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Discussion Starter · #1 ·
Hey guys. Some new sportbikes are coming with adjustable engine braking parameters, and I'm trying to figure out how this technology works.

Is it something that can be applied to bikes like ours via aftermarket black box, or is it too integrated/mechanical to work as a retrofit?

Anyone have any experience with the tech?
 

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I have no knowledge of this firsthand, but I assume that the exhaust valve timing is somehow operated under electronic control to generate the desired level of engine braking. This is essentially the same idea as the famed "Jake brake" isntalled on semis and the like.
 

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I think that the programmable engine braking (and a lot of other electronic tuning) is done on bikes with "ride by wire" technology, ie, the throttle isn't directly tied to the throttle bodies; the throttle inputs are fed electronically to an ecu that samples other inputs and applies the resulting sum of the calculations to the throttle bodies.

The new Ducati, Yamaha, Aprilia, BMW and Kawasaki 1000's have ride by wire and can be electronically tuned in a variety of ways, besides engine braking.
 

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I think that the programmable engine braking (and a lot of other electronic tuning) is done on bikes with "ride by wire" technology, ie, the throttle isn't directly tied to the throttle bodies; the throttle inputs are fed electronically to an ecu that samples other inputs and applies the resulting sum of the calculations to the throttle bodies.
Or simply put variable idle :)
 

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Discussion Starter · #7 ·
Ah okay, it's starting to come together (sort of) .

Ride by wire is pretty awesome.

Did anyone read the article (forgot which magazine) about torque by wire?? Now THAT was interesting!

On a side note, is the SV can-bus? Not sure that's the right term... basically the system that ties all of the electrical systems together on new bikes. Especially those with electronic suspensions.
 

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It also is controlled by the idle speed, higher idle= less engine braking.
 

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It is that simple, change idle when throttle is closed (which is when rider is braking).
Trick is to do it exact amount at different stage in that braking time. Like less engine braking (higher idle) when approaching corner, more when turning or even more when at apex.
 

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Regarding "On a side note, is the SV can-bus? " : every car / motorcycle ECU ( engine control unit) must have a way to communicate with external tools (for garage reprogramming) . Also, on the newer motorcycles ( e.g. Multistrada) and in almost all of the cars there is the main ECU and a lot of other satellite controllers ( electronic windows, suspension settings, dashboard, ...) and all of these are communicating among each other on a kind of a bus ( CAN, FlexRay, K-line, LIN). For the SV, I'm not sure if its the CAN on k-line but most likely its a K-line.
 

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What a lot of people don't realize is that engine braking isn't caused by the opening/closing of the intake and exhaust valves as that happens every rotation of the crank shaft, regardless of throttle position... people say "Engine braking is caused by compression"... no... because the air in the cylinder acts as an air spring... it's compressed, but then springs back, pushing the piston down which cancels out any engine braking that it may create.

What engine braking is caused by is the vacuum created by the closing of the throttle bodies... the piston is trying to suck air in on the intake stroke, but can't because the throttle body (bodies) is (are) closed. THAT'S where engine braking comes from.

Adjusting that engine braking is as simple as keeping the throttle bodies open slightly on decel. As others have said, raising the idle speed does pretty much the same thing just in a different way.
 

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I raised the idle on the SV1000 as the engine braking was even stronger than the 650 and it sucked at the track going from the 650 to the 1k, and then I added the PC3 with the factory dual yoshi maps, and the bike now barely has any engine braking. Took a few days to get used to it, I love it now, sooo smooth...I cant wait to go back to the track with the current setup, the injectors are also firing now when I let off the throttle, so when I get back on it now there's little to no hesitation as before.
 

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Spark timing can have an effect on it, too. I've noticed playing with the low load (closed throttle), above-idle advance on my Mustang. If I dial back the advance then I get quite a bit more engine braking, which I like.
 

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the injectors are also firing now when I let off the throttle, so when I get back on it now there's little to no hesitation as before.
They were firing before, too... otherwise it wouldn't idle :) Now they're just squirtin a little more.
 

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Like ZoSo said engine braking is mostly controlled by ignition timing.
Except maybe on our bike because I believe the injectors are turned off while doing off-idle deceleration (closed throttle)
So if you have the ability to remap the ECM then you can adjust your engine braking.

Also our bike does not use bus communication except for communication with the scan-tool. And that is one way communication so barely a bus system.
The SV has at most 3 control modules ECM ABS and cluster the rest are switches sensors and relays no need for a can bus like a BMW or anything else
 

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On the sv1k, taking out the secondary butterflies also reduced the engine braking some as well.
 

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Like ZoSo said engine braking is mostly controlled by ignition timing.
Except maybe on our bike because I believe the injectors are turned off while doing off-idle deceleration (closed throttle)
So if you have the ability to remap the ECM then you can adjust your engine braking.
All correct. On your newer SV, the fuel shuts off completely when the throttle is completely closed for more than a second or so.
Easiest way to reduce engine braking on partial throttle is to install one of Steve's aTREs.
If you get the switchable version you can do an A/B test and verify the difference.
If you get the GiPro version, it offers three different settings and a GPI

What a lot of people don't realize is that engine braking isn't caused by the opening/closing of the intake and exhaust valves
Actually it is. Air is pumped in and out without enough fuel to combust. The "pumping loss" is what we call engine braking.
You are right that the compression and power strokes are not involved. The throttle opening doesn't matter as much as the lack of combustion.
I can prove this to any Gen2 owner with an open mind.

(The next contributor to this thread will be JayV, wait and see) :naughty:
 

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All correct. On your newer SV, the fuel shuts off completely when the throttle is completely closed for more than a second or so.
Easiest way to reduce engine braking on partial throttle is to install one of Steve's aTREs.
If you get the switchable version you can do an A/B test and verify the difference.
If you get the GiPro version, it offers three different settings and a GPI



Actually it is. Air is pumped in and out without enough fuel to combust. The "pumping loss" is what we call engine braking.
You are right that the compression and power strokes are not involved. The throttle opening doesn't matter as much as the lack of combustion.
I can prove this to any Gen2 owner with an open mind.

(The next contributor to this thread will be JayV, wait and see) :naughty:

Gen 1s(where fuel isn't shut off) have just as good engine braking as a Gen 2
vacuum of closed throttle plates is what causes engine braking with idel set higher, throttle plates are open slightly more, means less engine braking
 

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They were firing before, too... otherwise it wouldn't idle :) Now they're just squirtin a little more.
Actually, they stop firing until the engine hits a specific RPM and then the fueling pulses are activated again to hold idle. :icon_biggrin:
 
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