Interesting. Would have thought the 2:1 would have made a bit more torque?

 

Never heard that one before....
The dip in that area is typical when tuning a 2 into 1 pipe. It's usually spark knock retarding the timing.
Regardless of the air to fuel ratio readout, it needs fuel added and a little timing removed to get rid of the dip there.

 

Who did your tune?

 

The other pulls didn't look like this. Not sure why he printed this one out. He installed an o2 sensor in each primary too. He explained what he was doing, and talked about smoothing and all that. Some of it went right over my head!

 

Why did you choose the pro stock over the black hole?

 

I got a good deal on a used one. Blackhole is supposed to be a tad quieter.

 

Well based on RB's website claims of this pipe I too would have expected a lot more.

How was TMM to deal with? Good dyno tuners or are they just there to collect the buck?

 

I've read a lot of claims (some on RB's website of course) of increased hp and even more torque. My results were indeed different. I like the looks and sound of these pipes. But maybe it flows a little too well for a stock 96" with cams. The pipe might be more beneficial on a 103 with some headwork. Even though RB racing claims this pipe works very well on a stock 96".

Torq Monster Motorworks is a great shop! (used to be Gilberts HD) I've dealt with them a few times. Justen (one of 2 owners) does the engine builds and tuning. He's a very top notch guy that knows his S#it!!!

 

I had similar results when going from 2:1 to true duals. The dyno results are almost exactly the same. The bike runs great and I haven't noticed any loss of power.

 

If you look closely the 2:1 did make "more" torque; maybe not a higher peak value, but it came on a little earlier and carried out a little further than the dual, so a wider torque band means more total torque across the RPM range. I was kind of surprised to see it carry further. Besides the WOT representation here, I would be curious as to the overall performance and drivability comparison at the lower operating range. While the results presented here may seem compelling, they should be considered carefully, the RB pipe has relatively short primary tubes as compared to the duals, and the low/mid 48 cam will respond better to the longer primary system. Do the same comparison with a mid/high cam and performance will lean in the favor the RB pipe. It would be interesting to see what a long primary 2:1 produces on the same bike, like the Fat Cat or Dragos. Even if another pipe produced better results, it still wouldn’t mean that pipe is the best for all bikes, it just worked best on that particular bike. The topic of exhaust is an emotional one for most, not all duals are the same and not all 2:1s are the same, you have to break down the details of the design of an individual system and match it to your cam, displacement, and riding style, too bad those critical details are not published by most manufacturers. Unfortunately most people buy their exhaust based on appearance and sound, with performance being the last priority. A lot of people want to believe the duals are better but there is simply no denying the performance benefit of scavenging achieved by a merge collector, no matter how you slice it. Is it possible that a specific bike can produce better results with a particular dual system than with another particular 2:1 system, sure? With all the variances in primary tube diameter and length, let alone muffler characteristics, it is nearly impossible to have a fair comparison among different production systems. Finding the "perfect" exhaust for your bike is a challenge for sure and one that usually takes a lot of trial and error and wasted money, regardless if your exhaust priority is appearance, sound, or performance.