So right at the moment, my Little Gray Duc is in the shop getting the wiring replaced to the fuel pump, you guys know the saga. They are going to see if there is anything they can do about the tank/wiring rub, but that is a different topic. Today, the local Hardley Ableson dealer is giving Demo rides, so I go ride of bunch of big ole slowass bikes. Hey, I'll ride anything as long as its ftee.
Back on topic. They had and S4 for sale, and they let me pull the tank to see if it's different from mine, which it is, a bit. But while I was in there, I notice that their S4 has the top of the airbox cut out, about a 6 or 8 inch square, and has a K&N type of filter same as mine, but mine isn't cut. Now other than more intake roar, is this a worthwhile mod, or will it screw up my fueling? I've been told by the shop that I bought the bike from (god, I feel like a chimney, what with all the smoke blown up my.....), that it has a DP chip or box or whatever to adjust the fueling for the pipes, and when it runs, runs real good, no lean surge, no popping, not loading up the plugs, not doing anything bad. Should I cut my airbox, or am I asking for trouble?
Robert
If you do have the DP computer you should be running an open airbox. Post the part# on your computer and I'm sure someone here will know. You try taking the top off and holding the filter in place with wire or wire ties and see how it runs. If it runs lean without the lid you have the option of springing for a Power Commander.
You're probably going to get lots of opinions on this, and here's mine. Airboxes are designed to resonate at a certain frequency and the resonance causes a high pressure pulse in the intake port just as the intake valve in each cylinder is opening, at certain RPM's. The airbox resonant frequency is designed to minimize flat spots by boosting the intake pressure at an RPM range where a motor might have a naturally occurring weak spot. The pressure pulses also compensate for the loss of pressure due to the intake restriction due to the airbox intake. "Sport Bike Performance Tuning" by Kevin Cameron (I think it's still available from Amazon or BN.com) where I got most of this info from has a formula for calculating the resonant frequency based on intake tract and airbox volume.
So, in theory you will lose something by cutting the lid.
Quote from: Langanobob on April 04, 2009, 08:41:33 PM
You're probably going to get lots of opinions on this, and here's mine. Airboxes are designed to resonate at a certain frequency and the resonance causes a high pressure pulse in the intake port just as the intake valve in each cylinder is opening, at certain RPM's. The airbox resonant frequency is designed to minimize flat spots by boosting the intake pressure at an RPM range where a motor might have a naturally occurring weak spot. The pressure pulses also compensate for the loss of pressure due to the intake restriction due to the airbox intake. "Sport Bike Performance Tuning" by Kevin Cameron (I think it's still available from Amazon or BN.com) where I got most of this info from has a formula for calculating the resonant frequency based on intake tract and airbox volume.
So, in theory you will lose something by cutting the lid.
This would be true if the factory designed the airbox for maximum performance. Reality is, just like exhaust, manufacturers have to design air intake to meet noise standards and fit on the bike. Most Monsters will gain something between negligible to a little gain from an open airbox. The biggest gain will be the wonderful honk. If you look at your airbox you will see the air intake itself is restrictive.
Howie,
I don't necessarily disagree, you may be right about Ducati tuning the boxes more for noise abatement than performance. This is an interesting subject. Didn't someone once post some dyno runs on the same bike with the stock and cut airbox? It would be interesting to see some quantified results. I know for a fact that dB's translate directly into HP on my butt dyno. I also know the airbox inlet is restrictive and the theory is supposed to be that the tuned volume resonance more than compensates for the restriction - but only at certain RPM's.
Brad Black has some dyno runs and somewhere on the net there is an article on the ST. Pretty much, HP gains are minimal and real life performance gains, well, who knows? As you said, with flat spots, maybe negative. With all the variables with jetting and mapping there may be no solid conclusion, other than a stock bike will suffer. My 750 is probably the worst example for increased performance, but it works well on the but dyno, and I love the music!
Soooooo, a definite maybe on the airbox mods. Any negative effedt on wet weather performance, as in water getting in there? What about the velocity stack kit that TPS or someone like that is listing on Ebay? I'm just wondering if anything is worth doing for some real world gains. If I decide to keep this bike, and it looks like I might have no choice but to keep it, I might make a little project out of it, we have the baddest ass cylinder head guys in the business where I work, I'm sure they wouldn't mind taking a looksee in there, they do like the way it runs stock. And they are definitely some serious tech heads when it comes to making more power. Right now, I have a Briggs and Stratton engine at work, for the kid next door that races go karts, were seeing what we can to to the head to make it breeeeeaaaaath. It's big bore and stroked, some head work should release some power.
And one other thing. What can I expect at the rear wheel of an S4 with Leo slip ons and a chip, with or without the airbox mod? Somewhere's in the neighborhood of 100HP? I hope? When I get the bike back, I'll get the numbers off of the box. Maybe someone can tell me exactly what it is I've got.
Thanks again, Robert
ime if it is tuned right it will make more power everywhere.
Quote from: brad black on April 05, 2009, 02:02:19 AM
ime if it is tuned right it will make more power everywhere.
brad,
Just to clarify it sounds like you're saying if it's tuned right it will make more power everywhere with the airbox opened up?
Basically the same as what Howie was originally saying about if he has a DP ECU.
So now we have the answer.
Edit: Howie, my apologies if it looks like I didn't believe you until brad posted his comments. You know the old saying about a prophet in his own land... :)
"if it's tuned right"
means that if the mixture is correct, whether by accident using the original ecu or modified via a dp ecu or pc3 or u59 or nemisis or rempapped original ecu, then yes, it will make more power everywhere.
it does not mean if the idle mixture of the std ecu is reset or if someone told someone that it should be ok or if it feels alright it must be alright or if it doesn't backfire on overrun (the old doozy) or someone said on the internet.
it means it has been checked and made right thru whatever means is selected.
If you have a cloth or foam filter you will be fine. For extra insurance you can leave the front on. This is a partial view of my airbox, just for an idea. The front is intact. Since yours has a Helmholtz resonator, not snorkels, you need to do differently. You can either cut a rectangle out of the top or cut the whole top, leaving just a ring to hold the filter in place. I don't think either way affects power. Post in Mods and Accessories and ask for photos. My bike makes 59 rear wheel HP at a higher RPM and the only engine modifications is jetting, air filter and slip-ons. Factory rating is 60 at the flywheel.
(http://i298.photobucket.com/albums/mm276/hlep2890/bike/IMG_0209.jpg)
I should have given credit to BCM for the Swiss Cheese design.
Quote from: howie on April 04, 2009, 08:29:13 PM
If you do have the DP computer you should be running an open airbox. Post the part# on your computer and I'm sure someone here will know. You try taking the top off and holding the filter in place with wire or wire ties and see how it runs. If it runs lean without the lid you have the option of springing for a Power Commander.
Ok, I think I have the right numbers, off the right part, maybe. Right next to the battery is a small 1 1/2 x 3 or 3 1/2 in electronic connector, which has 2 little wiring looms connecting to it. Do I have the right part? If so, here are the numbers of the right side of the connector.
IAW 59M.A1
IAW 59M.A1/HW010/09DA-036
12v=35800
and under the bar code towards the right side of the connector
20XFMPNCA
on the opposite side
61600.544.00
MS4DUCATI006
Anyone know what this means? Stock or DP? I'm thinking of cutting the top of the airbox, it seems to have a K&N type of filter in it, oiled cloth type, but I don't want to make any problems for myself. Any suggestions?
Thanks, Robert
stock.
Thanks, Brad. Is the solution to go to a Power Commander, or the Ducati part, or will the stock one adjust enough to cover the airbox, or reflash, or, or, or............
Suggestions?
QuoteSince yours has a Helmholtz resonator, not snorkels, you need to do differently.
Howie, on my M620 at the airbox inlet there is a smaller box with a round hole in it that the intake air charge passes by, but doesn't pass through. I was thinking that the whole air box was what made up the resonator, but if so, then what is this mini-box at the air inlet for? It looks like a resonator in that it looks like a big whistle.
Also, doing some Googling on this topic there are some opinions that the flat airbox air filter will dampen out most of a pressure pulse coming from upstream. This makes sense to me so it seems like the upstream airbox volume acting as a resonator is kind of inefficient. Interesting stuff and wish I had a dyno and a magic wallet. And 500 hours in a day.
That box is the resonator. AFIAK, it is there to reduce intake noise, not enhance performance. Your googling seems to substantiate this. To know for sure is difficult, a little like "does that big ass wing on the back of my car really help?" It seems most people get a slight gain with proper fueling, but since there is a gain from proper fueling anyway, I think whether it is worth it or not is both subjective and dependent on the person doing the dyno tune. I would think the gain is minimal since people get away with an open box and just a CO trim, which really has a diminishing effect as speed/load increase. Brad Black may have enough info to make you happy and save you many hours and dollars on dyno time. http://www.bikeboy.org/performance.html (http://www.bikeboy.org/performance.html)
Do keep in mind the butt dyno is important too. It may not be a real measure of performance, but aren't we doing these things for the smile factor? If I had the money and another bike, my bike would get high compression and flat slides. A lot of work and money to still have a slow bike, but...
Quote from: howie on April 13, 2009, 06:13:42 AM
That box is the resonator.
Interesting and you're probably right that it's not there for any performance gain. I think the rest of the box is supposed to resonate also, although at a much different frequency.
QuoteDo keep in mind the butt dyno is important too. It may not be a real measure of performance, but aren't we doing these things for the smile factor? If I had the money and another bike, my bike would get high compression and flat slides. A lot of work and money to still have a slow bike, but...
You're absolutely right. I'm interested in this airbox subject mainly as a wannabe scientist, not to eke out another few HP from an M620.