Guest Anonymous Posted April 27, 2002 Share Posted April 27, 2002 A/F meters are soooo cool... I finally got to take mine down to the local super to get a few groceries (see it really is a grocery getter!) and check out the mixture using the new AF Meter I installed. On a carbed car? Why? Well its going FI eventually so I just went ahead and did it knowing it could help tune my carb in. I was getting weird meter readings in the driveway just winging it, so ok, lets drive it, hmmm seems lean, like it goes off the scale lean under partial throttle. Idle circuit returns and its rich, jump on it and it goes from super lean to a nicely jetted secondary. Ok, well kinda narrows down my low speed jets I think, I'll fatten them up tomorrow and see how that works. It wouldn't bother me except its way lean and it is exactly at cruise on the freeway throttle position. This could have be catastrophic had I been in the heat and got it pinging. Moral of the story? Don't trust what your carb is telling you, if you use a Holley (or probably others) out of the box, you may be in a lean condition and due to not checking it properly (running new plugs, not let them idle much and take them out and read them) and the fact that the reading unless done properly as I said can get contaminated and give you a deceptive plug reading. This AF Meter stuff is pretty neat, watch the powervalve come in, where your secondary really starts pumping fuel. I urge you to include one if you havn't thought about it, even for Carb'ed cars (come'on ya neanderthal, keep your carb but at least tune it using a little better tools..) Regards, Lone Quote Link to comment Share on other sites More sharing options...
fl327 Posted April 27, 2002 Share Posted April 27, 2002 show us how. Quote Link to comment Share on other sites More sharing options...
Mike C Posted April 28, 2002 Share Posted April 28, 2002 Absolutely. I have a buddy with a built 258 in his CJ-7 and he went to the AF meter to try and cure funky carburetion. Turns out the 390 Holley on his jeep needed all sorts of tuning. I have already added one to the list to tune my Del'Lortos when I swap motors next month. Quote Link to comment Share on other sites More sharing options...
z ya Posted April 30, 2002 Share Posted April 30, 2002 I plan to get one real soon. What brand did you go with?? Quote Link to comment Share on other sites More sharing options...
fl327 Posted May 1, 2002 Share Posted May 1, 2002 hey lone, which fi are you gonna go with, tpi??? im gonna lay off the efi PROject. im gonna make a carb work for me, never really tuned one up and would like to progress in a nice evolutionary way rather than just jumping to efi. i think the 327 is gonna stay carbed, now that i know an lt1 will bolt up to the legendary m21. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 3, 2002 Share Posted May 3, 2002 Homebuilt MPI probably Len, I've got more room to work now, so once my bigger shop tools get down here I can probably seriously look at prototyping a system. It'll be a single plan manifold with injector bungs and fuel rail anchors breathing through either a 90 elbow with a single butterfly TB or converting a Holley to a EFI throttle body, that will work great, but I need to do some homework on how the IAC (idle air control or whatever it is)motor works in relationship to a holley and where it would need to be mounted. I'm convinced its the cheapest route for me, but thats a relative term, FI ain't cheap as you know, but I think I can still shave some dollars under a complete EFI package and hopefully have more flexibility. I know the single plane with short runners DEFINITELY won't run out of huff at 5000 rpms... This whole plan is sort of a collaboration with DavyZ which has a broader bigger picture such as single or twin turbo's blowing in the aforementioned EFI system (aftermarket computer). But that will have to wait until I have some of the mundane things in life like a job or money, some sort of life and a new GF. If you want to use a AF meter, just cop a 18mm anti-foul sparkplug adapter (look for the HELP line of replacement stuff, your kragen bud can hook you up ) and order a (I want to say the brand is Standard or Universal the box is in the car) 02 sensor part number SG12 (check that its the bigger 18 mm size as I'm pulling that part number out of my memory. Cut almost all the adapter off leaving the large nut, drill a hole in your collector or exhaust head pipe as soon as it comes out of the exhaust header so it stays real warm. If you have to move it further back for some reason, have a parts guy look for a universal 3 wire, they're 21 bucks or something like that, 3 wire maybe a tad more but not much), the 3 wire just uses a heating element so 2 of the wires are power, the other is the signal. Screw the sensor into the adapter (nut) and put the sensor through the hole. Weld the nut onto your collector/headpipe). I left it in while welding it and didn't have a problem, I figured it'd see heat anyway. The guages go from about 40-90 bucks depending. To tune the jetting, try to get the LED bars somewhere towards the mid-range as much as possible, for max performance maybe a tad fatter than that a bar or two into the rich, but watch jetting the primaries to fat though or the car will be a pig soon as the idle circuit drops out at partial throttle. Sorry it got so long, but I guess thats generally my style.... Regards, Lone Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 3, 2002 Share Posted May 3, 2002 Grumpyvette posted a pretty good link describing how to tune a carb with a home built O2 sensor. The web sight also describes how to build your own O2 sensor for a handful of dollars. http://www.bob2000.com/carb.htm Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 3, 2002 Share Posted May 3, 2002 Exactly where I got the info. Good stuff. Regards, Lone Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 13, 2002 Share Posted May 13, 2002 Anybody have experience adding an O2 sensor bung to an exhaust that's ALREADY coated? I've heard that it's hard to do this since the coating is inside the pipe as well, and the welder won't want to make a good weld. I definitely want to do this mod and use an O2 with the carb and with EFI when I do that later. Quote Link to comment Share on other sites More sharing options...
dmanzo57 Posted May 14, 2002 Share Posted May 14, 2002 Maybe you could grind the coating off where you want the bung. Weld the bung on. Then drill the hole out through the opening in the bung. Would'nt that keep the inside coating away from the weld? Regards, Don PS: I've got one on my uncoated exhaust and it has been a big help in tuning the carb. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted May 20, 2002 Share Posted May 20, 2002 more options http://www.dakotadigital.com/tech/ODY-13-2.htm http://www.techedge.com.au/vehicle/wbo2/default.htm http://www.scuderiaciriani.com/rx7/AF_meter.html http://www.nastyz28.com/perftune.html http://www.nastyz28.com/fuelie.html http://www.centuryperformance.com/vacuum.htm Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted May 20, 2002 Share Posted May 20, 2002 My exhaust guy has welded on coated pipes a few times. Sandblaster or a slight grind will allow the weld to work. The stuff on the inside didn't seem to be a problem... To do this right use a Techedge or FJO unit. Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 21, 2002 Share Posted May 21, 2002 Thanks everybody. I'll be putting one in one of the head pipes, right after the block huggers. Quote Link to comment Share on other sites More sharing options...
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