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stacey honn
Not a Newbie
Posts:28
Registered Users
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| 03/16/2008 7:52 AM |
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Finished tuning Sat. afternoon. LM-1 AFR wide band is the way to go. It was acually fun to do on the edelbrock. I would do a run, pull over and do a quick change of of rods or springs and all I had to do is take the air cleaner LID off. My cruise # is a bit fat at a low 14 high 13 but my tune kit was limited on rod size. I also put a stiff spring kit in so a part load on engine kept me right at a 12-13 so as not to lean out on a hill or heavy wind. I know we seldome use WOT but what the heck, I jetted down the back barrels cause this was such a blast to tune. At Wot I'm at a low 14. Don't think that is bad of a number on my first try coming from a rich 10.5.
I've read the replies about carb size and RPM and how you can get by with a little carb because your not pulling a lot of cfm. But a big carb dialed in with a wide band can work just as well, even if it's a tad big.
Too bad we couldn't start a Lm1 coop and share the darn thing. Of course I'm done, and once set, you shouldn't have to mess around anymore. Unless you like to mess around.
Next on the list is the Onan. I can hit a air fuel mixture just right!
Stacey |
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Balrgn
Moderator
Expert
Posts:805
Registered Users
Southern NH
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| 03/16/2008 12:28 PM |
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| Sounds like you have a success! Nice job! |
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1977 Argosy 20
454 V8 Gas
Southern NH
Maintenance Analyst
www.balrgn.com |
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Jim Elliott
Camper
Posts:61
Registered Users
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stacey honn
Not a Newbie
Posts:28
Registered Users
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| 03/17/2008 6:52 AM |
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Thanks for the link Jim. Funny thing is, that was the first link I found while researching Fri. night. I think I read about 5 different articles on tuning a carb with the wideband but most came up using a holley. I was realy looking for in depth tuning on an Edelbrock but didn't come up with much.
Now that my cruising a/f is at about 13.8 to 14 I wonder how that will affect gpm on a long run. I could order the next size fatter needles and get the a/f up a bitand be mor twards 14.7 What would you do. leave it or tweek it. Stacey |
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Jim Elliott
Camper
Posts:61
Registered Users
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| 03/17/2008 11:04 AM |
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Posted By stacey honn on 03/17/2008 6:52 AM
Thanks for the link Jim. Funny thing is, that was the first link I found while researching Fri. night. I think I read about 5 different articles on tuning a carb with the wideband but most came up using a holley. I was realy looking for in depth tuning on an Edelbrock but didn't come up with much.
Now that my cruising a/f is at about 13.8 to 14 I wonder how that will affect gpm on a long run. I could order the next size fatter needles and get the a/f up a bitand be mor twards 14.7 What would you do. leave it or tweek it. Stacey
Stacey, Since I consider a carb a carb you could go to the Edelbrock site on the 1400 series
and look at the fuel ratios and the jet/rods combo's charts.
I don't know what "kit" you have to tune your carb but your running rich (13.8/14.0) and the
fuel milage will suffer.
Two sets of smaller jets will get you in the ball park, Standard jets on a 1400 carb are 95s
so 93s &91s could be tested along with the mix to match rods......Please find out your jetting.
Also in play is the "Springs" that allow the rods to phase in/out depending on the vacuum level
and with my Rochester carbs I use 6 inch vacuum springs for the "Power rods" instead of the
stock 11 inch which simply dumps fuel in with a slight head wind or hill climbs.....
14.8/15.1 which may be a dab on the lean side for some works well for me but when I
hammer down and hit the floor board I prefer a 12.8 F/A ratio...Play time has arrived.
Stacey, I don't know if you have headers or not BUT once istalled with a "X" pipe that
will lean out your engine also, I have seen & tested a .2----.5 lean out.
Jim
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stacey honn
Not a Newbie
Posts:28
Registered Users
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| 03/17/2008 8:25 PM |
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| Thanks for all the info Jim. I bought a kit from a local speed shop that has all sorts of jets, needles, and springs. I currently have the # 8 springs in. The day I tuned the carb I had a pretty darn good head wind one way and with the wind on the way back. Into the wind vacuum was about 10. On the way back with the wind vacuum was 15/16. Under simulated head wind/hill climb the A/F was acually in the mid 14 range which I thought was pretty good. Keep in mind I'm not 3/4 or WOT getting up to speed, just pretty much getting her going. I'll play with one more set of needles to go a bit more lean for cruising, and step down to the #6 spring and see what I get. As far as the jetting goes, Im fairly comfortable with the jet size in front because of the WOT being a bit fat. Can't really say I'm ever going to need to the floor hill climbs. I'f I'm in 3rd overdrive I'll kick out the GV overdrive and I even have a 2nd gear overdrive. Hey, I'll play again if the weather clears in the next few days. I just got done welding up a receiver for the front end to carry all our bicycles around. M. cycle on the back, bikes out front. Now that is going to be a picture! BTW, I just signed up with Coach-Net tonight. Oh ya, and I do have ceramic coated Hookers on it. No X but the exhaust is like fort knox, so I would like the x, but not right now. Stacey |
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Jim Elliott
Camper
Posts:61
Registered Users
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| 03/30/2008 1:35 PM |
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Hi Stacey, How goes the battle?
Just printed out your last post so I could read it in total (toooo wide).....After a nice long trip over to Tombstone Arizona
in early March my vacuum readings range from 14-17 inches bothways on the trip...
No doubt my readings are a dab higher cuz of the ignition system cranked to the MAX (10º base & 22º mechanical)
along with a 10º vacuum advance.....Since the weather was soooo cool I ran 89 octane in the high country without
one ping......
Thorleys are on along with the "Summit racing "X" pipe and you can hear it coming on the pipe at 58 MPH, Sweet
sound it is 
I hope you have e'nuf rods to lean it down a dab more...If not it's jet change time, I don't mind 14.9/15.2 A/F
lite footing it down the road but once the hills come up and my vacuum drops down to 4" or below I want the
A/F ratio to be around 13.1/13.4......On our big dawgs at the track we shoot for a 12.6 A/F at WOT.
I believe the "X" pipe will lean it out just a dab more, I know on my Rochester carb with stock 73 primary jets
the "X" pipe & Thorleys leaned it out (almost) perfectly and a 6 inch vacuum spring was installed on the
"Power fuel rods" instead of the stock 11 inch....Good fuel saver since most motor homes (stock) languish
between 7" & 11" of vacuum with slight headwinds & small hills............
For grins why not check out your ignition system and see what the settings are at idle & thruout the
range up to 3000 RPMs.... Might surprise you......This is a good thread.
Jim |
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