I'll be getting a JDM ITR 4-1 header in a couple of weeks.. and I've read various posts (one in the ITR forum right now) about how people have their header ported.

Does this mean they just like, took a dremel to it and make the openings a little bigger or, is there more precision to it then this?

Would porting it by hand give any gains, or do you take it to a machine shop?

Thanks!

 

its just right where the header connects to the exhaust ports just right at the start of the header it can be ported becuse there is some bad welding at that point at the header.

 

The whole point is to have a perfect transition from the exhaust ports to the header. Not a bad idea if you have to head port and polished, same with the intake manifold.

I believe the term is called "port matching".

 

Go to http://www.sandmracing.com/m_e02_jdmheader.html and you will see the welds on the inside of the ports and how to remove them. HTH

 

Yes it is called port matching. The whole idea is to reduce the turbulence in that area and speed up velocity. You can also do this to your intake manifold if your feeling bored. Dont know if any gains will be had though. Depends on how sloppy a job the factory did.

 

I was suprised to see how sloppy those welds were, so I'm going to do something about that.

Thanks for the quality responses guys.

 

I ported my DC with a dremmel and various grits of sandpaper. As for gains.. whio knows. I did not dyno it. The welds were sloppy as hell though, I fixed that.

 

my dc jdm 4-1 gsr header was perfect out of the box, cant say the same for the head though

 

well thats why the dc puts out more power. those shotty *** welds.

 

Well, DC is also an aftermarket company. Their headers dont come on a bunch of factory cars, and also cost more, no?

 

cost more? the jdm itr 4-1 is a little more than the dc jdm 4-1 from what ive seen

and i was referring to brinks' post about him having to port his DC header


[Modified by crxfactor1991, 3:45 AM 3/1/2002]

 

why are header companies lazy? I mean, you would figure since customers pay $200-400 per header they should grind&polish the entries.

My first header was a peice of shiet Pacesetter. I had to grind out the entries (welding was worse than that pic) , and also had to make them consistent. The holes at that flange werent even straight. Pacesetter, Chikara

 

I meant stock JDM headers, not DC JDM headers..... As in came from honda OEM.

Are those more expensive than the aftermarket ones?

 

[QUOTE]why are header companies lazy? I mean, you would figure since customers pay $200-400 per header they should grind&polish the entries.

Ya but it's stuff like that you don't find out until AFTER you have already recieved and payed for the stuff....and let's be real, most ricers probably don't even look in the tubes they are more worried about getting the right color.

 

what's wrong with greddy?

 

b18civicHB, they are VERY overpriced, and they didn't give the guality it's supposed for the price they charge. believe me between Ractive and Greedy, a serious question have to be posed: Will I spend 400$ more for a name that won't give me more than Ractive that is 400$ less that Greedy???
And my question is : will it be benefic to port match the stock exaust manifold?? and the stock intake??