15:1 a/f = more hp than 13:1???
11-07-2005, 07:05 PM
#1
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15:1 a/f = more hp than 13:1??? Someone help me out here. I recently dynoed my car and my first pull was 498.9 rwhp with a 15:1 air/fuel. Dangerous, I know. 
But I had 0 KR. I dropped the air/fuel down thinking I had some power to be gained, but instead, I lost 4 horsepower with a 13:1 air/fuel. Why do you think this would be??? It makes no sense to me. I DID gain torque by dropping the a/f though.
But I had 0 KR. I dropped the air/fuel down thinking I had some power to be gained, but instead, I lost 4 horsepower with a 13:1 air/fuel. Why do you think this would be??? It makes no sense to me. I DID gain torque by dropping the a/f though. 
11-07-2005, 08:45 PM
#2
Originally Posted by WS6 GreeN
Someone help me out here. I recently dynoed my car and my first pull was 498.9 rwhp with a 15:1 air/fuel. Dangerous, I know. But I had 0 KR. I dropped the air/fuel down thinking I had some power to be gained, but instead, I lost 4 horsepower with a 13:1 air/fuel. Why do you think this would be??? It makes no sense to me. I DID gain torque by dropping the a/f though.
But I had 0 KR. I dropped the air/fuel down thinking I had some power to be gained, but instead, I lost 4 horsepower with a 13:1 air/fuel. Why do you think this would be??? It makes no sense to me. I DID gain torque by dropping the a/f though.
11-07-2005, 08:59 PM
#4
You may be able to get away with that on a dyno but unless you live in Anchorage doing it on the street is going to pop something... The highest I have ever dared for any extended amount of time was 14.0 (at WOT), but that was mid Winter and my IATs stayed around 30-40 degrees Fahrenheit... and yes it did scream at 14.0 AFR and 28 degrees advance... I stay around 13.6 AFR now, my DCR is 8.3 so I can live with it as long as I see no KR...
Good Luck,
Good Luck,
Last edited by SideStep; 11-07-2005 at 09:04 PM.
11-07-2005, 09:10 PM
#5
If you were sticking the WB sensor up the tailpipe, then that's your problem. Reading A/F ratio that way typically gives leaner readings than what is really taking place in the motor, often up to 1 point too lean. EG, if the motor is making 13.0:1 A/F ratio, it might be reading 14.0:1 at the tailpipe.
In your example, 15:1 at the tailpipe might actually be closer to 14:1 at the motor. You may not be as lean as you think.
In your example, 15:1 at the tailpipe might actually be closer to 14:1 at the motor. You may not be as lean as you think.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
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11-07-2005, 09:44 PM
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Originally Posted by gollum
Patrick,
So my 14.1 AFR reading taken at tailpipe is actually about 13.1 AFR before my Random Tech. CATS.
Thanks, Keith
So my 14.1 AFR reading taken at tailpipe is actually about 13.1 AFR before my Random Tech. CATS.
Thanks, Keith