What is a ballpark A/F ratio to shoot for?
11-05-2010, 09:58 AM
#1
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What is a ballpark A/F ratio to shoot for? I'm installing my new wideband next week and I'm wondering about some basics. I know every combo is different and some may want richer or leaner. What I want to know is what is generally acceptable as far as rich and lean? Like is 10:1 too rich? 13.5:1 too lean?
11-05-2010, 10:20 AM
#2
for a n/a motor at WOT its normally around 12.5-12.8:1, sometimes even a little leaner. 10:1 is far too rich, turbo motors might run 11.5 etc or slightly richer on boost.
idling and part throttle on an n/a motor you might see as lean as 15:1 on a properly set up car if it will take it. i think my carb set up gave 14;1 idling and 12.8 on wot when rejetted, but others might have more info for you.
idling and part throttle on an n/a motor you might see as lean as 15:1 on a properly set up car if it will take it. i think my carb set up gave 14;1 idling and 12.8 on wot when rejetted, but others might have more info for you.
11-10-2010, 08:27 PM
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I installed the wideband and got my truck started today. It worked awesome. I can make the idle bounce around 12-13. As soon as I touch the gas it drops to around 10. I can't really test it out on the road due to all the crazy cops around here. I won't get to do any WOT testing until I'm on the track this coming Sunday. Hopefully all goes well and I win some races and end up with a badass tune on my truck.
12-08-2010, 06:56 AM
#7
I have an LM2 by Innovate motor Sports. it is nice to have something with a record capbility since it can be hard (and stupid) to watch a wideband under WOT.
Don't know if that is the best unit, matter of opinion I guess. It does everything they say it will do. It not only records AFR but RPM and has 3 other analog inputs. I used the RPM functiion to calibrate my in dash tach. When you really get into it you can hook the MAP sensor to record vacuum, and for extra credit I have seen guys hook up a throttle position sensor to the carb linkage to record throttle position. With all that info on the same plot you can tune to a rats ***. It comes with free softare to review the data on a computer.
The LM2 unit is a little expensive and can be a little quirky to use. It hangs up now and then so have to turn it off and on to reset it. The record function only likes certain SD memory cards. The unit also looks pretty fragile as do the wire connectors. When all the wires are connected it is a little bulky. But for something that you don't need to leave connected all the time it is rugged enough.
It also has a full OBDII capability so you can use it as a full function scanner to work on EFI cars. Fortuntely my DD's are reliable enough that I haven't had to use it that way.
Don't know if that is the best unit, matter of opinion I guess. It does everything they say it will do. It not only records AFR but RPM and has 3 other analog inputs. I used the RPM functiion to calibrate my in dash tach. When you really get into it you can hook the MAP sensor to record vacuum, and for extra credit I have seen guys hook up a throttle position sensor to the carb linkage to record throttle position. With all that info on the same plot you can tune to a rats ***. It comes with free softare to review the data on a computer.
The LM2 unit is a little expensive and can be a little quirky to use. It hangs up now and then so have to turn it off and on to reset it. The record function only likes certain SD memory cards. The unit also looks pretty fragile as do the wire connectors. When all the wires are connected it is a little bulky. But for something that you don't need to leave connected all the time it is rugged enough.
It also has a full OBDII capability so you can use it as a full function scanner to work on EFI cars. Fortuntely my DD's are reliable enough that I haven't had to use it that way.
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12-08-2010, 08:24 PM
#9
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I went with the AEM because it was cheap and it had a "OK" reputation. Like Pop'n'Wood said, it's nice to have recording capabilities so you don't have to glance at the wideband during a run. I have mine mounted next to my tach/shiftlight, so I try to take it all in with one quick look.
12-09-2010, 08:54 AM
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rectangular port heads normally like leaner air fuel and more timing (although some dont mind bein a tad rich) so around 12.8-13:1. I find 13.0:1 works well.
Cathedral port heads 12.4-12.6 I ALWAYS find this is the best with less timing then the rectangular ports.
Cathedral port heads 12.4-12.6 I ALWAYS find this is the best with less timing then the rectangular ports.
12-09-2010, 04:07 PM
#12
14.7:1 is perfect stoichometric combustion air/fuel ratio on petrol, but wont make peak power. its the ideal ratio for emissions as mentioned, but 12.5 to 13:1 generally gives peak power on N/A motors from what i understand. turbo cars make good power at 11.8:1 while still being safe, any leaner might melt them. my old celica gt4 used to black smoke on boost at 10.5;1 and makre crap power, we mapped it to 11.5:1 and gained 35bhp
Whats a good middle ground for A/F 