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The Massive Pr1ck
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2,630 Posts
While there is no doubt that the different stacks on this box will alter power characteristics, don't believe the claims of 5hp by going topless on any motor approaching stock internals. One thing is for certain when choosing between two filter configurations: That is that the filter with more surface area will give adequate flow for a greater period of time than a smaller filter.

I did do extensive dyno testing back to back with topless, stock, stock filter, and K&N. While the filter changes made no difference, topless did make significant AF ratio changes throughout the powerband (sometimes lean, sometimes rich). This indicates different sonic and pressure pulse characteristics, but it does not indicate increased flow. This could also explain why some see better and some see worse gas mileage after going topless as even a few hundred rpm difference can make a significant and unpredictable swing in AF ratios. With a proper tune, changing to topless should offer no significant change to fuel consumption.

I actually had the highest number of the day with a top on run, but it was first run after pizza and the motor was a few degrees cooler. What does matter is that you pick a configuration and tune the motor to that configuration. If you change configuration after the tune, you will definitely have lean and rich spots within the power band. I finally chose topless only because I liked the sound.

Now if you are running a big motor, all bets are off.
 

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Molon Labe
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169 Posts
Discussion Starter #43
Mike, good writeup and agree 100%, i did do 2 dyno pulls in the same day with mine. 1st was the stock vented airbox and the secon was with the Motohooligan box. Before each run, drove quickly through rpm range, applied blms on my DTT tuner. The difference in max horsepower was 3.37hp with the best being the MH. I did not do a topless pull and not scientific but it seems to work and love the looks. My only issue now is i have a bug to get one of the Holy-Moto superchargers so the airbox may be leaving the bike anyway. The main reason for choosing it is i wasnt a big fan of the topless sound so hopefully ill like the SC buzzing away, :)
 

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The Massive Pr1ck
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2,630 Posts
Mike, good writeup and agree 100%, i did do 2 dyno pulls in the same day with mine. 1st was the stock vented airbox and the secon was with the Motohooligan box. Before each run, drove quickly through rpm range, applied blms on my DTT tuner. The difference in max horsepower was 3.37hp with the best being the MH. I did not do a topless pull and not scientific but it seems to work and love the looks. My only issue now is i have a bug to get one of the Holy-Moto superchargers so the airbox may be leaving the bike anyway. The main reason for choosing it is i wasnt a big fan of the topless sound so hopefully ill like the SC buzzing away, :)
Interesting that you gained 3.37 peak. What was the change in average hp and torque? I could easily see a different stack configuration moving peak hp up a bit at the cost of average hp and torque.

It would be nice to see the entire performance industry change over to showing changes in hp and torque averages, but then they wouldn't be able to sell about 90% of their crap. Regardless, that airbox is one nice piece of work and worth it on craftsmanship alone.
 

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Molon Labe
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169 Posts
Discussion Starter #45
Mike,

The MH airbox has equal length stacks that come with it, The torque only went up 1.43ft lb. max
The average HP increased 1.03 avg and Tq average went up .61 over the average
I agree, a lot of it is a crap shoot. As with many performance parts, dyno runs day to day can be different due to temp, elevation, humidity, density altitude etc.
The quality is amazing and I felt for the price, the craftsmanship was well worth the cost.
 

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Molon Labe
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169 Posts
Discussion Starter #47
Does this come with comprehensive instruction
yes it does, it was very simple to install, remove old airbox and velocity stacks, install new
 

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The Massive Pr1ck
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2,630 Posts
Mike,

The MH airbox has equal length stacks that come with it, The torque only went up 1.43ft lb. max
The average HP increased 1.03 avg and Tq average went up .61 over the average
I agree, a lot of it is a crap shoot. As with many performance parts, dyno runs day to day can be different due to temp, elevation, humidity, density altitude etc.
The quality is amazing and I felt for the price, the craftsmanship was well worth the cost.
That's mighty close. Close enough that a few degrees air temp difference or dyno variances could cause it. Was the tune optimized for both configurations? Were the runs on same day? If peak goes up by 3-5, but averages are about the same, I'm assuming that the stacks are either slightly shorter or larger. Is this the case.

Please don't think I'm picking apart your decision. I'm a motor nut and really enjoy the technical details. The airbox is no doubt a beautiful piece. For me, I could find nothing significant from airbox changes so put my effort into the pipe. With the pipe I got over 10% gains in peak and average hp and torque.
 

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Molon Labe
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169 Posts
Discussion Starter #49
That's mighty close. Close enough that a few degrees air temp difference or dyno variances could cause it. Was the tune optimized for both configurations? Were the runs on same day? If peak goes up by 3-5, but averages are about the same, I'm assuming that the stacks are either slightly shorter or larger. Is this the case.

Please don't think I'm picking apart your decision. I'm a motor nut and really enjoy the technical details. The airbox is no doubt a beautiful piece. For me, I could find nothing significant from airbox changes so put my effort into the pipe. With the pipe I got over 10% gains in peak and average hp and torque.

The runs were the same day, all I did was ride through the RPM's on each, apply the BLM's on the DTT tuner and to the run. The stacks are in between the original short and long as far as length.
 

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How do you disconnect the hose from the bottom half of the air box that goes in the direction of the seat, what does that get reconnected to?
 

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The MH comes with 2 new hoses..you don't need the stock hoses any more..the front hose connected to the brass tube has a spring inside..the rear connects to the rear cylinder head where you remove the old one and they don't crack or leak any more
Do you have a pic where the one to the cylinder head gets connected to on the MH airbox. Or is this hose redundant with the MH airbox, ignore that just read your post again it makes sense now
 
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