Unhappy with custum Headders !

Ok since its hell for me to import car parts from the US I went and got custum headers at a "reputable" muffler shop.

Since this is my first headder I dont know if its working properly.
Is the car faster . . .yes
I seem to have lost low end tork but have an increase all through the band starting at 4,500 rpm, I really havent had the chance to get out and floor my car, but honestly I expected more

Could it be the diameter piping I used?

I got 1 3/4" coming strieght from the engine on the headders then 2" on the second section and 2.1/4" dwn pipe all the way to the cat, I left everything after the cat stock

Should i get a higher flowing Cat?

Thre SOTP was way under what I thought it would be, Im still going for the S3 JWT Cams maybe this will help.

Any advise as to where I messed up?

Ok since i was so overwhelmed by all the responses I got I did some research and found out what was wrong.

It seems that the sensor located on the headers themselvs is only reeceving temperature and preasure from two of the primeries and not all four.

Im hving them redone this monday and hopefully all will work well

Well, another reason you might have lost low end torque is design. It could be the length of the primaries, the set-up if it is 4-into-1 or 4-into-2-into-1, and the secondary piping size.

Unless you already read it, you might want to check out Sport Compact Car - December 1999 Issue. there is a article on complete exhaust systems, starting from intake and ending with exhaust by Mike Kojima.

Also, this is the issue with the SR20DE header test.

I went and got rid of the headders and hade some new ones made, These are 4 into 1 and this time the sensor gets readings from ll 4 primaries. The low end tork incresed conseiderably and most important the sensor is working properly again.

Funny thing is for what ive spent so far i might as well just have gotton the HS headers.

Maybe later

CAMA are next

Hey everyone, since I got no real answer from any of you I went over to the guys at NZ primera car club and they really helped out.

The problem wasn;t the headder design at all, it was the O2 sensor, seems the idiots who made the headers acidently pased the welder over the sensore and f!@# it up. So I changed the sensore and alls well

Thanks

NZ dudes

Hey Willy,
Man, I can relate to not being able to get brand name performance parts since we don't live in the US of A! Anyway, I am looking to change out my headers as well - 4 to 2 to 1.....1-5/8" to 1-7/8" to 2-1/4". I just got a lil confused reading through the posts (and I'm too lazy to read it over), so could you tell me....was the only problem behind your lack of low end torque just because of the sensors, or did replacing the 4-2-1 to a 4-1 make the real difference?
Please lemme know.
Thanks.
FF

Sure thing,

The real problem was that the first set of headers had a leak, and in order to close it up the Mufler shop ($@%@) decided to weld it shut. But they did not remove the sensore and welded the poor thing causing it to go heywire.

So the design was really not the problem but the sensore itself, I belive the 4-2-1 setup was probably the best choice but as i cut that one up to make the 4-1 setup i can no longer compare. Anyway at the rate im spending on these damn headers (2 sets so far) I should have just orderd them from HS and paied ditues on them.

Im probably getting the JWT S3 cams in a week or two from Jim Wolf, that should really help.