Good point Brian, not sure about cars but when it comes to the japanese
harley carbs there are so many companies making jets for the same carb and
they are all punching them out so fast that the internal constant diameter
length is seldom an exact constant from just one manufacturer, let alone
between all of them. I'll bet some of you could get into working or polishing
the jets and hourglassing or funneling them and on and on(wouldn't mind
hearing about it to tell ya the truth, i don't know much about it besides
keeping it uniform).
Persoanlly I think what the jet size actually measures(smallest inside
diameter through the jet)should be the stated as standard and anything else
done(other then a hand drilled straight thru hole, which I like) should be
done to all the jets ever used in that carb so a #70 is a #70 and a #75 is a
#75, not that a #70 flows like a #75 but instead that it flows like an
excellent #70. In other words.. if you have a #70 that flows like a #75...
you either have a shitty #75 jet and should make it flow better, or you put
to much work into the #70 jet. I would think it would be much easier to put a
#75 in for the average guy(myself included)as long is it's built exactly like
the other ones your dialing it in with.. i always use the same set of bits,
handspin them and match port lengths of the jets for this reason. I think he
just wanted to know if there was an industry standard to the markings though -
lol. But what do i know, I had to look up propitious to find out it meant
advantage. :-)
TD
> I don't know if Holley still does it, but they used to flow test
> their performance jets and THEN mark them. The hydrodynamic
> propitious of the entrance, exit, surface finish, diameter and
> length of the orifice are all have an effect on the flow. I can make
> a # 70 Holly jet flow like a # 75 and a drill can't detect it
> because I won't change the diameter of the hole,
>
> Bryan
|