Supertrapp Supermegs Pipe Test - Mild 1250

[aswracing]

The above is using 30 discs


The above is using 25 discs


The above is using 20 discs

This bike is a 2007 XL883 with the following mods:

• Supertrapp Supermegs Exhaust System courtesy of mikeLI_77
• HAMMER PERFORMANCE 1250 kit (big fin version) with trick 30 degree reverse dome pistons
• HAMMER PERFORMANCE SMASH Head porting on the factory original 883 heads
• HAMMER PERFORMANCE IMPACT 560 cams
• HAMMER PERFORMANCE Air Hammer Air Cleaner
• DynoJet Powervision with wideband tuning kit used for tuning

Compression ratio is 10.5:1 and it's running on pump gas.

Comments:

As with the other recent tests, these are all 4th gear pulls.

Installation was straightforward, and it fit well, but man, that's some weird configuration for the oxygen sensors. I got'em on there, barely, but I really question whether you could actually run widebands on a street bike using this pipe. Pics to come, you'll see.

The pipe came with 20 discs. Mike included some extra discs so I was able to test all the way up to 30. With 30 discs, the screws were getting pretty short and there wasn't a whole lot of thread engagement, maybe 1/4". So I didn't feel comfortable going higher. I probably wouldn't even run 30 with the included screws on a street bike, but I figured it was OK for testing. If you get this pipe be sure to buy more discs and longer screws. Screws need to be stainless. Use generous amounts of anti-sieze every time you put it together (a small amount is included with the pipe).

Quietest pipe I've tested by a wide margin. Even at 30 discs, it's still a relatively quiet pipe.

Mapping took awhile because I was trying to keep the muffler from yellowing and that meant stopping and letting it cool at a lower temp than I normally would during tuning. I'm afraid I still got a little yellow creeping into the muffler. I've got a Supertrapp on my Dyna and it looks about the same, so expect it. The head pipes and collector got a lot of color into them, but of course, they're covered by heat shields in the normal case.

I did a total of about 170 pulls today between the Patriot and the 3 configurations of the Supertrapp. About 6 hours work altogether counting pipe swapping, mapping, and WOT pulls. I tried very, very hard to get every last .1hp out of each configuration, there it is.

You don't really see the top end changing much between the 3 disc counts, but you sure see it through the bottom and middle. Taking discs out makes it go more and more toward a dual torque peak shape, with a sag in the middle. Standby for a horsepower comparison chart.

[PiousDevil]

these threads are like christmas

[aswracing]

And of course, the comparison to the reference pipe ...



The Patriot remains undefeated on the top number. That's really remarkable considering all the good pipes we've put it up against. And it's not like it's bad down low or anything. Some pipes are a little stronger down low and/or through the middle, but not by a lot. The Patriot is just a really, really well designed pipe.

[sportsterpaul]

Aaron, was this with a closed end cap or open?

[aswracing]

Originally Posted by sportsterpaul

Aaron, was this with a closed end cap or open?

Closed. You don't want to run an open end cap.

[Screw Loose Dan]

Good stuff Aaron! And thanks to Mike for loaning the pipe!

[sportytrace]

That's a real pretty torque curve with the 30 discs. It's very interesting to see how the discs change the shape low to mid-range.
Thanks again Aaron for your time in testing these pipes. And thanks Mike for sending and sharing your new pipe!

Does the mule ever get out in the fresh air to see the views of Idaho?

[aswracing]

Originally Posted by sportytrace

That's a real pretty torque curve with the 30 discs. It's very interesting to see how the discs change the shape low to mid-range.
Thanks again Aaron for your time in testing these pipes. And thanks Mike for sending and sharing your new pipe!

Does the mule ever get out in the fresh air to see the views of Idaho?

It's kinda funny, we actually licensed the mule and got insurance for it, but it has yet to turn a wheel on the street since we owned it

Fortunately, we have other bikes!

[aswracing]

The other interesting thing about the torque curve ... look at the reversion way down low. You can really see it well in the 30 disc chart. Reducing the discs is making it go away. But reducing the discs is also causing a big hole in the middle.

I can't see going down to 20 and certainly wouldn't want to go less. Even though you're getting a little more at the very bottom, it's just killing the motor elsewhere.

It'd be interesting to see what it would do with more than 30 discs. My guess is, that real low end reversion would get worse, but it's so far down the rpm scale it doesn't really matter. I'm curious what it would do in the middle and on top. But 30 discs is already a real big block of stainless to be hanging off the back by those little screws. There's gotta be a limit to how many you can hang on it before something breaks off.

[rubine]

Thanks again Aaron for your time in testing these pipes. And thanks Mike for sending and sharing your new pipe!

I second that.. Its really great to have this kinda information put out there for everyone to see.