Toymods Car Club Inc: General Car Talk => extractors

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st184 sillycar
Forums Junkie

Location:
Melbourne
Registered:
June 2004

Re: extractors

Mon, 20 December 2004 01:02

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 )

Quote:

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.

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 :