anyone know if there is significant hp gain by installing true duals over a set of slip ons only ? I planned on purchasing a set of Reinhart slips ons and am planning on installing a stage II kit later on - would the true duals make much of a difference - sorry if i am sking something that has been discussed but i looked and couldnt find anything on this - i am riding an 09 street glide

thanks

steve

 

Here is what I was told. And please if anyone knows for sure, please correct me.
I also ride an 09 SG. The dealer told me that technically what is on there are true duals.
He said that when the pipes go together ( you know the whole 2 to 1 to 2 design that is new on the 09's) that the 2 pipes are together, but not into 1 pipe. Each pipe is its own pipe, they are just designed together where they go from 2 to 1.
Does this make sense? Not sure if I am explaining it very well.
If anyone know for sure, please let me know. I have always wondered if what they told me was true or not. The service guy that told me this didn't sound to convincing.

keep the rubber on the pavement,
orfy

 

Service guy is wrong. The 2 pipes come together. I have my stock headers hangin on the wall in the shed, I can take some pics of inside if you dont beleive me.

 

Duals make HP and lose some TQ. 2-1 (or 2-1-2) make TQ and sacrifice HP.

2-1(-2) for getting started quickly, duals for top-end.

 

Does anyone know if that is true? I would have thought that scavenging will improve flow thru the whole rev range?

 

I recently asked the same question and a search of the forum turned up some conflicting information, mostly be people who like to speculate rather than actually know, if that makes sense.

I talked to a very reputable and well thought of forum vendor that has an excellent reputation. They recently dyno'd a 2009 SG stock headpipe as well as both dresser duals and V&H power duals on the same bike, same day, same dyno and same dyno operator.

No power gains from the aftermarket head pipes. They could have easily lied to gain a sale as I was ready to spend but instead they gained a customer for life. I LOVE dealing with vendors like that and will continue to do so for a long time, and I like spending money.

I had heard that the 09 headpipes were pretty good, and this confirmed it for me so I just ordered slipons and called it good.

 

i assume that means the "slip-on" basically only improve the sound !

steve

 

Nothing is ever true across the spectrum like that. Different combos and what not will react differently and I doubt the dyno would even prove it out to be true on half the bikes out there. Too many guys use seat of the pants wishful thinking dynos and repeat what they read on here so they sound like they know what they are talking about.

I prefer facts. My 2 cents.

 

I recently installed the new khrome werks 3.5 touring mufflers. I have not dynoed it yet but there is definitely better throttle response especially off the line. They are very deep sounding but also very quiet. A little louder after a couple hundred miles. I considered true duals but don't want to loose bottom end.

 

The 09 headpipes are already a 2-1-2, so V&H power duals wouldn't be expected to do anything.

If the folks at Fullsac can be believed - based on their dyno testing, even the stock headpipes on CA bikes (with catalytic converter) do not restrict flow enough to alter performance on a stock TC bike.

The test described above apparently did not include a 2-1 system.