[SteveN]

Sorry for the long post, but this is interesting stuff...

Several posts have questioned the role of the lambda sensor and performance. Well I certainly found the combination for my bike.

Last week I installed the San Jose performance air filter and a new air snorkel/InDuct. Seat of the pants feelings was that the bike pulled much better from about 3000 rpm to the red line in all gears. This was shown to be true by 60-80mph and 80-100 top gear timed roll-ons and quarter-mile runs.

Compared to past times with my bike PRIOR to the air filter and snorkel installation, the bike was now faster:

60-80 mph and 80-100---

Stage 2, 3, 4 .1-.2s faster

Quarter mile times improved from an average of:

Pre-air filter, etc.---
12.03s

Post-air filter, etc.---
11.85s

I then DISCONNECTED the lambda sensor and another big improvement! Previously (prior to the air filter/snorkel) I had reported that disconnecting the lambda sensor, at least on my bike, decreased mid-range performance at all stages with the BBPower chip.

However, AFTER installing the air filter/snorkel, disconnecting the lambda sensor made a BIG improvement in performance. I also found that the BBPower chip settings changed dramatically from pre-air filter/snorkel setup.

Stage 5 is now best for mid-range through 8700+ rpms with little to no popping and overall a very smooth running bike.

Stage 4 is quite close in performance and smoothness. In fact gas mileage may be the only improvement if even that turns out to be true.

Stage 3 less improvement and Stage 2 doesn't give any improvement over times with the sensor connected.

Quarter mile times with the lambda sensor disconnected + the air filter combo have now improved to:

11.65s

60-80 and 80-100 mph top gear roll-ons improved on average another .1-.2s. I consistently get 60-80 mph times of 3.9-4.0s.

The Ducati ST4 (2 of them) that previously pulled my bike about 1 bike length on a 60-80 top gear roll-on now falls behind by about 1.5-2 bike lengths.

Just to make sure I wasn't imaging all this I re-connected the lambda sensor and retested roll-on times for stage 2, 3,4, and 5. The findings confirmed the improvement AFTER disconnecting the lambda sensor only WHEN the performance filter/snorkel are also part of the package.

SUMMARY: On my bike I find the best mid-range to red line performance combo to be-----

Current Setup:

Full Laser exhaust (open) + Laser cat replacement
BBPower chip
San Jose performance air filter
Snorkel/InDuct

Stage 5 (4 still very good)
Lambda sensor DISCONNECTED.

Without the air filter and snorkel, disconnecting the lambda sensor gives the poorer mid-range to red line performance at each stage setting.

As Lennie has suggested, lots of changes can occur when the bike starts gulping more air and not all these changes are apparent on a dyno.

Some may find this setup strange or question it, but it sure works for me. While I don't have any dyno numbers, quarter mile times at the same strip with nearly identical environmental factors certainly confirm these differences, not to mention the huge smile on my face everytime I hit the throttle in any gear.

And isn't that what all this is about. Good luck in your performance search.

steve

[This message has been edited by SteveN (edited 08-26-2001).]