I've been looking at the Great Header Test (see here) and have found it very helpful in deciding what header I think I want. But I don't see a DC 4-2-1 (USDM for ITR) on there... anyone have an idea how it would stack up?

Also any idea why Mike at Comptech says on their messages boards he wouldn't expect much more than 8hp from a Comptech 4-2-1 + cat back yet the Comptech header alone did 10-11hp on the Great Header Test?

Mostly curious about the USDM DC 4-2-1 because of a chance to get one cheap... surely someone has had one and dyno'd or knows some more info.

thanks guys

 

4-1 make better peak horsepower....4-2-1 will help ya in the mid-range.

 

Did you mention to mike that the testcar had a full smsp catback and testpipe?

 

well i didn't know that makes more sense


and yeah, more midrange is mostly what i'm after anyway. only wailing on the vtec occasionally (and at the track) but more midrange would be nice. so you all think the DC 4-2-1 would par up pretty good to the Comptech 4-2-1? cause that was the 4-2-1 i was considering... what about kamakazi, heard they were great for midrange

 

For the simple fact that the Comptech has stepped primarys, and the DC doesn't, the Comptech will make more power. On the whole, the Comptech is a better manufactured piece than the DC. The QC is much better. I have seen some very poor DC pieces, especially when you shine a light into the collector. Some welds are very poor....

 

Well if you must go with a USDM header, and want something new, the dc 4-2-1 is $300 doller range, comptech $600, mugen $800-900.

Someone just bought my old Comptech and powedercoated it looks great and I think it did a great job. If you're going to get something used, I believe TodaSi on this board has a couple USDM headers for B18C5, a Mugen and a ????? (Sorry Chad!)

 

I did my own little header test.
I had a GSR DC 4-2-1 header and dyno 181.7 HP (peak)
I then put a Type R DC JDM 4-1 header and dyno 177.2 HP (peak)
There were no other changes made, after some fuel tuning it went back up to
180 HP.
I could not get the engine to make more than 180 HP!!!
what gives?

 

A friend of mine had one on his GSR and it self-destructed pretty quickly (cracked at welds). He now has a Honda JDM and felt that there was a notable power increase.

'4 into 1' versus '4 into 2 into 1' is only one of MANY design features which affect power output. I'd suggest that you do a thorough search on the site.

Personally, I don't think that the DC USDM header is worth the time and effort to install versus the other headers available-including their own 'JDM' header.

John

 

thanks for all the input guys, as usual, good stuff

i think i will probably stick with trying to find a comptech 4-2-1...

*if* I end up going with a JDM header, do I only have to replace the cat, or go 2.5 all the way back to the exhaust? Or, is it even possible to leave the existing 2.25 cat with some sort of adapter or something? thx again

 

You can keep the stock cat but I would rather get a carsound cat. You can still keep the stock exhaust.

 

what about the kamikaze? they are *cheap*, are they junk?

 

What is the collector size of the comptech 4-2-1 header? I am not sure if it is 2.0 or 2.25. Also, did you ever end up getting you comptech 4-2-1? If so, how did it perform. Was it good in mid range and high end liek it is made out to be? Thanks!

 

All USDM headers that I know of that bolt up to the stock cat have 2" collectors. The only header that I heard that had a 2-1/4" collector was a custom one from Kook's. The JDM versions are 65mm. These measurements are all OD.

 

kamikaze's are more Supercharger oriented. http://www.theoldone.com