I hope I'm not opening up another huge can of worms here, but here's my dilemma.

I have a 2017 Fatboy S with 4,300 miles on it. These Screaming Eagles S series bikes come with the 110 SE engine and high-flow air cleaner.

I installed a Vance and Hines 2-into-1 Pro Pipe.

I know I need a tuner. I want my warranty to be good, so I am going with a HD Pro Street Tuner. I know there's better stuff out there, but I'm going with this one. And I know there are better people out there than the guys at the dealer to do tunes. But I HAVE to go with a dealer -- that friggin warranty again.

So -- I'm calling around dealers in my area for quotes, and the difference in price is big. The ones that want the most, obviously, are the ones who insist I need a couple of dyno runs.

But, do I? A couple dealers say no.

I'd love to hear your input and experiences.

 

Do it as many times as it takes them (the tuners at your dealership) to get it dialed in. I'm sure it will be expensive, but if they need more runs you'll have to do them anyway or be stuck with whatever 1 run tune they give you.

Usually more runs will yield a more dialed in tune.

 

If you have the funds, a dyno tune is never a bad idea. Even with just pipes, getting it dialed in "just right" is a good thing.

 

#1 question I would ask is if they are tuning to the epa required air fuel ratio or for best performance.

 

Well, not necessarily.

First thing I'd do if I were you, is just get the SEPST. That's the one you want, that's the one you've decided on, so just get it and put in the best-matched calibration it offers. Then run some auto-tune sessions -- it's free, and it'll help the SEPST get the tune dialed in as much as it can. If it runs fine after that, then you don't necessarily need a dyno tuner, because the range on the SEPST isn't all that great and there may not be that much more a tuner could squeeze out.

However, if you decide you want to get it professionally tuned, don't just settle for a dealership. There are independent dyno tuner guys who would probably be willing to do a tune for you using the SEPST, with the understanding that you are acknowledging that it's not going to be the best tune they ever did; it'll be what they can get within the EPA-restricted SEPST's range.

(and note, I'm using SEPST for "Screamin' Eagle Pro Street Tuner", not the other SEPST Pro Super Tuner).


Second, on the warranty -- it looks like you're not racking up the miles super quick, so there's a secondary warranty that may be of interest to you, that your bike is covered for: the five-year EPA emissions warranty. That lasts for five years or 18,641 miles (30,000 kilometers) and covers pretty much anything that affects emissions, so -- your warranty considerations may be well-grounded as you might be able to use that EPA warranty for several years to come.

 

Harley's all ape-**** over the huge EPA fine they had to pay, so I'm sure they're concerned mostly with compliance.

 

It is a waste to get the bike dyno tuned with that tuner

 

Thinking about it, that alone could potentially void your warranty. That's not a street-legal pipe, so your bike is already in a non-compliant state. I'm not saying they WILL void your warranty; I'm saying that they certainly could if they felt like it; the language in the warranty allows them to.

Just something to consider, if you want to keep your warranty intact. And if you decide you're keeping the pipe come hell or high water, then you might not be so concerned about the Pro Street Tuner? Your call.

 

First... I'd question how your warranty will remain intact once you put those presumably non compliant V&H pipes on it. AFAIK the consent decree started with 2017 models. Also remember, no matter what the dealer tells you, the dealer does not offer, provide, grant or deny HD's manufacturer's warranty. Only HD does that.

Secondly, as alluded too already, that SEPST isn't worth much. Putting warranty concerns aside, doing stage 1 tuning on a dyno with that thing would seemingly be a waste. Since EPA compliance is the name of the game, the unit will likely not be able to do much. You'll likely have to step out of EPA compliance (in the AFR, Spark, and various other tables) to be able to tune for best performance.

If maintaining the warranty is a must, and if installing the V&H pipes will void it, then that leaves you little in terms of options. You'll be limited to HD approved hardware (SEPST, HD approved exhaust/slip-ons, etc.). Once the HD dealer does the dyno tune you'll be left with your VE tables calibrated and the rest of the tunes tables (AFR, Spark, etc...) constrained by EPA compliance.

If warranty isn't an issue and you want to use whatever aftermarket hardware you chose, the again, using the SEPST would seem to be a waste. You would be much better off with a good aftermarket tuner - PV or TTS. With those tuners, in competent hands, there will be no constraints and you'll be able to achieve the best possible performance results.

As to the notion of "Auto Tuning". THERE. IS. NO. SUCH. THING. What there is - is an attempt (let me re-emphasis - it's an attempt) to Auto Calibrate the VE tables. That's "essentially" all it does. That in itself does not constitute a "tune" or "tuning". Some might say that the notion of "Auto Tuning" is a marketing gimmick to separate the ignorant from their money. Maybe - but whatever. Anyway, to state it another way, if you think you can go out and buy one of these tuners, install it, press the little "Auto Tune" button, and the thing will then "tune" your bike for you, then you are sadly mistaken.

Also that Smart Pro Tuning Module (with wide bands) is seemingly also a waste for various reasons - to include the notion that it will tune your bike with "Auto Tune".

To be fair... Yes the SEPST can get the VE tables back into calibration after an install of something like the V&H pipes, but again the resulting tune will be constrained.

As to the original question about needing to dyno after installing the pipes. Installing the pipes will introduce new error in the VE tables. Will that newly introduced error be significant enough to require re-calibration of the VE tables? Perhaps. I would probably re-calibrate the VE's one way or another. The best results - in that regard - will be achieved with a dyno. Can you get reasonably decent results (A.K.A. close enough) with "auto tuning"? Meh? Perhaps...

 

I bought and dynoed with a powervision 2. It saves the stock tune. You can flash it back for warranty work, and flash you custom tune back again after.