Whos running MAC21's with the Parabolic Q-Pipe

[Tony Jacuzzi]

Looking for a good starting point pipe length using a modified MAC21 with the Parabolic pipe on a new 3.75 lb hydro (60 % w/ AB 1450 3.2"). I would like to ensure that I build enough "flexibility" into pipe mount location. Thanks Tony J

 

[Joe_Knesek]

Looking for a good starting point pipe length using a modified MAC21 with the Parabolic pipe on a new 3.75 lb hydro (60 % w/ AB 1450 3.2"). I would like to ensure that I build enough "flexibility" into pipe mount location. Thanks Tony J

Tony, I'd start @ 7.75. I'm setting mine @ 7.5 but my pipe has a bit more volume. I'm running the same motor and pipe combo in my new mono and have it set @ 7.75.

 

[Don Ferrette]

Looking for a good starting point pipe length using a modified MAC21 with the Parabolic pipe on a new 3.75 lb hydro (60 % w/ AB 1450 3.2"). I would like to ensure that I build enough "flexibility" into pipe mount location. Thanks Tony J

I'd also say 7.75" which is where mine is set at in my 21SGX w/ MAC21. B)

 

[John Knight]

Tony,

My son's 20 rigger, MAC 21 with the AB 21S quiet pipe is also at 7.75". His engine runs better with the 21S version rather than the 21 quiet pipe. My NR likes the 21 quiet pipe instead.

John

 

[izitbrokeyet?]

My NR LS is liking that AB21s pipe pretty well....havent tried the parabolic yet

 

[izitbrokeyet?]

I'm guessing the 3-port exhaust with eybrow center wont like that Parabolic.

(tons-of-area up top)

any thoughts?

 

[Don Ferrette]

My NR LS is liking that AB21s pipe pretty well....havent tried the parabolic yet

The 21S is a parabolic pipe. B)

 

[Bob Kensill]

My Mac 21 likes the 21S pipe,but my CMB green head likes the long muffled pipe.

 

[izitbrokeyet?]

The 21S is a parabolic pipe. 

pay me no mind.....I'm an Idiot

well.........looks like the NRLS is liking the parabolic.

for some reason I always thought the "S" was for small volume :huh:

maybe nextime I'll actually read the info......in stead of looking at the pretty pictures :huh:

 

[Rick Cesati]

KB...definately try the original parabolic..my NRs like them better than the S (short) version...to be fair I never did much prop work with the S pipe.

L8r,

Rick

P.S. Only 978 useless posts to catch you!

 

[John Knight]

Kevin,

My NR LS, for whatever reason I have yet to find out (more testing time and I could), becomes hard to find the needle with the 21S (yes, parabolic). The "S" means in fact short version so you are right in that respect. The std or original parabolic works best for my NR. I suspect that the NR (especially a modified one)is a combo of high rpm and torque unlike the MAC which is mostly an rpm engine. The 21S is really an rpm pipe hence the better fit for the MAC. I am sure that it could work with the NR but I haven't spent the time to work with it. Tried for a couple of hours one day and put the std parabolic back on it and it flew. Too much work to try to find the sweet spot, especially when it was 95+ degrees that day.

My son's runs well with the 21S and the MAC. Yep, I have both of the pipes. And I do have spares. More $$$ to Andy! I am sure he will tear up when he sees this.

John

 

[tracerbob]

I'm running the parabolic "s" pipe on my NRLS in a microburst 20 and it runs great! Haven't even drilled out the stinger. And no problem with finiky needles. Running right at 9" from the cylinder center to the weld.

 

[John Knight]

Bob,

My son's 20 Seaducer with a NR engine in it runs with a pipe length of 7.75". It is not a CMD pipe however. I cannot run it at 9" if we want to stay with or lead the pack. Much too long for us. Rarely do I have reset the needle at that length. Try is next time just for grins.

John

 

[Buckshot]

Tony,

I'm running the std. parobolic pipe on my .21 MAC powered Hummingbird hydro and in my Seaducer at 8.06". At the NAMBA Nats. last weekend was the second time the A-hydro was in the water and it took a first in one heat. Shot at 71 mph. With more prop. / pipe work hope to hit high 70's to low 80's. Got the "S" pipe but have yet to try it.

-BUCK-

 

[Tony Jacuzzi]

John K, check your PM