I remember a link maybe a few months back about porting of the jdm 4-1 header. For those who have done it, what was actually done and how much or a gain was it to have it done?

Thanks for any help/input.

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I had mine port matched to the exhaust gasket.

1 - Take header to welder, have them weld a bead on the outside of header.

2 - Take header to porter, tell him/her to use ear protection (it's loud as hell)

3 - Clean up header after the work is done, install and call it a day.

It definately helps the air flow.

 

http://www.sandmracing.com/m_e02_jdmheader.html

 

Anybody happen to have dyno numbers pre and post porting? Thanks.

Tony

 

I believe Jeff from IB said he saw 3whp after they modded both the ports and collector.

 

You realy don't need to weld the out side up also. My Dad has been welding for 30 some odd years and I took the header to him and asked him to weld the out side so I could port the inside. He said that it was not needed and if he did weld it, there was a chance of it warping. I ported it fine with out welding the out side. Also, if you port it your self, use fawking ear plugs. I heard a nice ringing in my ear for about 3 days cause I did not even think about it.


[Modified by AssPenny, 10:41 AM 4/2/2002]


[Modified by AssPenny, 10:42 AM 4/2/2002]

 

How did you port it? Dremel? What grinding stone do you use?
How hard is the weld to grind and how long?
Sorry for all the questions.....hehe
Any ideas?

 

To port it I used an air speed grinder with a chunky grinding stone. Then once I got the bulk off, I switch to a smaller stone, then finished up with a flapper wheel (for thouse that don't know, its a wheel with pieces of sand paper sticking out of it). Took me about 2 hours to grind them all down. Just take your time and make sure you don't cut into the primairies as they are realy thin.

 

D-
nice header. you think the SMSP mod was worthwhile? or was there no real comparison of before and after?

BTW, nice boots. who's going camping?

 

D did the porting and got it welded, I did the collector and had Airborn coat it.

 

So you ported your JDM 4-1 yourself without extra welding on the outside??? How long has it been since you have done this??


[Modified by eg-six, 9:43 AM 4/3/2002]


[Modified by eg-six, 9:43 AM 4/3/2002]

 

Have not had it on the car yet due to other reason. I'll let you all know how it goes and if it cracks, I'll post it up on here.

 

D took it to the extreme on the ports so the welding he had done on the outside may have been needed. But when I port XR4Racer's JDM header I just remove the excess with an air grinder, which goes very fast compared to a Dremel. You could remove most of the flange in 2 hours with an air grinder and a good metal cutting burr. I did that about a year ago and to my knowledge it hasn't crack yet. Just remove the weld that protudes into the ID of the tubing and don't touch the leading edge of the weld too much. Remember a good weld is only as strong as the thinest piece of material that is getting welded.

 

Onyx who wishes he had ported his before it was Jet-Hot coated

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SMSP &raquo;</TD></TR><TR><TD CLASS="quote">
D did the porting and got it welded, I did the collector and had Airborn coat it.
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Dave,

What did you use to port the collector?
Did you take a measurement of the ID of the collector after the port job?

 

jesus christ, back from the dead. this post is over a year and a half old. lol. nice.