Does anyone have any dyno numbers of a 103 with the Cobra power port dual headpipes, and the 4" race pro? I've heard the 103 likes more back pressure. Would this combination open it up too much and cause it to lose HP?

 

No, you would lose torque that you would definitely feel in the seat of your pants. The duels won't kill you, but the large baffle on the pipes will. I was seriously considering Cobra's because I love the sound, but after talking to Drago, Fuel Moto and V&H, the consensus is unless you have a real radical build and want to tach it out all the time, any baffle larger than 2" will cause a serious tq loss. Fuel Moto even suggested a 1 3/4" baffle for my build.

 

So the Header pipe would be OK, but the 4" slip on would cause me to lose torque. That's not what I'm after. I want more sound, but the other reason for pipes is for performance gains not a loss. What is the best header, slip on combo for the the best sound / performance gains? I really like the look of the duals. Do you have to go to a 2 into 1 to get performance gains?

 

You will get the absolute best performance from a 2-1. Almost everyone will agree with that. I had one of the best performing 2-1's and I went back to a 2 pipe look because that was the look I was looking for. I am using the FM X-pipe header and dual mufflers and felt very little difference. I may have left a couple of hp and/or lbs. of tq. on the table. I dynode at 110 hp and 119 tq. I can live with that. To answer your question, the dual pipe will not hurt you. It's not the size of the pipe, but the size of the baffle. If I'm not mistaken, that Cobra has a 2.5" or 3" baffle. That's why they get that deep rumble we like, but you WILL feel the loss of torque with that big a baffle.

 

They do have a 3" baffle. Is there a slip on that has a smaller baffle, yet still has the deeper tones than stock?

 

I say unless your bike is going to spend its time on a dyno or a racetrack, or you have something to prove to your buddies racing red light to red light, a few ft.lbs of tourqe or a few ponies don't matter for squat at the end of the day. I just ran the Cobra true duals on mine and everyone kept telling me how bad it would run. They were full of crap. It runs cooler, sounds better, and what "little" it may have lost on the dyno. it was well worth it everywhere else. My seat of the pants dyno feels no difference at all!

 

If your refrencing better performance over stock, your original setup ( Cobras & Rineharts ) will be more performance than stock.

Now if your looking for everything you can get tq/hp you should talk to your dyno guy. Remember you could take the same set up to two different dyno guys and get totally different results.

Someone who has a lot of time in the booth knows what works and what does not for each individuals needs. JMO.

 

That's the kind of real world input I'm looking for. I was getting the impression I would lose power over the stock set up. That would be crazy to spend close to $2000 with AC, header, pipes, and tuner to lose power.
I'm not after every HP I can get. I came off of an EVO and the 103 will run off and leave it on top end, but the bottom end torque just isn't there like the old EVO had. So losing more torque had me concerned. The EVO had true duals and screaming eagle pipes, and AC.

 

I have to respectfully disagree with ga. mason. You might not feel any difference with the 3" baffle if you still had a cat, because it creates the backpressure you need. But if you decat or go with any aftermarket header, you will lose a LOT of torque under 3500-4500 rpms and I guarantee you will feel it.

 

Yeah, those Cobras and some other newer mufflers have the big 3" baffles because they are designed to be used for headpipes with the cats still in. Thing is they don't advertise that since they want to sell them to everyone, and not just to those with catted headpipes.

I've heard a couple of builders say that the Kuryakyn Crushers are good mufflers that make power. I run 4" Rineharts (2.25" baffles) with one wrap of muffler packing held against the inside of the muffler with Fullsac screens (not wrapped around the core), and for my build, I don't think I'm leaving any hp/tq on the table.