Suggested AFR for VP Racing Octanium leaded with BP98

Hi All - Does anyone out there happen to have tuned a N/A vehicle using BP98 as a base and mixed in the VP Racing Octanium at the recommended blend,that's one can to 38 litres, and can recommend a good AFR to being targeting the tune for?

If I'm understanding the course material correctly, I also/first need to establish what the correct Stoichiometric to set the lambda value to 1.0, and then tune from there using lambda as my basis?

You really need to give more details about the engine system and application. Generally thermal management and combustion stability are the primary concerns (tending to richer) then torque. Best torque is usually +- 0.05 around 0.87 lambda on NA applications if not knock limited.

What engine and is it direct injection or port or carb/Throttle body injected, what compression ratio, is it on load for 11 seconds or 1 hour endurance stints on a circuit or flat stick in a boat hull?

Ah I see.

MV Agusta F3 800 - N/A Motorcycle, with track focus

Port Injection ~14.5:1 compression

Hopefully someone here has experience with the platform.

Can you dyno the bike or do you need datalog in track?

Do you have any knowledge of factory tune?

Can you fit a knock listening system and run ear buds?

Can you run EGT or head temperature sensors?

Probably safe to start closer to 0.8 lambda with the fuel additive and try leaning it out progressively.

I do have access to all of the above, and the bike will go on a Dyno run by someone who knows what they're doing (not me) to get the best results.

What I'm looking for is guidance on the starting point from those who have run this mix before so we head in the right direction from the get-go.

Steve,

Couple of things

1. Unleaded gasoline has a Stoichiometric of 14.7:1.

2. Mixing octane booster will not change the Stoichiometric.

3. Using a leaded octane booster with unleaded fuel is not needed, use the unleaded VP stuff. That's what I do.

4. If the engine genuinely has a static compression ratio of 14.5:1 - Use a race fuel. This will tell u Stoichiometric on the data card.

5. I run 99 unleaded and I add 100ml to 20l of fuel. The instructions on the back tell u mixing ratios if u don't want to kill the lambda sensor. This gets me to approx 102 RON.

Thanks for that info, very usefile.

I did look at the 'unleaded' version, and found it was 7 numbers increase, where as the leaded was 8 numbers, and mixing at the full strength ratio, one can per 38 litres with the unleaded version, still added lead...

I'm all good if I need to replace the O2 sensor now and again, it appears with my bike it's a narrow band and not used by the ECU for 'performance tunes', just for emission control, so it may end up being switched off completely.

I am also looking at using the AIM LCU ONE lambda controller/logger, which comes with a wideband sensor that if the description is accurate, won't have an issue ( or less of one ), with a leaded fuel.

Looking at the data on the LCU ONE, it uses a Bosch LSU4.9 sensor, these are not designed for use with leaded fuels. They typically last around 50 hours in a leaded fuel exhaust before they fail from the lead deposits clogging the sensing chip.

That particular octane booster works quite well.

I'd likely start at .85 lambda with conservative timing and see what works best on the dyno from there, but you could certainly start richer or leaner than that. I'd be more careful with initial timing while you sort out AFR.

Thanks for confirming both of those

50 hours on a sensor should be fine, as for me that's between 35-40 track days....though I will see what is out there for leaded compatible sensor.

Thanks for the pointer on the AFR - I'll get the logging sorted out and see where we're sitting.