dfoxengr

i would like to relate these q's to high/low compression and displacement

1)what are the effects of longer primaries/secondaries before the first collector or only collector(4-1)

2)effects of stepped ssecondaries on 4-2-1

3)proof of the effects of anti reversion chambers, and these are simply spaces around the primaries after they are stepped to larger secondaries correct?

4)d-shaped curves effects and would there be benefits of doing this on more than 1 radius say in a curvy type header

5)d-shaped ports in the intake manifold and head ports add to effectiveness of the header designed with dshapes in mind?

6)the flat side in d-shapes are on the short side radius all the time correct?

ill try to think of more. maybe SMS and Randy can pipe in here.

sCeRaXn

Bump cuz id like to know too

dfoxengr

i doubt that vtec would make a huge diff in header design

dfoxengr

dfoxengr

dave? randy?

dfoxengr

...

dfoxengr

another try

Ekasey

I know you would like all of these answers related to compression and dsiplacement i will do the best, i knwo you only wanted dave or randy but im chiming in

1. Well Primary length is mainly dictaed by rpm range. For example on a given engine Optimal primary length may be calculated at 30" before the collector. This will allow the header to operate in the rpm range dictated by the engine builder or request by driver car owner etc.

While bore stroke compression etc do have an effect on primary length it is not nearly as important as the rpm range the engine will be driven in.


2. Im assuming by stepped secondaries you are reffering to the length of tubing after the first set of merge collectors. Most engines do not seem to benefit from this as such a large diameter is not needed. However we have been recently experimenting and testing things like "big step headers" and ones that have adjustable secondary sizings. Alot of the time when i'm spec'ing out a header if it needs to go up to a rather large secondary size in comparison to the primary's (depending on engine) i will just enlarge the primary collector outlet to accomadate that size


3. You will need to look up Jim Fueling (sp?) he was the original person behind the AR chambers I heard rumors that they may have worked on older engines where gas speeds RPM ranges and pretty muhc everything was much slower. However on today's engines think of it this way. By the time a pulse travels down the tube and out to the collector (and if there is reversion occuring) and gas starts to flow backwars up to another tube, Another pulse would already be traveling down and through the said tube to defeat it. I;m thinking of a way to set this up in a model but i'm not handy enough with solid works or a program thats capable of doing this

4. The effects of the D shape curves are to speed up gas velocity as the pulse travels down the tube, i haven't seen any positive results on this but who is to say it isn't worth a try if there was a non time consuming way of doing this. Anyone have any data i would lvoe to see it

5. The intake manifold is a whole other monster to conquer in itself, depending on over all engine design architechture etc. certain changes to the intake tract will effect the exhaust. Mind you on some engines it may have no change on others it may have a very drastic change

6. From what i have seen yes and that would seem to make sense

I;m not overly well versed in the D shaped tube stuff so bear with me on that will put some more thought into it tomorrow. Sorry for the spelling / ghramatical errors im sure there are some Hope this helps lets get a good discussion going here

ShaunRR

Re the AR chambers; from what I gather, they are best used when engine confines don't allow a decent amount of primary to come straight off the exhaust port.

Also, I have seen Randy do a lot of D shaped primary stuff. He might be the best person to ask about that.

dfoxengr

nah casey is cool too, lol

so for higher rpm you would want a longer primary correct?
say you decided on x length primay, you then put your 2 Y collectors after x amount of piping, and then 30" later add your final Y?

by stepping i didnt mean a drastic change in tubing size, only say 1 3/4-1 7/8, just an 8th...

did you figure out if the flat part of the D is on the short side radii of the IM?

i guess so many exhaust pulses per second would continue pushing the previous ones out of the way therefore making AR chambers useless, that makes sense to me, especially at 8k rpm or so.

ShaunRR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridvteceg &raquo;</TD></TR><TR><TD CLASS="quote">
so for higher rpm you would want a longer primary correct?
</TD></TR></TABLE>

No, shorter.

Combustion Contraption

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rochesterricer &raquo;</TD></TR><TR><TD CLASS="quote">No, shorter.</TD></TR></TABLE>

Im gonna go with longer. Im looking at it as the opposite of intake manifold design.

ShaunRR

Nope, its shorter. Are Kamikaze headers know for making a lot of low end power?

Combustion Contraption

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rochesterricer &raquo;</TD></TR><TR><TD CLASS="quote">Nope, its shorter. Are Kamikaze headers know for making a lot of low end power?</TD></TR></TABLE>

Doh!

I remain undecided.

Ekasey

ugh i really need to make it a mission of mine to go through and make significant chnages in the ehader design while on the yno to show the drastic changes it can have. Shorter = higher longer = lower

Rocket

Go here http://www.n2performance.com/.

Jim McFarland, Performance Professor, is pretty good. Sound principles if you want to build you toolbox of knowledge.

Combustion Contraption

Great link, Rocket.

dfoxengr

any one else.?

KhanhCord

great questions i needed to know those 2 ..

btw ..dont mean to hi-jack thread but any1 knws if all b18s headers have same/diff primaries ID ...each different company makes differ ID size or all same for b18s?
sry for the n00b Qs

thz

dfoxengr

bump

dfoxengr

tttt

dfoxengr

one more try

machine4321

yea i would love to hear more on stepping
great thread
thanks

machine4321

up for knowlage (jumping trowing fist in air alla J.I Joe fasion)

KhanhCord

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridvteceg &raquo;</TD></TR><TR><TD CLASS="quote">tttt </TD></TR></TABLE>