New Headers for my '04 S

[BoxsterLewis]

j.fro wow didnt think it was that big of a difference lol. I mean i felt a pretty nice bump after densorkle but might have to try headers if its swimming in a ocean!

[Jaxonalden]

Remember guys, the engine is a big air pump and the more efficiently you can draw the air in and blow it out the more power you'll make.

That’s why opening up (desnorkeling) the air intake, installing a low restrictive air filter, adding a turbocharger, supercharging are great ways to increase the intake volume. The same can be said about headers, there're less restrictive than stock and that compliments the scavenging of the cylinder to make way for the next charge. But not as much as to burn valves by not providing the proper back pressure.

Nitrous Oxide, now that's a different animal and doesn’t follow this line of thinking.

[j.fro]

The headers really woke the engine up, especially from 3000-6000. However, I already had better flow from modified cats and the muffler, and a less restrictive intake system (including the desnork). But, like the ocean, I'm finding that you can get into much deeper trouble. I'm chasing a CEL, but I've got a couple of things in the works... we'll see how it goes.

[Kevfra]

I too bought a set of the $100 headers from eBay, no idea if they are from China or wherever as they all look the same, packaged the same etc. Nice looking when they arrive.

Removed my old with no exceptional difficulty, pressed out the four studs on my vice with the old over-sized socket trick, again no problems.

Installed first header - problems. After two days of dicking around I have found the screw holes are badly misaligned, and no way can these be installed as arrived. Using as a template the old gasket and/or the old manifold, the holes are way off.

The bad news is this causes the new bolts to cross thread, and the aluminum heads are so soft that even finger tight at first is enough to bugger a thread - then you're in for some work. I have had to redress four holes of threads, and I only used my fingers to spin the bolts. The misaligned holes on the new headers drove the bolts at a bad angle, and working under the car it's too tough to see perfectly.

The flange can indeed be drilled and made right, so this is not the end of the world. I'm just saying that when you buy some of these first of all be prepared (tool-wise) to drill if needed, then step one compare your old gasket to the new flange before going any further.

I'm not finished yet, but I hope I won't have any more bad reports!

[Kevfra]

OK - job is done.

Installed and removed four time each side for fitting and drilling. What a pain! Some holes were off by as much as 1/4inch. The other flange with three holes lined up fine.

When/if I ever have to get involved in there again I'll be looking at some heliocoils to keep things strong. Not a good situation, and again I was stripping the first few threads just with my fingers - that is some soft material!

I assume the five hundred dollar headers are perfect, and hey maybe so are every other set of one hundred dollar headers, and I just got the bad one. But I'm telling you check first before against your stock gasket before you start installing.

[chaudanova]

Originally Posted by Kevfra

I too bought a set of the $100 headers from eBay, no idea if they are from China or wherever as they all look the same, packaged the same etc. Nice looking when they arrive.

Removed my old with no exceptional difficulty, pressed out the four studs on my vice with the old over-sized socket trick, again no problems.

Installed first header - problems. After two days of dicking around I have found the screw holes are badly misaligned, and no way can these be installed as arrived. Using as a template the old gasket and/or the old manifold, the holes are way off.

The bad news is this causes the new bolts to cross thread, and the aluminum heads are so soft that even finger tight at first is enough to bugger a thread - then you're in for some work. I have had to redress four holes of threads, and I only used my fingers to spin the bolts. The misaligned holes on the new headers drove the bolts at a bad angle, and working under the car it's too tough to see perfectly.

The flange can indeed be drilled and made right, so this is not the end of the world. I'm just saying that when you buy some of these first of all be prepared (tool-wise) to drill if needed, then step one compare your old gasket to the new flange before going any further.

I'm not finished yet, but I hope I won't have any more bad reports!

Kevfra, which eBay vendor did you get your headers from? Just curious of which vendors are selling the versions with the fitment problems... While they all look pretty much the same, seems like some people are having fitment issues like yours, and some people are not reporting any problems with fit at all...

[Kevfra]

I bought from tuningpros in California, but I can't knock them. Their service was great, shipping immediate, price best, and they communicate. I think all of these headers shown in this price range are identical from one source, and there is a quality control issue. The only thing I think a vendor should do is make sure the product is ready to ship by looking at things like the holes etc. I sent a note to tuningpros to advise them of this issue.

Meanwhile the car runs fantastic, a dramtic improvement. But it also runs a bit hotter which I expected. It seems to me with the O2 sensors reading higher hydrocarbons ala no cats, the mixture will be more lean, and that will drive up the temperature. I have no science to back this up, just trying to figure out what the computer is doing.

[blue2000s]

Originally Posted by Kevfra

Meanwhile the car runs fantastic, a dramtic improvement. But it also runs a bit hotter which I expected. It seems to me with the O2 sensors reading higher hydrocarbons ala no cats, the mixture will be more lean, and that will drive up the temperature. I have no science to back this up, just trying to figure out what the computer is doing.

What makes you think it's running hotter? Are you seeing higher water temperature?

[Cloudsurfer]

[QUOTE= Meanwhile the car runs fantastic, a dramtic improvement. But it also runs a bit hotter which I expected. It seems to me with the O2 sensors reading higher hydrocarbons ala no cats, the mixture will be more lean, and that will drive up the temperature. I have no science to back this up, just trying to figure out what the computer is doing.[/QUOTE]

There should be no change in the mixture the DME is calling for (other than compensating for the improved exhaust flow), as it uses the first set of O2 sensors to adjust the mixture. The secondary O2s are there to monitor catalytic efficiency, not to adjust engine parameters. What did you do with your secondary O2s, anyway?

Patrick