6pack wrote:I'm having a brain fart and without re-reading the whole thread, I'm not remembering what you mean by 'extractors'. Can you refresh my memory for me?
trailerpup wrote:I think I found out why the 3.7 runs like a 2.4... the stock exhaust manifold with the cold start converter... Putting the header on was like pulling the dry cleaning bag off from over the head of my 3.7... It can finally breath (or exhale, if you will). You can really tell the difference. I was thinking about getting the PCM tune so I could get the shift points re-calibrated, now I have none of the shifting (lugging) problems that I'v'e had since going to 35s. The gutless wonder all of the sudden has guts. Throttle response is the biggest part. From 1200 rpm up it finally can get out of it's own way. I have tried both the Volant and Borla cat-backs and neither made any noticeable difference, except for the unbearable drone in the cabin. I run the Volant CAI on the intake side and the stock exhaust from the header back. To be honest, I have been thinking of trading in for an Alpha. Then they announced the H3T and the fact that all will be available with front locker next model year. So, I was gonna wait and trade in. Now I am think I can keep my H3. It really is that much a difference for me. Install was a snap. I removed the CAI and washer/coolant reservoirs, and EGR to gain access. Worst part was extracting the stock monstrosity. The header slipped right down in there. I used a new exhaust to head gasket, stock manifold to head bolts, grade 8 bolts/nuts, etc. for header collector to stock exhaust pipe. The doughnut gasket from the stock manifold is re-usable and fits on the header collector pipe. I would say it took 1.5 hours to do the job. The o2 sensor port on the header puts it pretty close to the passenger shock tower. However there is no interference from Engine vibration. But, it looks like it will be a biatch to change the sensor out if I ever have to. I am wondering if there is a "low profile" o2 sensor that will work on it. The stock sensor is like 4 inches in length!!
The header eliminates the 1st catalytic converter (incorporated into the stock exhaust manifold) and the 1st o2 sensor which sits about the stock manifold converter. This causes the computer to throw a code for the o2 sensor... as if the o2 sensor needs to be replaced. Keep in mind that I have been running it for a day without the 1st o2 sensor attached. This has caused no discernible problems other than the "check engine" light being illuminated. I am researching what voltage the computer is looking for from the 1st o2 sensor under normal operating conditions to eliminate the code. This could take the form of installing a resistor or tying the 1st o2 harness into the 2nd 02 sensor (which sits below the stock manifold converter). It is my understanding that the converter incorporated into the stock exhaust manifold is there for cold start conditions only and it's absence will not cause a bad sniff reading for emissions testing.
So there you have it. I will update as things progress. But, so far, so good. Also, my H3 is 2007 3.7 adventure with 7k miles, BFG 35s on 16x8 wheels. For the record; messing with my H3 - I have money to throw at it and it is more of a hobby for me. Maybe I can be the guinea pig here and we will see what happens. I have the stock manifold in a box if I need to revert. But, so far... I am sold! I am wondering what a PCM tune will do now! Here is a picture of the header installed (it's down there somewhere) and a picture of my rig when I drove it up the mountain today. If anybody has any input, chime in. From my searches on the internet I found no info about somebody actually installing this thing!!
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