a friend and i recently purchased two brand new jdm 4-1 headers from japan.
yesterday my friend got his installed, so we thought we'd go to do some testing of the new piece of equipment.

the car seems to have neither gained nor lost anything in terms of performance. between the three cars we had been using as before and after benchmarks, the results were exactly the same.


we're going to try and get some dyno results up shortly.

this result has led to me not installing my header, and advertising it in the local classifieds. looks like i'll be going down the path of custom equipment once again.

 

i said this before and i will say it again
bolts ons dont do ****!!!
sure maybe a few wheel hp but you cant feel a few hp
you cannot really feel a difference when you install an intake an exhaust or a header to a stock car ( well at least i dident with my car)
and if you really think you feel a difference its mostly just in you head


Modified by riceball777 at 1:15 AM 11/26/2003


Modified by riceball777 at 1:15 AM 11/26/2003

 

Well thats not totally true. My car feels and is faster on the higher end of the rpm band 5000-7500rpm range with a jdm DC type-R 4-1 header than my old 4-2-1 DC. This is on a road racing LS.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 &raquo;</TD></TR><TR><TD CLASS="quote">i said this before and i will say it again
bolts ons dont do ****!!!
sure maybe a few wheel hp but you cant feel a few hp
you cannot really feel a difference when you install an intake an exhaust or a header to a stock car ( well at least i dident with my car)
and if you really think you feel a difference its mostly just in you head


Modified by riceball777 at 1:15 AM 11/26/2003


Modified by riceball777 at 1:15 AM 11/26/2003</TD></TR></TABLE>

idunno, I felt a difference with my AEM CAI and Tanabe Racing Medallion and I'm positive I'm a little quicker with them than without. I understand what you mean though. Big power gains shouldn't be expected without a whole system, IE, a full header-cat-exhaust system, etc. etc.

 

in both my GSR's i could tell the difference between all stock and i/h/e. your right bolt-ons don't make a huge difference but there is some and its usually in the high end

 

With my 99 SI I felt an actual power increase with my AEM CAI. But the HKS Hiper catback didnt do **** and the DC 4-1 header did even less. It might have been fun to put them all on at once...........

 

what is your setup? you may have an "oversized header" for your setup. also, tuning, primarly VTEC lobes, need to be tuned cuz it is probably running lean with a JDM 2.5 header. i noticed immediate gains with my DC JDM header. rpms climb hella quicker and power output after vtec is excellent. good luck

 

they do make a noticable seat of the pants difference.

for a more tangible result, i gained 10kw (roughly 13hp) at the wheels by changing the stock system to a 4-2-1 custom made header flowing into a custom 2.25" straight through and by changing from 14 degrees btdc to 18 degrees btdc.
i gained a further 3kw (roughly 4hp) peak power by changing to a 2.5" cat and cat back.

unfortunately i lost my stock dyno sheet.

here is the 2.25" cat back dyno chart

here is the 2.5" chart

and here is a stock type-r just for the hell of it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 &raquo;</TD></TR><TR><TD CLASS="quote">i said this before and i will say it again
bolts ons dont do ****!!!
sure maybe a few wheel hp but you cant feel a few hp
you cannot really feel a difference when you install an intake an exhaust or a header to a stock car ( well at least i dident with my car)
and if you really think you feel a difference its mostly just in you head


Modified by riceball777 at 1:15 AM 11/26/2003


Modified by riceball777 at 1:15 AM 11/26/2003</TD></TR></TABLE>

SURE THEY DO!

 

ok...so your telling me..that replacing your stock airbox with resonator and air tube and all, and that replacing your stock BAFFLED muffler, and stock 40 pound exhaust manifold, with an after market Air intake, straight through muffler,and header dont yeild a difference?..o wait you must drive a FORD, sorry...

 

You really shouldn't judge the power gain of a product by the butt dyno. More than likely it is waaaaaaaaaaaaaaaay off.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18CmeFLYby &raquo;</TD></TR><TR><TD CLASS="quote">ok...so your telling me..that replacing your stock airbox with resonator and air tube and all, and that replacing your stock BAFFLED muffler, and stock 40 pound exhaust manifold, with an after market Air intake, straight through muffler,and header dont yeild a difference?..o wait you must drive a FORD, sorry... </TD></TR></TABLE>

 

my friend had suffered loss on his lowend on his b18b after installing a 4-1 header.. my 4-2-1 helped my engine rev smoother up to 5k after the upgrade.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IntEGNYC &raquo;</TD></TR><TR><TD CLASS="quote">my friend had suffered loss on his lowend on his b18b after installing a 4-1 header.. my 4-2-1 helped my engine rev smoother up to 5k after the upgrade.</TD></TR></TABLE>

haha....yesss and your point?

4-1 is meant for top-end power
4-2-1 is meant for low-end power

Just out of curiosity, why did you go with 4-2-1?
It doesnt make sense to me for the simple reason that after first your above 5,000 anyway when you shift, so why do you care if it revs nicely to 5....you want it to rev nicely through vtec

 

he doesn't have vtec and he probably doesn't spend much time above 5k rpm.

 

One of the best bolt ons I did for my car (That at least registered on the butt-dyno) was replacing my stock and semi-clogged cat with a high-flow one...

IMO Bolt ons, by themselves, do not give significant power gains, but when used in conjunction with complimenting parts, their efficiency does increase...

 

Certain 4-2-1 headers CAN produce good gains in the upper rpms also. The jg edelbrock pro-flo header produced 13 peak whp on a gs-r with only an intake (no exhaust mods) in issue 31 or 32 of import tuner. They we focusing on the header's ability to produce up to 10 flbs/tq in lower rpms, and as stated 13 whp up top, a header for the road and the track as they proclaimed. The mag mentioned even greater results with the 3 inch racing b-pipe.

 

lol @ clogged cat. let me guess, your timing jumped a tooth too, and you lost 10hp because you werent using platinum plugs.

cats rarely clog, its just an old v8 excuse to run open exhaust.

 

Rarely doesnt mean never.

I believe someone with a Civic SI dynoed at 90hp because of a clogged cat. Once that was removed, numbers jumped amazingly.

 

what was the brand

buy my gsr

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RedTegLS &raquo;</TD></TR><TR><TD CLASS="quote">With my 99 SI I felt an actual power increase with my AEM CAI. But the HKS Hiper catback didnt do **** and the DC 4-1 header did even less. It might have been fun to put them all on at once...........</TD></TR></TABLE>

people think they've gained hobs of horsepower & torque because with a CAI you can acually hear the engine... lol gained prob 5hp

 

you can't just put a heafer on your car and except all ton of power you gotta get a tonof air coming in. Plus you need a good exhast get it out.

 

after i put my jdm header on i found that acceleration from 80 to about 110 was no problem and it did not drag as it would on a stock header...

 

You won't feel or gain much with just basic bolt-ons and a JDM 2.5" 4-1 header. Once you install larger cams, then you will reap the benefits of the larger 4-1 header. In my old set-up I was running a Comptech 4-2-1 header and it was very good for my set-up; IHE, CTR cams, etc. But with the JDM header I could feel better top-end power. However, my wife hydro-locked my engine before I could get it dyno'd.

But the point I'm trying to make is that until you upgrade to larger cams, a header is a header is a header.

The JDM header was one of the last parts of my engine plans. So be sure to plan your engine mods accordingly prior to dropping big bucks...

But since you have it, keep it and save them for when you get bigger cams.

Biggest bangs for my buck: AEM CAI and CTR/ITR cams... oh, and dyno tuning!

 

It was hard for me to tell the difference when i added a DC JDM ITR header to my GSR HB. But the header dropped my 1/4 mile ET by .1 .