next time you get together do some 5th or 6th roll ons from say 60mph and see how they compare. I was back and forth between the 255's and 254's but Rich67 made my choice a little easier.

 

There is nothing here that surprises me, except the dyno numbers, and you can't expect runs done a week apart, let alone a year apart, to be an accurate comparison. The next "test" you mention will show the same results. Anytime you let the bikes run the 254 will out run the 255. For short bursts, low in the power band, the 255 will feel stronger. In tight mountain riding (I live in Colo too) you'll have to keep the 254 at 26-2700 rpm or better to stay ahead of the 255's. I wouldn't recommend pulling any grades at lower revs than that anyway.

 

We have some good trips planned this summer, Sturgis being one of them, so there will be alot of comparisons be done. The difference in pulling power is what surprised us both as mine hits hard and signs off, The 254 bike is so mellow it does not seem to be pulling that hard, But it runs mine down pretty quick. it's deceiving how fast it is.

 

Like Ocezam, I'm not surprised by the OP's report except that I wouldn't expect the 255's to produce higher peak-HP numbers. OTOH, peak HP and TQ numbers alone are practically meaningless to me without knowing the shape of the curves. Pitting a 255 and 254e bike together in a quarter-mile drag race or a 2nd-gear romp, all other factors being equal, would have me betting on the latter bike to be ahead at the end. This is because almost any aftermarket cam will outperform the 255's above 4500 rpm, and in a drag race you are probably in that range at all times except briefly when coming off the line.

But we all know that peak-RPM performance is not the design goal of the 255 cams. They are unabashedly a low-to-midrange torque profile, and nobody tries to push these off as racing cams. Well, nobody except HD who at times in the past has labelled them "For race application only," but that translates into "Your warranty may be kaput," and "We don't certify them as EPA compliant for street use." Nobody will be recommending them for competition use, except maybe a stump-pulling event.

Echoing Ocezam's comments, another observation is that comparing the dyno numbers of two different bikes dynoed a year apart is questionable, and many factors like humidity, temperature, and probably the alignment of stars and planets can alter the results. Just for kicks, take the bikes out and crack them off at 50mph in 5th gear, a real-life scenario that simulates passing a truck without downshifting, and compare the results. Unless drag racing is an important activity in your life, maybe passing a truck or pulling up a mountain grade with minimal downshifting is really something more applicable to daily life on a touring bike. Not everyone would say "yes," but many of us would.

I think the two bikes may produce similar TQ numbers with the 255's peaking at a lower RPM and the 254e curve extending out further to the right of the chart. You've stated that the 255 bike has the nod on the low-end, which should be no surprise to anyone. I'll also bet that the 254e bike is really producing more peak-HP on a given day.

 

I'm not sure I've missed this somewhere in the thread... Are the bikes 96's or 103's? With the small bump in compression of the 103" I'd expect this comparison to favor the 254e to a higher degree in the 103's. I believe the perceived "lack of a bottom end" with the 254 would be non existant, and the added top end of the 254 would be even more noticeable.

My SE203's were not my cam of choice, but were virtually free from a friend (Thanks Rich! He's known as PuttNutt24 here on the forums). I was pleasantly surprised at the increase in torque below 2500. I did not expect it and wasn't searching for it but it is there. I attribute this to the small bump in compression of the 103". The added bit of compression simply makes the motor more accepting of a wider range of cams.

 

Both bikes are 103", and close to the same mileage,

 

Interesting information, thank you.
I'm wondering what the difference in MPG is between the two bikes. Perhaps you can post that after you two get back from your trip.

 

I have a 2012 FLHX with the 254e cams, and it starts to pull way before the earlier mentioned 3500 RPMs.

 

do you have a dyno graph and what kind of mpg are you getting? I am just waiting on my gasket kit to get here as well as the tools to install mine.

 

I don't have it dyno tuned yet, I have the SEpro tuner with the canned setting right now. I will get a dyno tune this spring. Guess I haven't checked mileage either sorry not much help.