, causing a time delay in the O2 sensor readings. The main one I heard, and believe, is the exhaust scavenging of long tubes causing a lean condition.

As one of the tuners I asked this question to said, "Shorties are just glorified exhaust manifolds made from tubing that are sold to the masses as something new and great, but do virtually nothing for you except empty your wallet. You might get some benefit if the original exhaust manifolds are terrible, but it is very little for what you pay."

Hopefully, this clears this question up. If not, talk to Bill or Corey about this subject, as you have PHP tunes. They shouldn't steer you wrong about this subject.

 

Your money, your choice. Like I said, changing the delay for the 02 sensors isn't going to make a detectable difference on a basically stock truck.

 

FWIW per OBX these headers utililize the stock O2 sensor position.

 

Stealth, I MAY owe you an apology, and if so, I'm sorry. There has been so much posted in this forum on the subject of headers that I thought, well, he knows how to "search" and,.... :o

Anyway, the BEST advice I saw here was to talk to Bill about this. He will certainly know if your PHP tunes need to be adjusted, and, he'll be able to tell you why. I would consider anyone else's opinion as exactly that, an opinion.

Personally, I know very little about exhaust systems except to say they are complicated enough that if one is badly set up it is going to cause undesirable interactions with your engine. I've always heard that long tube headers and "X" or "H" pipe exhausts are going to require custom tuning. And, that "shorty headers" are just for looks.

As I said though, a competent tuner like Bill Cohron or Mike Troyer will give you a valid answer - a much better one than any of us can provide. We both know Bill won't try to sell you anything you don't need and I doubt Mike would either.

- Jack

 

We're cool Jack. I did do a search and uncovered nothing pertaining to my original question (hence why I make threads, I always do my research), with an advanced title search with headers and custom tunes got nothing except for one thread from 2002 I believe. Advanced title search here is da bomb.

I'll be contacting Bill.

 

Ask a real tuner like Bill.

The O2 transport delay is the time it takes between the injectors opening and the O2 seeing the change. A good place to start when tuning for LTs is a 25% increase in the time value or revs in older pcms.. The pcm will learn some of the change, but it only in specific load and ect ranges, and with min and max allowed learning.