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How many people think this would be worth purchasing.

  • Yes, I would buy a kit.

    Votes: 17 40.5%
  • No, I wouldn't buy a kit.

    Votes: 13 31.0%
  • I'm not sure, I would like to see the kit first.

    Votes: 12 28.6%
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Discussion Starter · #1 · (Edited)
Here is a cheap and effective way to modify your stock air box for increased performance, WITHOUT RUINING OR REMOVING ANY STOCK COMPONENTS!

Before you start reading, I am having shim kits made. It will raise the air box lid and the tank. This is a great kit that will actually do something for your bike and is a small investment when compared to some other aftermarket performance intake systems. it does not require a Power Commander or other fuel processor as long as the O2 sensor is hooked up and working. It also keeps the stock Positive crankcase ventilation in place. I sell these on ebay, just do a google search for "Brains Air box Mod and it will show up in your search results. Since this has gone so well and I am selling a lot of these I made a website to better serve my customers. I can offer a lower price on my website vs ebay. go to www.thebrainsplace.com , I also have another project for the liners that should be HUGE. It's on the website as well. Please read on and see the evolution of a great product. I hope you enjoy yourself.

1.There is very little room for airflow/circulation around the outside of the air box as the gas tank fits very close EXCEPT in the two inlet areas of the air box.

2. This area receives higher atmospheric pressure or increased air flow that is forced up under the tank and into the two openings cast into the top cover.

3. The top cover is made so that it aims the incoming air streams downward thru the air filter and into the air box plenum. Next time you have your air box open take a look at the top cover and you will see a simple ridge molded into the plastic. If you look closely you will see the ridge lines up exactly over the center of the air filter. It seemed as though the only improvement a person would need to do is raise the whole top cover approx 1/4" to 3/8" higher to drastically allow more of this air to ram thru the air filter.

4. The stock air box closely resembles a tunnel ram intake on an automobile engine.

5. The stock air cleaner (or K&N) has plenty of area for the air that is needed.

6. Raising the air box can be done on the cheap side.
All you need to do is find a piece of 1/8” thick rubber sheet that is fairly firm so it wont squish flat. I used a piece of 1/8" thick recycled rubber mat. You can use whatever you have handy, as long as it has a smooth surface on both sides. You only need about 7 inches. Get a piece of paper and some chalk or lead pencil and make a tracing of the air box cover. Cut the shape out with a scissors and then transfer to the rubber sheet. Once you have it cut as needed, use the air cleaner screws to hold the spacers to the air box cover making sure the spacers are flush with the inside edge. Screw the screws through the rubber to hold it in place. If this is done correctly the inside edges will be lined up and flush with the inside of the top cover so there will be nothing to cause air restriction. You will need to do some cutting to the spacers in two spots as the both sides of the cover have corners. don't worry about screwing up if there is plenty of material, just try again if you mess up. Now turn the cover over so the spacer is facing down. Press the top cover and seals against a cutting board, bench top - something flat and cut off any of the spacer sticking out past the outside edge. You will need to do a good job here, as it is a very tight fit with the rest of the air box and frame. Place the top cover over the air filter and screw it on. Be very careful because the screws are going to be barely protruding thru the shim material and you don’t want to strip out the threads in the air box. Start all the screws into the air box equally and tighten them gently and evenly so you don’t break the plastic or strip the threads, longer screws may be needed. It is important that the sides be totally sealed by the spacers or the Ram air will leak out and you will lose the effect. Step back and look at the opening now it is much bigger. If you are interested in the math here it is.
All dim’s are in centimeters and is the area calculated for each opening. The modified opening is calculated with a 1/4” increase in height. More height will of course give greater opening size and a larger % increase.

Throttle bodies, (TB’s)
43 mm diameter (4.3 cm) = 14.52 Sq cm x 2 TB’s = 29.04 sq cm

Stock Top cover inlets,
Front inlet = 12.1 sq cm,
Rear inlet = 7.25 sq cm
12.1+7.25= 19.35 sq cm total (-9.69 sq cm less than TB)

Air filter opening, 30.48 sq cm (1.44 sq cm bigger that TB)

Modified top cover, raised 1/4" inch,
Front inlet = 16.93 sq cm
Rear inlet = 9.677 sq cm
16.93+9.677 = 26.6 sq cm thats a 27.25% increase, -2.44 sq cm less than TB’s BUT a 7.25 sq cm increase over stock per 1/4 inch, 3/8 in would give you more than the TB's total sq cm approx 30.2 sq cm or a 35.9% increase )

I would think the perfect size would be slightly larger than the TB’s total area. This 1/4" change is still a large increase over the stock opening and did not damage any stock component, utilizes the factory design, adds higher density air to the TB’s plenum in greater volume.


I just added these pic's. the seals are hard to see with black, on black, on more black but i think you can figure it out. i ended up using recycled rubber sheet. the rubber was a bitch to cut so it looks crude. it actually has stuck to the airbox it sealed so well. i will probably make another set out of something easier to cut so i get straighter edges. this was just another step in my prototype process. the rubber sheet i used was 1/8" thick so i had to make a total of two per side. i could add another 1/8" piece to arrive at 3/8" thick. it will rub the hell out of the bottom of the tank but a guy might be able to put a couple washers under the tank mounts to slightly raise the tank another 1/8".

In the 2nd picture. do not add this foam air dam on the left side. it doesn't belong there. i assumed mine was lost after a service repair. it was never there in the first place. i have driven the bike with this in place and it made a huge difference for the worse.apparently the air rushes up the left side and is trapped by the air dam on the right side or it just chokes off the available air. I have attached a pic of the air box shim kit I am having professionally made, on this first page so you don't have to hunt threw the whole thread.
 

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Discussion Starter · #3 ·
air box noise

Looks good will have to look at this next filter cnahge. I imagine it is to cold to know if any performance boost. Wonder if you can tell any difference in intake noise?

Dave
yeah hard to tell performance wise. the ram air effect will only work as speed increases. i couldn't tell any difference in noise as the muffler is pretty loud inside the pole building. i will have to take a pic of the mod. the foam pipe insulation was just about the prefect density and thickness to start with. plus it is closed cell foam so it will seal properly. both sides are sealed, just the original inlets are open just like stock only they are bigger now. also no glue or adheasive was used so nothing to try to remove later. basicly a foam spacer. very simple. the hardest part was cutting the outside so there was nothing sticking out. it is a VERY close fit in there and anything protruding will knock the foam out of position. even though it is only a 1/4" higher the inlets look much bigger. i believe i gained 37% more inlet area. the best part is if it doesnt pan out i can put it back to the way it was with no losses. i am excited to ride it. maybe another month or so i hope. come on global warming.
 

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Discussion Starter · #4 ·
results so far

Looks good will have to look at this next filter cnahge. I imagine it is to cold to know if any performance boost. Wonder if you can tell any difference in intake noise?

Dave
here is what i have so far.
1. there is more intake noise at cruise speed but it disappears at most any other speed especialy if throttle is more open.
2. the power really seems to come on hard at 40 - 50 mph which is about the speed where more wind is generated and power seems to increase as speed increases.

i had to unplug the battery so the ecm would reset. it had a flat spot at 2000 - 2500 rpm and it fell flat on its face over 4000 rpm and actually "bobbled" or "stumbled" at 5000 rpm and it would run really hard at this speed stock. it seems better now after the unplug. i might unplug it again as i may have plugged it back in to soon. i think a power commander would be the way to go in the future. then you would know for sure it is running correctly.
 

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Ram air

Brain,

Sounds good, you will soon be able to test the air intake mod better. Keep us up to date. I still have not heard of anyone else doing this.

Wonder if the exhaust is stock?

Dave
 

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Discussion Starter · #6 ·
Exhaust is stock execpt for the muffler is a roadhouse slip-on

Brain,

Sounds good, you will soon be able to test the air intake mod better. Keep us up to date. I still have not heard of anyone else doing this.

Wonder if the exhaust is stock?

Dave
Exhaust is stock execpt for the muffler is a roadhouse slip-on. i forgot to add that i could lift the front end almost to the end of the shock travel with clutch full engaged and in 1st gear when it was stock. now i can almost lift the front tire off the ground all the time (almost). i think the thing that was disconcering was it seemed to take the stock ECM time to learn what it needed because of all the various throttle positions @ various rpm's possible during normal driving conditions. i actually did the ECM learning similar to what you see on the internet when they program a power commander. i would get it in high gear slow down to 2000 rpm then give it approx 10% throttle untill it stopped accelerating. then slow to 2000 rpm and do a 20% untill it ran out of steam. after that then 30, 40, 50, 60, ect, ect, untill i was doing WOT. due to excessive speed i did some of this in 4th gear. i seemed to get better results after doing this rather than just driving around hoping it would see all the different conditions over time. now this could all be my perception of reality. all i can say is it did run crappy and now it seems to run pretty darn good. i still need to do some more 90% @ 5000 - 6000 rpm runs to get the top end totally tuned in so i guess i'll just keep trying and posting the facts as i get them.
 

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Make a difference

Brain,

It is obvious you have made a significant difference in air intake. The changes in performance and need to re-learn indicates a big change.

Most other methods introduce a bunch of noise. The big V Twins make a lot of intake noise if wide open. With this mod the air box is still shielded by the gas tank and pointed forward.

I think you are on to something.

Dave
 

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Discussion Starter · #9 ·
No jetting needed

This is one of the great mods of all time because it costs so little. If it actually provides about 1/3 more air, one might need a jet kit to get the most out of her-Zioo
The best part of all. Liners are fuel injected. No rejetting needed.
 

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Discussion Starter · #10 ·
Intake noise

Brain,
Most other methods introduce a bunch of noise. The big V Twins make a lot of intake noise if wide open.
Dave
i have noticed the more i get in tune with it, that it is a lot noisier at part throttle right where you cruise at. it is not noticeable at less or more throttle but right where the throttle is at when cruising approx 1/4 throttle or so. it seems to be there regardless of RPM. the sound is coming from the front of the tank more than the rear most likely because the intake is bigger in the front. i'll have to wait untill i can race a few guys to tell the performance gains for sure. i am going to change spark plugs soon and i will get some pics when i do. all i know is it is VERY strong at mid range RPMs 2500-4000 right where you do most of your driving. i smoked the rear tire inadvertantly friday going around a corner slow in first gear. sounded so cool. there was a guy on a crotch rocket and he had a big grin on his face and watched me the whole time untill out of sight. i drive kinda sporty. i think you guys should give this a try and let me know what you think.
 

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Brain-I have a vstar 1100 custom. Will this work on it--Also, will the K and N filter work on my2000 Vstar 1100-and will it affect jetting, what does it do to gas mileage and performance--I have the air mod kit i got online cheap, but i like what you describe---the kit i got provides a template on how to open holes in the side of the air box and then they provide mesh to over up the holes , a little work involved.

thanks for the input
 

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Discussion Starter · #12 · (Edited)
Air box mod on 1100 v-star

Brain-I have a vstar 1100 custom. Will this work on it--Also, will the K and N filter work on my2000 Vstar 1100-and will it affect jetting, what does it do to gas mileage and performance--I have the air mod kit i got online cheap, but i like what you describe---the kit i got provides a template on how to open holes in the side of the air box and then they provide mesh to over up the holes , a little work involved.

thanks for the input
The air box on the roadliner/stratoliners are totally different from the v-star's. the principal is the same for all engines as they are all basiclly airpumps. the more air you can get in the more power you will make. if you can get forced induction them you'll get more air into the motor and create more power. it just happens that the roadliner/srtatoliners have an intake plenum that allows it to be raised easily to allow more of the air to enter AND enter under pressure once you get up to a certain speed. to answer your question on jetting.
Yes, you will need to re-jet if you modify the air filter so it will get more air. the reason being that if the air filter/air box is restrictive it is like applying the choke to the engine. if you allow more air in then the choke is now off (or reduced) and you run leaner. depending on how much change you incorporate will determine the leaness you will get out of the change. more is not always better either as you will lose velocity which could cause less torque to be made. i would suggest you start small and work your way up untill you find the sweet spot, especially if you are modding your stock components. you can always make openings bigger but it is hard to make them smaller once you go to big. then you have to spend money to reverse what you have done. this airbox mod on the road L/ strat L is nice because it is totally reverseable with no damage or change to stock componets. if you dont like it take it out and your back to stock. plus it is as cheap as you can get. i spent $5.00 on a cocktail the other day and pee'd it out 20 min later yet i still have my air box mod for the same money. i can't loose with this mod especially if i do see increased HP/TQ. i would suggest you take a good look at the airfilter on your bike. generally the airfilter in not the flow loser. is there a way to space the cover out without cutting metal/plastic to do this yet increase the opening? it may be as simple as making a spacer to extend the outer cover. remember it doesnt take a ton to make the area a lot greater. 1/4" gained me 25% more intake area. if your inlet size is bigger then maybe an 1/8" will get you the same gains. there are area calculators on the net that work great for this type of calculation ( i hate math) so if you know the opening size you can see how much impact you are making. here is a simple calc that you can use, just click on the shape you desire then enter the info.
http://www.onlineconversion.com/shape_area.htm
Good luck
 

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Discussion Starter · #14 ·
More results

i just raced a buddys Honda VTX1800C and smoked him bad. i heard they were 104 hp @crank and 107tq but he didnt come close to the Stratoliner. i even let him get the jump and maybe 1-2 shift was stayin same but 2-3 shift i was walking away big time and never looked back. we did a few different runs in diff gears and i could spank him at any time. not sure if the airbox made the difference or if Strats can just spank the piss out of a VTX1800. i thought it was going to be closer than it was. any info on this would be nice to hear. anyone else spank a VTX with a stock strat?
 

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Spank more than the VTX

i just raced a buddys Honda VTX1800C and smoked him bad. i heard they were 104 hp @crank and 107tq but he didnt come close to the Stratoliner. i even let him get the jump and maybe 1-2 shift was stayin same but 2-3 shift i was walking away big time and never looked back. we did a few different runs in diff gears and i could spank him at any time. not sure if the airbox made the difference or if Strats can just spank the piss out of a VTX1800. i thought it was going to be closer than it was. any info on this would be nice to hear. anyone else spank a VTX with a stock strat?
Do some internet research on the Roadliner/Stratoliner. It has been tested against all of them and comes out on top of most of them; the general consensus was everyone fell in love with the motor. I personally really like it because of it's flat power band. When I had my Power Commander mapped last summer (Power Commander and Yamaha Speedstar exhaust with O2 sensor removed) the numbers spoke for themselves. 86.9HP at ~3500rpm 116lb torgue at ~2400rpm. By the time the torgue flattens out the peak horsepower takes over.
 

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HP/Torque

I think the power of the Liner at the crank is 103 Horsepower and 124 ft lbs torque stock.

I see a slight variation in numbers on a dyno. 86 to 91 horsepower, and torque is always around 114 to 117 ft lbs torque.

Guess we need to check which numbers we are compairing crank or at the wheel.

Dave
 

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These incredible motors deserve to be in some kind of motorcycle hall of fame. I say race them on the track and not on the street, though, except in the briefest of forays. Does anyone have a comparison of the fuel injected v. non-fuel injected motors for hp and torque?
 

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The question regarding the V-Star 1100 and the air box kit gets revisited and well it should. For example this owner has a 2000 V-Star 1100 and as of the date of the post, was just getting into it. With the stock filter, the additional air probably will help without rejetting and without pipes or baffle adjustments. With that model the owner can get slip-on exhausts and save money. However that will require rejetting. If the kit he mentions is put on the air cleaner and he goes to K & N, rejetting will be required. In either case, it is strongly suggested that the two carburetors be synchronized with each other. zio
 

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Discussion Starter · #19 ·
god dang my bike is strong

well i keep racing and i keep winning. i think this mod has really made a big difference for me. she pulls so damn strong above 50 mph that i can pull away from anybody so far. i think by retaining the EXUP and opening the airway i have gained significant horsepower. i have not race my brother yet but we have done some pretty hardcore runs and i think i can pull on him near top end. maybe even in the lower gears as well. he dyno'ed at 107 rwhp and 110 rwtq. he has an 2002 heritage soft tail just rebuilt (hopped up). if i can hang with his heritage i must have gained quite a bit of HP from this mod. i have yet to lose a race but i am sure my day will come. just to keep this in perspective i mean cruzer/touring big V-twins. not crotch rockets or vmax.
 

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I know it's been a few months, but have you ever gotten a chance to go up against your brother's S/T?
How are your racing stats keeping Brain?
 
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