MoTeC Global Forum

Hope this is in the right category as it is related to tuning.
After watching the excellent webinar run by Pete about tuning the engine offline with data logging I was curious to everyone's thoughts and opinions on this subject.
Unfortunately i don't have access to a dyno so all my tuning is done live with someone driving the car for me on the street or using the logging option as discussed in the webinar when driving by myself.
My question is what gear is it best to use when loading the engine for a lambda trace to use for this method ? I would assume that at a given load the lambda reading would be slightly different in every gear correct ?
Should you always use the same gear for each time when doing lambda tuning or is it not so important ?

The slapping of the throttle will be enabling the acceleration enrichment, so you would want the avoid that.
The highest gear is best, but <practicle for street tuning.
you should have similar data in every gear.

So 5th gear on a 5 speed gearbox would be best ?

20B wrote:So 5th gear on a 5 speed gearbox would be best ?

Using the lowest gear that you can achieve traction in, yet has a sensible duration to achieve smooth log graphs.

Yes a higher gear will be great, but there are obvious safety and legal aspects doing that on the road.

But with logging, you can use many driving conditions and view at your leisure

I got pretty close with my fueling using that webinars idea of trying to stay in a cell for 1-2 seconds by using my brakes. I'd pick a cell I wanted to get to, run up to the cell carefully apply the brakes while staying in the cell and logging, let up on the brakes, move to the next cell, repeat. Pulled over grabbed the logs into I2 did my lambda was to each cell and bingo it was almost spot on for the next pull. I used 3rd out of 6 gears to stay legal.