3 inch collector length

[Larry Woodfin]

Racers,

my Crate Racer [355 sb Chevy] uses an off-the-shelf Hooker Super Competition [equal lenght] It's 1 5/8 tubes with a 3" flanged collector. The collector straight section is about 10 inches. I have been running a bolt on extension of 18" making the total collector about 28 inches. My thinking, this may be longer than needed.

The car runs 10.70's [hot weather] weighs 3050 w/driver so is making in the 460 - 470 horse range. Also, powerglide, 5800 converter, shifted a 6800, crosses about 6800 - 6900.

So my question, what is a good guide line for collector length?

Thanks
Larry Woodfin

[OldSStroker]

I don't know how this will apply with things as "high tech" as they are today but way back, I spray painted a stripe the length of the collector, made a few passes and then sawed it off where the paint wasn't burnt off. Seems it would burn off the paint a certian length down the collector and the thinking of the day was that was the length I needed. Maybe someone here has the "formula" to figure this out now.

Ken

The paint and burn method has drawbacks and isn't usually recommended. It seems that it you do it once, cut the pipe then do it again, it will suggest cutting the pipe again, and again and...

Larry (maxracesoftware) has some programs and discussion relating to this. Try searching on his name.

[gas]

[The paint and burn method has drawbacks and isn't usually recommended. It seems that it you do it once, cut the pipe then do it again, it will suggest cutting the pipe again, and again and...

Larry (maxracesoftware) has some programs and discussion relating to this. Try searching on his name.

Kinda like cutting something twice, and it is STILL too short.
I consider programs/formulas a good STARTING point. On track testing either confirms it, or will overrule it. Some have even (mistakenly) used dyno peak power readings as their gage, to determine correct length. If one prefers to use this method to determine length, again, recognize it as a starting point.