I wish I could post the actual charts, but this dyno only creates DOS files, and I have no idea how to post that. Anyway, this is the summary of the results.
Four end caps were tested. Two designed and built by Fourlix[one with a 1.5" outlet, one with a 2"], one designed by my fab shop owner, and one stock cap. The bike they were tested on had a Team Pami ignition box, and a K&N filter on the carb, but no other mods. Let me start off by saying, this is what I would call a Monday bike, as it seams to produce more power than it should, even with the stock end cap. Here are the numbers, from worst to best-

Fourlix 1.5" cap: Max HP-47.9, Max torque-43.4 ft/lbs. Although this cap had low rpm readings and high rpm readings that were equal to the stock cap, the peak power and torque fell flat and failed to equal the stocker. It was also somewhat louder than stock, so there is no area were this end cap has an advantage.

Stock end cap: Max HP-50.8, Max torque-45.5 ft/lbs. Remarkable #'s considering it's a stock bike. I knew it was dialed in, but I didn't suspect it was that good.

Fourlix 2" cap: Max HP-51.2, Max torque-45.4 ft/lbs. this cap held about 1 HP over stock all the way through the rev range untill peak at 6700 RPM. At peak, the advantage dropped down to .5HP, but from peak on to the end of the pulls, at 8400 RPM, it help a 2 HP advantage over stock. This consistant advantage speaks very well for it's design, but it is a good bit louder than stock, and would not work in noise restricted areas.

Knutz Cap: Max HP: 51.8, Max torque: 46.8 ft/lbs. Although this end cap only produced 1HP more than a stock cap at peak, and help a 2HP advantage from peak on up to the end of the test, the results below peak are better than expected. At 3500 RPM, this end cap actuall made 8 HP more than the stock cap, and 13 ft/lbs of torque more. It uses a 3" pipe on the outide of the cap, but is actually just 2.5" internally. It is slightly louder than Fourlix 2.0" cap, but no were near as loud as a Big Gun exhaust.

I'm not sure if I will produce these caps or not, but wanted to share the results with you all. It seams that a poorly designed cap can actually hurt your performance, despite what it may feel like. I did not expect any of the caps to do worse than stock, and thought they all would produce better peak #'s. The theory about a smaller output helping boost low RPM torque is out the window as well. The largest outlet made the best low end #'s by far.

I'll see if Vegas650[Sandpig] can post some pics of the end caps for me, so you can all see what the designs look like. Fourlix didn't try to make his pretty, he just wanted to test the design. If I can figure out how to post the charts, I will.

 

WHat bike is that on?

 

Don, how do these results compare to the aftermarket full and/or slip-on exhaust numbers? Higher,lower,close?

Thanks for the test results!

Steve

 

8 hp and 13 torque? THats a nice gain for an end cap! From what I have seen.....more full exhausts don't add a lot on top for the DS either. You may be onto something there.

 

Knutz, Great! info.
All the endcaps I have out their were 2.5"ID. I wish I would of sent you my endcap for this test(my bad). How does these Endcaps compare to a quality slip-on(on the same bike)?



Biggerisbetter.

 

Due to the fact that this bike runs so much better than most bikes, even with the stock cap, I can't tell you for sure. I've never had an aftermarket pipe on this bike, and the only one I have laying around is a Ron Woods Racing pipe. From the claims of most pipe manufacturers, my end cap seams about equal to them on the peak #'s, and outshines even them on the bottom end. I find it hard to believe too, but I have the charts here in front of me. Each cap was tested with 2 runs each time it was installed, and each was installed twice, just to ensure consistancy. Jetting was kept the same for each cap, as it seamed ideal for all.

To try to compair it to aftermarket pipes would be increadably difficult. If I compair it to this one, then someone else will want it compaired to that one. If someone wants to bring their [near] stock bike to town, with pipes[stock and aftermarket], and pay for more dyno time, I'd be happy to work with them on it. I currently have a stock pipe that can be used with my end cap and a stock cap, I have a Custom X exhaust that could be tested, and I have the Ron Woods pipe. I have to send back Fourlix's caps eventually[when ever he wants them now], and the bike I was using for testing is being sold and I'm building the motor up, so it' will no longer be available.

 

ONCE AGAIN ~ what bike are y'all talking about? and with which pipe?

 

<< ONCE AGAIN ~ what bike are y'all talking about? and with which pipe? >>


The DS650 with a stock pipe.

 

Thanks Knutz!

I have been experimenting with different end caps on my White Bros. pipe as well. Haven't done any Dyno's tho. Just dynoed by the seat of my pants!LOL

 

Knutz, I personally don't find it that hard to believe, I have rode with many DS's with ALL kinds of exhaust systems, and I have faired well enough NOT to go buy a $$$$ slip-on. And I'm NOT just talking about the drag-strip. I'm more impressed with my Endcap in the trails/tree-shots. The torque is good enough to make up for my short-comings as a rider in a difficult climb.

I am even More pleased now that you have proved my beliefs on a Dyno. However I do also believe that the Stock/modded Exhaust may come up short with a higher performing engine (703). But maybe intime you can answer that question as well.

I hope that you do start making the Endcaps, so people can spend the money they save on a CARB or a CDI![img]i/expressions/face-icon-small-happy.gif[/img]


Biggerisbetter.