Articles & photos


883 with the 1250 kit hit 100 HP Mark

21-12-2012 - Hammer Performance is testing our Torque Hammer exhaust on a stock Sportster 883. And later on a 1250 build and maybe a big bore build. They are the first to hit the 100 HP mark with there 1250 Kit.

Here is the stopry from Aaron at Hammer Performance on a 2007 883 Sportster. Twin Motorcycles is a Hammer Performance Partner to. The parts can be bought through us to.


Twin Motorcycles sent me a Torque Hammer pipe to test, and I've finished the first test, which was to see how it performs on an 883:



In red is the bike bone stock, an 07 883.

In blue is the same bike equipped with a Torque Hammer pipe and an Air Hammer air cleaner (3" offset style), as well as a tune loaded with TTS Mastertune.

Some items of note:
This is an 07 883 and is a bit weak, making slightly less power than a typical stock '07 883 (and I had to really beat on the bike to even get that 46hp number). However, the power gain from stock is almost exactly 30%, which is what was claimed for the pipe. So in terms of percentage gain, I can confirm TM's claimed result.
This result is after tuning. Before tuning, using the tune as provided by TM without changes, I got 57.4hp.
Tuning consisted of timing and fueling adjustments using TTS Mastertune, starting with the TM provided tune. The cylinders were tuned independently for a flat 13:1 afr. They weren't all that far out though. Timing was also adjusted. Most of the improvement from 57.4 to 59.9hp came from the timing adjustment. The motor wanted 31 degrees total advance and the provided tune had 37.5 degrees.
The muffler was equipped with a baffle in it's tail piece for the above pulls. Some testing was also done without the baffle or tailpiece. I'll show that result separately.
I also tested just the air cleaner, without changing the pipe (stock pipe still in place). I didn't spend a lot of time dialing it in but it was making around 53hp.

The Torque and HP Graph below



One of the things I did was go ahead an put the Air Hammer air cleaner on before I swapped the pipes. I then tested with the stock tune and with the TTS canned tune that's designed for stage 1 type bikes.



You can tell by the a/f curves that I didn't do much tweaking on it, but here it is for what it's worth. With some more work I'm sure I could've got the red line into the 54's, 55's would be doubtful. So that shows you about how much of gain comes from the pipe.

Sure, I can do torque curves ... I generally avoid putting too much onto one sheet just because the sheet gets too busy and it's hard to see what actually happened. So when comparing two configurations, I usually just show power or torque on a sheet, but not both.



Here's another sheet y'all might find interesting:



In blue is the final result, after tweaking the TM map.

In red is the initial result, using TM's tune as provided.

The top end gains in particular came largely from taking out some timing. All I can figure is they have slower burning gas in Nederland. 37.5 degrees is way too much for any XL I've ever dyno'ed. The blue has only 31 degrees

Here's what the Air Hammer Airfilter alone did for the 883:



Like I said, I also tested the Torque Hammer with and without the baffle:




Forcewinders have always really impressed me, they perform much better than you'd expect them to with that itty bitty element. The length of the tube is something the motor likes. You just have to watch out for the bowl vent issue if you use them with a CV. But other than that, it's a good air cleaner. Not as good as the AH, but the AH has a ton bigger element.




OK, so tonight we tested the Torque Hammer pipe on a mild 1250 build. Here is the result 100.9 HP and 82.1 ft/lb SAE corected on the REAR wheel.

This bike is a 2007 XL883 with the following mods:
Torque Hammer Exhaust System from Twin Motorcycles
HAMMER PERFORMANCE Flat top 1250 kit (big fin version)
HAMMER PERFORMANCE SMASH Head porting on the factory original 883 heads
TTS Mastertune used for tuning

The bike has the stock lifters, pushrods, rocker arms, valve springs & hardware, throttle body, intake manifold, ignition coil, etc. Compression ratio is 10.5:1 and it's running on pump gas.

As you can see, the double torque peak became much more pronounced at the 1250 engine size than it was in the 883 result. Generating double torque peaks like this is a technique that 2 into 1 pipe designers often use to broaden the powerband. It's very effective at producing both bottom and top end, so long as they don't let the drop in the middle get too bad.
This is not some ringer set of heads, this is the standard SMASH service we perform to 883 heads for $750. It includes new high flow stainless steel valves in the 1.760" intake and 1.530" exhaust sizes (stock are 1.580/1.350) as well as the CNC port and valve seat work. This particular set of heads flowed about average for SMASH 883 heads, or even on the low side of average. They all come out in a pretty tight range though.
This bike has a steel rear wheel and pulled about the same peak numbers in 4th gear as 5th gear.
I was actually surprised at how easy it was to hit 100hp. Right out of the box, with the motor still pretty cold and the tune way out in the weeds, it made 92.5hp on the first pull. Minor tweaking of the a/f and a good warming put it into the 97-98 range. After fine tuning we were banging off 100hp pulls left and right, some in the 101's and even a 102 without the air cleaner.

So here's a summary of this pipe testing so far:

The current 1250 configuration is shown in blue (1250 kit, Smash head work, Impact 560 cams, Air Hammer air cleaner, Torque Hammer pipe)

The 883 configuration is shown in red (stock 883 with Air Hammer and Torque Hammer)

The stock 883 is shown in green.

Here is the same comparison for torque:



Here are 2 sheets to see hoe the baffle for the sound effect's the performance. It's a good Exhaust with baffle and still makes a shit load of HP and Torque.

When you wanne go wild for the sound, just take the baffle out and look at the midrange (: