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Location:
East Maitland NSW
Registered:
December 2004
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extractors
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Sun, 19 December 2004 12:35
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hi guys
i have been told that the best type of extractors for road use are 4-2-1. but i have also been told that cylinder one and four must join, then two and three before all joining into one. is this true or should you follow your engines firing order?
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Location:
Melbourne
Registered:
June 2004
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Re: extractors
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Sun, 19 December 2004 22:30
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| Meat_rack wrote on Sun, 19 December 2004 23:35 |
hi guys
i have been told that the best type of extractors for road use are 4-2-1. but i have also been told that cylinder one and four must join, then two and three before all joining into one. is this true or should you follow your engines firing order?
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Dude: the objective of extractors is to have pulses evenly spaced when pipes join. That means the primaries need to be joining 1+4 and 2+3 when they merge into the secondaries, because those pistons fire at even intervals from each other, i.e. one whole revolution.
Joining 1+2, 3+4 would probably make a whack off-beat exhaust note (slightly WRX-like perhaps?) but wouldn't be terribly efficient.
I hope that helps.
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Location:
Castle Hill, Sydney
Registered:
February 2004
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Re: extractors
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Sun, 19 December 2004 23:35
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4 to 1 extractors are pretty common?
i read on toymods somewhere, 4-1's give more top end power and 4-2-1's give more low down power, just find out where your engine makes all the power and that'll help u make ur decision
eg: i have a 2tg hybrid with most its power up high, so went with 4-1's
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Location:
Melbourne
Registered:
June 2004
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Re: extractors
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Mon, 20 December 2004 01:02
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Depends on who you talk to. Some people swear 4-1 is the only way to go, others say 4-1 just looks pretty and does nothing. I think people who talk trash about either sort have just had/made a poorly tuned set of extractors, or a sloppily made set with poor flow in some of the pipes.
Below From the horses mouth ( Pacemaker )
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A 4-into-1 design is perhaps the most traditional design. This design is common to the US market and is well used within the drag race fraternity. The basic principle behind the design is that the scavenging effect within the collector cone effects the three remaining pipes (in a V8 half), instead of limiting the pulse to the very next pipe in the sequence. This generally results in a header that performs very well in the mid-range to top end of the engines performace.
A TRI-Y on the other hand splits the firing order evenly and uses the secondary pipes as sequential collectors. This results in generally a greater scavenging effect due to the fact that scavenging is achieved at 2 different points in the header design, firstly at the primary to the secondary collector and secondly to the secondary outlet collector. Generally this improves torque in the lower to mid range perfomance of the engine.
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So there ya go: Tri-Y is more efficient at scavanging low-mid RPM, but 4:1 flows easier and starts working better at high RPM.
Tuned-Length DeFillipo extractors for Holden 5L :
Gemini 4cyl 4-2-1 :
See - 1+4 join, 2+3 join.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: extractors
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Mon, 20 December 2004 03:52
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When I had mine built, the exhaust shop guy said he'd have to do 4-2-1 because there wasn't enough room for 4-1.
Whether there is any other benefit/problem with 4-2-1 over 4-1 besides size restriction, I don't know.
4-2-1
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Location:
Sydney
Registered:
August 2004
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Re: extractors
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Mon, 20 December 2004 04:53
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If you look on Billzilla's site, in regards to a 4AGE 4-2-1 extractors are apparently best suited, in the 4+1 2+3 form.
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: extractors
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Mon, 20 December 2004 04:56
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| db__ wrote on Mon, 20 December 2004 12:53 |
If you look on Billzilla's site, in regards to a 4AGE 4-2-1 extractors are apparently best suited, in the 4+1 2+3 form.
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The matching of ports of the extractors in 4-2-1's is based on the firing order of the motor.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: extractors
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Mon, 20 December 2004 05:43
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my take on all this is that 4-2-1 will give you better scavengine in mid to high rpm... and 4-1 is for top end.. for me that means if you have a power band _starting_ around 6000rpm, you would only want 4-1. but if you have a power band starting around 4-6000rpm, you would want 4-2-1..
4-1 and 4-2-1 also have different length primaries, so there is more to it than just one or the other, as you can tune 4-1 to work with lower rpm.... thing is, when you have a reflected wave travelling up 4 pipes, it will not be as strong as travelling up two pipes 
Cya, Stewart
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Location:
Melbourne
Registered:
June 2004
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Re: extractors
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Mon, 20 December 2004 10:17
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| oldcorollas wrote on Mon, 20 December 2004 16:43 |
my take on all this is that 4-2-1 will give you better scavengine in mid to high rpm... and 4-1 is for top end.. for me that means if you have a power band _starting_ around 6000rpm, you would only want 4-1. but if you have a power band starting around 4-6000rpm, you would want 4-2-1..
4-1 and 4-2-1 also have different length primaries, so there is more to it than just one or the other, as you can tune 4-1 to work with lower rpm.... thing is, when you have a reflected wave travelling up 4 pipes, it will not be as strong as travelling up two pipes
Cya, Stewart
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Exactly.
Either type can be tuned for higher or lower RPM by the length of the runners. I guess the harmonics of a 4:1 system are more efficient than 4:2:1 at high RPM. Maybe it's just easier to get bulk-flow through a 4:1 system.
Also, alot of people want to run the stock catalytic convertor, which in most new cars needs to be really close to the engine. That automatically means 4:1 extractors for alot of people, as it can half the distance before you can mount the cat.
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Location:
Sydney
Registered:
April 2004
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Re: extractors
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Tue, 21 December 2004 03:22
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what about for turbo cars,I never seem to hear anyone doing them,whats the go?
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Location:
Melbourne
Registered:
June 2004
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Re: extractors
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Tue, 21 December 2004 07:21
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It doesn't really matter, coz there's so much back-pressure exhaust scavenging will be minimal to non-existant. Also, the intake-charge is being forced into the cylinder hard enough to push the exhaust gas out anyway.
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Location:
Tamworth
Registered:
June 2004
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Re: extractors
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Tue, 21 December 2004 10:46
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um hey guys i dont really exactly know wot extractors do.....  but um would it b worth while getting them put on a 21r-c?
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: extractors
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Tue, 21 December 2004 11:57
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| cheese_cracka wrote on Tue, 21 December 2004 18:46 |
um hey guys i dont really exactly know wot extractors do..... but um would it b worth while getting them put on a 21r-c?
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No, not really, unless you get them free/cheap
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Location:
Tamworth
Registered:
June 2004
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Re: extractors
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Tue, 21 December 2004 12:01
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| CrUZsida wrote on Tue, 21 December 2004 22:57 |
| cheese_cracka wrote on Tue, 21 December 2004 18:46 |
um hey guys i dont really exactly know wot extractors do..... but um would it b worth while getting them put on a 21r-c?
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No, not really, unless you get them free/cheap
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would they add any sort of power increase or would it just make it more fuel efficient(if thats wot it does..??.?)
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Location:
East Maitland NSW
Registered:
December 2004
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Re: extractors
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Tue, 21 December 2004 12:06
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they will do both
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: extractors
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Tue, 21 December 2004 12:32
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| Meat_rack wrote on Tue, 21 December 2004 20:06 |
they will do both
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Probably 1-2% of each
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Location:
Tamworth
Registered:
June 2004
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Re: extractors
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Tue, 21 December 2004 13:16
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so thars pretty much no point then.....??
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: extractors
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Tue, 21 December 2004 13:22
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ahh no...
might help a bit, but only do it if they are free/cheap.
the rest f the exhaust should be upgraded at the same time.
here's mine.. home made.
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Location:
East Maitland NSW
Registered:
December 2004
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Re: extractors
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Tue, 21 December 2004 13:23
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well i belive there is a noticeable diffirence when extractors are fitted to a car. plus it means your car doesnt run as hot and therefore less strain on the motor.
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Location:
East Maitland NSW
Registered:
December 2004
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Re: extractors
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Tue, 21 December 2004 13:29
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hey oldcorollas what does that system that you have on your car sound like as i am thinking about just having one hotdog instead of two.
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Location:
Rosanna, Melb
Registered:
June 2002
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Re: extractors
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Wed, 22 December 2004 06:10
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Extraactors for turbo engines (Tuned/equal length turbo manifolds) do exist and can make a significant improvement over factory or log type manifolds.
They aren't really that big because you can find improvements elsewhere, eg diff turbo or more boost, cheaper than a really nice manifold.
And post turbo the design of dump pipe and wastegate pipe is an issue in itself.
Hen
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Location:
Melbourne
Registered:
June 2004
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Re: extractors
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Wed, 22 December 2004 07:08
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| Henn wrote on Wed, 22 December 2004 17:10 |
Extraactors for turbo engines (Tuned/equal length turbo manifolds) do exist and can make a significant improvement over factory or log type manifolds.
Hen
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Wouldn't that be more a problem with messy, poor flow through crappy cast factory manifolds, rather than benefits from tuned length exhaust runners? From what I've read, it's most important to keep the pulses at the turbo housing evenly spaced, so that the pressure and flow through the turbine & housing is as even as possible. I think this is where most of the benefit is in twin-scroll exhaust housings, because it's easier to keep the exhaust pulses from different cylinders from "seeing" each other. i.e. an L4 motor would run cyl 1&4 through 1 scroll, 2&3 through the other.
I don't THINK exhaust scavenging is a priority with turbo engines anyway. I think you'd get as much/more benefit from keeping the xsorszt manifold as short as possible, to keep the heat in the gas, and the velocity as high as possible.
hhmmm.. . - ask Peter Luxon at APS. He'll know 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: extractors
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Wed, 22 December 2004 10:33
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| Meat_rack wrote on Wed, 22 December 2004 00:29 |
hey oldcorollas what does that system that you have on your car sound like as i am thinking about just having one hotdog instead of two.
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it's very quiet. if you have a cat, it will be as effective as a resonator as it is a pretty big restriction.
this is a 2" system on a 1.3L motor that revs to 8000rpm. i get much more intake noise than the exhaust.
as for turbo manifolds... having equal length pipes will mean the exhaust pulses will hit the turbo at even intervals. that is probably a good thing.
having tuned length is primarily an exhaust scavenging thing, BUT it may help if you manage to have a positive pulse hit the exhaust valve such that you minimise intake blowing through the chamber. but thats a pretty small window of rpm...
Cya, Stewart
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Location:
Maitland, NSW
Registered:
August 2003
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Re: extractors
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Tue, 28 December 2004 06:28
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Meat rack
Guess what - i just fit extractors to the car that you are buying!! how about that!!
I believe they are 4-2-1's
Stu
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