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Discussion Starter #1
Okay I've seen the previous threads on removing the airbox cover and people claim to pick up a few extra ponies. I have the V-Mod Mufflers and SE Airfilter with the new '04 Stage 1 Flash (for the 28T Pulley). Dealer and HD catalog says the Flash can be used without the airbox cover.

My question is will this cause the bike to run any leaner? Right now it's right on with the A/F ratios and my current setup.

Second question is without the airbox cover if I got caught in a rainstorm would I run into any potential problems with sucking water down into the engine? The dealer said this is a possibility and he wouldn't run topless in the rain. If that's a risk why would HD tell you to remove the cover?

Does the intake noise increase with this mod? How much?
 

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Good questions Motown_VROD, I'll be doing the exact same next week with the exception of the 16 gauge double barrels. Did you get a dyno run done after the flash?
 

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Discussion Starter #3
Sure did... Here is a copy of my previous post with the results:

Great Dyno Results w/ V-Mods, K&N, and Stage 1 Flash
I installed the airfilter, V-Mod pipes, and downloaded the Stage 1 flash and she runs great. I've noticed a little hesitation at WOT around 4k just for a second before the Rod is warmed up. After about 5 minutes the hesitation is completely gone.

I had it put on the dyno at the dealership yesterday to make sure it wasn't running too lean in any areas of the RPM band. I wasn't going to do this, but since HD changed the map to lean it out a bit because the '03 verison was a little rich I wanted to make sure it wasn't too lean. The dealer didn't want to install the download with the V-Mod pipes because he said HD doesn't want that done because the bikes will run bad (stories about stalling at idle, ect...). I quickly convinced him to do the download and wait and see what the dyno says. He was amazed at the results. The bike at 2000k was a hair lean (with a 4th gear rolling start), but I doubt I'll ever be there in the band in that gear cause it's lugging there. Regardless, it was just a tick lean. Between 3k and 5k it was a little rich, but above 5k it was right on. The dealer was amazed how close the download matched the setup.

I was even happy with the HP results... I pulled 110.8 HP and 76.2 ft/lbs of torque at the rear wheel. That's more than the dyno result posted on the V-Mod website, so that makes me happy! Don't know if this is true, but the dealer said their new dyno room is larger and gets better airflow that would probably help the numbers out a bit. That room wasn't ready yet, so they used the current very small dyno chamber. What do you think, would it help the numbers???

Regardless this is a good increase of 8.2 HP and 4.3 ft/lbs of torque over the stock V-Rod. I can notice the increase when exiting turns and the rear wheel breaks loose now more than before.

Have to say I love the bike even more now than before. Now I'm not embaressed when other Harley's pull up next to me and twist the throttle!
 

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Looks good Motown_VROD. I'd still like to hear from the rest of the group about your second question and going "topless"......
 

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Motown_VROD

Regarding your question of running in the rain. Two weeks ago I made a 200 trip in the worst rain I have seen in a long time with no problems running topless. The increase in intake noise is substantial, but I personally like the sound. You only hear it when you get on it hard. As for it running leaner, I cannot tell you because I have the SE Race tuner and it was dynoed with it being topless. I will not put the top back on!
 

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Tonight I removed the airbox cover and took the long way home. Seemed to run just fine. BTW, that's the ONLY mod I made (instead of changing several things at once...). I'm running stock 16ga SE's, the K&N filter, and the factory ECM flash for that combo. It ran great before, and still seems to run great. If I see any wierdness, I'll report it.
 

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I clipped mine to the bottom half of the air box with an office binder clip. If I decide to keep it this way, I'll probably opt for the HD solution - sticky tape. Report: First tank of gas topless, same gas mileage.
 

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Discussion Starter #10
What does the group think of running topless and the potential for rain to enter the intake?
 

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New pipes were put on Tuesday 10/14. On the way home, it was running RICH, backfiring evry time I let off the throtle. Got home and pulled the airbox cover & remounted the sensor adn problem fixed. Noise Good. Me likey noise.........can't hear myself type anymore. lol
 

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In order of H2O to get into the engine it would first have to get under the air box skin (good chance of this), over the upper lip of the lower half of the air box (what with gravity and all pulling things toward the center of the earth, it is getting tougher here, but still possible), through the oil impregnated K&N air filter (I would only run topless with the SE {K&N} air filter, and you know what they say about oil and water...), then UP the 3" velocity stacks to get to the intake... I am not saying that it COULDN'T happen. I'm not saying that it DOESN'T happen. But the amount of H2O that must enter the engine in order to be a detriment would be difficult to intrude under normal (non-typhoon) conditions.
Just my $0.02

Scout
 

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WHY "RUNNING TOPLESS" IS A BAD IDEA

The airbox on a VRod is part of a tuned lenght intake tract that was refined by computer design. This is one reason the velocity stacks on the throttle bodies are different lenghts. A lot of incredible science went into the design. Intuitively You might be inclined to think that because having an airbox on makes quite a "air sucking" sound that there is a lot of restricton in the air intake and be inclined to remove it. You would be dead wrong. There is a lot of science in this inake system. In fact, it is able to build an intake pressure slightly greater than ambent air pressure! It also is able to preserve any regurge that can happen at the point of fast decelleration or slow idle. If you take the airbox cover off you will face the followng negatives:

1. A reduction in HP and torque of about 2 to 4%. Maybe about 6 HP!

2. You wife will say, "Why do you always smell like gasoline fumes?" The regurg will flow onto you and settle into your clothing somewhat. You fuel economy will drop slightly (loss of gasoline vapors).

3. Your air inlet temperature sensor will not be measuring true intake temperatore so may get warmer than ambient air and so your engne may not enrichen when it is very cold outside. This improves the smoothness of the engine.

If you want to improve the airbox here are some things you can do:

1. Ensure the rubber seal is tightly inplace and smooth. Glue it into the lower airbox wth slicone gasket material or GE Silicone II cement. Oil the top of the gasket slghtly and make sure the seating surface is smooth.

2. Remove any flashing or rough spots from the nside of the intake "trumpet".

3. Shave the rear of the intake trumpet vertcal column so that it come to a sharp point on the inside of the airbox. HD didn't do this for fear people would get cut on it. But a cross-section of that column should have a teardrop aerodynamic shape.

4. Use plastc Epoxy putty/filler to fill in the roof and transition point just inside the airbox where the trumpet dumps into the airbox plenum. Smooth this transition.

5. Use a low-restriction filter element in the airbox (K&N, etc.)

6. Ensure the front of the trumpet (inlet opening) is not obstructed.

That is it... if you think I am wrong ask youself... would a computer optimized design with advice from Porche (who is the king of tuned intake tracts) create an airbox that reduced your performance? If you tell me you are taking the airbox cover off ("running topless") and seeing higher numbers on the Dyno there is somethng wrong with your Dyno. Maybe you think you and your pals are better engineers that the incredible minds, experience (Porche-HD), and computing power (the cumalative minds of many scientists) that went into ths design... then so be it, "Run Topless" you silly goose!! ;-) Porche is one of the few companies with the technical sophistication to create a tuned intake tract that uses intake pulses to compress intake air (making it denser)... few companies can claim that.
 
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Dyno Topless vs. Top On

Motown_VROD

Regarding your question of running in the rain. Two weeks ago I made a 200 trip in the worst rain I have seen in a long time with no problems running topless. The increase in intake noise is substantial, but I personally like the sound. You only hear it when you get on it hard. As for it running leaner, I cannot tell you because I have the SE Race tuner and it was dynoed with it being topless. I will not put the top back on!
Next time you get to the Dyno do a run with the top on and one topless and you will be putting the top back on. It is good for about 6 lb ft torque. Forget about "the sound" that isnt' a good performance metric -- has no relevance at all. In fact a tuned intake track that uses intake pulses to ram a bit of extra air pressure into your cylinders has a very restrictive sound. But if you know what was actually happening you would trust the science that was put into it. Also you are likely to run leaner than you should be without the box cover because the intake temp sensor will read warmer than the ambient air actually is. When the engine is cold and very cold ar the ECU enrichens the fuel just a bit.

Don't get caught up in this hype from non-engineers re: "Gaining more horse by running without the airbox cover." It is a myth started by amateur modders that think they know more than modern science.
 

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Dyno Topless vs. Top On

Motown_VROD

Regarding your question of running in the rain. Two weeks ago I made a 200 trip in the worst rain I have seen in a long time with no problems running topless. The increase in intake noise is substantial, but I personally like the sound. You only hear it when you get on it hard. As for it running leaner, I cannot tell you because I have the SE Race tuner and it was dynoed with it being topless. I will not put the top back on!
Next time you get to the Dyno do a run with the top on and one topless and you will be putting the top back on. It is good for about 6 lb ft torque. Forget about "the sound" that isnt' a good performance metric -- has no relevance at all. In fact a tuned intake track that uses intake pulses to ram a bit of extra air pressure into your cylinders has a very restrictive sound. But if you know what was actually happening you would trust the science that was put into it. Also you are likely to run leaner than you should be without the box cover because the intake temp sensor will read warmer than the ambient air actually is. When the engine is cold and very cold ar the ECU enrichens the fuel just a bit.

Don't get caught up in this hype from non-engineers re: "Gaining more horse by running without the airbox cover." It is a myth started by amateur modders that think they know more than modern science.

As far as rain... I thnk it could be a problem in a very heavy rain... but you problably would look for cover in it and get off the road anyway. Not cause you might melt but because the cagers have trouble seeing you and will run you down. Running the airbox cover (as you should) The trumpet on the intake comes in at an up angle 8 degrees or so-- maybe that is to reduce the liklihood of water gettng in but a little fine water mist is often benefical to the engine and dampens the flame wave front just a bit and I think improves the overall smoothness of the engine. A little water doesn't hurt... even if it settles in the bottom of the airbox it won't get high enough to flow into the velocity stacks! Ha. Don't worry about the water.

Intake sound you hear with the airbox isn't indicative of a restrictive air intake tract -- on the contrary. There is some REAL science at work here to use inake pulses to compress air going into the cylinders a bit more than ambient. The additional intake density is worth about 4 to 6 lb ft of torque, better fuel economy, and you won't smell like gasoliine after a ride anymore (since you are absorbing some "blow off" regurged gasoline fumes)..
 

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Next time you get to the Dyno do a run with the top on and one topless and you will be putting the top back on. It is good for about 6 lb ft torque. Forget about "the sound" that isnt' a good performance metric -- has no relevance at all. In fact a tuned intake track that uses intake pulses to ram a bit of extra air pressure into your cylinders has a very restrictive sound. But if you know what was actually happening you would trust the science that was put into it. Also you are likely to run leaner than you should be without the box cover because the intake temp sensor will read warmer than the ambient air actually is. When the engine is cold and very cold ar the ECU enrichens the fuel just a bit.

Don't get caught up in this hype from non-engineers re: "Gaining more horse by running without the airbox cover." It is a myth started by amateur modders that think they know more than modern science.

As far as rain... I thnk it could be a problem in a very heavy rain... but you problably would look for cover in it and get off the road anyway. Not cause you might melt but because the cagers have trouble seeing you and will run you down. Running the airbox cover (as you should) The trumpet on the intake comes in at an up angle 8 degrees or so-- maybe that is to reduce the liklihood of water gettng in but a little fine water mist is often benefical to the engine and dampens the flame wave front just a bit and I think improves the overall smoothness of the engine. A little water doesn't hurt... even if it settles in the bottom of the airbox it won't get high enough to flow into the velocity stacks! Ha. Don't worry about the water.
Intake sound you hear with the airbox isn't indicative of a restrictive air intake tract -- on the contrary. There is some REAL science at work here to use inake pulses to compress air going into the cylinders a bit more than ambient. The additional intake density is worth about 4 to 6 lb ft of torque, better fuel economy, and you won't smell like gasoliine after a ride anymore (since you are absorbing some "blow off" regurged gasoline fumes)..
No myth about it at all. Overblown? Yes. Are people ill-informed? Yes. Do newbies fock with sheet they shouldn't?
However, the science of HP is fairly simple, get the most gas/air in as quickly and efficiently as possible and get it the hell out in the same fashion. "FLOW" is king. That's why the Revo has 4 valves per, amongst other goodies to increase fast flow.
Removing the lid or partially or drilling holes is fine and it can work provided a higher flow air filter is also installed and provided you do the appropriate exhaust modifications as well. Of course, an auto-tune or preferably a dyno tune is also mandatory. The gains are not bragging rights, but you will see gains if done properly and it's necessary IMO, if changing to a higher flow exhaust.
Now, add Stage II cams with these mods and you'll get some real set-o-the-pants gains. Good numbers.


http://www.epi-eng.com/piston_engine_technology/volumetric_efficiency.htm
 

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Good write up, the gas smell is the very true!

WHY "RUNNING TOPLESS" IS A BAD IDEA

The airbox on a VRod is part of a tuned lenght intake tract that was refined by computer design. This is one reason the velocity stacks on the throttle bodies are different lenghts. A lot of incredible science went into the design. Intuitively You might be inclined to think that because having an airbox on makes quite a "air sucking" sound that there is a lot of restricton in the air intake and be inclined to remove it. You would be dead wrong. There is a lot of science in this inake system. In fact, it is able to build an intake pressure slightly greater than ambent air pressure! It also is able to preserve any regurge that can happen at the point of fast decelleration or slow idle. If you take the airbox cover off you will face the followng negatives:

1. A reduction in HP and torque of about 2 to 4%. Maybe about 6 HP!

2. You wife will say, "Why do you always smell like gasoline fumes?" The regurg will flow onto you and settle into your clothing somewhat. You fuel economy will drop slightly (loss of gasoline vapors).

3. Your air inlet temperature sensor will not be measuring true intake temperatore so may get warmer than ambient air and so your engne may not enrichen when it is very cold outside. This improves the smoothness of the engine.

If you want to improve the airbox here are some things you can do:

1. Ensure the rubber seal is tightly inplace and smooth. Glue it into the lower airbox wth slicone gasket material or GE Silicone II cement. Oil the top of the gasket slghtly and make sure the seating surface is smooth.

2. Remove any flashing or rough spots from the nside of the intake "trumpet".

3. Shave the rear of the intake trumpet vertcal column so that it come to a sharp point on the inside of the airbox. HD didn't do this for fear people would get cut on it. But a cross-section of that column should have a teardrop aerodynamic shape.

4. Use plastc Epoxy putty/filler to fill in the roof and transition point just inside the airbox where the trumpet dumps into the airbox plenum. Smooth this transition.

5. Use a low-restriction filter element in the airbox (K&N, etc.)

6. Ensure the front of the trumpet (inlet opening) is not obstructed.

That is it... if you think I am wrong ask youself... would a computer optimized design with advice from Porche (who is the king of tuned intake tracts) create an airbox that reduced your performance? If you tell me you are taking the airbox cover off ("running topless") and seeing higher numbers on the Dyno there is somethng wrong with your Dyno. Maybe you think you and your pals are better engineers that the incredible minds, experience (Porche-HD), and computing power (the cumalative minds of many scientists) that went into ths design... then so be it, "Run Topless" you silly goose!! ;-) Porche is one of the few companies with the technical sophistication to create a tuned intake tract that uses intake pulses to compress intake air (making it denser)... few companies can claim that.
 

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K&N filters allow more minute particles, that's how they achieve the flow. That change also goes against the gist of the entire write-up as making changes to a "tuned" system.

I would guesstimate 90% of the V-Rods have some sort of mod to the air-box, along with exhaust changes and a proper dyno. All have garnered gains.

Ask yourself this? LOL! The EPA is king of the HD tuning department. In fact all manufacturers. Neither Porsche nor Willie himself can skirt EPA requirements. Hence the so-so factory tune, hence the 2-1-2 exhaust, hence the restricted air-flow.
 
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