something i've been meaniong to ask...

noticed it when instsalling the OBX headers.
the header that meets the block is smaller than factory headers.
measured the diameter of the header inlet and it was smaller than the factory.

is it possible to get a hp increase from a smaller piping?

 

the hole in the gaskets were way smaller than the factory gasket

 

interesting...I will measure the inlets this weekend with a digital caliper to confirm this. There are other things that might be incorporated in the header design that can increase flow other than diameter, but I am a bit surprised to hear that they aren't bigger than stock. The one thing I noticed is that they aren't very smooth inside because of the welding. My Audi header is made in a lost wax casting process out of inconel steel and is butter smooth inside.

 

i saw ome where in a post that these headers were less than $400, can that be true? is that each? isn't comptech like $1200?

 

yes comptechs are around $1000+ and OBX's can be had for around $330

 

Has anyone figured out how to get rid of the resonance issues yet? I can live with them, but it would be nice to get rid of it...

 

OBX headers are very poor quality. At best, they will give the youy same gain as comptechs because they are a rip off of comptechs design, but they are made in taiwan by the lowest bidder (im serious). They arent stainless steel, they are mild steel i think, so they will rust out faster. the build quality of them is shoddy at best. but for the price, its not THAT bad.

 

Tim,
Back it up with some facts!

"they are mild steel i think"

Do us all a favor and shut the pie hole, unless you have some info that can be verified other than your "I THINK SO CALCULATOR"

Iggy

 

I had the headers installed this weekend (Thanks Ray and Ivan!). The stock header part that attaches to the engine is indeed bigger than the OBX (and I assume the comptechs as well as stone headers). We took measurements but I'm too lazy to get them right now. The link below shows the two side by side.

headers

Funny thing was that I had my headers done by some great Audi guys! See my thread for details.

 

thats what mike b at comptech poasted on their forums. they are stainless too, but the metal isnt as good quality.
you want proof iggy? here http://www.comptechusa.com/cgi-bin/f...m=24&topic=108

 

Mike B. also says that w/o CARB certification, OBX headers are illegal in every state ... I'm not saying he doesn't know what he's talking about but as far as I'm aware, CARB certification only applies to California...

So unless CA = every state, then he is in fact wrong about the CARB statement.

Comptech is cool and they're great for supporting Acuras, but I have a hard time accepting what an employee of Comptech says about one of his competitors thats underpricing them by more than 50%.

That said, I do believe that OBX headers use a lower quality stainless steel than the Comptech headers. I don't think that it would have a negative impact over the life of the car though. Chances are, the car would die before the steel starts to fall apart.

 

I see what you are saying. obviously his opinion is biased. A few states have strict emissions like CA does now, and require that certification, but how would i get cought? i mean are DEP police going to search the engine bay of my car?? I dont see any sense in spending over $1100 for comptechs when i could get OBX's for less than half that.

 

The stock ports are bigger than the OBX by 2mm. The stone headers ports are port matched and they will be as big as the stock ones!

 

Beruity, did you measure the Stone and the stock? Hey have you been to the track lately? I know you were planning on going but I wasn't sure if the weather has allowed you yet.

I agree with Liqice. Comptech is great but Mike B. did come across a little harsh once and very biased (obviously). I do agree that OBX are of lesser quality than Comptech but not $700 worse! Not sure about the stone headers but reviews seem to be good.

 

Do the stock ports neck down right after the flange? Do the OBX headers maintain diameter all the way down? Which one best matches the exhaust port on the head? I don't know- I've never had mine apart.

Sometimes, a smaller, better matched header pipe will still make more power, simply because of the turbulence it eliminates at the exhaust port. Size matters, but not always how you think.

 

Ferizzo,

Yes, I did. The stock is bigger by 2mm. I asked for the stones headers to have bigger ports by 2mm. In any case, they are portmatched.

I am planning to go to the track this weekend, Saturday. The NED will open Wednesday night.

My CLS needs a nice detailing and swapping summer tires before hitting the track at NED...

See you there?

Nashua.

 

They are stainless steel.