Do your race motors live between 2000 and 4500 rpm's and between 40-70kpa?

 

Here is where it works. This happens to be about 4 min of operation.

http://www.nbs-stl.com/CRX/Autocross...and%20Time.png

What's your point?

 

I can see how that would make sense - presumably race engines are always running in the power band and therefore looking to be nailed around the 12.9 (or whatever lambda given you probably aren't running stock Gas)??

 

I can run 93 but I elect to run 110 leaded. It just smells better.

I run the Sporty at about 13.8 AFR most of the time. Keep in mind that a motor running thru a cat will kill the cat at those AFRs. Back firing thru the exhaust will also kill them.

Andy

 

Just putting your statement into context.

 

Pretty decent read.


http://www.diyautotune.com/downloads...20Shootout.pdf

 

Why talk high performance then state you are willing to kill power using higher octane fuel than necessary?
Since gasoline makes the power, the more additives introduced reduces the amount of gasoline in a gallon.
Rule of thumb is to run the lowest octane the engine will tolerate when tuned for best power.

On another note, I would not recommend tuning a race engine with NBs that will be run in high load/rpm areas most all the time. (Racing)
This is exactly the opposite as the typical street bike runs most of the time at cruise and light loading with a lot of low rpm/load running. (Street)
Narrow band sensors are very accurate and fast acting so tuning a street bike with NBs is more desirable than wide bands whereas a race vehicle run in high MAP are more desirable because most all running will be at 12.8-13.0 AFR.
JMHO,
Bob

 

That motor has no knock control. In competition, it is run way harder that I could ever duplicate on the dyno. It is typically run in 100-120 degree air in the dead of summer. Whatever air above asphalt is in dead of summer is. Way hotter than you would ever want to test on the dyno. Leaving a little HP on the table is way less of a problem than leaving engine parts in the sump.

I would much prefer running a wide band in it's sweet spot compared to running any NB right at it's limits. What happens to your tunes when the 02's start getting lethargic with age?

I will take a wide band every time.

Andy

 

Are you saying that a WB doesn't get lethargic with age?


I don't see how tuning a race car has much to do with tuning our Harley street engines. Best power, most efficient engines I have ever worked on would never be tuned with lambda sensors period. Turbine inlet temp is the key. Brings about as much to the conversation as tuning a race car that lives above what most of our Harley red line is set at. BUT the good news is. It is living above where NB are accurate at and I don't believe anybody is suggesting to use them there. So, you have to take a WB sensor or get good with EGT tuning. Back to our world. Most of these bikes live between 2000-4500. There are thousands out there running around for over 100,000 miles running closed loop controlled by NB sensors. With no ill affects.


I don't know how many performance Harley Vtwins you have owned and tuned. I own several and I understand that the calibration allows me enough room to have an area tuned for performance and an area that can be ran in closed loop controlled by NB in the same calibration.


Example. 120 with a procharger making 200hp. Tuned w/ TTS and the area from 2000-3500 from 30-70 kpa is running in closed loop. Doesn't affect the performance area of the calibration one bit. Because that area is not in the performance area of the tune. These are street bikes. Where customers are concerned with gas mileage and to have good power. Good news is. Most of the time the throttle is open from a steady state. You get into the 80-90 kpa area and you are out of the NB closed loop area anyway. It has been thought out pretty well.

 

The stock VEs? I don't know how accurate they are but what I do know is that the fuel table on my stock map is set from 14.7 to 14.2 across the board. The stock map for my bike doesn't richen up until you hit the high rpm areas or WOT.

Unless I'm wrong (which I very well could be) my ECM works off of the feedback from the 02 sensors with the stock tune and more than likely just uses the VEs as a starting point of reference.
This is the reason why I don't put much faith in the stock VE settings.

For all I know the factory could of averaged or factored out the VEs from a few samples and applied them across the board for production.