Bumpster....

 

lol, so what part of half *** tune did you not understand?

that was the first log taken

 

He's probably leaning back in his computer chair, with chip crumbs all over his shirt, laughing and spilling more food all over himself while we all sit here wondering when the hell he's going to post again.

 

 

I need help with my pre cat o2 problem. any takers?

 

I think he went into severe depression when the vikings lost.

 

Start a new thread. This isn't the place for it.

 

Ok guys, I didn't forget about this thread at all, I just haven't found the time to post up my findings. Now that I had quite a few guys post up with naturally aspirated combinations what I wanted to discover or see was the correlation between displacement, intake manifolds and header size.

The first thing that's bothersome for me to see is that those of us running the OBX long tubes with the small primaries and small collectors are showing restrictions by 5200RPM"s (where a lsx engine starts to shine). When viewing everyone's log file I was watching the KPA vs TPS vs RPM.

What was crucial to me in viewing the logs is how close people could get to 100KPA (kilopascals) or 1 atmosphere. Of course MAP readings are going to flucuate SOME as turbulant air chugs on by but this shouldn't vary more than 2-3KPA. Corey was the ONLY person to hit 100KPA out of all the log files I looked at. For his combination he has no restriction. Anyone else here who posted logs (including myself) apparently has "some" issues to work out with either an intake or exhaust restriction. If you have a CAI of sorts then I'm sure you don't need to worry about your intake tract.

Next, onto the intake manifold, I don't see this being as much of a factor as the intake tube. The manifold's job is to "tune" the airflow of the engine to operate within a certain operating range. Runner length, plenum volume and TB size all work together respectively to attain this.

Lastly and what I wanted to get into is header size and engine flow requirements. It appears as though from the logs that you guys have posted that only 2 of you have exhaust that matches your engine requirements. Skeet and Corey (blackgmc). The rest of us have to get our **** together. I believe what's happening is in order for us to reach 1 atmosphere is that we need a more free flowing header that will meet the pumping requirements of our engines. On a 6.0L, I don't think anything less than a 1 7/8" header with a 3" collector will suffice. On a 5.3L, a 1 3/4" header with a 3 inch header seems to come close but still may be a tich on the small side. For a 4.8L a 1 5/8" header would be close but a 1 3/4" header would be better.

Excuse me if this post seems cluttered as I am in the middle of a home remodel, I'm tired, don't have the concentration to put towards this right now but at least owe it to you guys to explain what I was after. There you have it. Now on to shop for some new headers that don't cost a small fortune.

 

Haha thanks for the info Joe. Glad you at least gave us an explanation

 

1 7/8" for me. Anything less was financially irresponsible given the slight cost difference.