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Looking at Cobra Speedster Slashdowns for my '08 FXDL. I very much like the look of long, slash cut 2-2 pipes, and I have noticed there aren't many options for this setup compared with how many 2-1 setups you can buy. Talked to one of the indy mechanics I deal with who said that 2-1 is night and day better performance than 2-2 and I would be much happier with 2-1 even if it doesn't look as good. But Cobra says that:
"The Speedsters all share several key features, the first being the PowrPort cross over. This device connects both exhaust pipes from the front and rear cylinders, and promotes improved exhaust scavenging. This produces more power from what looks like a traditional 2-into-2 system."
So, will this cross pipe make enough difference so that I can have the looks and performance I want? Or is it just a gimmick? My guess is it does improve things, but it still isn't as good as a 2-1. I don't have to have the loudest, most powerful bike on the road, but for what full systems cost I want to get my money's worth. What do y'all think? Any advice is appreciated.
2-1's are known to produce more power historically. It's all about the back pressure and where the "pulse wave" hits. There's lots of information on this on the web. I suggest you do some research. It's a good learning process too.
The indy mechanic shouldn't have given such a broad statement. There's plenty of poor performing 2 into 1s out there that can't keep up with many 2 into 2s. Point is, not all 2 into 1s are created equal.
The crossover deal works in theory, but doesn't always translate in real life (at least IMO). I think it really depends on crossover size, placement, engine combo, etc. I think the OEM has it figured out pretty well, though.
I once ran a Khromewerks 2 into 2 (with crossover, V&H baffles) on a bike and it exhibited a torque dip right in the main cruising rpm range. Funny enough, with a non-crossover 2 into 2 V&H setup there was no dip. Similar length pipes, same baffles. Go figure. My one Sportster makes 106 wheel with V&H Sideshots (short 2 into 2 with a crossover). The torque comes in stronger off idle than any other 2 into 2 setup I've ever tried (I've tried a ton). Sometimes I've had the crossover setup work in my favor, sometimes not.
My best advise is to study dyno charts of bikes with the exhaust systems you are considering, preferably with similar engine combos. Will help you see where they excel, don't excel, etc. Once cams with overlap are put into the equation, the good pipes really begin to separate themselves from the bad ones.
all parts must play well together. where the 2/1 shines is in the upper rpm bracket. if you are low key rider, and you like the looks, then eye candy it is. the danmoto i run improved the 6k range the way my machine is setup, really does not come on strong till 4k range.
The problem is that many compare bagger TDs to a 2 into 1 and find that the 2 into 1 wins. As usual they are not looking at the whole picture..
Example.
Which one sucked here? A thunderheader over a stock head pipe and Cycleshacks on a 2000 fxdx. Later I traded the TH for Krome works arIII 2 into 2 and made even more HP.
2-1's are known to produce more power historically. It's all about the back pressure and where the "pulse wave" hits. There's lots of information on this on the web. I suggest you do some research. It's a good learning process too.
Back pressure is never a good thing in an exhaust system but rather a necessary evil.
There's just as many **** poor 2in1s out there that would fall well short of the numbers I just did with TDs. But it's also not just about the numbers. It's about the curve and the area under it. Do I have the best looking curve? Nope. But its pretty damn good and I've sure seen a whole lot worse coming from many of the 2in1s out there. "Historically" many of them have some pretty ugly low end dips in torque.resulting from reversion.
If you WANT a 2in1 there's fine ones as well. I just don't care for the look or the sound of them and they aren't mandatory to making good power.
Someone mentioned Khromewerks. They've been making some well performing stuff for decades and are a favorite of mine as is Rush.
Unfortunately manufacturers like these are discontinuing a lot of good cans/pipes because of misconceptions.killing sales to people who would otherwise prefer a good 212 or TD. I would've ran the Khromewerks HP Plus slip ons on their cross under X pipe in a heartbeat but it doesn't work on Softails. I've seen some real nice torque curves from them that would rival even the best of the 2in1s out there.
To further expand on Max's post because too many here have RELUCTANTLY gone to a 2in1 because they've been told they HAVE to to make good power. How many 107s hit 130hp at all? I did in STD and did 127 in SAE with square torque numbers. Probably would've hit 130 in SAE in an A motor. And while the Pro Streets are loud, they have a nice deep, bassy note to them. Nothing beats the sound of TDs.
I'm not trying to take away from a good 2 in1 to those that want/like them.
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2-2 vs. 2-1
