CUSTOM , HEADER ( 4-1 & 4-2-1 / Selection / Design / Fabrication )

[A20A1]

PLEASE TAKE A LOOK AT THE HEADER FAQ THREAD
IF YOU WANT TO BUY INSTEAD OF MAKE YOUR OWN HEADER (CLICK HERE) (http://www.3geez.com/forum/showthread.php?t=37261)

1) Choosing Type of Header; 4-1 or 4-2-1
Plan where you want to make power and what kind of driving you will be doing.
Long pipes move the power down in the RPM, Short pipes move the power up in the RPM
- 4-2-1 offers more usable/broader rpm range and often more torque through cylinder pairing.
- 4-1 have longer primaries in most cases moving torque up in the powerband
- Long Tubed 4-2-1 Does the same as a 4-1 but offers the advantage of cylinder pairing.

2) Designing The Header

The stock EFI 4-2-1 manifold and pipe is about 26" long.
The stock Carb manifold is about 10" - 13" long.

4-2-1 Sequential Pairing of cylinders when you have longer primaries like those found on 4-1 headers
4-2-1 Non-Sequential Pairing cylinders then primaries are not as long



Here I did all the equations for you, using multiple sources.



NON-Sequential 360-DEGREE COLLECTOR 4-2-1 Header For A20A Accord
1) Short Tubed 4-2-1 Design
2) Cylinders 1+4 , 2+3 Paired
3) Small exhaust Diameter for Primaries and Secondaries
4) Long Secondary length after header.


(4 pipe) 1.375" diameter Primaries 18.25" long
(2 pipe) 1.625" diameter Secondaries 12.25" long
Header Length 30.50" long
(1 pipe) 2.000" Secondary pipe 30.50" long

Total lenght 61"



Sequential 180-DEGREE COLLECTOR 4-2-1 Header For A20A Accord
1) Long Tubed 4-2-1 Design
2) Cylinders 1+3 , 2+4 Paired
3) Large exhaust Diameter for Primaries and Secondaries
4) Short Secondary length after header.


(4 pipe) 1.500" diameter Primaries 36.50" long
(2 pipe) 1.625" diameter Secondaries 12.25" long
Header Length 48.75" long
(1 pipe) 2.000" Secondary pipe 12.25" long

Total Length 61"

Now the muffler after the 61" will be the first LARGE change in cross-sectional area / volume.
This is where return pulse will be created. The muffler must be chambered to allow for the
cross-sectional change as well as flow the appopriate amount of CFM.

In this Case a Hooker Aero Chamber good for 200 HP or 441 CFM with 2.50" inlet and outlet diameters.
You can argue about reducing the 2.50" outlet of the header to 2.25" even 2.00",
but as long as the pipe flows the CFM I need I don't see it hurting much.

The Bit after the muffler in this image is a 2.50" SMSP catalytic convertor. :)
http://i23.photobucket.com/albums/b351/Wendy_girl/exhaust12.gif


Bells Formula With Some Minor Tweaks.


Using EVO of 190 ( Exhaust Valve Opening )

1) HPL = ( ( 850 x ( 360 - EVO ) ) / RPM ) - 3
2) HPL = ( ( 850 x ( 360 - 190 ) ) / RPM ) - 3
3) HPL = ( ( 850 x ( 170 ) ) / RPM ) - 3
3) HPL = ( ( 850 x 170 ) / RPM ) - 3
4) HPL = ( ( 144,500 ) / RPM ) - 3
5) HPL = ( 144,500 / RPM ) - 3

Using RPM 6800
6) HPL = ( 144,500 / 6800 ) - 3
7) HPL = ( 21.25 ) - 3
8) HPL = 21.25 - 3
9) HPL = 18.25
HPL = 18.25"
EPL = 21.25"

Using RPM 6500
6) HPL = ( 144,500 / 6500 ) - 3
7) HPL = ( 22.23076923077 ) - 3
8) HPL = 22.23076923077 - 3
9) HPL = 19.23076923077
HPL = 19.25"
EPL = 22.25"

Using RPM 5500
6) HPL = ( 144,500 / 5500 ) - 3
7) HPL = ( 26.27272727273 ) - 3
8) HPL = 26.27272727273 - 3
9) HPL = 23.27272727273
HPL = 23.25"
EPL = 26.25"

Using RPM 3600
6) HPL = ( 144,500 / 3600 ) - 3
7) HPL = ( 40.13888888889 ) - 3
8) HPL = 40.13888888889 - 3
9) HPL = 37.13888888889
HPL = 37"
EPL = 40"

EPL = (HPL + 3)

USING EPL = 26.25 ( Exhaust Pipe Lenght )

CID Equation
1) HPD = ( ( SCID x 16.38 ) / ( EPL x 25 ) ) x 2.1
2) HPD = ( ( 29.75 x 16.38 ) / ( EPL x 25 ) ) x 2.1
2) HPD = ( ( 487.305 ) / ( EPL x 25 ) ) x 2.1
3) HPD = ( 487.305 / ( 26.25 x 25 ) ) x 2.1
4) HPD = ( 487.305 / ( 656.25 ) ) x 2.1
5) HPD = ( 487.305 / 656.25 ) x 2.1
6) HPD = ( 0.74256 ) x 2.1
7) HPD = 0.74256 x 2.1
8) HPD = 0.74256 x 2.1
9) HPD = 1.559376
HPD = 1.50"

1) HPD = ( ( SCID ) / ( EPL x 25 ) ) ) x 2.1
2) HPD = ( 487.305 / 765.625 ) x 2.1
3) HPD = ( 0.63648 ) x 2.1
4) HPD = 0.63648 x 2.1
5) HPD = 1.336608
HPD = 1.375"

CC Equation
1) HPD = ( ( SCC ) / ( EPL x 25 ) ) ) x 2.1
2) HPD = ( 488.750 / 656.25 ) x 2.1
3) HPD = ( 488.750 / 656.25 ) x 2.1
4) HPD = 0.744761904762 x 2.1
5) HPD = 1.564
HPD = 1.50"

1) HPD = ( ( SCC ) / ( EPL x 25 ) ) ) x 2.1
2) HPD = ( 488.750 / 765.625 ) x 2.1
3) HPD = ( 0.638367346939 ) x 2.1
4) HPD = 0.638367346939 x 2.1
5) HPD = 1.340571428572
HPD = 1.375"

--------------------------
119 cid
SCID = 29.75
1955 cc
SCC = 488.750


Other Formula


40.592” (7500 RPM 210 EXH DURATION)
42" - Out of Tune
- 43"
--- 44"
----- 46" (6500 RPM 210 EXH DURATION)
------- 48" (AVERAGE 210 EXH DURATION)
--------- 50"
----------- 51" (7500 RPM 253.5 EXH DURATION)
--------- 52"
------- 54"
----- 56"
--- 58" (5500 RPM 210 EXH DURATION)
- 59"
--- 60" (AVERAGE 253.5 EXH DURATION) (6500 RPM 253.5 EXH DURATION) (7500 RPM 288 EXH DURATION)
----- 62"
------- 64"
--------- 66"
----------- 67"
--------- 68"
------- 70" (AVERAGE 288 EXH DURATION) (6500 RPM 288 EXH DURATION)
----- 72" (5500 RPM 253.5 EXH DURATION)
--- 74"
- 75"
76" - Out of Tune
83.78” (5500 RPM 288 EXH DURATION)


Remember the engine moves in and out of tune
throughout the RPM range so I did averages
instead of going strickly based one setting.

The "OUT OF TUNE" I added to set limits based on averages.
Then I did calculations @ different rpms @ different exhaust durations.
If you look how the 288 @ 5500 rpm droped below the out of tune...
I'm figuring this is because such a high duration was not ment for
such a low rpm.
So I assume building a header with that length would do more harm
then good. Or not.



Comparison Between Chart and Bells Formula Figures.


EPL ( Exhaust Pipe Lenght )
EVO ( Exhaust Valve Opening )

Optimum EPL using EVO of 190 and RPM range of 3600-6800 is 30.625" with optimum diameter of 1.375"

When trying to find the collector outlet diameter, use about a 20% larger pipe than the primary header pipe diameter on 4cylinder motors.

1-3/8" _or_ 1.375" + ( 1.375 x 0.20 ) = 1.65" which is close to 1.75" collector diameter
1-5/8" _or_ 1.625" + ( 1.625 x 0.20 ) = 1.95" which is close to 2.00" collector diameter
1-3/4" _or_ 1.750" + ( 1.750 x 0.20 ) = 2.10" which is close to 2.00" collector diameter
2.000" _or_ 2.000" + ( 2.000 x 0.20 ) = 2.40" which is close to 2.25" collector diameter

On V8's use collector equations as follows.

1.375" x 1.750" ~ 2.50 Collector
1.625" x 1.750" ~ 2.75 Collector

Header Plus Secondary Pipe Lenght | Header Lengths
51.75" (5500 RPM 190.00 EXH DURATION) EPL = 25.875" (using Other Formula) vs. EPL = 26.25" (using Bell's Formula)
58.00" (5500 RPM 210.00 EXH DURATION) EPL = 29.000" (using Other Formula) vs. EPL = 26.25" (using Bell's Formula)
72.00" (5500 RPM 253.50 EXH DURATION)
83.75” (5500 RPM 288.00 EXH DURATION)

40.25" (6500 RPM 190.00 EXH DURATION) EPL = 20.125" (using Other Formula) vs. EPL = 22.25" (using Bell's Formula)
46.00" (6500 RPM 210.00 EXH DURATION) EPL = 23.000" (using Other Formula) vs. EPL = 22.25" (using Bell's Formula)
60.00" (6500 RPM 253.50 EXH DURATION)
70.00" (6500 RPM 288.00 EXH DURATION)





Header
Primary lenght,
lenght of 4 and 2 pipes on 4-2-1
or lenght of 4 primaries on 4-1.
Primaries,
length of 4-2 pipes.
Secondaries,
length of 2-1 pipes.
Collector length,
length of pipe after 4-1 primaries merge.
Exhaust
Secondary length,
length of pipe after primaries but sometimes including
part or all of collector length. Secondary length is said
to be important in making torque, even more so than
primary length.
Total length,
Lenght of Primary and Secondary together

Primary , Secondary
Lenghts | RPM
________________________________
28.375 - 26.000 | 6500 - 7000
30.000 - 28.375 | 6000 - 6500
33.625 - 30.000 | 5500 - 6000
36.000 - 33.625 | 5000 - 5500





The basic ideas for building a header are:

1) Broaden power over a wide power band, not
just tune for high narrow peak power ( HP / Toruque )

2) Maintain exhaust velocity (scavenging vacuum)

3) Lower Backpressure as much as possible




TIPS:

Dont port your exhaust port to match the header flange,
a 1mm larger flange port all the way around will allow
the exhaust port on the head to act as an anti-reversion dam.

AR or anti-reversion is any area inside a pipe that allows
flow in one direction while inhibiting blow in the reverse direction.

AR is mostly used to address reversion at low engine speeds
where long duration cams cause the air/fuel mixture to get contaminated
by reversion.


Another Formula :
L = (850 X ED) / RPM
L = length of primary pipes in inches
ED = 180 degrees + number of degrees exhaust valve opens BBDC
RPM = engine RPM at peak torque
Secondary Length approximately 2/3 Primary Length



Mine
http://i23.photobucket.com/albums/b351/Wendy_girl/car%20stuffs/A_F_header_side.jpg
http://i23.photobucket.com/albums/b351/Wendy_girl/car%20stuffs/A_F_header_front.jpg
Justins
http://memimage.cardomain.net/member_images/1/web/469000-469999/469581_180_full.jpghttp://memimage.cardomain.net/member_images/1/web/469000-469999/469581_179_full.jpg
http://memimage.cardomain.net/member_images/1/web/469000-469999/469581_181_full.jpghttp://memimage.cardomain.net/member_images/1/web/469000-469999/469581_182_full.jpg

[PhydeauX]

For some reason I thought I had already posted this here, but I guess I didn't. He has a chart for calculating the proper lengths based on cam timing and rpm.

http://www.billzilla.org/engexhaust.htm

Just to be sure you read that right. That chart doesn't tell you the length of the primaries, but of the whole exhaust system. A 4 - 1 should be half the calculated length. Its probalby not going to be practicle to have the exhaust that short on a 3g so just hook it up to a regualr cat back.

andy

[A20A1]

------------------------------
LINKS
Here are some sites to look at when shopping for materials... I know places like burns offers discounts if you order in bulk.
BURNS STAINLESS (http://www.burnsstainless.com/index.htm)
PITSTOP USA (http://www.pitstopusa.com/)
STAINLESS WORKS (http://www.stainlessworks.net/)
RRE (http://www.roadraceengineering.com/mandrelbends.htm)
TRC (http://www.toyotaperformance.com/)
CHASSIE WORKS (http://www.cachassisworks.com/header.htm)
HEADERS BY ED (http://www.headersbyed.com/hdrkits.htm)
JC WHITNEY (http://www.jcwhitney.com/autoparts/ProductDisplay/s-10101/storeId-10101/p-5411/c-10101/catalogId-10101)
S&S (https://ssl10.mysecureserver.com/bosstoolscom/store/store/comersus_listCategoriesAndProducts.asp?idCategory= 19)
BY REQUEST:
PITSTOP USA (http://www.pitstopusa.com)
Product ID: SCHSO63041
Description: SCHOENFELD SLIP-ON 4 TUBE COLLECTOR - SLIPS OVER 1-5/8" DIAMETER TUBING - 3" COLLECTOR DIAMETER - #SCHSO63041
Quantity: 1
>Handling Charge: $1.00
>Order Sub Total: $29.95
>UPS 2nd Day Air : $25.61
>Grand Total: $56.56

SUMMIT (http://www.summitracing.com)
Product ID: HOK-12540
Description: J-Bends 1-5/8" Mild Steel
Quantity: 6
Charges for your order include the following:
Parts: $77.70
Handling: $8.45
2nd day air shipping charges: $25.60
Current charges to your credit card are: $111.75
http://www.jcwhitney.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10101&storeId=10101&langId=-1&productId=184675&mediaCode=ZX&appId=391415
http://www.jegs.com/cgi-bin/ncommerce3/CategoryDisplay?cgmenbr=361&cgrfnbr=841
http://www.ssheaders.com/JBends.htm

Basically this stuff is really complex and takes lots trial and error to get it right. I have been doing a lot of research on tube lengths, etc and still it's something that is pretty mush trial and error and dyno time, which I hope to be doing a lot of here soon.
It's good too see you were just as serious about getting a header made for your motor.
A few values I considered:
Cam profiles, Diameter, Length, RPM, CID... but even thene there are more variables to consider... it's all about timing/tuning the negative returning wave... the collector plays a role too chaniging the wave from short to long broadening the power range. When I made the chart in the header FAQ I did a lot of averaging to help get ball park figures... I never thought to question the primary and secondary 50%/50% length logic though.
In the end I didn't have much money to do what I wanted.
I noticed burns stainless has a build sheet... but some of the values they ask for I don't have. Right now I am interested in venturies cause since I've seen drag headers with 2" chokes/venturies and even if you didn't understand exhaust systems you know those cars wouldn't add restrictions if it wasn't going to help.
My understanding of any 4 cylinder pairing in a 4-2-1 was that the benifit came from the pairing of cylinders into two pipes before the collector... this way the scavenging wave returns back to the original cylinder that made the positive wave but while in the secondaries the negative wave also effects the cylinder its paired with. The term in one of the books I have was that pairing 4-1 and 3-2 evenly spaces the pulses and gives you "Full Resonace"... in a 4-2-1-3 firing order.
Same with a 2 cylinder motor.
I suppose the 4-2 and 3-1 design would be simmilar yet the pulses would be closer...
Anyways nice header, I'm looking forward to the dyno... in my PM I did't realize what you header looked like or if you had it hooked up to the exhaust... put a muffler or res on it quick. :lol: At least I'm not the only one that knows what i sounds like though.
Not the new one, no

What size pipes did you use for primaries and for secondaries? PM me if you don't want to post it.


i think we should do a little competition and see who can make the best header on 3geez...
no matter, the best on one car won't be the best on another, so it's not really something that can be scored
I dunno I tired to get a wide range when I tuned my header even though it might not seem like it... I would like to make a new one and have someone with a stock cam try it out.

I found some flux cored stainless wire... http://www.brazing.com/products/Weld_flux_cored_stainless/
I have no problem getting access to Co2...

[shepherd79]

nice work mike.

[wprocomp]

man that collecter is frakin huge mike!...I am looking at it wrong or does the downpipe angle to the left?
I wouild like to see an comparison between yours and a pacesetter....as big as it is I would assume yours would outflow it greatly...hmm..
BTW: what paint did you use? I used that engine paint from auto-zone and it burned right off until I found out that you are supposed to use a sealing primer to keep it on there...if you want it to stay you need to use that

[2old_honda]

Man I cant believe I havent seen this thread. Anyway, Mike good work! Very nice! We need more pics. :)

[Don87LX]

THats be-yu-ti-ful work mike. You should get great flow with the exterior welds (even if they are supposed to be interior), hope it all works out. YOu could get rid of the engine shaking the welds loose by solid mounting your engine ;-) If you like a numb ass...

[Mike's89AccordLX]

Get some sound clips of that baby Mike!!! Great job I have been waiting for a long time to see you do this and I'm amazed. Keep up the great work!

[markmdz89hatch]

Hey Mike, is there any way that you might be able to get hp numbers from that header? I know you have a ton of other perf. add-ons too, but just to see the gain from you header as opposed to stock.
Also, could you possibly snap a pic of the underside of the car. Just basically from the ground in the front of the car, just so I can see how low that header hangs, to see if I'll have any clearance issues with my ultra-low suspension.
....and as always, SWEET!

done!
I'd obviously pay for shipping too, and toss a few extra bux your way for the trouble.

actually, if you have a diagram, with dimensions, of the header/head flange that you need, e-mail it to me. I have a friend of the family that works at an old machine/tooling shop. He might be able to make this for you.
Just let me know if you want me to look into anything for you.

[120hpcanadian]

i don't know if this has been posted here already , but when welding cast iron remember to let the weld cool very gradually even putting it next to a woodstove wouldn't be a bad idea it will help stop cracks. and if your welding straight castiron to cast iron an arc welder will do the trick nicer then a mig. :cheers: remember let the weld cool as slowly as possible.

[Robs89LXi]

Below is an email I sent to Tom Fowler of OPM AutoSports. Anyone interested? Be sure to check the web address listed in my note.
.................................................. ....
Date: Thu, 12 Feb 2004 12:19:09 -0500 (Eastern Standard Time)
From: "Tom Fowler" <[email protected]> Add to Address Book
To: [email protected]
Subject: Re: Headers for 86-89 Accord LXi
We have not made that header in a few years due to lack of interest. I could make another run, but it would take 7-10 orders. It's a custom race unit like our other Honda headers, hand-made 4-1 race header open pipe does not bolt to cat.
Tom Fowler
OPM AutoSports
248 Castleberry Industrial Dr
Cumming, GA 30040
[email protected]
-------Original Message-------
From: The Jadusinghs of Houston
Date: 02/02/04 14:14:43
To: [email protected]
Subject: Headers for 86-89 Accord LXi
Hello, Tom. Just spoke with one of your sales reps, and she directed me to you for this. I am interested in finding out more about a part you list on your webpage. It is the "Full-Race Exhaust Header" for an "86-88 Honda Accord LXi"
http://www.opmautosports.com/produc..._accordlxi.html
Would you please send me some more information on this product (what brand, availibility, quantity, associated flanges/gaskets, performance specs, etc.) as well as any pictures you may have of it? I am a member of an Accord club, and a group buy may be possible if it fits what we are looking for.
Thanks in advance.
Rob.

Oops. Try this.
OPM MOTORSPORTS (http://www.opmautosports.com/products/honda_accordlxi.html)
Everytime I try to post the link, it tries to shorten it, and omits parts of it, so here it is in two pieces. I guess you will have to type it in your address line manually.
http://www.opmautosports.com/product/honda_accordlxi.html
Hope it works this time.
Okay, now I'm getting pissed! What kinda POS forum is this?
ACCORD LXI RACE HEADER (http://www.opmautosports.com/products/honda_accordlxi.html)
Okay, I see that now. Why did it not do it the first time? Anyway, he says it's a 4-1 in his reply, so I'm not sure. I've dropped him another note already, asking him for more info, so I'll pass that along as soon as I get it.

[Justanothermike]

still looking for someone to dyno your header? we're gonna dyno the car again and we could probably fit in a header comparo while we're doing it. The only concern i could think of is install difficulty with the one piece header cuz we'll be on the clock on the dyno and the car still has AC and PS so lemme know

[Justin86]

Well some people have been asking me about building one so I finally got it done. I'm gonna be working on exhaust and intakes also here soon. I'm gonna been hooking up NXRacer with these new parts to get dynoed march 5, but so far just driving around I have been impressed.

I went with that flange because it was cheapest on and less chance of warping. The specs I'm going to keep under raps. Not sure on a price yet but I'm looking at around maybe $200 uncoated, maybe more or less I'm still looking at some options.

[AccordEpicenter]

looks good but id use a better flange. Good work though

[Robs89LXi]

Looking real nice. I agree about the flange though; a single unit would give more support. Any specs (tubing diameter, exit size, etc.?). I'll be looking for one eventually.

[2drSE-i]

i agree with the flange, but shit man nice job! how much u thinkin about charging for those?

well its definately not the common after market header, he made it himself.

[Accordtheory]

Interesting. Does the 3g have a different firing order than the integra/civic? I always see cyl 1 paired with 3, and 2 paired with 4. I noticed you didn't do that. Also, how did you calculate what length to make the various sections of piping? (the sections look longer than a common aftermarket 4/2/1 header) I'm curious to hear the dyno results..

[AccordEpicenter]

Interesting. Does the 3g have a different firing order than the integra/civic? I always see cyl 1 paired with 3, and 2 paired with 4. I noticed you didn't do that[/U] Thats a new one on me... ive never seen that. I think if you had a 3/8ths steel one piece weld flange youd be better off... betcha weirRacing might be able to make them...

[SteveDX89]

Interesting. Does the 3g have a different firing order than the integra/civic? I always see cyl 1 paired with 3, and 2 paired with 4. I noticed you didn't do that. Also, how did you calculate what length to make the various sections of piping? (the sections look longer than a common aftermarket 4/2/1 header) I'm curious to hear the dyno results..

Look closer. Cylinders 1 and 4 are together and 2 and 3 are together. It's like that on just about all Honda 4-2-1 headers.

[Strugglebucket]

yeah, A20 fires 1-3-4-2 just like other hondas.

justin that's a neat design. with those long primaries i would think performance wise it would be somewhere in-between a 4-1 and the normal 4-2-1 designs you usaually see.

[Justin86]

well I believe they are all the same 4-2-1-3 firing, but with most basic aftermarket headers they have 4&1, 2&3 together. Thats what I ran with but looking at some race header designs they have 3&1, 4&2 together. It makes sense to have the pulses seperate, but these new designs that are selling for $800+ and make the most overall power they use 3&1, 4&2 together. Also I did look at a bunch of header design programs and one that involve cam profiles. From what I was getting should be the best and what lenghts I see on products don't add up right.
With the average product like DC they follow those basic designs with the 4-2-1 like having the primary and the 2nd the same length. But the length are way to short and are best suited for highlift/duriation, high reving car. Then with the $800 race headers they use tube lengths longer then what the design programs say, but they still make better top end and midrange power then you would think. Basically this stuff is really complex and takes lots trial and error to get it right. I have been doing a lot of research on tube lengths, etc and still it's something that is pretty mush trial and error and dyno time, which I hope to be doing a lot of here soon.

Yea I have 3/8" flanges right now, but there is a local shop with a CNC plasma that I got them done at. As it being one peice flange or not, I'll do what ever I'm asked of. I did them seperate to save money and I heard it wil help prevent warpage and leaking....


justin that's a neat design. with those long primaries i would think performance wise it would be somewhere in-between a 4-1 and the normal 4-2-1 designs you usaually see.
Yea that is what I belive is behind them. If you guys have seen the new honda tuning on page 48 there is an example of these $800 headers. They don't follow the typical header designs you see on the streets, this is stuff used by racing teams that is now being applyed for the rest of us. They have the all the benefits of a 4-1 and 4-2-1 while now of the side effects.

yea I have flex pipe farther down on it

[mykwikcoupe]

hey man just a thought but make one for the jdm b20a for me so i dont have to modify one. id pay the same price maybe a little more since there is a little difference. ill send you a gasket to make the flange and just add those pipes to this flange. sounds easy enough huh. let me know. mike

[Justin86]

hey man just a thought but make one for the jdm b20a for me so i dont have to modify one. id pay the same price maybe a little more since there is a little difference. ill send you a gasket to make the flange and just add those pipes to this flange. sounds easy enough huh. let me know. mike

yea I could prob do that, would need a pic and some measurments to make sure it would fit.

[895spdforfree]

good job man i was thinking about buying a pacesetter withing a month or 2 but your header would be much better..

[b20a86lude]

holy damn thats nice i like that header it remindsme of a mugen header that they made back then for u accord guys hey how much are u sellin these headrs for u cam make a ass load of cash by sellin these here and sellin them on prleude power .com in the 2nd gen forum its real nice work i really like that header u should consider makin them for us b20a guys id def buy

[mykwikcoupe]

cool man let me know when you finish the orders you have now on the a20a pipes and well start on the b20a. Dont want to throw a wrench in the works by changing stuff to early. Anytime is good for me just send me a PM when your ready. Mike

[Justin86]

cant wait till the 5th!! too bad we wont be able to start with a baseline. . . . .no base line is better then no dyno run at all.
I think some one around here did get a base line dyno awhile back, if I can just find that thread.

[Justin86]

Yea I tried to look at all those different profiles, and then I looked at the race headers and half of them didn't seem to follow those basic principles. So I tried to stick with the basic principles as best i could but I didn't go with the 50/50 ratio of 1st to 2nd piping.

[Accordtheory]

yeah, I guess I was confusing myself about the cylinder pairing order..the cylinders that fire 360deg apart should be paired, and that would be 1&4 and 2&3 in this case. But it doesn't matter for me anyway...

[3_GENCYCO]

When can i buy one? im ready for one now. i was just shopping for a header...

[Justin86]

Well I will be getting it dynoed on March 5 and after that I will figure what to do about production and the price. I wish were able to get a base dyno run first, but another guy did it a year ago and got 83hp/94tq on his 87 Lx-i and that goes with the typical 15% drivetrain loss. So NXRacer and his 86 Lx-i should be close to the same.

[Vanilla Sky]

with me getting ready to start planning a custom header, i'd like to see how this one does...

as for your flange, that's just a local job, right?

[Justin86]

yea I had the flanges done locally with a CNC plasma.

[A20A1]

What are your thoughts... for those of you that wander around honda-tech

http://www.honda-tech.com/zerothread?id=1161501

...

I got my welder back from my friend... :) I'm gonna mess around, I haven't gotten my hands dirty in a while.



I don't know what your header looks like so I can only give you a general answer about what it is and how it works.

It's usually a larger sized chamber close to the exhaust port in the primary tube of the header and functions like a step. It's designed to keep the exhaust gasses from flowing backwards into the cylinder before the exhaust valve closes. This will help ensure that the cylinder gets filled with the freshest intake charge that isn't contaminated with leftover exhaust gasses, which will make more power. Like fluid, it's harder for the exhaust gases to travel backwards and upwards over a step than it would be if it was a simple round tube with no steps.

That's what it is and how it works in a nutshell, I'm sure the header manufacturers like Dave from SMSP etc could give you more detailed explanation.

A stepped header delivers a short duration (short duration = narrow affected rpm range / long duration = broad affected rpm range) expansion wave when the positive pressure wave reaches the step.
In headers the Positive waves exit through the exhaust valve and exhaust gases move in the same direction of the wave towards the open end of the pipe... once the positive wave exits the pipe is returns a negative suction wave that travels back up the pipe towards the cylinder... but the exhaust gases move opposite the direction of the negative wave. This is supposed to help lower the pressure in the cylinder and help it fill better. True that the smaller diameter also acts as a restriction to the exhaust gasses...



REVERSION is the secondary pressure wave that travels back up the primary pipes and enters into the cylinder on valve overlap. As this pressure wave travels back up the pipe, it brings with it all the residual gases still left in the pipe. This is what contaminates the fresh intake charge. Enter in stepped headers and ANTI-REVERSION chambers, placed at strategic locations in the primary pipes. These methods are employed to tune the arrival of the exhaust wave and to diminish the effects of the high pressure in the pipes. The results are higher volumetric efficiency and more power.
...it sounds like someone is suggesting they block negative expansion waves... the negative wave is what gives you the scavenging effect. Scavenging = :thumbup: so blocking the scavenging wave isn't a good thing... timing when it reaches the overlap period is.

Reversion is usually when the exhaust gases enter the cylinder or intake manifold and act against the incoming air... usually it's because of high overlap cams operating at a low engine rpm. Or a poorly designed header.

I'd say a stepped header may add some low speed gains but I would rather tune the tube lengths and diameters to get the most power for my application.

I see Hytechs Anti-reversion chamber as an Expansion chamber that flows freely in one direction but not in the other... this is okay for limiting the exhaust from reentering the cylinders but when you expand gasses they slow down :thumbdown: .
Good exhaust systems usually try to keep exhaust velocity high :thumbup: ...without adding too much restriction which is what increases pumping work. :thumbdown:

Small pipes = More velocity :thumbup:
Small pipes = More restriction :thumbdown:

Large pipes = Less Velocity :thumbdown:
Large Pipes = Less restriction :thumbup:

I wont try to knock Hytech's idea... but I don't see why you would want it if you have a properly tuned header. IMHO


Negative (returning) expansion waves are undesirable in headers and manufacturers often design in things like steps and anti reversion chambers to help reduce this pulse. Scavenging is very desirable but it is a "suction" created behind the departing pressure wave pulse, when the exhaust valve opens. That suction helps create a vacuum in the cylinder so it will fill more completely with a fresh intake charge and therefore make more power. A Negative returning pressure wave HURTS the scavenging effect because it actually pushes exhaust gasses back into the cylinder reducing cylinder filling efficiency.

Normally, every time the exhaust pulse reaches a point in the exhaust where it opens up into a larger area like the collector, a reverse pulse wave is reflected back up the pipe towards the exhaust valve. Negative pulse waves are going to happen in every header design so the best header designs incorporate features that help to reduce this effect as much as possible.

Certain design features like making the primary tube opening slightly larger than the exhaust port and smoothing the transition or "step" into larger diameter piping help reduce the negative pressure pulse wave. The first anti reversion feature I mentioned creates a physical step for the returning pulse wave to overcome, in order to re-enter the cylinder. The smoothing of the transition area when moving into larger piping which can be in the primary tubing and collectors helps to maintain velocity and significantly reduce the strength of the negative pulse wave.

There are other things that can be done like using cone shaped collector extensions and designing steps into a headers primary tubes at specific distances to help cancel out negative pressure waves. Building headers isn't an exact science, but it is a science and simply building them using different lengths and diameters of tubing that work isn't always the most effective way to make power on every application.



These pressure waves can be used to our advantage because they have the effect of moving gas particles along with them. A positive, or high pressure wave will propel gasses in the same direction that it is travelling. A negative, or low pressure wave will propel gasses in the opposite direction that it is travelling. Take a moment to let this sink in, because this simple fact is at the heart of exhaust system tuning. Although the pressure wave is moving at the speed of sound, it will propel the gasses at a much slower speed. An example of this is a boat that catches a wave from another boat that is motoring by. As the wave passes it will propel the boat in the same direction the wave is traveling, but at a much slower speed, and the wave will eventually pass the boat completely. This is the same thing that happens to the gas molecules in the exhaust system as a pressure wave passes through them.

These pressure waves respond in an interesting manner when they reach a sudden area change in the pipe. An example of a sudden area change is the collector, where the two pipes empty into a larger diameter pipe, a megaphone, or the end of the exhaust where the pipe empties into the atmosphere. When a pressure wave reaches a larger cross sectional area, it will reverse its sign (positive becomes negative, and negative becomes positive) and its direction. For instance, when the exhaust port first opens, a strong positive wave will travel to the end of the pipe, change to a negative wave, and travel back to the exhaust port. This is called a reflection. Both the positive wave traveling towards the end of the pipe, and the negative wave traveling towards the exhaust port will propel exhaust gasses towards the end of the exhaust system which is exactly where we want them to go. The amount of time that this cycle takes is defendant on the total distance that the wave has to travel.

I dunno... both my engine building book and the site quoted above say that the negative waves assist gas outflow.
Maybe I am mis-labeling or mis-interpreted what hytech labels as a negative wave in relation to what I'm describing and thats where the confusion exists...
.
.
.

[Justin86]

Well I designed the header for someone with more mods then basic and at least a 272 cam.

well no dyno yet, but here is what it sounds like with my new exhaust set up........
http://www.sirrommotorsports.com/photopost/data/500/228calebsexhaust.mov

[NXRacer]

new header pics
http://www.3geez.com/showthread.php?p=500527#post500527

[Justin86]

yea but the only problem with that for me is having to get a spool gun($400) and a new tank for the CO2. If your current tank has the 75% CO2 mix you have to get a different tank for some reason to run the 100% mix. I'd rather save up to get a TIG

[A20A1]

I could make one for the B20 it would help a lot if I had an engine to weld it on so I know it fill fit for sure.

Maybe find a old head with simmilar ports to the B20... then lay it on the A20 block and secure it down... it should give you some idea. :dunno:

[Justin86]

Yea that what I'm thinking along as the deck height and oil pan clearences are similar to the A20
ok and we we say B20 you talking about the JDM accord B20 or the prelude B20. Other wise I could use a pic of the engine/oil pan, where I can get a head to weld on, and dimiensions of the engine. Hopefully the A20 block is similar other wise I would need the actual engine to make it fit for sure.

[epic1400cs]

yea but the only problem with that for me is having to get a spool gun($400) and a new tank for the CO2. If your current tank has the 75% CO2 mix you have to get a different tank for some reason to run the 100% mix. I'd rather save up to get a TIG

Its my 2 cents but I also recommend to go for TIG with Argon gas if possible. With TIG you can control the heat area much much accurate = constant welding bead = good strong finish. Especially with stainless steel, if you use gas-after-flow well, you don't need to do much after welding. I guess, the pipe wall thickness would be a couple of millimeters and the falnge will be like 9 mm so if the TIG welder can handle 120 Amp that would be fine. There are lot of option available these days - pulse, step etc - but unless you use thin sheet under 1mm or welding gas tank, the basic one - just on/off plus gas after flow control - will do the job. Good luck.

[Justin86]

yea you read my mind and I have been in the market for picking up a TIG and plasma cuter, maybe some other goodies. I want to start working with aluminum and SS more and the TIG is the best bet. I like the MIG a lot for welding thicker steel but when I starting welding thinner stuff it took me awhile to get a good weld. It was either too hot or not enough penetration at first.

[epic1400cs]

I want to start working with aluminium and SS more and the TIG is the best bet. I like the MIG a lot for welding thicker steel but when I starting welding thinner stuff it took me awhile to get a good weld. It was either too hot or not enough penetration at first.
Sir Justin 86, yes TIG is the king. If you want to work with aluminuium, you might want AC/DC out put switch - alu wants to be welded in AC than DC. Also for thin material, step will be handy to control the heat build up they say, but the price will be very expensive. I have worked with TIG first as a job and recently I have bought MIG for my DIY project. Portable MIG is good for its price but DIY range doesn't come with variable amparege control - like low, mid, high and I need to control heat build up by welding speed and wire speed. So you cant always weld with your best condition. Also you grip the TIG torch like pencil, not like stick, which give you more accuracy.

[Micah 89LXi]

the level of dedication in your work is amazing man...i am really impressed...alas i have have an Lx-i EFI engine....and further down the road id be really interested in purchasing one...maybe ill just have to get the DC Sports one...good work tho man

[NXRacer]

i've been rolling with this header and you dont really need a dyno to show the crazy gains in response and power.

Dyno numbers would deffinately be nice though.

[Strugglebucket]

what ever happened to Justin86's header?

[onliLX-i]

So this means us guys without headers are still screwed. I might buy a used header just because there is nothing else. Where can you get a used one? I am also wondering what the down pipe diameter is? Anyone know what the DC sport header down pipe size is?

I see. I wish I knew about this forum before I had my exhaust redone. 2" cat back. I would have to replace all that piping to take any advantage of a header. The guy at the shop told me anything bigger than 2" would be anti-beneficial. Started rattling off about back pressure. What about scavenging you !#%*&.

It is all we can still get that is commersial.

Why restriction? A choke?

[spnrx]

I'm still lost as to what to do Exhaust wise, A guy told me $280 for a 2.5" Cat back with magnaflow muffler. What headers would be best? like I heard Pacesetters weren't that good but a good number of people use them on here.

[loko84hb]

looks like those guys could make sum sick ass headers...at a pretty penny...

[onliLX-i]

Does this cteate a vaccume effect to suck the gasses out? What if you just ran the four header pipes all the way back to the bumper and had four exhaust pipes? I know this is rediculous but what would that do?

[A20A1]

It would sound like a motorcycle... (Harley)
You would hear the individual cylinders firing.

You wouldn't get any assistance from one cylinder creating vacuum for the other cylinder since the pipes don't merge thru/into one.

[A20A1]

So I figure most of you want 4-2-1...

Well only problem for me is that I would need more die's to accomodate the different pipe diameters and that will blow the initial header cost thru the roof... subsequent headers will be cheaper.

Good news though is the 2-1 merges are easier to come by... and much more selection for me to shop around.


Decisions decisions... :)

[chainz]

It would sound like a motorcycle... (Harley)
You would hear the individual cylinders firing.

You wouldn't get any assistance from one cylinder creating vacuum for the other cylinder since the pipes don't merge thru/into one.

I get it! So that is why some 90's GM V6s with dual exhaust (Luminas, Grand Prix, etc.) have that gargling sound - cause you are actually hearing 2 separate 3 cylindar exhausts?

[A20A1]

yeah the more you split them apart the more it goes from a tone to a pulse.

[88Accord-DX]

It would sound like a motorcycle... (Harley)

If the Accord would sound anything like a Harley, the header would need to have the exhaust pipes coming out the side of the car back behind the front tire. LOL

[Acid X]

It'd be nice if us californians had more headers that were smog legal.. :(

[Strugglebucket]

phuck smog legal.

run what you want and then swap the stock parts back in every two years. consider it a labor of love.

[Acid X]

Yeah, but that seems like a PITA.. Its pretty hard to put in headers with AC stuff, lol.

[gfrg88]

well just gut all that ac crap and you wont have to worry about it :D and that really doesnt get in the way of installing them....

[Acid X]

Have you seen my AC stuff?

No way i'd gut it, its a brand new system. haha... 1800$ ac system that was put in right before i got it.

[gfrg88]

ok, nevermind then, i really havent seen your system that well, mine doesnt work so im thinking about it, and itll be less weight for me and more room for turbo :D

[Acid X]

Good luck with smog, lol.

[gfrg88]

im not worried aboug smog, a couple extra bucks should do the job, trust me ;)

[B16KILLA]

im not worried aboug smog, a couple extra bucks should do the job, trust me ;)
I know a place that does "special" smog.

[A20A1]

I'm not sure if you've heard anywhere else, but Paeco offers a header for us.
$260.
Not sure of the design either.

Thanks, they are 4-1

The also offer an exhaust system as well... looks decent. :D

[A20A1]

I didn't send them an e-mail, I looked at their PDF. :)

It doesn't say 4-1 it says Four pipes to one collector, or something like that.

[gfrg88]

hmm, i was checking out paeco too, i noticed they have engine kits for honda 2.0, is that for our cars?? they seem too have a lot of nice parts there for us :D

[A20A1]

or used to have

[gfrg88]

so all those parts they "have" arent available anymore :hs: and i was getting so exited :sadwave:

[A20A1]

so all those parts they "have" arent available anymore :hs: and i was getting so exited :sadwave:

Some of them aren't

[gfrg88]

so i have to call them up for whatever i want to see IF they have it then??

[gfrg88]

after about a month or two i got an email back from them:


Giovanni -
We can furnish the engine kit for either of these cars. Please give us a
call if we can help you.
Carl at PAECO
(205) 823-7278

[A20A1]

My head will explode... I just added a few more calculations/formulas to the first post... rearanged a few posts, basicly updated it some.




The more vigorously gas molecules shake, the hotter the gas gets, and since sound cannot move faster than the velocity of gas molecules you can determine the speed of sound by the speed of molecular motion.

v = wavelength*frequency
or
v/frequency = wavelength

engine frequency = RPM*15 (really the frequency of the exhaust valve opening)


800 degrees Fahrenheit speed of sound is 1740.59 ft/s

(1740.59ft/s)/(RPM*15) = header length in feet

1 ft = 12.000 inches
1 ft = 0.3048 meters
1 in = 0.0254 meters


http://www.sengpielaudio.com/calculator-speedsound.htm

engine frequency = RPM*15





Optimal Velocity of 240-260 FPS