Engine Sweet Spot

[tundra tom]

During the Hunt for Red October Ride I was checking the tach out while hitting the twisty's. Most of the time the tach would be in the 4000 - 6500 range in 4th and 5th gear and 3rd for the tight corners.
I've tried running 6500 - 9000 rpm and one (or more) gear lower and still do on occasion but tend to go back to using the big block torque method and not spin it up.
Granted I do have the fly's pulled, benefiting the bottom end. Am I the only one that hangs in the midrange?

 

[Cap'n Bob]

When playing on the C14, that's where I stayed the most!

 

[obrienl]

My bike is stock and I tend to play in the 5000-8000 or so range to use the engine braking.

 

[tundra tom]

My bike is stock and I tend to play in the 5000-8000 or so range to use the engine braking.

Lonnie, as a race engine builder once told me.."Brake pads cost allot less than engine re-builds". Of course YRMVG. 

 

[obrienl]

I use both engine and brake pads.  It's even really rare that I am riding somewhere that has curves so I wouldn't consider it abusing the bike.  Now if I were in North Carolina or something I would definately has to make some adjustments.

 

[s.ga.rider]

I am on the other end. If I am in some curves I run around 4-5k but around town I usually run lower rpms, 3-4k.

 

[bob14]

Don't push like I used to 4-6 in the twisties and in town 3-6
tooooo many LEO and Idiots in town to enjoy the power

 

[Fred H.]

I'd prefer to keep the RPMs down lower and have more torque there than having to spin it up to 7K-8K rpm just to get anything out of it, and low end torque is what you really need on a touring or sport touring bike, not high end HP like you want on a sport bike.

Before I removed the secondary butterflies, I found I had to do a lot of downshifting and spin the engine up into the 6K rpm range to be able to get any torque out of it. After removing them, I find I can easily pass in 5th gear at 4K rpm and have enough torque that I can just roll on the throttle.

This is why I'm trying hard to convince the companies that are offering to reflash the ECU that they really need to look into opening up the butterflies at a lower RPM, cause this does indeed provide more usable torque down lower in the rpm band where you need it.

Now that the ECU has been downloaded, I've had a chance to see just how restrictively the secondary butterflies are programmed from the factory. They pretty much open them wide up at the higher RPMS (around 8,000 rpm), but in the lower ranges, like around 3K rpm for example, they are closed down to only 24% when the main throttle is at 40% and only open up to 33% when you open the throttle to 76% and 41% at full 100% throttle opening. This means that even though you are opening the throttle 100% at 3K rpm, the secondaries are only open 41%, and thus they are the restricting factor and are in control of the ramp rate and how fast the engine responds to your throttle commands. A change at the primary throttle of 60% (from 40% to 100%) only results in a change at the secondary throttle plates of 17% (from 24% to 41%). Once you see the actual mapping of these secondary throttle plates, it become obvious how restrictive they are.

There also is a second map for them that is used in the ECO mode on the 2010 and 2011 bikes which is programmed even more conservatively.  At 40% throttle and 3K RPM in ECO, the secondaries are only open 18%. At 100% throttle they are only open 25%.

The result is that they end up acting just like restrictor plates do in NASCAR engines. They simply limit how much air (volume) can flow into the intake in the mid range RPMs. Which is right in the heart of the power band where you need it most.

The biggest gains will be seen by making adjustments to them in the 2,500 to 6,000 RPM range and to make them track the main throttle plate changes in a more linear manner, changing both the percentage they are opening, and the ramp rate that they open at.

 

[MAN OF BLUES]

so with that mindset, just how do you keep the VVT circuits clean, they sure don't seem to be getting much usage there..... )

heaven forbid they would have made this bike with a 5 speed tranny....