i noticed a part throttle miss around 2000 rpm in 2nd gear when accelerating gently around 30mph. Since i jetted the Holley 6210 way lean for MPG i assumed it was just too lean. With the Racerwholesale A/F gauge i saw it was too rich! Seems my modified power valve was not yet closed as i slowly backed off as it neared the speed limit. ....well i sure don't miss those days before oxygen sensor tuning! some of my tips are at http://community.webtv.net/MATTGRU/AFtesting
not for novices

So the local cop comes after me again! Crime: DRIVING WHILE IN A VETTE! (was going 40 in a 45)
As soon as i saw him turn around i went down a dirt side street, made a left at the next corner which was ONE WAY and i was going the wrong way (no sign at the corner) Well, that sure lost him :lol: (only going 20) :rolleyes:

 

I know I asked this before and I have the info for the sensor printed out. Which sensor and gauge are you using. This is going to be a winter setup for me so I might be contacting you at a later date. Thanks Gordon

 

Gordonm
i used the AUT-9901 from Racer wholesale. It is marked with the ratio, and i found it to be accurate.
The sensor came from an auto parts store; a popular model is what i asked for. When he asked for the year, i told him, and he says THEY DONT COME WITH THEM ..... :rolleyes: so i said IF IT CAME WITH IT, I WOULDN'T NEED IT :rolleyes:

 

Thanks for the info. I will probably put it in the collector so in your article you say it should be a heated sensor. Should it be a heated sensor.

 

From the vettenet on what A/F ratio should we be looking for.


Assuming that the equipment is accurate and that there is no exhaust leaks I
would consider the 13.3:1 A/F ratio on the ragged edge of being too lean. We
shoot for a 12.8 - 13.2 here for most naturally aspirated engines at WOT.
Some engines such as LT1/4s like the leaner side of these numbers for a few
more HP. We also take atmospheric conditions into account when setting up an
engine. For example, if the temperature is uncharacteristically cool, the
barometric pressure is high and the humidity is low, we will bias it towards
the lean side. This is because if any of these conditions change back to
normal the engine will usually go more rich. Some engines are quite
sensitive to A/F ratio tuning and others are not. L98s like the rich side
(around the 12.6 - 12.8 area) to help prevent their tendency to get power
robbing ignition knock retard. But then again we often find exeptions to
these rules of thumb.

Because your A/F readings are linear across the RPM range, an adjustable FP
reg should be all you need if you want to richen things up a little. An
additional one - two pounds should put you in a very safe but effective
range. Or compress the stock FP regulator with a small wheel puller while
monitoring the fuel pressure for slight FP increases such as this if you want
to save money.

As stated earlier, we are assuming that your readings are fairly accurate.
Many shops are using various wide band A/F ratio monitors, some home made.
We use the Horiba brand which is expensive but considered by many to be one
of the more accurate. We have noticed discrepancies with other wide band
units that have been brought to our shop by customers. Because of this I
usually like to stay away from that ragged edge of being too lean.

Tyler
90ZR1

 

All you ever wanted to know about A/F meters and O2 sensors. Took me awhile to find this link again.
http://www.scuderiaciriani.com/rx7/AF_meter.html

Tyler
68 L88 clone.

 

Great site thanks for the info.