Re: Tuning Results From An O2 Kit?
[Re: YO7_A66]
#936970
03/09/11 10:58 AM
03/09/11 10:58 AM
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Joined: Jul 2007
Posts: 531 Virginia
JimG
mopar
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mopar
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Posts: 531
Virginia
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Quote:
How can you achieve 14 plus in N and have it rich enough to get it to warm up? I cranked my electric choke to the max setting and I left the ms's set at 1 full turn and I will try and restart it again once the engine is completely cold again and see what happens on the guage. If this does not do it, I may consider adapting a manual choke.
Holley-type electric chokes get no feedback from the engine. You just put 12 volts on a bimetallic heater, and the choke begins the process of opening. In an effort to make the choke stay closed longer, you can crank it richer, but then it might be too rich at first startup, and the choke might close when you turn the engine off for 20 minutes. Not good.
I copied (sort of) the factory choke arrangement from the 70's. I bought some normally open temperature switches (50 degrees C, if I remember correctly); they are approximately the diameter of a dime and about 4 times as thick) and put a power resistor in PARALLEL with the switch. Mine worked out to be 10 ohms, but a small rheostat would make it adjustable. I mounted this on a small rectangular piece of stainless steel (so it's purty) drilled a hole and mounted it under one of the intake manifold bolts. The power for the choke is fed through this circuit.
When the engine is cold (and the temperature switch is open), power to the choke flows through the resistor, making the opening rate slower. Once the engine wams up (and the switch closes) full 12 volts is applied to the choke heater.
You adjust the choke so that cold start is right. You tweak the resistor size and the location of the entire mechanism (some places on the engine warm up faster than others) to get the opening rate set properly.
If you're interested, send me a PM and I'll send you a temperature switch - I've got a bunch of them. Quote:
I am wondering if 14+ in N is just too lean of a goal. I just read a thread where someone said that it is better to run the N reading in the 13.0-13.5 range. I am not sure where to aim for now. The 13.5 range would allow the cold startup to improve until the warmer outside temps get here.
Idle is an area where you should just ignore the meter and set it the old fashioned way, IMHO. Of course, use the meter as a sanity check, but idle is an area where some engines are happy richer or leaner than others.
I'm glad you got a wideband meter. Carb perfectionists such as yourself should have every possible tool at their disposal.
Good luck,
Jim
ETA - switch is wired in parallel with resistor, NOT series. That wouldn't work very well.
Last edited by JimG; 03/09/11 11:50 AM.
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Re: Tuning Results From An O2 Kit?
[Re: JimG]
#936971
03/09/11 11:21 AM
03/09/11 11:21 AM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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Jim, ""When the engine is cold (and the temperature switch is open), power to the choke flows through the resistor, making the opening rate slower. Once the engine wams up (and the switch closes) full 12 volts is applied to the choke heater."" That is a great idea. I am fighting this right now in the cooler 45-50 degree outside temps. If I set my choke at #3 (3 marks from the back), it is too rich to start. If I set it at 3 marks from the front, then it opens too quickly and with the carb set leaner now (14.2-14.4), it is a fight to keep it running long enough to get some temp into the motor. I am going to test a couple more positions on the choke and maybe a larger primary squirter and see if I can get the startup a little easier in the cooler weather. If this does not work, then I might get with you on your change. I am hoping that I won't have this much cold startup problems once the outside temps go back up. Thank you.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: Mr340]
#936973
03/09/11 02:16 PM
03/09/11 02:16 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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Gary, I have a O2 bung welded into both of my header reducers. I am currently learning with one sensor in the drivers side reducer. My plan is once I get some tuning time with one sensor, I would like to buy a second gauge for the passenger side just so I can watch both sides. Is it overkill for the second sensor? Maybe, but I would not know for sure until I install it or move my existing sensor to the other side.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: Mr340]
#936974
03/09/11 04:25 PM
03/09/11 04:25 PM
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Joined: Feb 2003
Posts: 21,318 Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Manitoba, Canada
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On a cold start with the choke on in park, my a/f was in the low 13's during the summer. When fall rolled around and the temps were not far above freezing, that a/f went to the low 14's. I would warm it for 30 seconds, kick it down and go. During that initial part of cold driving where my choke was still closed, I found my a/f didn't really change as the choke opened. However if I tried a cold start with the choke wired open, it would want to run very lean like 16-17:1. I was running a thermoquad at the time with the stock choke with the electric heating element disconnected. Headers, aluminum heads and a stock cast iron intake and I found it took a bit longer than necessary for the choke to open, especially compared to the stock heads w/ manifolds and a functioning exhaust heat crossover in the intake. Next time I would just do a manual choke instead. Quote:
Good info I'm thinking of purchasing a kit soon. One question I have is these lc-1 and lm-1 kits are a single sensor correct/ which bank are you guys monitoring? Or Do you switch the sensor between banks or put the sensor in the H-pipe if so equiped?
Thanks Gary
I just picked one bank and installed it. I jet both sides of the carb the same so I don't really see a reason to run two o2 sensors. Another thing I read was running an engine with an unpowered wideband o2 sensor can ruin it because soot/carbon can build up on it and without it being powered, it's heater isn't running to burn that stuff off.
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Re: Tuning Results From An O2 Kit?
[Re: DaytonaTurbo]
#936975
03/09/11 04:47 PM
03/09/11 04:47 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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If I go to two o2 sensors, they would both be permanently wired in. My only thinking of running two was to be able to see if there was any issues with one side or the other. Thanks
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: superbyrd]
#936980
03/16/11 01:30 PM
03/16/11 01:30 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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12's: Right after cold startup 13's: during the warmup (before actual running temp) 13.8-14.5: N idle (actual running temp) Hi 13's: in D with foot on brake (example: stop light) ??.?: Stop light to light accel? 14.5: Cruise 12.5-12.9: WOT -------------------------------------------------------------------------
I have read a few articles lately that show that 14.7 is a good goal for a steady cruising ratio. I have also read where this is too lean and it should be in the upper 13's. What ratio are you running at a steady 45-70mph or so. Thanks
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: DaytonaTurbo]
#936982
03/16/11 05:06 PM
03/16/11 05:06 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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I will aim for 14.7 as a target and see how it reacts. If all is well, then I will aim for the 15's and see what happens. Thanks for the reply.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: YO7_A66]
#936983
03/17/11 09:35 AM
03/17/11 09:35 AM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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With a 4 barrel carb, would it be easier to disconnect the secondary side until I get the primary jetting/squirter/cam, pv/pvcr's, and primary WOT done?
Am I going to have any issues just running the primary side at WOT or do I need to test WOT with all four barrels?
Thanks
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: DaytonaTurbo]
#936985
03/17/11 04:52 PM
03/17/11 04:52 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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Daytona, I can see it both ways. I could tune the primary WOT only (once the main jets are tuned for cruise, then tweak the pvcr's and pv (2 door vs 4 door) to try and obtain the WOT number) and then hook up the secondaries and then finish the WOT tune on the secondary side, or I can leave it on 4 barrels and tune the secondary to suit. I was just curious which way would be best. Thanks for the reply.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: radar]
#936987
03/17/11 09:49 PM
03/17/11 09:49 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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Are you guys still seeing the 6-10 jet size difference (Holley style carb) from front to back after tuning with the 02 kits?
I think that I have my choke setup about right and after repairing my font squirter threads, I got the car started back up with minimal problems during warmup. I was able to get the neutral idle to 13.8-14.2 which I am comfortable with in 70 degree temps. One more cold startup test and I should be ready to test drive it and check the jetting. Thanks again.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Tuning Results From An O2 Kit?
[Re: YO7_A66]
#936988
03/29/11 09:25 PM
03/29/11 09:25 PM
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Joined: Jan 2003
Posts: 5,446 Indiana
YO7_A66
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I think that I have my cold startup problem cured with the Holley Choke Delay Kit. This choke delay allowed my much leaner idle circuit to richen up long enough to get some heat in the motor. After the engine reached running temp, I leaned out the N reading a little bit more and now I am at 13.8 on the O2 gauge in low 40's outside temps. I will lean this out some more as I drive the car, but for now I am comfortable with that reading. I noticed something that confuses me and I am looking for an answer. In N, the car was showing 13.8 on the gauge, then I dropped the car into D (with my foot on the brake) and the rpms dropped down to 850rpms (which is typical), but the O2 gauge LEANED OUT to 14.2. I was guessing that the 13.8 reading was going to go richer once I dropeed it into D with the extra load, but I was surprised to see it go lean to 14.2. Why did it do this? Is this typical? EDIT: Am I idling in N on the transition circuit and when I put it in D, it is idling on the idle circuit?
I am just trying to understand the readings a little more before I get it out on the street and start tuning the other circuits. Thanks allot.
Last edited by YO7_A66; 03/29/11 10:30 PM.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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