Are jdm headers really that benefitial?

Don't get me wrong, i heard stories about jdm headers giving u 8 hp at top end and such, but are they really that different from regular dc-sports headers?
I talked to a friend with a type-r who had both dc sports and jdm type r headers, he says go with the dc sports. i'm like whoa man...i heard they're way better then dc sports headers, he says its just a waste of money. He also dynoed both of them.

Does anyone have info on this subject? Like dyno sheets compared with both headers? B/c i am very vexed on this topic.

 

Um...you shouldn't base your opinion from one person. Also, there is no way that a regular non-JDM DC header will perform better on an ITR than the stock JDM ITR especially on an ITR.

Do a search for the DC JDM and the JDM ITR headers. There's a lot of information out here about them.

 

I made about 12WHP with the JDM header AND testpipe.

 

Where did you gain most of the power top end? Did it sacrifice low and mid? Also would you know if you can achieve the same gains as a test pipe by gutting out your cat?

 

anyone ever think of trying on a stock JDM GSR header? 4-2-1 with a 2.5" collector.. ? would DC sports happen to make one?

 

I have a JDM GSR header 4-2-1 with a 2.5" collector sitting in my garage...who ever wants it can name me a price...I bought the usdm dc 4-1...yeah the JDM GSR headers look huge compared to the USDM GSR 4-2-1.

 

jdm 4-1 is the best , esp for the itr, i know alot of hguys rolling with that with the test pipe and are making big gains with that set up . , nevver anyone dissatisfied with it that i know of .

 

I've heard nothing but good things about the JDM ITR 4-1. First of all, it's OEM so you won't have a problem with fitment and clearance(unless you are slammed to the max) and it's dyno proven.

 

do you guys think it will be good for my 94 LS too? currently i have the dc 4-2-1 on my car. would replacing it with the jdm 4-1 be an upgrade or just stick to the dc?

 

I really dont know, becuase I never did a baseline run. My bad! After I removed the B-Pipe and ran straight out the test pipe...I gained 3WHP pretty much all the way across the band. I would assume the top end was most benefitted from the header due to the 4-1 design. 4-2-1 headers usually gain in the midrange.

 

did you remove the catylitic converter?

 

On my GSR with i/jdm/e it made a big difference.

Lets have a comparison.
My buddy has a 94 GSR, same intake and exhaust as me, but he has the DC 421. He also has aem pullies, wider tires than me and fully adjustable stuts with springs. I consistently beat him by .1 or .2 in the quarter mile. He drove my car and said he can tell a big difference between his car and my car.

Get the JDM, its worth every penny.

 

Yea. I had a test pipe (straight through) in its place.

 

oh.....yes yes, i feel enlightened.

 

I got rid of my USDM DC 4-1 for the JDM DC 4-1 and haven't looked back. The JDM is much better if you're trying to put down serious power.

 

I'm dynoing my car tonight with:

AEM CAI
JDM 4-1
Carsound 94006 cat
OEM b-pipe and muffler
18 degress timing

First run will be without wideband A/F, next two will be with wideband, I might take off the PS belt for one of them as well.

here's some "baseline" pulls for my car (18 degrees timing, AEM CAI)



I'll post the results tonight.

 

please post those results ASAP...thanks man

 

the JDM 4-1 gives 6-8 whp more than the regular 4-2-1 header, BUT t the cost of low/mid range. I have been doing a lot of research and looking to a lot of dyno plots with the same results, more power on top and less low/mid range. It all depends on where you want the power. If you are a drag racer, you will want nothing but top end since you will be keeping your revs between 5.5k-8k. If you are a daily driver who wants nice, linear power thoughout the power band for everyday driving (mostly in the mid range), a 4-2-1 design is desired.
Want I want is to "have the cake and eat it". I want more power on top without ANY loss at the low/mid range! It sucks to spend $700+ for a JDM header and 2.5" cat and still have the same area under the curve. That's almost what it comes down to! Your basically paying lots of money to move power from your low/ mid to the top! This should be FREE!!!!
Of course, there is also a way to way power thoughout the whole rpm range, and that is with a header with very long primaries like the SMSP but I think that cost wven more cash!

 

https://honda-tech.com/zerothread?id=74611

yep, lots of low end loss there.

 

well,
1.- I have 3 dyno plots in front of me that show that!
2.- For every rule, there's an exception!
3.- NOT every car is the SAME!
4.- MOST importantly, you did not do a run with an aftermarket (DC, Comptech, etc) header to compare with! I made 5 whp over stock with my Comptech 4-2-1 header. You made 8 whp over stock, so a JDM header and 2.5' will give me only 3 more whp??!!! NOT!! Refer to #3.

 

depends, with a stock exhaust you'll gain 3 or so I'm sure. I need a real exhaust

and you're right, not every car is the same, I've seen OBD2R2 gs-r's with the same mods as my car except with a dc 4-2-1 and apexi ws exhaust put down less power than my car at the low end. we could hitup the dynocenter but I'm not THAT bored to compare #'s.

 

8 peak hp is pretty damn good, considering all he has is an intake and advanced timing...(besides the header)

the jdm 4-1 is better suited for more flow...(cams, headwork..etc)

and it still makes 8 peak hp on a practically stock engine...thats bad ***

 

if I only had a JDM and 2.5" cat........ 180+ whp????........ wake up!!! sorry!! I satrted dreaming for a while!! hehe

 

With my setup I experienced no loss of "low end" power. It feels stronger from 1-8k RPM, but the highest gains are felt at 6k when the intake manifold opens up.

Of course I might not have lost any low end because of my non-straight-through muffler.

Once again, THE JDM IS WORTH EVERY PENNY!!! BUY IT NOW!

 

how much bottom clearance would I lose with a 4-1 header?

I scrap the front end of the car sometimes while going over some steps driveways and would not like to mess up a brand new header!