Had the Bird Dyno'd

[porterb123]

I wanted to find out if the gut I bought the bike from lied about the 158 hp and to check the air/fuel map. Went to Lunfords Honda here in Houston. The mechanic who did the dyno run builds motors for road racing and even had a Bird motor on his bench...good guy.

Anyway, the fuel map was close to perfect, really flat across the rpm range..no adjustments.

139.4 HP

80 ft, lbs Torque

Dynojet 250 machine

Temp of 90 F

K&N filter

PC 2

Yoshi RS3 header system

How much HP does the ram air sys. add at speed?? These power readings are not really any better than than the cycle mags post for stock machines. I know the header removes alot of weight that helps in the power to weight ratio, but had assumed more power from this setup.

As a side not the mechanic told me about an R1 he dyno'd and checked the fuel map on...perfectly flat A/F ratio and 161 HP. No turbo or nitrous. I asked if he knew what they had done. His reply was they would not say...just wanted to check out their work!

Watch out for a stock looking R1 in Houston!!

Porter

[ironmike]

A number of variables come into play, but generally speaking it seems a 6% boost (at very high speeeds.. yeah, I know that's subjective) is typical. Some folks in the aviation field can offer more specifics, but that's the general consensus for unassisted (no turbo/supercharger) ram air applications.

[Pete in PA]

6% for ram air is what I've heard also.

So there is a Dynojet model 250 out now, my last run was on a model 150.

I got 135 for my bike bone stock.

[pace]

Also bear in mind that you will see significant discrepancies across individual dynamometers - even those of the same brand/model. A bike with 130WHP on one dyno might produce 142WHP on another. Remember these dynos are really measuring torque (and then extrapolating horsepower), and there are several different methodologies of metering this output at your rear wheel.

-Pace

[SwampNut]

How much HP does the ram air sys. add at speed??

One of the mags did a ram air test once and came up with 3-5 HP typically. The XX and busa were most efficient.

[bar10dah]

A bike with 130WHP on one dyno might produce 142WHP on another.

I had the same dyno guy run my bike on two separate occasions. He had replaced his dyno since the first time he ran my bike, so I got a chance to see the difference two separate machines could make. The first time I got 137hp and the second 132hp. The first time I believe the temps were about 10 degrees cooler, too.

[bar10dah]

Oh, and I was at about 1.1 kft in altitude.

[RodeRash]

I have a little problem believing the 6% ram air numbers. Aprillia is making a big deal about their new ram air system. It's located in the high pressure area on the nose of the fairing (like an RC 51). They claim in their press release 3% at maximum speed. I would maybe believe 3-5 HP at top speed on the BlackBird. Probably closer to 3.

[ironmike]

As I understand the 6% concept, that's at the crank... so deduct the average of about 15% drive train loss... For example, an engine producing 150HP at the crank, enhanced a 6% ram air factor (at some obviously high speed, value X), is now producing 159HP. Ok, now deduct the usual 15% drive train loss (159 x .85 = 135.15). So, that engine which was actually producing 127.5 RW/HP (crank HP of 150 less 15%), when enhanced by ram air (at X speed) picks up about 7.5 HP... which is down to about a bit over 4% at the rear wheel...

The math is only approximate (too many other variables come into play), but you get the idea..

'Doesn't sound like much, does it..? But, dependent on a number of variables, not the least of which is the efficiency of design, it can (and most likely will) make a difference.