Honda CBR 600RR Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
384 Posts
Interesting...but since the stock power level is more than I can already handle (i.e. still in the slow group at track days), I'm inclined to believe him. Now, if I was racing and every single horsepower will make a difference, I might disagree.

I think most of us here know that after market exhausts are mostly to save weight and because we like the looks/sound, not for the power.
 

·
Registered
Joined
·
8,768 Posts
what they do NOT discuss there, is what type of o2 sensor is required for the type of work that would be required for a self learning ECU

of which, NO motorcycle made today that i am aware of, ships with a wide band o2 sensor.
 

·
Registered
Joined
·
1,389 Posts
yeah i don't really agree with this article , i didn't get my bike tuned for huge numbers , if i wanted big numbers i would have gotten a liter bike
what i did was was a more efficient running bike , with a better A/F ratio that was smoother through out the whole range ,
now as a result of getting a better A/F ratio the bike made more power , which i didn't really care about , all i can say is i felt the difference between the two maps in the bike and liked the way the power felt after the dyno, she is quicker now
 

·
Registered
Joined
·
197 Posts
Discussion Starter #5
yeah i don't really agree with this article , i didn't get my bike tuned for huge numbers , if i wanted big numbers i would have gotten a liter bike
what i did was was a more efficient running bike , with a better A/F ratio that was smoother through out the whole range ,
now as a result of getting a better A/F ratio the bike made more power , which i didn't really care about , all i can say is i felt the difference between the two maps in the bike and liked the way the power felt after the dyno, she is quicker now
Same here, that`s what I thought when I read that
 

·
Registered
Joined
·
7,219 Posts
yea but even the article said, if you have a highly modified engine, dyno becomes useful.
a race bike which is highly modded should still gain from dyno..
02 sensor job is to correct fuel air ratio so i think that kind of makes sense.

stock o2 sensors are like Go-No Go guages as far as my understanding.
it either meets the requirement or it doesnt ( the fuel air mix) and depending on that the ECU adjusts or doesnt adjust the mix.

wideband meters, like you find on cars with aftermarket turbos are just more detailed o2 sensors that will give you an actual reading .

but paying dyno fees to get a couple of Hp is def a huge waste of money unless you race.
 

·
Registered
Joined
·
1,389 Posts
at temp with mods , my A/f was dumping fuel in the lower rpm range ( under 6k)
that was with the map from dyno jet for what i had on the bike , so we brought those numbers down , and took the waves out of the A/f line , i still have one more option and that is the ECU unleashed re-flash which is suppose to tune each cylinders A/F and not all 4 as a whole
also it pretty much removes the rev limit bumping making the rev limit smoother or so ive been told buy the ones that have done this



now ignore the hp curve and just look at the A/F om the bottom
 

·
Registered
Joined
·
8,768 Posts
yea but even the article said, if you have a highly modified engine, dyno becomes useful.
a race bike which is highly modded should still gain from dyno..
02 sensor job is to correct fuel air ratio so i think that kind of makes sense.

stock o2 sensors are like Go-No Go guages as far as my understanding.
it either meets the requirement or it doesnt ( the fuel air mix) and depending on that the ECU adjusts or doesnt adjust the mix.

wideband meters, like you find on cars with aftermarket turbos are just more detailed o2 sensors that will give you an actual reading .

but paying dyno fees to get a couple of Hp is def a huge waste of money unless you race.
Sort of right

A narrow band o2 sensor isn't a go no go sensor it gives variable voltage based on the amount of oxygen in the exhaust, a wide band is far more detailed ... neither control **** its up to the ecumenical to interpret the results and thus modify for

The problem with bikes is no ecu adjusts and on general the bikes are lacking one MAJOR part that is in all adjusting fuel control systems and that is intake volume (mass airflow sensor) right now motorcycle fuel injection is about on par with the fuel.injection system found on mid 80s camaros, tpi which is a closed loop fi system


Sent from my DROIDX using Motorcycle App
 

·
Registered
Joined
·
7,219 Posts
yea i didnt think about the MAF sensor. thats a good point.

has anybody had their bike dyno'd by two different machines? to compare the outputs.
i remember reading something that talked about dyno's being drastically different idk...
 

·
Registered
Joined
·
25 Posts
I work for a dyno company, so I have direct experience with this...

What they are saying would be true IF:
The ECU is self learning and re-tunes based on O2 sensor output
The ECU stays in closed loop at WOT
Fuel at WOT is based on O2 feedback

This is possible, but it depends on the actual control strategy of the ECU being used at the time. I have no idea what Honda is doing, but I doubt it even looks at the 02 at WOT, it probably just uses it at idle and part throttle for emissions purposes and ignores it above a certain amount of RPM and load.

Most ECUs have a range of adaptability built into them that can compensate for changes to a certain extent. An ECU might be able to compensate for a filter and pipe's increased airflow just fine. In the case of many production cars it can in, but in some cases a re-tune is needed to get the most potential out of this mod. My personal 2011 Mustang GT is a good example of this - change the air intake tube and filter assy and you usually need a new tune to compensate for the car to even run right. My old 2003 Cobra accepted a different air intake just fine and gained 25hp with no tuning needed.

So, it depends on the computer. But for them to make a blanket statement like that is wrong unless every bike ECU out there is self-learning and closed loop at WOT - which I doubt.

What they are saying about testing temp is true though. Make sure that all tests were done at the same temps to assure that you are seeing consistent and comparable data.

Also, test on the same tire at the same pressure. I have seen 7 to 8hp difference between the stock street tire and a race slick on a ZX-10. The slick was gripping the roller and had more rolling drag, which showed as a power loss at high speed.
 

·
Registered
Joined
·
2,722 Posts
What they are saying about testing temp is true though. Make sure that all tests were done at the same temps to assure that you are seeing consistent and comparable data.
A custom map usually takes 2-3 hours to complete. The temperature almost always varies during that time. Of all the dyno graphs I've seen (mine included), the temperature for the last run is higher than the initial run. How is one supposed to make sure temperature stays consistent?
 

·
Registered
Joined
·
8,768 Posts
A custom map usually takes 2-3 hours to complete. The temperature almost always varies during that time. Of all the dyno graphs I've seen (mine included), the temperature for the last run is higher than the initial run. How is one supposed to make sure temperature stays consistent?
its more about engine temp

a few degrees of air temp change will not make or break a tune


the goal is to ensure the bike is say @ 180 degrees every time a pull is started


not 115 the first pull, 140 the second, and 220 the third
or what ever.
 

·
Registered
Joined
·
6,283 Posts
the article is sham. the writer is using half baked info and fooling people who does not understand how control system work.

first,O2 senor is design for detecting fuel burning efficiency, not output. depends on the engine system, having good combustion efficiency may not always equal power output.

also, tuner looks for linear HP and torque gain through out the power band. an O2 senor will by definition does not have the capability to detect that.

i hate people perpetuating those pseudo engineering knowledge online. the general public will not know the difference.
 

·
Registered
Joined
·
6,283 Posts
A custom map usually takes 2-3 hours to complete. The temperature almost always varies during that time. Of all the dyno graphs I've seen (mine included), the temperature for the last run is higher than the initial run. How is one supposed to make sure temperature stays consistent?
once again, the ambient temperature delta would not make that much of a difference in the performance. in thermodynamic, the power output is a function of the working fluid's lowest temperature and its highest temperature.

for gas combustion, the highest temperature is the same. while the ambient delta is typically not large enough to make any significant impact during normal day operation.

though efficiency can vary slightly due to temperature growth.
 

·
Registered
Joined
·
25 Posts
There are three temperatures that come into play:

Ambient air temp - usually the dyno room temp. If the room has a good exhaust extraction system, this should not vary more than 5 degrees or so during the course of the test. If they are using something like SAE power correction, then it somewhat compensates for changes in ambient air temp. If the room does not have good exhaust extraction, power will usually drop as the test cell gets contaminated with exhaust gasses, causing oxygen levels to drop and CO / NOx / CO2 levels to rise in the room. It doesn't take a lot to have a major impact on power - forcing your engine to ingest exhaust gases is bad.

Intake air temp - usually similar to ambient temp, but can be warner depending on what the engine is breathing through. This is usually the air temp that the ECU reads, so keeping this cosistent pays off.

Coolant temp - Monitored by the ECU to determine overall engine temp. If the engine is cold, the ECU will be in cold start mode and adding more fuel - which could help or hurt power depending on what you need. If it is too hot, the ECU could (not sure if this ecu does this but some do) start pulling timing and adding fuel to try and cool the motor down. Normally this is fairly steady if you have the vehicle fully warmed and adquate cooling airflow in place from a fan system.

A proper test session should have the baseline tests done with the bike fully warmed up to realistic and repeatable levels, and each subsequent test should allow time for the bike to heat or cool so the bike can be run again under the same (or very close) test conditions. Once you start splitting hairs over a couple of horsepower, this is mandatory to get good data.

You should see the measures that the NASCAR guys go to in order to measure 1hp at a time out of 800+
 
1 - 16 of 16 Posts
Top