Mufasa Dyno Day

So I just got back from Nels, horrendous traffic on the way back so didn't get to play much at all, but we spent 3 hours strapped down working on various things. We experimented with a bunch of things and found a few good pieces of information.

1: We tuned it with my 4.5" velocity stacks and got the final numbers for that. Threw on the short stacks I have, similar to the stock ones, and LOST a good amount of torque everywhere under peak HP, though the peak remained similar. Interestingly, it did gain power after peak, but at this point your already in the over-run area where power is falling off, so not terribly useful.



2: PX-500 on vs PX-500 off = 1 less whp and 3 less lb-ft, so not a huge amount.

3: The crankcase evacuation system I made is doing it's job, but, there's a restriction elsewhere (probably the intake cam) holding the bike back. Numbers were only +1.5whp and -1lb-ft (somewhat within the margin of error), so essentially the same, but the engine is far healthier having all that acidic crap sucked out the exhaust than pooling in the crank case, so it's staying.

4: The 450cc Bosch injectors at 4 BAR (531cc at 4BAR) make quite the show when doing work! They're exceptionally easy to tune compared to the stockers or the modfied Siemens Deka 550ccs I was using previously. I filmed this with the short stacks so it would be more visible while we were testing the shorties.


5: In confirmation of my theory from 2016 that basically everyone shot down and called me crazy for, we did a 5th gear pull on the dyno after all the tuning work was done. The bike swung SUPER lean right at 4700 RPM and he backed out by 5200 where it was still lean (it went from a good solid 13.1 AFR to 15 with only a gear change). So, we made a by-gear PC-V map and fattened 5th up by 15%, sure enough, works great. SO!!! There IS a weird scenario with the roadster v2 ECU 20776 MAPs and 5th gear fueling, hidden from view in TuneECU, that causes 5th to lean out. Glad he found this!

6: Ignition timing in the 9,000 RPM Carpenter map is garbage. It has too little timing in the 30%-80% throttle areas from 3,000-6000 RPM, added 7 degrees and the engine smoothed out dramatically. instead of wavy part throttle charts (you can feel it as the bike bucking a bit), now they're super smooth. We also found that the 17 degrees at full power there leaves about 15 HP on the table. By going to 21 the bike gained, smoothed and is just happier. We tried 23, no gains at all, but no losses, so 21 is not on the edge, it's the sweet spot.

7: COP conversion performed as it should, didn't help, didn't hurt. No reason to do it unless you have a reason besides power i.e. cleaning up under the tank, making space for other items, bad coild and COP is cheaper etc.



With this, I call Mufasa DONE for now. This has validated a lot of things, next trip to Nels Mufasa will be wearing a Sidewinder with the exact same tune, I'll ask Nels to dial it in, and we'll get a real comparison using the same bike, same dyno If it makes more with the sidewinder, I'll layout for a can of VP oxygenated fuel and see what it makes.

One more point I'd like to make, any AFR richer than what you see above lost power. 13-13.2 made best power.

50% throttle made 170hp/152lb-ft
60% throttle made 200hp/170lb-ft

Knowing that answers a lot of questions about launching in 1st for me, specifically why instinctually I can't get my hand to go past 70-80% in 1st, cause its making a **** ton of power already lol.

Here's new and old laid over each other, I miss-rememberd, gained 1.5whp lost 1lb-ft, so definitely within margin of error. I may not be error though, evac systems are known to rob a bit of torque in exchange for HP so who knows. Interesting how timing curves can change things isn't it?

Excellent write will also be interesting to see the difference with the sidewinder, good job please keep up the great work.

Is this still with the Carpenter short duration inlet can?

It is indeed still the carpenter baby cam. I want to get the sidewinder comparison done, then after we do our many thousands of miles road trip in October, I'll add in the man sized cam and test with whichever pipe makes better power Will give me a 12,000 mile built engine inspection point, conveniently.

Great write up again.

I do enjoy reading about your obsession with power.

Funnily enough, it's the learning that keeps my interest. The fact my bike gets better and faster as I go is a desirable side effect.

Hold up. I must have missed something on point #6. I seem to remember you having 250+ hp before. Now you're saying that adding timing at the top added 15 hp. Shouldn't you have 265+ hp now instead of 252?

Maybe when people purchase a Rocket, there should be a warning on it like medication:

"May have side effects"

1. Lust for mods and power gains.
2. Sore facial muscles after sustained silly grin.
3. Lengthened forearms.
4. Improved grip strength.
5. Puckered sphincter.
6. Ability to loose annoying passenger at a flick of the wrist.
7. May cause stress and sleepless nights to Harley riders.