Headers with SC

[Lukexskywalker]

Just wondering if anyone has DG headers on a supercharged xterra or fronty? About a year ago when my head gaskets went I replaced the cracked exhaust manifolds with DG headers. I must say My truck has lost major power I have no bottom end power anymore. My truck would take off from light no problem and now there is no power until 3000RPM. If I was to do this all over again I'd throw the stock manifolds back on in a heart beat. I do understand that throwing headers on a vehical you will loose a bit of bottom end power, for instince my girlfriends truck (Darcvader) has headers on her truck but hers is naturaly aspirated and I don't notice it nearly as bad compared to mine.

I have replaced 02 sensors, MAF, Knock, and cleaned T body butterfly because of dirt build up thanks to crappy K and N filters and still no improvement. Just wondering if there is someone here who has a sc truck with headers and would probably notice it more with a auto trans.

Ive talked to some people that say to throw a tuner into it... But I don't think they make one At least superchips or bully dog don't. Now when I got the exhaust done to fit the long tube headers I got magnaflow heavy duty cats with midbed 02 bung so the sensors would reach. Currently I am running stock 02 sensors with no extensions or cheaters and they reach the cat no problem with no codes.

Just wondering what some options are here everyone seems to praise putting headers on but personally I regret putting them on, or at least putting them on a SC model. Is flashing the ecu an option? maybe getting it re mapped? Since my exhaust has been modified a lot to fit these damn headers I don't really want to go back now to stock...

[buttsy]

Did you keep the stock pipe size, or go with larger pipe?

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This post has been written entirely in recycled electrons by a bonehead on a Galaxy S4. Also from inside an igloo. Why not, I'm from the "North" right?

[Lukexskywalker]

The pipe size is bigger than stock but its been that size for years since Drew did the exhaust. All I got done to fit headers was basically take out stock cats and move them down a bit because the headers are long tube. Note as well Darcvaders truck (Morbs Old truck) is the same exhaust size as mine I believe 2 3\4" and same headers and hers runs fine, I think it might have something to do with mine being sc.

[Bow_Tied]

Larger pipes, especially the primaries on a header, will do that to any vehicle - lose the low end torque. It might be helping your high RPMs power/rev quicker but that is kind of the opposite of what you want.

I don't know S/C'd Xs but perhaps you can change pulley size on the S/C to make better use of the larger exhaust?

[buttsy]

From what I've read SC trucks are far more sensitive to pipe diameter changes than normally aspirated ones. Even a small change can affect them. I've been looking at headers, but I was going to keep the stock pipe size till the muffler. I'm even debating my cat and muffler options to avoid losing too much scavenging.

Ron brings up a good point: what about changing the pulley on the SC? Something tells me Mike Fortin changed his, you may want to ask him about that.

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This post has been written entirely in recycled electrons by a bonehead on a Galaxy S4. Also from inside an igloo. Why not, I'm from the "North" right?

[PiDGE]

Do they make a intake manifold spacer for those motors? When I put the Nismo cat back on I felt the same feeling. Lost a lot if low end. I then put the manifold spacer on and all was good again. Orrr option two. You know what that is

[Adam]

I even noticed a slight loss on mine. It has more power past 3000. Have you checked your Ignition timing? I bumped mine up a few degrees and noticed a bit more pep but not sure if you can do that.

[Bow_Tied]

What's option 2? Vk56 swap?


Sent from my shoe phone.

[Snafu]

Ask Jayman his thoughts on the headers with SC

[Lukexskywalker]

Thanks for the input guys, I believe Jaymans truck has AC headers and correct me if im wrong but I think they're a shorty header that bolts right to stock cat?? Not sure but if that is the case maybe his wouldn't be as bad as mine being long tube header.

I understand the theory about the bigger exhaust, For instance when we pipe a motorcycle we have to re jet the carb (if its carbureted) to make the bike richer. I was maybe thinking that throwing the headers on that the sensors would pick up on whats going on and the ECU would dump more fuel where needed etc. But I believe something else needs to be done. I will think about what to do either timing or pulley or talk to a engine performance shop and see what kind of ideas they have. Long story short not impressed with headers.....

[Snafu]

Yes he does have the shorter version that bolts to the cat (assuming his truck did not come with 4 cats). If he had 4 cats then the shorty headers would eliminate the first set. Jayman would give you an idea of how he felt when he swapped over to the headers (even if they are the shorter versions).

With the 4 02 sensors the first (ahead of the cat) should tell computer how to modify the fuel (assuming all else works). The second set of sensors are 'reference' (not sure exactly but being post cat it should tells the computer how well the exhaust was cleaned by the cat...if it fails then CEL).

The stock computer can manage some fuel adjustments but I do not know the working range and whether enough fuel can be delivered. If the computer can be tuned then it might help to get a tune after you have made your changes (at least it would help give you the most bang).

I only mention the tune because the guys at the subaru club are adamant that a tune is needed with the turbo 4 even if just changing to a cold air intake. Maybe it is just the subaru?