I am thinking of putting on a set of Dressor Duals on my 2010 FLHR. I already have V&H ovals on my bike and will likely use the same mufflers for the duals. My question is I have checked other threads and some report a small loss at low and mid range but more power at high end. I realize that I have a touring bike and most of my riding is highway miles so I was wondering what the other members think. My ride is stock except for the ovals and I am thinking of adding a Zippers high flow and Thundermax tuner. I am looking for opinions whether they be negative or positive or not. My buddy says I should get the Fuel Moto 2-1-2 instead as I would have the best of both worlds. More power and less heat. I would appreciate all opinons. Thanks
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v&H dressor duals- more power or not
- Thread starter Meso
- Start date
Mariah Chante
New member
Went with the Dresser Duals, Monster Ovals, SE Breather and PCV. I was more after the sound rather than power increase. After installing the package and a map from Fuel Moto, I can tell you that I certainly didn't notice any power loss at all. I did notice a substantial all around power increase in all ranges over the stock setup. No dyno, just seat of the pants.
I've got the Dressers and Hi-Output SO's on my FLHXSE. Friday, my scoot goes in for the EFI tuning on a dyno.
I didn't notice any power loss over stock, but heck, the bike is fast enough as it is. I wanted a nice sound, and a nice look. Both were achieved. After the tuning, any power I lost will be back, and then some.
Now, if I could only find a way to restore the power that I lose from living at 6000+ ft over sea level.....
I didn't notice any power loss over stock, but heck, the bike is fast enough as it is. I wanted a nice sound, and a nice look. Both were achieved. After the tuning, any power I lost will be back, and then some.
Now, if I could only find a way to restore the power that I lose from living at 6000+ ft over sea level.....
your buddy is right. you will have a minor power loss by going with the true duals due to a loss of back pressure. But you will be able to make up for it with the tuner and A/C.
Your best bet is the 2-1-2. gives you the most back pressure and also maintains a good dual sound. Most bikes are going with that set-up now anyway. hear great things about power gains, and heat distribution.
this is not from personal experience but what other guys that have made the change have told me.
Your best bet is the 2-1-2. gives you the most back pressure and also maintains a good dual sound. Most bikes are going with that set-up now anyway. hear great things about power gains, and heat distribution.
this is not from personal experience but what other guys that have made the change have told me.
imported_%TEAM JACOB%
New member
Your buddy is giving you good advice. I will suggest you call Jamie at Fuel Moto & Steve at Fullsac and ask the experts which pipe they recommend and listen to their reasons why.
thanks for the input. I will be attending a rally on the weekend. Hope to see and hear more bikes with close to what I am looking for. That will make my decision easier. Living in Canada the choices are usually Rhinehart with some V&H. I have never seen or heard of anyone with Fullsac and FuelMoto.
Mathilda Rose K
New member
Our Jackpot 2/1/2 head pipe works extremely well. Performance wise it provides excellent low end torque with a nice broad power spread that cannot be matched by a true dual design. This pipe features tig welded 304 stainless steel construction and we offer a lifetime warranty. With both our 2/1/2 as well as true duals you will see a signifigant reduction in heat.
McIntyre2K7
New member
There's so many misperceptions about exhausts, it's an even bigger can of worms than cam design. It's not easy to capture some of the physics in a sentence or two, which is partially why so much bad information keeps getting repeated.
A 2-1 or 2-1-2 system (where the two cylinders merge in a collector) is generally a more efficient system than a true dual system at lower rpms because it scavenges better, not because there's more backpressure. The true dual systems generally gains an advantage at high rpms because they are able to move greater volumes. (these are broad generalities, not a hard and fast rule)
Back pressure doesn't make power. Back pressure is the resistance to airflow due to downstream restrictions, and it hinders power production. Delta pressure, on the other hand, is the drop in pressure that occurs when a gas (or fluid) travels across a piping component. The larger the Delta P value, the higher the pressure drop is, and the faster the exhaust gas will travel through the system.
Make your exhaust tubing too small, and the air flow becomes restricted, slowing the gasses, and increasing reversion at the cylinder, which hurts power production. That's backpressure. However, if the exhaust tubing is too large, the gasses will not accelerate to the maximum possible, which reduces the Delta P value. What we want is the tubing to be just the right size to effect maximum velocity through the exhaust, in order to increase the pressure drop behind the exiting gasses.
So why do we sometimes intentionally try to slow down exhaust gasses? Probably because the exhaust wasn't designed properly, and we're getting wave reversion at the cylinder. Energy waves occur with our exhaust pulses due to the rapidly expanding gasses. They travel down the pipe at a very high rate of speed, and when they reach the end part of it makes a 180 (due to the low pressure of the ambient air) and travels back up the exhaust pipe. The reversion wave passes through the exiting exhaust gasses (which are traveling about 5 times slower), and tries to re-enter the combustion chamber. If the exhaust valve is open, the reversion wave pushes against the incoming fuel/air charge, harming power production. If the exhaust valve is closed, the reversion wave turns around again and heads back out. That is what we want to happen, and eventually the wave will dissipate all it's energy going back and forth.
If our exhaust system isn't properly matched to our motor, the reversion wave can make the bike very sluggish at low rpms. If we install torque cones or lollipops, sometimes we can slow down the exhaust gasses enough to match cam timing. However, a better idea is to have a properly designed exhaust without restrictions, and a properly tuned bike.
A 2-1 or 2-1-2 system (where the two cylinders merge in a collector) is generally a more efficient system than a true dual system at lower rpms because it scavenges better, not because there's more backpressure. The true dual systems generally gains an advantage at high rpms because they are able to move greater volumes. (these are broad generalities, not a hard and fast rule)
Back pressure doesn't make power. Back pressure is the resistance to airflow due to downstream restrictions, and it hinders power production. Delta pressure, on the other hand, is the drop in pressure that occurs when a gas (or fluid) travels across a piping component. The larger the Delta P value, the higher the pressure drop is, and the faster the exhaust gas will travel through the system.
Make your exhaust tubing too small, and the air flow becomes restricted, slowing the gasses, and increasing reversion at the cylinder, which hurts power production. That's backpressure. However, if the exhaust tubing is too large, the gasses will not accelerate to the maximum possible, which reduces the Delta P value. What we want is the tubing to be just the right size to effect maximum velocity through the exhaust, in order to increase the pressure drop behind the exiting gasses.
So why do we sometimes intentionally try to slow down exhaust gasses? Probably because the exhaust wasn't designed properly, and we're getting wave reversion at the cylinder. Energy waves occur with our exhaust pulses due to the rapidly expanding gasses. They travel down the pipe at a very high rate of speed, and when they reach the end part of it makes a 180 (due to the low pressure of the ambient air) and travels back up the exhaust pipe. The reversion wave passes through the exiting exhaust gasses (which are traveling about 5 times slower), and tries to re-enter the combustion chamber. If the exhaust valve is open, the reversion wave pushes against the incoming fuel/air charge, harming power production. If the exhaust valve is closed, the reversion wave turns around again and heads back out. That is what we want to happen, and eventually the wave will dissipate all it's energy going back and forth.
If our exhaust system isn't properly matched to our motor, the reversion wave can make the bike very sluggish at low rpms. If we install torque cones or lollipops, sometimes we can slow down the exhaust gasses enough to match cam timing. However, a better idea is to have a properly designed exhaust without restrictions, and a properly tuned bike.
C
"Cooool."
Guest
A well designed true dual system will not lose power when compared to the stock header system at any rpms. The good 2-1 and 2-1-2 systems may have a slight advantage at low rpms, and the true dual systems might have a slight advantage at high rpms, but on the street, it's often difficult if not impossible to feel the difference in performance between the two. A couple of ft/lb difference at 2500 rpms cannot be felt by the seat of the pants.
I put the fullsac conversion on my bike earlier this year. I was running SE 65115-98 slip ons at the time. If there was any loss of torque at low rpms, it wasn't noticible. When I swapped the whole system for a Rinehart true dual system, it felt stronger everywhere.
A riding buddy of mine put a set of Rinehart true duals on his 07 CVO glide, and had it dyno tuned. He gained both hp and torque all the way across the band, adding almost 11 hp and an equal amount of torque.
For the OP. I found a dyno chart from another member who changed from stock headers to V&H true dual headers, keeping his V&H Ovals. It's pretty clear that he suffered no loss of torque as a result of changing to duals.
I put the fullsac conversion on my bike earlier this year. I was running SE 65115-98 slip ons at the time. If there was any loss of torque at low rpms, it wasn't noticible. When I swapped the whole system for a Rinehart true dual system, it felt stronger everywhere.
A riding buddy of mine put a set of Rinehart true duals on his 07 CVO glide, and had it dyno tuned. He gained both hp and torque all the way across the band, adding almost 11 hp and an equal amount of torque.
For the OP. I found a dyno chart from another member who changed from stock headers to V&H true dual headers, keeping his V&H Ovals. It's pretty clear that he suffered no loss of torque as a result of changing to duals.