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

Sounds like you have a success! Nice job!

http://www.chevyhiperformance.com/t...index.html



Hope the above link will work.

Jim

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 


 

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