Someone emailed a "performance cam" question

sam2019

Administrator
Staff member
Distributor
Developer
477 Owner
21. September 2021, 20:09

I received this via email and I have to say I share this sentiment:
These performance cams for stock bikes without programmable ECUs are nonsense. Anybody telling stories about more power is making it up or delusional. Why? because the valves are open a bit longer or the opening is a bit wider/deeper BUT the ECU rules the amount of fuel mixture and as long as that does not change the timing and positioning of the valves makes zero difference.


Comments? Does this have any bearing on Dools dyno results? I know he has the PT but did he change the fueling in the map before the dyno run?
 

Sasa

Mediocre pilot - Average mechanic - Crazy tinkerer
Staff member
Developer
477 Owner
The guy is partially correct.

Even if you make no changes, the stock ECU will "self-adjust" to the higher amount of air reading the output from the O2 sensor.
In cruise phase the lambda will tell the ECU the mixture is too lean (as a consequence of the higher amount of air provided by the higher lift/duration of the performance cam) and the ECU will act accordingly, adding fuel to the mixture. So closed loop is covered.

That isn't true for the open loop phase, when the ECU will read its own table to look how much fuel it has to inject and that, unfortunately, has to be changed to take full advantage of the performance cam.

Anyhow please bear in mind that the stock map is rich at WOT above 5000/5500 RPM. That is done to provide some additional cooling to an air cooled engine, therefore the performance cam will still prove beneficial, even in the open loop!

It won't be the same as properly fueling it, but the difference (specially at higher RPMs) should be noticeable!
 

Dool

Backyard Bodger
Staff member
Distributor
Developer
477 Owner
21. September 2021, 20:09

I received this via email and I have to say I share this sentiment:



Comments? Does this have any bearing on Dools dyno results? I know he has the PT but did he change the fueling in the map before the dyno run?
Which Dyno Run ? I am running RB on both bikes and have been for months. With the PT it would have been changed from run to run.
Good email, it has me wondering what he is trying to say and how it relates to my results:unsure:

Placebo effect comes into play with Ego, o_O like when you get a Cam fitted and you pick up the Bike and part with the Money, it hurts less if the bike runs really good and strong so all the quicker you can forget the Money spent.
If you believe it helps also, skeptics who just fit the Cam ( or have it fitted ) and skimp on the way to more power are easily convinced that they have been ripped off.
Plus some people are Noisy, they buy something , it doesent meet "Their Expectations" so they make a noise.
 

sam2019

Administrator
Staff member
Distributor
Developer
477 Owner
Placebo effect comes into play with Ego, o_O like when you get a Cam fitted and you pick up the Bike and part with the Money, it hurts less if the bike runs really good and strong so all the quicker you can forget the Money spent.
If you believe it helps also, skeptics who just fit the Cam ( or have it fitted ) and skimp on the way to more power are easily convinced that they have been ripped off.
Plus some people are Noisy, they buy something , it doesent meet "Their Expectations" so they make a noise.
Well, it was a pre-sales question so he was basically asking if its worth buying the cam without also having the FuelX. I told him I am not sure but would put it to the discussion. I think the question has been perfectly resolved by Sasa. I know i could have told him to ask in the forum but the thing is, for some people asking something publicly is a big step and I really wanted this cleared up. So maybe after reading the reply here he will register too ;)
 
Top