FAST wideband

[foxspy]

Hey guys,

Has anyone compared their FAST wideband accuracy to other wide bands?

Mine seems off. I was on the dyno and my FAST was reading 11.94 and the dyno was reading 12.5:1, this is with nitrous. While N/A, my FAST was saying 12.5:1 and the dyno was saying 13.0:1. So it's about .5 off.

This is at WOT. Not sure if it's off by the same percentage everywhere.

What do you guys think? I made best power by tuning to the dyno's wide band.

I had another wide band in awhile back and it was about .7 off. I called FAST and they sent me an option file to "calibrate" the O2.

 

[norbs]

Was the sensor brand new on the dyno? Is your sensor new?

 

[foxspy]

The filter on the dyno was brand new.

My sensor is about 3 yrs old, about 12k miles.

 

[bruce]

Originally posted by foxspy
The filter on the dyno was brand new.

My sensor is about 3 yrs old, about 12k miles.

The filter has little to do with the actual accuracy of the sensor.
Or how the unit's been taken care of.

You should be tuning for the best HP, the actual AFR really doesn't matter. You just need to know what numbers correlate to what's a good baseline. A dyno doesn't begin to themally load an engine like a full run does. I'd use the info., for developing a good base line, and then developing the tune from there.


BTW, I've run a dozen or so cars about back to back on my own WB, and have seen anything from a 10.8 to 12.2 as being best, at the Nats. Tuning to a number will get you in trouble, in the long run.. Just pointing that out since some folks seem to miss it.
HTH

 

[norbs]

Well i have s solution for your problem but its going to cost you $349 and you have to build and adapter to use the ntk sensor.

You need to purchase an innovate lm-11 unit and connect your old ntk sensor to it, do a datalog with the fast in open loop. Compare datalogs under the same conditions and you will see if theres still an issue with your fast box.

 

[norbs]

Also, Bruce i do not understand that one car will make more more than another at the same a/f. An engine is just an air pump, and for a certain mass of fuel its going to produce similar results, provided all other variables are constant within reason.

 

[bruce]

Originally posted by norbs
Also, Bruce i do not understand that one car will make more more than another at the same a/f. An engine is just an air pump, and for a certain mass of fuel its going to produce similar results, provided all other variables are constant within reason.

There are many different preferences in tuning. Timin will have an effect on indicated AFRs also.

Any AFR richer then Stoich., is only being used for in cylinder cooling. Some tunes that say use more timing, need more cooling to stay out of detonation.

The cylinder to cylinder variances, between each cylinders firing, aren't to be trivialized. A great deal of the latest technologies are about balanacing the differences. ie while folks hype the friction differences between roller and flat lifter cams, it's as much about grinding accuracy as friction. Take a look at the diameter of a lobe grinding wheel. The reason it's so large is to min the variances from one lobe to the next.

It all does matter. Look at the extremes in detail that a NEXTEL engine shop goes to. It's about the details that wins races nowadays.

 

[foxspy]

Originally posted by norbs
Well i have s solution for your problem but its going to cost you $349 and you have to build and adapter to use the ntk sensor.

You need to purchase an innovate lm-11 unit and connect your old ntk sensor to it, do a datalog with the fast in open loop. Compare datalogs under the same conditions and you will see if theres still an issue with your fast box.

Is there still only the FAST wide band you have to purchase to use w/ the system?

Or can I get the LM-1 unit and use that sensor w/ the adapter.

 

[norbs]

No, you can;t use any other wideband with your box and the output is not compatible with the lm-1. You can only use the lm-1 as a reference if you un hook the fast input and run it closed loop How else are you going to determine if your sensor is no good or the fast calibration to the sensor?

 

[JZ 97 SS 1500]

Where is the cheapest place to get the FAST wideband from??

Jose