OBX Headers
 

Anyone try these? They appear to have smaller primaries than the other standard eBay headers. Anyone know the tubing diameters?

Its hard to say, but those maybe be file photos. Looking at the sets on Ebay, each one appears to look kinda different ??

most of them are the same. there's one guy who posted a pic of the 'usual' ebay headers; the rest look like a new breed.

most of the headers out there have primaries that are way too big for the boxster. these look like they may have narrower tubing, which would yield a lot more power. i've got questions in to a few sellers & will post the result.

How small do you want the primary diameter to be?

I have M2 (ebay) headers; they have a 42mm primary OD. This seems a pretty reasonable primary size to support a 250-280 hp car.

I guess you could increase midrange torque a bit by going to a slightly smaller diameter.

wow; that's almost perfect for the 3.4L tuned to 6700RPM torque peak.

which engine are you running them with? how's the build quality? notice a power improvement over stock? thanks.

Mine is a mostly stock 3.2; as you said, perhaps a little smaller diameter would be better.

I haven't installed them yet! :)

So far I am impressed with the build quality. The flanges are thick. The welds look good - not gorgeous, but plenty good. I had to sand off a bit of casting residue and use a grinder on some spots, but nothing major. I hope to install them tomorrow and will report on how they fit.

Let us know how it goes. Btw, one eBay seller returned an answer. The OBX are 1-5/8 primary and 2-1/2 secondary, which is spot on for the 3.2 & 3.4, but a bit large for the 2.5 & 2.7.

Sounds the same as the m2. I have to measure mine; I think they are 2". My car is WAY rev happy. Not much down low, but feels like it could pull way past redline. Need to dyno it sometime.

How do you plan on reconfiguring the catalytic converters ?

where are you measuring when you refer to primary and secondary.

lobo - the primary is the diameter of the tubes that touch the motor. the secondary is the narrowest part of the tube that feeds the exhaust pipes.

as to the OBX? well, i ordered a set.....and sent them back. they are absolute shyte. the transitions from the valve exit's oval shape to the primary tube's round shape are atrocious. they just sort of bent a tube & shoved it into another tube. not even centered at the valve outlet. they tried to mill out the metal to make a smoother transition.....they failed.

check it out:

Wow, that really looks home-made... :rolleyes:

The m2 headers I got are done with a similar idea (shove round tubing into oval), but they actually fill-welded the transition on the inside. It's not perfect, but a LOT better than in your picture!

I've had the m2's on for a couple of months now. Fit was great on the drivers side, but not good on the passenger side. I had to bend an underbody panel bracket out of the way to make it fit.

They certainly do transform the car though. The sound is really nice above 3,000 rpm, both from inside and outside the car. No droning or vibration or other negatives. Power delivery is much more peaky. There is a marked difference going above 3,500 rpm. Without a dyno run I am unable to tell whether that is because the headers rob torque down low, or because they add torque above...

I personally feel these headers are an outstanding modification. For less than $100, you get a radically different feeling car. Whether they add hp or not is secondary in my opinion - I like the way the car feels!

Do you remember the Thickness of the flange? you still have those headers on your car?

GOD no; did you read the post? they showed up & looked HORRIBLE. i never installed them. i have no idea what the flange thickness was, but my guess is 3/8". do not buy these.

i tried them and they are horrible, instead i would recommend you to topspeed they are on ebay, and way better than OBX stuff.