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Hey all,
I might dyno tomorrow and this dyno does not have a wide band o2 sensor, so I was wondering how should I go about tuning the a/f ratio. I have an s-afc, should I hook up the blue wire for the o2 sensor reading option it has available. Should I tune by egt's, etc???? Thanks
SH
T78
 
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If you don't have a wideband, I would recommend tuning by EGTs. Keep em below 1600F (pre-turbo) to give you some margin of safety. Good luck!

Sean
 
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If they don't have a good O2 sensor on hand, they don't know dick about tuning cars. find a place that has one, or at least a tail pipe sniffer.
 

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I wouldn't tune by EGT's. My EGT's were easily 60C lower on the dyno than on the street.

Later, Steve
 

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You CANNOT tune by EGTs. Each gauge will read a bit different depending on where the probe is located at. You need to get a A/F gauge or find a dyno with one. The latter is preferable for tuning.


Lar
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Since this is my pet subject, I'll hammer in a couple more nails. :) A while back three of us were tuning our single turbo cars on a dyno with a wideband. We all had GReddy EGT gauges, with some variation in the probe locations. With all three cars tuned nice and flat at about 11.4:1 AFR, the EGTs were as follows:
Car 1 with probe in corner of collector = about 790 C.
Car 2 with probe in #6 runner = about 770 C.
Car 3 with probe in center of collector = about 890 C.

If we'd been tuning by EGTs would we have leaned the first two cars out? Would we have richened the 3rd car up? The 3rd car will indicate 800 C with the AFR in the low 10s. The first two probably wouldn't indicate 850 C until they hit the mid-13s or 14:1. That's dangerous, isn't it?

With EGT readings you just don't know what you have in the way of AFR unless you've correlated them with a wideband. And even then, you can't pick out lean and rich spots in the RPM range with an EGT gauge. I agree with the guy above who said, Find another shop.

Steve
 
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