tuned pipe fuel tubing outlet?????

[laxmasta2039]

hey guys,
i recently learned through several posts [yep, it took three or four guys to teach me] that the little tubing outlet on a tuned pipe is going to the fuel tank [on a nitro engine]to pressurize it [forcing it into the carb], and thought i could now pick out the right pipe for my engine. when i started looking, starting w/ tower's selection of MAC and stinger pipes i noticed that none of the pipes were either for .18 engines, they were all race-class sizes [like .12, .21, etc] or did any of them, except for the fat car ones, have outlets to stick fuel tubing on.
does anyone know what size [between a .15 and a .19-.21] would be better for a .18 inboard K&B engine, and why none of the MAC pipes have fuel tubing outlets???

[Ron Olson]

I saw your posting on the other site and no one answered you yet. Go with a larger sized pipe (the .21). A lot of racers go to a larger pipe, why, I don't know, something about the power band. This will give you a BIG selection of pipes to run.

[laxmasta2039]

ok.,
will do. i looked on Rocketcity's site, they had a huge selection along with several "pressure fittings" i'm guessing these are what one uses to get pressure from the exhaust into one's fuel tank. i'll probably get the MAC .21 marine, a standard .15 mount [since that's the size of my exhaust port] and pressure fitting. i also noticed they had padded clamps [for holding the pipe out over the transom] i think i'll try making my own, they look pretty simple.

[Ron Olson]

Jim Irwin advises to use the Du-Bro #241 pressure fitting on his pipes. It's small but if that's what he says to use, I use it.

[laxmasta2039]

Ron,
hammer gave me a link to a site that carries .18 car pipes for 18 bucks....these pipes are for .15-.18. how much better would it be to get the MAC .21 marine pipe as opposed to one of these?
also, i noticed they sell big-bore carbs for .18 engines, 23$. again, would it be worth the extra money to use a big-bore?
im just not sure what i should save on, and what i should get top-quality of.......i dont have enough to get the best of everything.

[Ron Olson]

I was surprised to find out that a car pipe worked better on my .12 mono than the Mac pipe, at least 5 MPH worth. The carb can wait if you want to go with it. K&B usually matches the carbs up pretty well with their engines.

[laxmasta2039]

hmmm....
does this mean that it might be better to go with the cheaper pipe? great!