header question?

[torinoredcivic]

please tell me which option is the best for header?
1. straight pipes running from each cylinder and going half car length?
2. 4-1 header with no backpipe?
3. 4-2-1 header with no backpipe?
4. or 4-1 header or a 4-2-1 header with backpipe?

this is only for track use and i can get custom ones made so dont consider noise and tell me which one would be the best.
thanks

[Belette]

What kind of track you will put this car ? big curve ? round track or anything else ?

Surely if you go on track let full back pipe at home , every race car that i've seen had only no more than 2-3 feets of back pipe on side, but I think is for not black smokin' under car, rather than tunining ( maybe too that not overheat valves )...

4-2-1 headers will give you a little bit more in lower rpm & torque, but a little less at higher rpm, It depend too that your entire setup... It will be better if you need 'some torque' in big curve.

4-1 Let almost no restriction, can handle higher rpm better, but little lost in lower power band ... Excellent into highspeed racetrack, but need some engine replacement like intake, valve spring, bigger cam (if you're not v-tec)



Good luck !

:shock:

[91civicDXdude]

take a look at the d series bisimoto race header and that will tell you the optimum design..

equal length stepped primaries, a venturi, and megaphone style exit.

[Belette]

take a look at the d series bisimoto race header and that will tell you the optimum design..

equal length stepped primaries, a venturi, and megaphone style exit.

Sure ! Bisimoto headers is the best, DC sport a very good one too, but if you don't have 900$ to spend for a Bisi headers, or you don't have partner too feed you some cash, go with pace setter with no coating ! you will pay hit 1/6 of bisi price !

:shock:

[kommon_sense]

The bisimoto header is about $600. From what I've seen, it is well worth it performance wise. Only problem is that it doesn't allow for powersteering which is an issue for those of us building up the daily drivers :)

[torinoredcivic]

sorry i forgot to mention that i meant drag racing use.where i llive there are no official race tracks just regular meets and races on a closed public road.
so i think that a sime 4-1 header with something like 2 to 3 foot piping would be the best.right?

[transzex]

4-1 header, 30-32" primarys, 2.5" collector about 14-24" long depending on the heat stripe.

Make sure to route the tubes properly........

2-1
4-3

[torinoredcivic]

hey i always thought that it was 1-4 and 2-3 are you sure about that?

[kommon_sense]

Firing order is 1-3-4-2

So it should be 1-4 and 3-2. Dont' know why you would want to pair 1-2 and 3-4.

[S Q A D]

4-1 header, 30-32" primarys, 2.5" collector about 14-24" long depending on the heat stripe

who makes headers with these specs? any compnay out there that even comes close to this ??

[transzex]

Firing order is 1-3-4-2

So it should be 1-4 and 3-2. Dont' know why you would want to pair 1-2 and 3-4.

You pair the cylinders at 180 degrees CRANK rotation, not firing order!

Look at the custom headers, you'll see it.

Had a nice long chat with Dave Stradilus at SMSP.

[torinoredcivic]

please guys decide what is best i need to know coz there is not much time left

[kommon_sense]

Firing order is 1-3-4-2

So it should be 1-4 and 3-2. Dont' know why you would want to pair 1-2 and 3-4.

You pair the cylinders at 180 degrees CRANK rotation, not firing order!

Look at the custom headers, you'll see it.

Had a nice long chat with Dave Stradilus at SMSP.

I know diddly about header design, but I have to say that doesn't make sense. Seems like you would want to pair the primaries to flow better which would have to be done based on firing/combustion order. If 1-2 are paired together than you have a pulse from 2 and then immediately from 1.

I just had a thought. You said you talked with the folks at SMSP. SMSP only designs 4-1 headers. Design philosphy there may be very different from a 4-2-1 header (which I was referring to). 1-2, 3-4 makes some sense for a 4-1 header which would most likely have a bigger collector than a 4-2-1.

[transzex]

Dave also makes 4-2-1 headers.

You have to understand how exhaust gases scavenge, esp. the cylinder next to it.

EDIT.......SMSP 4-2-1 header with 1-2 and 3-4 pairing......

http://www.automotivetech.org/photopost/data/520/3011smsp_header-med.jpg

[sgvridgerunner]

Cylinder pairing must also take runner length and powerband into account. That why pro teams "tune their pipes." They build them to work in a specific rpm range. Find the exit velocity of the gases at all rpms, display them on a spreadsheet. Determine what lengths you want to run, then pair the cylinders accordingly.
Most production headers are 4-1 3-2. For our rpm range I think thats fine, but if you want to get the most scavenging that physics has to offer, you'll need to research your specs.
My personal favorite - the zero B-pipe tri-Y. Spoon and Yoshimura use this design. More torque than a 4-1, but almost the same flow. It will also help dampen this argument. Look at it and you'll see what I mean.