| Author | Message | ||
     Dwardo |
I'm wondering if there is any hard data showing that opening up the airbox on a tuber with mild upgrades like a slip-on will really add any meaningful power. Same for a Forcewinder. I kind of like the funkiness of the stock bread box but I'm toying with doing the open airbox mod. I've read all the threads about catch cans and don't think I want to go there at this time but I realize that I'm giving up a HP or two not doing that. I already have a K&N filter so I'm think of (1) doing nothing but adding a slip-on, or (2) doing the open air box but leaving the breather in the box. I'm probably too cheap to buy a Forcewinder unless I find a screaming good deal. Thoughts? Thanks. | ||
| Mbsween |
Dwardo, No you're not going to gain meaningful power. You might get 2 - 4 HP on the top , depending on the combination of pipe and airbox. The big thing you'll lose are weight (pipe swap) and the big dip in the standard tuber power curve. If you read the old battle2win mags, you see modest power gains overall, but you'll see huge gains at certain points in the rev range. That alone to me is worth it. If you have a carb bike, you'll need to rejet, the FI bikes work best with the race ecm. You can use a Power commander etc , but you have to do the mapping. I wouldn't do one without the other (airbox & pipe) So since you already have the K&N filter, finish gutting the airbox and add a slip on. Next would be the rejet or Race ECM. You'll notice the difference. Good luck matt | ||
| Cbm2 |
The Harley Big Bore Intakes is fairly cheap ($150) compared to most of the other ones. Comes with everything you need like the breather kit and mounting bolts. {  , | ||
| Aesquire |
Mbsween's right, The original Muffler/Airbox setup is supposed to be especially quiet at the RPM's that the EPA measures these things. Quite brilliant design. Gutted airbox ( pics & variations all over the site, here ) and slip on defeat that purpose, and that power dip. How loud you wanna be? Big gains only come from bigger jugs, cams, and/or head work. I think the near stock setup of slip-ons etc. you are talking about ( What most folk seem to use, I'd bet ) flows enough until you really go for the higher H.P. Consider a modern rubber mount Sportster only has 61 ponies, & our M2L's have ( stock ) 91, and you see we run closer to the edge than a Hog. | ||
| Warlizard |
As mentioned, you will maybe gain a few HP. I went w/ the Force and Supertrapp combo to get a little more at low/mid RPM's. I also think the stock box is hideous. Even if I lost 5 HP, I w/ have changed it. In addition, I needed some sound. Riding a quiet bike can get you killed around here. You can make the bike "quicker" by changing the gear teeth. To get real gains, you need engine work. | ||
| Jramsey |
A cheap performance mod that you can "feel" the diff. is to cut 2" off the snorkel,move the AIT sensor the same distance towards the throttle body and slip on a K&N RD0720 filter. It measures 6 x3-3/4x 2-7/16 ID. About 35 bucks at the local auto parts store. It all fits inside the stock air box that some people call a benign tumor. | ||
| Wardan123 |
Before I got my Buell CF air filter (mostly for looks) I did gut the air box and install a K&N air filter. My results felt very dramatic once I gutted the internal stuff. The only you might want to do is to secure another Breadbox before you do it. (So you can go back to stock if you wish.) |
