Ramair filter arrived...

[HansO]

Just kidding of course, crazy pricses

 

[Speedy]

Gentlemen, might there be interest in this? This plenum would be molded, clamp directly to the throttle bodies, use an external filter, could be used as a supercharging plenum instead of the god awful ones in current use (with an appropriate restraint), and would require a trimmed bearclaw or fabricated trim piece to attach to the bearclaw/tank tabs. Ram air horns, nozzles, etc. could be adapted to the plenum as well. I also already know that there will be some intake noise, an intake note that stays constant but changes in frequency and amplitude with increasing throttle opening and rpm.
If there is sufficient interest, I will look at tooling and prototyping costs and then determine a projected unit cost.

 

[Steel]

Bloody tightwad

Damn right!

I'm saving my money for gas to ride to Florida next week.

 

[IMFASTTOO]

WELL those close fitting plenums will kill the hp output on the Rocket

 

[Speedy]

Painting with a pretty broad brush there! Absolutely, if everylast hp at peak rpm is desired, this is not the way to go. If you want the most average hp across a wide range of rpm, a properly sized plenum is the only way to go. If you run the salt flats or drag race exclusively, run individual TB runners. But if you want a wide power band, use a plenum much like virtually every modern roadrace bike has under the tank. All performance choices on street bikes involve compromises. Let each rider choose what works for their riding style and useage. To say that this or that kills horsepower is useless unless you say how much is lost, at which rpms it is lost, and more importantly, acknowledge where power may be gained. Only then are potential users informed and able to make better choices.

 

[happyhenry]

wow,i guess you you told us. i am intrigued by this concept,but what are the hard numbers here ??.what can we expect to gain overall,more torque down low,a more consistant torque curve.and how do we know anything without some kind of testing or computer modling.these bikes came with a plenum stock, and it doesnt seem to work very well on these bikes.i threw all that extra plumbingaway and use 3 unifilters,it was a huge improvment.

 

[steve59]

.......

 

[Speedy]

My response was not to "tell you" anything but to remind Art that his statement was so broad as to be near meaningless. I acknowledge that he is correct but also that having the most peak horsepower is not every rider's wish. Many of us prefer a broad power band with early torque delivery and accept that we won't win at the drag strip.

As to the stock plenum, it is a compromise as well. However, the problem with it is not the plenum itself but the dual small inlets into it and the ducting to them. The inlets are in the wrong place; they are too small, there are two of them; and the ducting leading to them is very constrictive.

The model I posted is a compromise as well. Several weeks of computer simulations of the intake, cams, and exhaust systems of the R3 led to the development of a header and intake modifications and then to two plenums, one of which you see here. Dyno testing evaluated the designs and indicated that the designs while not perfect where way better than stock. The design goals where to stay under a 6,500 rpm limit, work very well with stock cams and a good aftermarket header, such as the Predator by Sam, or the one I designed, built and use, which is not marketed, and then also work with cam upgrades that do not move the rpm limit to 8,000 plus rpm but stay in the stock range.

I have no issue with Carpenter Racing, their engine modifications, or exhaust header. They apparently work well and are reasonably reliable. My hat is off to them for accomplishing what they set out to do. Nonetheless, their package is not for everyone.

As to what one can expect with a sound plenum design: more average horsepower over the designed rpm range. This plenum will start making a difference at about 1,900 rpm, increase torque significantly at 2,400 rpm, levels off up to 3,000 rpm and then rapidly increases torque to 4,000rpm at which point ithe torque curve begins to taper back. There is a loss of horsepower above 5,500 rpm compared to individual filters but power there is still greater than an under tank K&N. And all of this is varied by the exhaust system used.

The combination I used on my bike, with stock head and cams, was tested on an eddy current dyno which allows controlled acceleration rates (and one I did not own or operate.) At 20% throttle, 75.79 ft/lbs were developed at 2,500 rpm. At 30% it pulled 103.59 ft/lbs and at 40% throttle it pulled 120.85 ft/lbs at 2,500 rpm. For those of you who have dynoed your bikes on eddy current dynos, these last numbers are probably close to what a stock bike with Jardines and three filters pulled at WOT. And at WOT it pulled 155.75 ft/lbs at 3,936 rpm. However, by 5,500 rpm torque was down to 114.10 ft/lbs where it leveled off and gradually dropped to 107 ft/lbs at 6,500 rpm. I have dyno charts to back these numbers up as does the shop that did the testing. And my bike is listed on their shop wall as producing more torque than any naturally asperated bike they have ever tested.

This suites my riding style and the fact that I ride two up with my spouse frequently. I don't care that it doesn't have more total horsepower than some other R3's. With this much torque across the normal operating range it is a blast to drive, is smooth as silk, has no intake chirpping, and pulls like a 16 year old with a new PlayBoy.

 

[barbagris]

I do love it when engineers talk business.

 

[bruce aussie]

Very interesting someone with some numbers to help us less informed. Would it be possible to post some photo's. Do you run a big KN on the front of that intake with a custom claw over it?