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Old 02-12-2013, 08:42 PM   #27
ebrabaek OP
Beastly Adventurer
Joined: Jan 2010
Location: Grand Valley, Colorado
Oddometer: 4,871
Originally Posted by HighFive View Post
1) still bet she's getting enough air at intake, but we shall Visual appearances can be deceiving. Don't confuse velocity for flow rate. They're not the same thing. The intake pulls in a known volume based on the displacement and stroke....same exact volume every intake stroke. A reduction in the snorkel diameter midway would cause an increase in velocity thru that area but the flowrate of air remains unchanged. As a twin cylinder, the volume is only half of the total consumed (400cc per cylinder)....and these occur at different times relative to each other. So, the total demand on the intake is never more than what is required by only one cylinder at a time.....that is what's being fed.

Indeed, the air velocity will slow down as it enters the Collector (the larger box at the filter). This is good. A bit calmer air at the Collector. Atmospheric pressure typically fills any void (or vacuum created) nearly instantly. That will happen effortlessly without the bike in motion, simply because of the nature of the pressurized environment that we live in (though you don't physically feel that 14.7psi pressure). It's present always....more or less. Now, add to this some additional pressure from the forward motion, and the box is sure to stay fully pressured or even slightly compressed state. Additional air will not enter the box until one of the intake strokes occurs, and creates a void to fill, so to speak. Keep in mind this is happening only every other stroke across both cylinders. So, there is always a one stroke period of time for the box to refill before the next stroke. However, in reality it would refill almost instantly. Just another way to visualize how much time to move air in before it's used again.

A Triple (like Tiger) would be pulling in air constantly, but only by 1/3 the total perceived need. Aaaah....what rambling we've created. But fun conversation, nonetheless. Air is a fluid, yes, but compressible gas, thus much faster equalizing. There is an infinite amount constantly available at the ready. Behaves nothing like a liquid.

2) a good Dyno Operator should be able to give you one curve containing the best of both worlds "as a practical matter". Are you planning to RACE your F8? If so, then yeah...I could see a need for an absolute max HP curve. But I'm guessing that doesn't serve your best interest for the long haul. The custom tuning along with the new fuel control measures will likely produce such nice results, it will all be better than what you had before (assuming the stock ECU was not properly optimized). Caution: Extra Curves only cost me extra money. I only did it for experimentation and knowledge. I always ended up settling on one permanent best compromise.....very happily. FWIW

3) in matters of the Dyno Map versus the AT....

The Dyno will be used to build a "Fuel Map". That is the table with +/- adjustments in fuel injected. This is the one that matters most and will be left (or loaded) into your PCV. When the Toggle Switch (a separate item you must install) is turned OFF, you will be running on this fuel map. The PCV actually has the capability to hold a separate fuel map for every single gear on the bike. So, to take full advantage of such a sophisticated system, you need to wire in the gear indicator wire (where you pull that from on the F8, I am clueless). Consequently, done properly your Tuner will build 6 separate each gear. It's not mandatory but very beneficial.

When you download maps on Internet from Dynojet, you are receiving a Fuel Map variation. The Fuel Map has no bearing on the Auto-Tuner (AT). And the AT won't do a darn thing until you a build (fill in) the AFR table (Air Fuel Ratio)....but with what? No one really ever says....and I've not seen one to copy over. SO, you start with nothing and begin guessing....which could be inefficient at best, and harmful to the motor at worst. I finally settled on loading an AFR value of 13.2% across my entire table for my WRR.

When the Toggle is turned ON, the AT unit is self-adjusting the fuel curve (all over the place) until the O2 sensor is reading that exact value at that particular set of parameters (RPM & TPS)...nanosecond by nanosecond. My experience on the WRR was that the AT was reacting faster than the ECU could process....making the performance a bit choppy and unsettled in on/off...stop & go Trail conditions. So, I learned to always turn off my AT and go to my main fuel curve whenever offroad. The AT was clearly best employed in more steady state riding along roads & slab. Just be very careful NOT to accept the Trim Values imposed on the fuel curve (temporarily) by the AT unit whenever you plug in your computer to the PCV. as that will permanently overwrite the curve you paid dearly to create on the Dyno. If you saved a copy of that file on your PC, then no can always reload your Main Dyno curve. I must have saved mine in 3 separate places, I think. .

My $2,000 worth anyway.....

Ha ha ha.... Yes amigo... what have we done............... We shal see on the intake side.... You could be correct.... I could be correct..... Your in Dallas...Yes...???? I will be in Dallas somewhere between April, and June for a few weeks at the DFW area riding the stimulator for our new aircraft..... Dyno hits nothing with the box open... I buy the espresso...... Dyno goes bonkers with the box open..... You buy it..... and then we have a scotch..... Gonna be interesting, as it is purely is speculation. I have complete confidence in Eddie. I have watched him work his magic on their crf 450, and at the time the SXW. His bikes wins races, but more importantly he is a good man, that knows his stuff. In all practicality, I would have enjoyed one box, like the katoom guys can re flash their ecu.... But it is what it is. I think it might take a little.... read a lot learning on my behalf, But I am assured that I will not use low end torque. I saw that when he build my other thumper. Most will say that it lost low end torque, but it just is transparent as it takes off rather fast above 4-5k rpm. His race bikes spend most of the trottke either on or off, so delicate trail work might be something different than that. Visited another racer in Kali over the weekend, and he mentioned that on todays modern fi mx racers... The hardest part of riding them is from the truck bed to the track........ I think we are not alone on the monkey jumping stuff. Just waiting for the return. There will be pictures...... and videos..... and ehhhh.... uhhhhmmm... grin's.... and such...

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