Combustion experts: You got some 'splainin' to do

[blowndodge]

Your forgetting that air is mixed with that fuel trosco. At any given throttle opening your letting in a certain amount of air (opened throttle butterflies). The TFI allows more fuel to be brought into the air to mix at whatever throttle opening you have.

In theory, optimal mileage would be produced at the optimum air/fuel mix ratio. That ratio gives the best "bang" for the buck per cycle.

As Bob asked earlier about pushing down the piston, I feel the need to shed light as he is thinking in the right direction.

To get a stock engine to produce more power you need to add a bigger payload (fuel and air) to the combustion chamber. This larger payload will burn longer and thus driving the piston further down the bore before expending all it's energy.

That's why when I hear reports of who's done what to their Nomad and how much more powerful it is I know if it's physically true or not.

Example: The limiting factors as to why our Nomads are low on power is in the head and injection system. I know some are going to say, "wait!! "exhaust and air intake are it!"

Those are "after the fact" mods that are tailored after the engineers determine how much power the engine will make and design the ports in the head, valve size and lift and duration (amount of time the valve is open) THEN design the exhaust and air intake opening based on that.

You can't add more fuel and air if the head and valve train doesn't support the additional fuel your trying to introduce.

If you look at a Meanie 1600 you'll see a different head design, different cam, larger injectors. This tells you right there that adding an exhaust and intake system to your Nomad is not going to make it haul a$$. It may run a little more freely but thats it.

You need to get a bigger charge in the engine to allow the burn to last longer, thus pushing down the piston further to get power.

There are many other factors like weight of the crankshaft that allows how fast a motor can rev up. Light crankshafts whip up quickly but provide no enertia. Heavy crank engines has lots of "flywheel" enertia. This means that once the crank is spinning it tends to want to continue to spin. Light crankshafts spinning can be stopped more easily by drag placed on the engine.

A Nomad with a lightened crankshaft, fully ported head with bigger valves with more lift and duration with a large injections system WITH a free intake and exhaust system would totally blow by a V2K Vulcan.

Just take a look what HD did with their V-Rod. It's a small V-Twin that hauls A$$. Light weight crank; head design totally different than a Nomads to flow more fuel up to 9K rpms.

With AQMD smog restrictions, HD is going to have to go to this water cooled design with all their bike soon.

Hopefully this explains some of the questions that my earlier answer opened up!

[phenrichs]

That brings up another question BD. Is the cylinder and block the same on the nomad and meanie with just a different head? I wonder if it would be like the older chevy v8's where you could swap heads and boost flow or compression to get some more ponies out of it. The bigger injector is an interesting item as well.

And boy when HD has to go to all liquid cooled you better get in line cause the waiting list for Vulcans is gonna get longer than it already is.

[dogdoc]

mpg DO go down my in city went from 30-32 down to 28-29 not bad but down. Im sure hwy will too. Not sure how some claim they went way up on the hwy. different strokes for diff folks I guess.

[blowndodge]

The ECU is different on a Meanie OP. One of the parameters is that the redline is 6200 instead of 5900 I believe.

[phenrichs]

hhmmmm. Just pondering the ridiculous that's all. you know kind of like the hd guys did when they started with 120 inch engines and leftside belt driven blowers. Just thinking about how much more potential one of these beauties really has.

[blowndodge]

You have to experiment and fail until you hit on something that works.

In my motorcycle drag racing days head porting was part of the "unknown". One year somebody (Byron Hines of V&H) came out with ported heads for his rider's (Terry Vance) honda 750 4 cylinder bike. that bike made so much more horsepower that team dominated racing for 20 years. His "discovery" soon became known amoungst the racing crowd and now head porting and shapes and designs are a common practice. Head porting is the #1 factor in producing high horsepower.

Reading his story he said he was just playing around in the flow room with some old heads and stumbled on it.

[Todd]

Originally Posted by Doc (Lonewolf)

mpg DO go down my in city went from 30-32 down to 28-29 not bad but down. Im sure hwy will too. Not sure how some claim they went way up on the hwy. different strokes for diff folks I guess.

Keep playing with your setting Doc until you reach that sweet spot. Mine did the same as far as losing MPGs and on the Custer trip I kept fiddling with it just in small increments at a time....now have it up around the 40mpg avg range WITH the performance benefits.

[phenrichs]

Todd that is exactly what I am doing now. I was getting 32 hwy to Custer. Plugs tell me it was rich.

[caper]

Explosion is result of expanding gases,from an ignition source, a bomb,in gasoline engines? in rifles,Its how you harness the explosion, force a piston down, bullets to accelerate etc. Personally I don't think its the expansion of Heat .Heat is the byproduct!

[reaper]

Originally Posted by todd (Nomadis Custodis)

Yeah, it's a little hotter than stock........keeps melting a hole in the top of the pistons though

no wonder he needed a TFI

[AlabamaNomadRider]

You guys are way over my head. I just ride em, take em to the expert when it comes to things like what you are talking about.