Hey. I have the SE Street Legal Tuner. It gives you the ability to change the VE tables up to 5% but not the Lambda tables. What I dont understand and what I have not been able to find doing internet searches is this. How much effect does a 1% change in the VE tables have to the Lambda tables? Thanks.

 

I don't know if there is a direct relationship to be made. The Volumetric Efficiency table is the efficiency of the engine at a given rpm. It isn't going to make much difference at 5%. I know the Street tuner won't work with performance cams but here is an example for you. A stock cam ve table at idle would be around 85% efficient and the mixture would be ideal or nearly. If you added the 5 to it it would be around 90% which would be as far as you could go. The efficiency didn't change you just told the ECM it did and the ecm thinks it needs more fuel. It may make it change enough you would smell it a little when cold. If you put drop in cams in you would have to drop the VE in the idle area down to between 55 and 75% VE. They would be running more rich than the stock cam was at 90% because the cams with more duration and overlap than stock cams aren't as efficient as the stock cams at idle rpms. When you get to 2500 or so rpms the stock and performance cams will be running about the same efficiency and the numbers will be around 85 to 90 and both will be at the same AFR everthing else being equal. If you go on up to WOT at 4000 or so rpms you will be at 95 or so on the stock cams and performance cams will be from 100 to 120% and both at the same AFR. Hope this helps. Changing exhaust, cams, porting the heads, Valve sizes, and different intake system all change the VE of the engine. How much air the engine is capable of moving through the engine is what the VE is in simplified form.
Since you can't change the AFR tables on the street tuner it is more important to understand the effect of different exhaust systems and air filters make. A 2 in 1 will improve the efficiency of the engine at idle to wot so it will need to be richened up 3 to 5%. This is all subjective but should give you an idea of what the VE is. Due to the scavaging effects of the exhaust and ram effects of intake and longer duration cams you can have over 100% efficiency.

 

Approximately .068 lambda. General rule of thumb is 10% change in ve equals 1 afr. Not a guaranteed formula but will get you close.

 

Thanks for the information. That is what I looking for. The SE Street Tuner is not ideal. But it is slightly better than a stage 1 download. When I bought my bike I got it for next to nothing with the reward points I received. The bike is just a stage 1 using Harley parts.