Convergent Angle is the angle of the bends used to make the collector. We offer four angles 12, 15, 20, & 25.

A collector with a 12 & 15 degree convergent angle offers the highest velocity and performance gains.

20 & 25 degree convergent angles are used where space constraints are the primary concern.

The inlets of a Merge Collector are swedge up to slip over your primary tubes.

When ordering ask for a collector with a Tube O.D. the same as your primary tubes.

We stock collectors with 2,3,4,& 5 inlet tubes.

Collectors with 6 or 8 inlets are avialable by special order. A pair of 3 or 4 into one collectors are much more effective than a single 6 or 8 into one collector.

304 stainless steel

We have found ASTM A-269 304 micro seam welded tubing from Rath-Gibbsion to the highest quality and consistent available.

321 Stainless Steel has a resistance to high temperature fatigue making it a good choice for turbo charged applications.
(Wall Thickness) Gauge
Mild steel collectors are available in 16 (.065") & 18 gauge (.049).

Some 304 & 321 stainless tubes sizes are also available in 20 gauge (.035")

1008 Mild Steel
12 Degree collectors are the most commonly used standard collectors. They are highest performing and the longest collectors we offer.
15 Degree collectors are measureably shorter than a 12 degree with little lost in performance.
20 Degree convergent angle collectors offer a small increace in performance over the 25 degree, for
25 Degree convergent angle collectors are the most compact we offer. They are used in applications were space constraints are the primary concern.
Collectors can be ordered alacarte or fully assembled.

For each component welded to the collector a Weld Fee will be charged. Fees vary with tube diameter, material type, and additional fabrication required.

The Minor Diameter,Throat or Choke is based on the power band (useable RPM range) of the vehicle.

Applications with a high and narrow operating range require less restriction at the throat of the collector.

Divergent Angle
Selection of the correct Major Diameter is based on the peak exhaust volume (C.I.D. x RPM).
Megaphones are commonly used in open header applications (no tailpipe). Megaphones are constructed from rolled and seam welded sheet metal.
Reverse Cones are recommened for all open header applications. Some amount of restriction is necessary for the Merge Collector to function properly.
Straight Tube
Turbo Transition
V-Band Clamps used in conjunction with SPD sealing flanges offer a strong, gasketless seal. Flanges can be used at the minor dia. , major dia. , or virtually any were in the system to aid in installation and removal .
Collector outlets can be form to except most Turbo Flanges.
Fees for forming outlets vary as some require additional fabrication
3 Degree transition are the most gradual transitions we offer. 3 degree transitions can achieve a maximum step in diameter of 1/2" in most material.
7 Degree transitions can achieve a maximum step in diameter of 3/4" in most material.
13 Degree transition are the most abrupt transitions we offer. For application where space / overall length is greatest concern. 13 degree transitions can achieve a maximum step in diameter of 1" in most material.
The traditional Merge Collector is constructed from prebent tubes machine cut and hand fit to form a pyramid inside each collector for proper airflow management.

Use the buttons on this page to learn about the options, terminology, and how we build our part numbers.

Many competition engines are designed to utilize the benefits of a Merge Collector, especially in the case of a naturally aspirated engine. To realize the full potential of an engine, the exhaust system must be tailored to the specific application. Just as you choose a cam shaft designed for specific needs, the exhaust system must be matched to your engine package, drive train, weight, and track.

If are not sure of your header / collector design fill out the Vehicle Specification Form and fax it to us. Using engine, vehicle, and track information we can design a system that will help your engine realize it's full potential.