Dyno numbers and Wideband funnny stuff
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TECH Junkie
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Joined: Nov 2001
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From: Glen Burnie, Md
Dyno numbers and Wideband funnny stuff Let me hear what you guys think about this.
1st: 346/369 14.6 avg A/F .933-.966 02s
2nd: 342/365 13.6 avg A/F
3rd: 339/361 12.6 avg A/F .988-1.0 02s
Started way lean but it made most power across rpm range there. My thinking is that yes you can make more power leaner, but to a point. If your way lean (like 14.6:1, thats almost stoich best for max gas milage maybe ) theres no fuel there to make power. But the closer I brought it to where the "ideal A/F ratio is the worse the numbers got.
The cars first pull was made cold (well 160 degree coolant temp the car had been sitting for hours, it was on is first warmup cycle) Usually LS1 make the most power on the third or so pull (getting up to 190 or so operating temp) then start dropping off so I think that heat soak is ruled out.
What do you all think the possibilites may be? I have what i think it may be but I dont want to draw any conclusions for anyone want some answers unbiased by what my answer would be. This was on the pumpkin by the way, lid, headers and anti-tuning, the more I tried to get it where it should be the more it fought me
<small>[ April 13, 2003, 09:40 PM: Message edited by: GrannySShifting ]</small>
1st: 346/369 14.6 avg A/F .933-.966 02s
2nd: 342/365 13.6 avg A/F
3rd: 339/361 12.6 avg A/F .988-1.0 02s
Started way lean but it made most power across rpm range there. My thinking is that yes you can make more power leaner, but to a point. If your way lean (like 14.6:1, thats almost stoich best for max gas milage maybe ) theres no fuel there to make power. But the closer I brought it to where the "ideal A/F ratio is the worse the numbers got.
The cars first pull was made cold (well 160 degree coolant temp the car had been sitting for hours, it was on is first warmup cycle) Usually LS1 make the most power on the third or so pull (getting up to 190 or so operating temp) then start dropping off so I think that heat soak is ruled out.
What do you all think the possibilites may be? I have what i think it may be but I dont want to draw any conclusions for anyone want some answers unbiased by what my answer would be. This was on the pumpkin by the way, lid, headers and anti-tuning, the more I tried to get it where it should be the more it fought me
<small>[ April 13, 2003, 09:40 PM: Message edited by: GrannySShifting ]</small>
Staging Lane
Joined: Feb 2002
Posts: 97
Likes: 0
From: Newport, Michigan
Re: Dyno numbers and Wideband funnny stuff Well, maybe if you look at the RPM where each of these maxes occurred, it might shed a little light on your situation. For example, the WOT AFR does not stay constant from 4,000RPM to 6,000RPM.
Also, peak torque and peak HP occur at different RPMs, so at what RPM is the AFR taken and at what RPM is your O2 reading at???
Also, peak torque and peak HP occur at different RPMs, so at what RPM is the AFR taken and at what RPM is your O2 reading at???
Re: Dyno numbers and Wideband funnny stuff My auto tap never reads right on the dyno.I've seen .60- 1.2volts while dynoing.On the street under load it's normal.
Did you A-tap after on the road to see if the #'s came back down?Mine do.
Did you A-tap after on the road to see if the #'s came back down?Mine do.
Thread Starter
TECH Junkie
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From: Glen Burnie, Md
Re: Dyno numbers and Wideband funnny stuff The air/fuel kept same trends for each run slightly leaner at beginning than end. Reverse of what it should be but I didnt feel like tuning the car with bogus wideband readings The a/f number I gave was prolly .2 leaner at start of pull and .3 richer at the very end is most variance, very stable a/f.
Doesnt make sense. Still made decent power (the first pull) for headers lid and ported TB. Wanna get this hoopty tuned and the rest of the boltons on her and see what she does <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Doesnt make sense. Still made decent power (the first pull) for headers lid and ported TB. Wanna get this hoopty tuned and the rest of the boltons on her and see what she does <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
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Re: Dyno numbers and Wideband funnny stuff Were you at Hefners? Next time the reading goes funky, move the wand. I had a wierd A/f on one pull and it changed solely from doing that.
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