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Discussion Starter · #1 ·
Hello fellow V-Roders. I have a 2010 NRS stock. I am thinking of installing Akrapovič exhaust with DNA filter and topless. My question is, PCV with readymade map or PV? I know that PV with TT is a really good combo but I don't have access to a proper dyno or a highway for a proper auto tune. Does anyone have a map that can share?

Thanks
 

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Either will be fine. I would highly recommend you buy from Fuel Moto. If you buy from Fuel Moto they will upload a map onto the unit for you that matches your mods. I had a PCV with the Dynojet canned tuned and then just recently made the switch to a PV with the Fuel Moto map. Night and day difference.

Also, why topless? It does absolutely nothing.
 

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Discussion Starter · #3 ·
Thanks jfisher for your recommendations although I will have to check if they can ship to Greece, the relevant cost etc.

Even though the PV is better, I can not get in Greece the target tune. So in order to have a proper map and tune I need the best possible solution for a decent price.

Topless provides little more free breathing for the bike
 

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Thanks jfisher for your recommendations although I will have to check if they can ship to Greece, the relevant cost etc.

Even though the PV is better, I can not get in Greece the target tune. So in order to have a proper map and tune I need the best possible solution for a decent price.

Topless provides little more free breathing for the bike
Why can't you get the Target Tune? Emissions? It's been proven, recently at that, that running topless does absolutely nothing besides make more noise. I would even argue that when the bike is actually moving you probably lose power as you lose the snorkel from the top of the air box.
 

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Discussion Starter · #5 ·
The official dealer for dynojet in Greece, as far as I know, doesn't supply it. I will email them, just in case they can provide it. It goes without saying that this will be done, after the world wide quarantine ends.

Even though I can not prove it, I have read that running topless gives better breathing to the engine. Your point of view, is new to me. Can you please post your source so that I can compare notes?
 

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The official dealer for dynojet in Greece, as far as I know, doesn't supply it. I will email them, just in case they can provide it. It goes without saying that this will be done, after the world wide quarantine ends.

Even though I can not prove it, I have read that running topless gives better breathing to the engine. Your point of view, is new to me. Can you please post your source so that I can compare notes?
Anthony Rodrigues did a back to back to back dyno of all the mythical methods and posted them on Facebook. Well known tuner in Australia. Zero changes to both whp and AFR:
603904
 

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Discussion Starter · #7 ·
Jfisher, thank you very much for the lead mate. I will check this guy out. Anyway, I have read in other threads about the O2 banks sensors problem with Akrapovic exhaust.

What other exhaust would you recommend?
 

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Jfisher, thank you very much for the lead mate. I will check this guy out. Anyway, I have read in other threads about the O2 banks sensors problem with Akrapovic exhaust.

What other exhaust would you recommend?
My understanding is that's only an issue if you're trying to use the stock narrowband sensors and trying to auto tune / datalog (the stock sensors don't protrude far enough into the flow of exhaust to get accurate readings). This is not the case with the Dynojet Wideband O2 sensors. Using the stock narrowband sensors is almost pointless imo due to the limited range the NB's can read. The AFR you want to actually be at isn't even within measurable tolerance of the OEM NB sensors. IMO the Akra is by far the best exhaust available. May not be the most powerful, but the quality, fit and finish and sound is to die for. I'll give up a couple of hp for those things.
 

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My understanding is that's only an issue if you're trying to use the stock narrowband sensors and trying to auto tune / datalog (the stock sensors don't protrude far enough into the flow of exhaust to get accurate readings). This is not the case with the Dynojet Wideband O2 sensors. Using the stock narrowband sensors is almost pointless imo due to the limited range the NB's can read. The AFR you want to actually be at isn't even within measurable tolerance of the OEM NB sensors. IMO the Akra is by far the best exhaust available. May not be the most powerful, but the quality, fit and finish and sound is to die for. I'll give up a couple of hp for those things.
Trust me, no picnic with WB either. Reversion in the pipe alters what the sensors sample and the AFR will not always be what you are getting into the cylinder for AFRs. Sometimes the engine will bitch about it in how it runs. In the two data runs I've done even with trimmed reducers and ports using NB sensors on a near perfect super trap tune that ran well pre autotune via MyTune and logs, it's quite noticeable. Worst case, you can always fall back on the base TT cal and take the sensors out of the loop. Basically run it open loop if needed to keep a stable tune. You can also blend the lower non altered ve from base cal to the gathered data from WB beyond 5k rpm and come up with a cal like that. Then remove the sensors. This will also kill the adaptive learn which I've never found v rod friendly anyway. I disabled mine many years ago after fighting with it. Tune remains stable since that. Many different methods and over the years of pissing around with autotune devices, expecting it to work as advertised is extremely optimistic on the users part.
Ron
Ron
 

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Discussion Starter · #10 ·
Thank you both. In my understanding is that the best solution is to make an open loop by removing the O2 WB sensors and after some rpm. My most efficient, money wise and easiest solution is the PCV with the stock O2 sensors. Pick up the base tune from the Dynojet site and adapt it, if need be. I will ask if they can supply the TT with the O2 WB sensors and at what price for the PV.

If anyone has a map for Akrapovic exhaust and DNA/K&N filter and likes to share it, I would highly appreciated it.
 

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Thank you both. In my understanding is that the best solution is to make an open loop by removing the O2 WB sensors and after some rpm. My most efficient, money wise and easiest solution is the PCV with the stock O2 sensors. Pick up the base tune from the Dynojet site and adapt it, if need be. I will ask if they can supply the TT with the O2 WB sensors and at what price for the PV.

If anyone has a map for Akrapovic exhaust and DNA/K&N filter and likes to share it, I would highly appreciated it.
I would recommend buying from Fuel Moto and have them load a MAP on the PCV ahead of time. The base map on their site is just that. A base map. It was not very good at all.
 

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Ron when you said " reversion in the pipe alters what the sensors sample " it made me think of a couple questions - is it the shortness of the pipe that contributes to reversion, or the smallish exit diameter ( one exit vs two exits stock H-D and a 2.5" open baffle on most V Rod pipes ) or maybe a combination of both ? I'm just wondering if that pipe is building excessive back pressure that's affecting it's tune ( due to not passing enough exhaust volume to scavenge properly ) For the hell of it on the Dyno or even riding it someone needs to take a longer open muffler like a Bub7 or a Bassani with a 2.5 " baffle or twin stacked carbon mufflers and substitute it in for the Akro muffler and see what happens. I think it would be easier to tune and release another 4-6 Hp. All I can say is if I snubbed my 2.5 " muffler down to the diameter of the Akro muffler exit it would lose a lot of top power and " snap " power or the willingness to rev quickly that requires a more open pipe. I love that Akro pipe but I honestly think that muffler is to restrictive and holding it back, messing up the tuning. Just a thought - I haven't delved into any tuning beyond a Dobeck piggyback with no O2 sensors but my bike runs perfect. Disabling the auto tune like you did makes sense - genius ! I'm learning here - (y):geek:
 

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Ron when you said " reversion in the pipe alters what the sensors sample " it made me think of a couple questions - is it the shortness of the pipe that contributes to reversion, or the smallish exit diameter ( one exit vs two exits stock H-D and a 2.5" open baffle on most V Rod pipes ) or maybe a combination of both ? I'm just wondering if that pipe is building excessive back pressure that's affecting it's tune ( due to not passing enough exhaust volume to scavenge properly ) For the hell of it on the Dyno or even riding it someone needs to take a longer open muffler like a Bub7 or a Bassani with a 2.5 " baffle or twin stacked carbon mufflers and substitute it in for the Akro muffler and see what happens. I think it would be easier to tune and release another 4-6 Hp. All I can say is if I snubbed my 2.5 " muffler down to the diameter of the Akro muffler exit it would lose a lot of top power and " snap " power or the willingness to rev quickly that requires a more open pipe. I love that Akro pipe but I honestly think that muffler is to restrictive and holding it back, messing up the tuning. Just a thought - I haven't delved into any tuning beyond a Dobeck piggyback with no O2 sensors but my bike runs perfect. Disabling the auto tune like you did makes sense - genius ! I'm learning here - (y):geek:
Don't think it's the muffler itself. ID is huge in there. More likely the way the baffle works. A good portion of the exhaust hits the back wall, outside of the baffle tube then needs to rebound and exit the baffle. This rebound along with the short system is likely what will cause more reversion effect for tuning, then say a much longer system. The standard baffle the pipe comes with is quite short, reducing this rebound effect. Take it out completely there will be next to no effect but it will be loud. Don't think in that setup, there would be much restriction for the top end. Identifying reversion when tuning and knowing what data to accept or not is either hit and miss or somebody that does this on a daily basis and knows how to tune around it. I'm hit and miss but the signs get clearer the longer one plays with it. How one rides to collect data can make or break a good tune. Object one is never use any data that the engine was exposed to light load. This is the main pit fall of road tuning a bike. Dyno way better in that regard.
Ron
 

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Very Interesting ! Now I understand whats going on inside that muffler - its basically reversing the flow to help cancel noise and lower frequency since its so short - my WR 400 has a 45mm outlet and works great but the V Rod Revo 1250 engine is over 3 times that displacement, using about the same size exhaust outlet. No matter how large the muffler is internally all the exhaust has to exit through one small hole which in no way is large enough especially when Akro is reversing/ reflecting the flow/power pulses. The long Cone Engineering Quiet Reverse Cone Megaphone pipes I put on my Triumph Triple work in a similar way as the Akro on a 3 cylinder into 2 muffler setup that I built using a Triumph Daytona race header assy. and Delkevic mid pipes - It runs great despite Cone Eng. telling me those were not performance mufflers - their straight thru ones are - and the quiet ones I fitted have two small 1" outlets or 6.28 square inches for 900cc triple power pulses vs the Akro with only 5.5 square inches for 1250cc twin power pulses. I may have lost a couple absolute top Rpm Hp but like jfisher said about the Akro I'm Ok with that for the sound quality and smooth exhaust music not that no longer makes ears bleed. I read somewhere that a couple pounds of back pressure is best for performance - no more - be interesting to measure the back pressure in the Akro then compare to a straight thru longer muffler with the same db and see what the ease of tuning requirements and max power out difference would be. I agree with your observed light load road testing problem - it's like our old carburetor days set the full power main jet first, then the needle, then the low speed jet then idle mixture - get that out of order it's just a tail chasing exercise - (y):censored:
 

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Sorry its pi r squared -not pi d squared. so .785 x 2 muffler exits = 1.57 sq inches vs 2.405 sq inches x 1 muffler exit for the Akro with backpressure creating reverse pulsing - a 2.5" outlet is 4.908 square inches. Dramatic difference ( not taking into consideration pipe length created back pressure ) but twice the area of the Akro, similar to the area of the two stock revo mufflers. Two 4" Supertrapps or one 5" V5 have probably more exit area than that, especially with open end caps.
 
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