Determining Correct Header For 403s

Well to start off, I’ve read many header articles and I’ve searched quite a bit.
I am looking to determine the correct header for my application.
My current setup is:
91 Integra Rs 113k miles
generic short ram(maybe switching out to cai)
custom 2.25 exhaust with a supertrapp
Crower 62403s
S-AFC
remote fuel pressure regulator

I’m going to advance timing soon, and have adjustable cam gears but I need to install them.

My main use of this car is a daily driver/auto-x/High Speed DE, I’ve never drag raced the car and probably never will. I need the powerband to be between 4500-6500.

Some of the headers I have looked at are(listed by increasing price):
Chikara Tork-step(may lower power band too much)
Greddy (looks to be a decent header)
DC sports 4-2-1 SS(for some reason I don’t like DC Sports)
Apexi (would require modification of cati.e. test pipe)
Comptech Mig or Tig Welded (looks to be the best, but as such is the most expensive also would require modifacation of cat)

Any advice, comments, flames welcome just make sure it’s constructive. I’d like to get peoples personal experiences with particular headers if possible, and what other people are using with simular setups.

Once again I ramble on.

get something with a 2.5 collector. big cams like to breathe, but then again, u really can’t take advantage of a big cam unless u got some kind of head work done, so that all the parts will work in harmony with each other.

nice JUN header copy without the JUN header price. 2.5 collector too.

www.camp1320.com sells em. ask for Thomas.

for the 90-91 tegs, you will have to modify 4-1 headers to fit because they will hang low due to the 4 runners going down to 1 then the cat. other headers not made for the car but b-series will fit but if its not for the 90-91 tegs, it will require some mods to make it fit. sorry bro if you dont like dc, but they make the best headers that will bolt right up onto the 90-91 teg made for the 90-91 teg.

Integ5150: I’d rather not go with a 2.5 collector because I would have to redo my exhaust. The largest size I could go is with a 2.25 collector. I’m not sure, but I think the greddy has a 2.25 collector.

g2ls_integ: I don’t plan on using a 4-1 header at all so it’s not that big of a deal. If it comes down to me having to use a non 90-91 specific header, I’ll just have to use a test pipe custom made to replace the cat and fill the gap.

A header with a 2.5" collector would be overkill with 403’s and stock compression. The collector on the Greddy is 2". It’s very similar to the DC design. I’m not aware of any non-custom header for the B-series that has a 2.25" collector.

I think the stepped, TIG welded Comptech header is the hands down winner. Unfortunately, it’s also the only listed header to surpass the $500 mark.


Tom

I’m the most interested in the comptech header, I was unable to find the differences between the mig and tig welded. Is the tig welded the stepped header or is the mig welded also a stepped header. If it’s a difference in welding I might go with the mig welded one just because it’s hella cheaper.

As for the 2.25 collector header, I think spoon or mugen makes one but it’s supposedly 900 bucks. Someone on the boards said that top speed makes a 2.25 header, but I have been unable to verify this.

Hell for the price of the comptech I might as well get the an-r header.

I’m pretty sure both Comptech headers are identical except for the welds.

And all non-custom USDM B-series headers have 2" collectors to fit the stock cat. Spoon and Mugen make 2.5" and 2" headers but not 2.25".


Tom

if you want good high end, 4-1 is the way to go…

Quick addition I’m planning on installing some p30 pistons which will bump my compression up to around 11:1, would this bump in compresion warrent a increase in collector size and exhaust diameter?

More input on this would be cool, i’m, right on track with stubbs, 10.7 CR, 403’s etc, 2 1/4" exhaust…

does anyone has know of a header with 2 1/4" collector, would a 2" be enough for 403’s with a high CR?

would a header with 2.5 inch collector fit on to the stock 2.25 pipe?

The stock pipe isn’t 2.25". But, you can modify pipes and use reducers to fit just about anything. Just keep in mind you’ll be going backwards in terms of desired performance.


Tom

the TOP SPEED header for an Integra should be a 2.25 inch collector. Ive been searching around on them and found some pretty high praise. TIG weld, SUS 304 construction and 2’’ for civics, 2.25 for integras and 2.5 for the type r model. I think they run about 215-225 with the g2ic.com discount. look in the group buy section.

At least from the few pictures I’ve seen, the Top Speed header looks like a pretty nice piece. Can’t comment any further.

If it actually has a 2.25" collector, it won’t fit the stock 2" ID cat. At least not without tapering down.


Tom

Alright, I’m pretty sure I’m going to get the comptech mig welded header.
But this raises some issues since it’s for the 94-01 integra.
The modifacations I need to do to make it work are to extend the o2 sensor wire, and to either get a test pipe or make an extension to bridge the gap between the collector and the cat.
Let me know if I’m forgetting anything, or if there are other options.

BTW: Isn’t the type-r header the same length as the 91 header, or am I majorly mistaken.

EDIT: Yes I was majorly mistaken, the type-r header is several inches shorter.