well I guess I will do my part in adding to the archives… I have a few files that I have saved over the past year from the boards so here they are…
WHAT IS THE BEST HEADER FOR MY CAR?
WHAT’s the best header for a GSR?
the answer to what is the best header depends on where you want to end
up with your GSR when all the mods are done (long but worth the read):
- bolt ons only
eg. of this setup/engine combo: i/h/e, cam gears, FPR, underpulleys, ECU reprogram or VTEC controller/Fuel controller.stock compression.
USDM DC 1 piece 4-2-1
In this engine combo, the 2 piece DC 4-2-1 (not the 4-1) header with the
smaller 2 1/4 in collector is the better choice. BTW the Comptech and Greddy header 4-2-1
lost to the DC Sports in SCC mag’s Oct 99 header shootout in a bolt-ons only GSR (AEM CAI and Greddy exhaust).
BTW if you are thinking of trying the USDM ITR header: the USDM ITR header is 2 in. too long on the GSR and you will need a smaller cat to make wverything fit. The USDM ITR header fits perfectly onto the LS.
- moderate upgrade
eg. of this combo : add overbore TB, Skunk2 intake manifold, ITR or Spoon or Crower 63402 or 63403 cams, bigger 270-310 cc/min injectors, thinner mugen gasket (for 10.3-10.4-1 compression on a GSR or 10.9:1 on an ITR), plus most listed in 1. (notice I stayed away from Skunk2 VTEC cams with the reports of breaking due to poor coating materials which do not allow oil to bond to the surface and causes seizing at the rockers from no oil film between the cam lobe and rocker, Skunk2 had a complete recall…should be ok now):
Here for this engine combo, the JDM ITR 4-1 header with 2 1/5 in. collector is better (The new DC Sports JDM 4-1 with big ass JDM collector is on this list now too) .Drop this puppy in a boltons only engine combo and you lose midrange like no tomorrow. This header needs a custom Carsound 54000 universal 2.5 in cat to make everything flow right and fit. The stock cat will NOT hookup and you will need to weld on an O2 sensor bung to the Carsound cat. Adrian Teo makes custom 2.5 in. cats . Magnaflow now has a new 2.5 in. cat available. Stay away from the Random Tech cat please (big quality control issues).
(NASTY!!)
http://hybrid.honda-perf.org/tech/jdmhdr/index.html
http://hybrid.honda-perf.org/tech/jdm41/
http://www.itr-nc.com/members/cat.htm
Here’s the JDM DC Sports 4-1
if you don’t want to do all this cat fitting and welding an O2 sensor bung onto the cat, then the next best is the USDM DC 4-1 (with a dinky 2 1/4 in. collector and use your stock cat) but expect less gains.
- extreme all motor mod
eg. of engine combo: Toda cams (A,B,orC) or Jun type 3 cams , 11:1 or more compression from
pistons, ported head, 10,000+ rpm redline from ECU reprogram, plus listed in 1 & 2.
the best header here is the Spoon long primaries 4-2-1, Mugen 4-1 with JDM colector (not USDM collector)
or even better the Hi Tech long primaries 4-2-1…all with the a bigger
2.5 in. outer diameter collector,…make sure the Mugen has a bigger
Japanese collector and not a small USDM cat compatible collector… yes
you will need either Carsound 54000 Universal or Adrian Teo 2.5 Cat with O2
sensor bung welded on here too. Jegs also sells a Dynomax 2.5 in. cat that will work with
the help of your local muffler shop. A 2.5 in. exhaust donut needs to be ordered ahead of time.
Hi Tech long primaries hybrid 4-2-1
Spoon long primaries hybrid 4-2-1
Mugen 4-1 (long primaries)
- JRSC or Vortech SC :
best header here is the 2.5 in. short primaries 4-1 with 2.5 in.
collector or the Hi Tech SC 4-1 short primaries superheader with 3 in.
collector (need appropriate sized Carsound Universal cat and welded O2
sensor bung).
Kamikaze short primaries 4-2-1
Get the SC first then the header and cat.
- Links to Custom Cats (2.5 in. to 3 in. OD)
hybrid. honda-perf.org/members/falconer/converters.html (remove the space between hybrid. and honda-perf, copy to your browser location bar)
http://www.car-sound.com/3univ.htm
http://www.magnaflow.com/03cat-back...tconverters.htm
- Examples of not thinking ahead and making a booboo…you now have to
buy a 2nd header.
if you got a DC 4-2-1 with Todas…the cams and big compression, big air fuel in and big amounts of burnt gases will be choked by the small
collector.The cam’s gains will be stiffled by that header which is very good but for the bolt-ons crowd only.
if you drop a Mugen 4-1 with Japanese collector or Spoon long primaries 4-2-1 in a bolt-ons only car it will lean out the car big time and not
provide enough backpressure for enough gas velocity to leave the head leading to a loss of power. The Mugen 4-1 with compatible collector to
a smaller US cat (in the Sport Compact Car great header test) lost 1-2 lb ft of midrange torque.
if you got the DC 4-2-1 header and then got the JRSC the collector would choke off the SC extra burnt gases from escaping compared to the
kamikaze. The Mugen 4-1 long primaries or Spoon long primaries 4-2-1 meant for all motor power would be too long for the SC and blunt the
gas exit velocity out of the head.