Exhaust manifold (tube header) for 2,0TC

[NOSferatu]

I link this older question here, because the car specs are found there

http://guy-croft.com/viewtopic.php?t=47 ... 53bf39e1bf

So my question:

What lenght of primaries and what diameter would be good for my setup with 4-1 manifold?
How about the measurements of collector and outlet tube?
I ask these measurements for 4-1 manifold, because I have one such already, and I just want to know if it is not even near to recommended.

If I remember right, primaries lenght is about 670mm and diameter 36mm.

I also have one 4-1 manifold that is 850mm long, but it doesn't fit into car without modification, and diameter of tubes is 40mm inside. Is that too much?

[Guy Croft]

Your spec:

Fiat 2.0TC
Regata or Ritmo 105 pistons
43,5 inlet valves fully flowbench ported head
10:1 CR approx
Straight shot inlet manifold with 45mm throttle bodies
Hestec fuel injection/ignition.
4-1 tubular header


What length of primaries and what diameter would be good for my setup with 4-1 manifold? How about the measurements of collector and outlet tube? I ask these measurements for 4-1 manifold, because I have one such already, and I just want to know if it is not even near to recommended. If I remember right, primaries are about 670mm and diameter 36mm. I also have one 4-1 manifold that is 850mm long, but it doesn't fit into car without modification, and diameter of tubes is 40mm inside. Is that too much?

To be honest, the 4-1 with 40mm bore and 850mm will be as near to correct as you are going to get on that motor, use it. As for the tailpipe (the tube downstream of the collector, go for 50mm bore. Use a large capacity straight - thru silencer (muffler) of 57-60mm bore with fully perforated liner 3.2mm holes, glassfibre packed. Typically it will need to be 18" x 8" x 4" oval or bigger.

GC

[NOSferatu]

Thanks very much for your reply!

Shamed to tell, but I seemed to remember incorrectly the bore. I just hauled the manifold from folks, and it seems that the inside diameter of the primaries is not 40mm but 42mm. Is it still good?

In Finland it seems to be quite understanding policy for performance exhaust, so I have always used two straight throuhg 2,5" mufflers after about of one metre of 2" pipe from collector. I haven't had any comments about the noise from authorities.

[Guy Croft]

40mm will be fine too, length is more critical than diameter.

GC

[Greenwood037]

What length/diameter would be best for a supercharged 16v? We are looking at very high boost figures, over 20 psi (intercooled, twin screw). Exhaust valves will be stock sodium cooled valves, but the exhaust port will be ported. It is in a race car, so anything shorter than probably 4 or 5 feet would be workable.

Also, for a supercharged race engine, would 4-1 or 4-2-1 be best? Torque will not be a problem, so I would think the 4-1 would be best.

Thanks
Jason Greenwood