AB parobolic / S pipe comparision

[anthony_marquart]

Here are links to my AJM R2 design. With the AB Parabolic quiet pipe, then the cooper S pipe.

S pipe is way louder but also had better RPM. I was just looking at some video and now I can see the direct comparison. Too bad no radar gun..

The S pipe has to be set longer than the AB if you are going to make the same change.. The S was a dog at the short lenght of the AB,.. Both pipes launch about any prop on this particular boat design.

Just wanted to share the comparison for people doing .21 riggers. . The AB pipe was way easier to set up and get running well. The S pipe took some trial and error..

AB pipe http://www.youtube.com/watch?v=9-xdI8lBrTU

S pipe http://www.youtube.com/watch?v=9TIJb4pak98

 

[anthony_marquart]

what would be any of your thoughts on the difference... looking now,.. it's hard to tell which was faster..

 

[Duck899]

I think the S pipe video is quicker.....sounds like more rpm

 

[John Knight]

Anthony,

Which 21 AB parabolic was used? There are 3 of them, short, regular and the long.

 

[anthony_marquart]

there were also fat ones.. This was not the fat one, it was the one for 180 deg headers.. I'll look for a pic

 

[Duck899]

Was it this one?

AB21RX nitro

 

[RodneyPierce]

if everything else was the same (prop etc) I am going to say the S Pipe was quicker assuming the AB pipe is un muffled. Def turning more RPM with the S.

 

[Mike Larson]

John..., maybe Anthony... pic your AB pipe if you may... I have one, and could test accordingly... anthony can you give us lengths of the s and AB?... 7 7/8ths on the S, just aint gettin it.... mike

 

[John Knight]

there were also fat ones.. This was not the fat one, it was the one for 180 deg headers.. I'll look for a pic

There were 3 parabolics, as noted above, and then the FAT pipe, which was not considered a parabolic. Then the additional 21 pipes came out. Take a look at Andy's site and you can see all of his pipes he sold. You should find the one you are running while comparing to the S pipe.

 

[anthony_marquart]

its definitely the older pipe from AB,.. not trying to down any pipe.. just showing my results..

 

[JeremyEdge]

I think by Sound, the AB pipe holds the speeds thru the corners better than the s pipe.But the s pipe is faster.I would run the ab pipe for heat racing.

 

[anthony_marquart]

Are any of those new AB pipes available?

 

[John Knight]

its definitely the older pipe from AB,.. not trying to down any pipe.. just showing my results..

How about posting a pic of each pipe you were running.

 

[anthony_marquart]

Here is the AB pipe,.. with the stinger extended.

 

[anthony_marquart]

OK,,, HERE is really is..

 

[anthony_marquart]

I can't find a pic of the s pipe.. but it's the normal s pipe,.. from Glenn,..

 

[Duck899]

That AB pipe looks like the parabolic except really cut short.

 

[anthony_marquart]

I was tuning it pretty short.. it worked well also.. the boat was clocked at I think 69 with the ab pipe. Never been on radar with the S pipe.

 

[John Knight]

It looks like a parabolic but as it is too fuzzy and not close enough for detail. I cannot tell if it is the 21S (short) or the 21 standard parabolic version. It is not the 21L (long) version. There are performance differences between each of the parabolics and between engine brands. I have all of them and have run them all too.

 

[moparbarn]

anthony, is the pipe drilled around the stinger, down inside the muffled section. if it were an unsilenced pipe, they would be in the rear/convergent cone around the stinger. that would help narrow down which version ab parabolic it is. i"m running an AB billet muffled pipe on my .21 jae/cmb, it LOVES it. 2 versions of that pipe long & short (xs &xt i think). i have the short one. physically smaller than my original irwin S pipe (not the woods/cooper version). i need to compare them one day...........