"Proper carb tuning?"

Some say the "real" way to get your carbs set right is to go to a dyno and use an O2 sensor to tweak everything in just so optimal HP and best gas mileage, etc. Many claim they can do it all by ear, and phooey on all that high technology. So it would be good to hear some pro/con on that question. And also if anyone knows where a dope like me could take my car and have a "proper" dyno tune done in the Baltimore - Wash. DC/VA/MD area, pls advise. Also, if you can omit the dyno (I ain't buying one of those) and just use the O2 sensor (which I might buy), how does that work out?

Kelly, I know AtSpeed has a dyno. I believe AutoFab does also.
I will find out where Reggie and Elwood get their cars tested and post that for you today.
Good to hear from you! Where ya' been hiding?

Here's a nationwide list of places that do dyno testing. There are a few shops near us:
http://www.explorerforum.com/forums//showthread.php?t=151076

You can tune it using either a narrow band air/fuel mix meter (most popular, cheaper but less accurate) or a wide-band version (less popular because it's more expensive and isn't meant to remain in the vehicle but more accurate).

More convenient to do on a dyno, but they usually charge $50 bucks for 2 - 4 dyno "pulls" and I suspect that it'll take 4 pulls to dial your carbs in. That's a LOT different than tuning an EFI using a laptop while pulling since you know all bout changing jets and all that goes with it.

I have a CB Perf narrow band air/fuel mix meter more or less permanently mounted in my car and I actually look at it more often than is necessary (because it's there). I used it initially to set up my jetting and since then it's just a novelty. I never use it to set air or fuel flow mix in the carb throats and usually set carbs up for flow balance by ear, listening to the hiss through the throats or watching the rock of the engine, and then sometimes use a Snail-o-meter to check my work.

gn

I wonder how many dyno shops would be able to tune carbs.

For a wide band, would a probe up the tailpipe work?

I was going to install a bung but I didn't want to mess up the coating on my exhaust.

If a bung is needed, could it be glued in place with some kind of special stuff instead of being welded?

no the bung has to be welded, but the old style exhaust gas analyzers we used to have here in the state still work pretty goood, but they are hard to find, i just use my flow meter and a hose to listen for the right hiss. bill

Here's a good source for a wideband: http://cgi.ebay.com/ebaymotors/AEM-GAUGE-TYPE-6-IN-1-WIDEBAND-UEGO-CONTROLLER-30-4100-_W0QQcmdZViewItemQQhashZitem5adaa4cd47QQitemZ390215290183QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

I am waiting for Vince and Gerd to commit about the tailpipe/probe comment!

Mike, it doesn't have to be welded, but it sure makes it easier. Our cars all have nice short exhaust systems, and the A/F mixture needs to be read as close to the exhaust port as possible.I have seen an exhaust extension made up with a bung in it work, but it is easier to weld a bung in, then plug it with the included plug after tuning is done.

Kelly, a snail and a plug reading is probably good, but a wideband O2 sensor temporarily in there is better. I could probably do it by ear like Gordon, but I am a more visual person, so I like gauges(thus the snail). Also, when I set the idle mixture, I like to use the low range on a dwell/tach meter, it shows a 20 rpm change in speed. That I can hear, but I like to SEE it.

Don't bother with a narrow band, our cars need to run near the full rich reading on a narrowband gauge or a bit richer than that. I had a narrowband gauge on the dash too, but have removed it. I left the CHT gauge there, that is a keeper.

Ron, either that UEGO or an LM-1 are good ones.

Picking up on Danny's comment about running rich; my narrow band meter usually runs 12.5 - 13 in "cruise" below 2,750 rpm, and shifts up to about 13 - 14 above 3,000 rpm. I got a chance to watch it on the New Hampshire Turnpike last week and played with readings at different speeds up to about 4,500 rpm (I was pulling away from a Miata right about then).

gn

I thought maybe I could use some kind of electrically conductive, heat resistant kind of stuff to stick the bung in the pipe.

There's an "app" for that.......

I don't know of any low-cost epoxy that wuld do the trick for you AND survive the heat extremes.

I would drop by a local place that does tuner cars or EFI motorcycles as they tend to play with exhaust parts a lot and may have experience with (a.) putting O2 sensor bungs in and (b.) especially on ceramic coated ones. Or, you could get a "dress collar" for the bung which is basically a washer shaped to the diameter of the exhaust pipe and installed under the bung to cover any ceramic chips that might occur during drilling.

However!!!!

Since all you really want to do is set up the jetting on your carbs, which only would need an air/fuel mixture gauge for a weekend or maybe only a day, I would find someone in your area that has a wideband gauge that you could either visit and use or borrow for a case of brews. Then all you'd have to do is shove the probe into your muffler outlet and get to work. No bung needed. That's how they're designed t be used - with a probe put into the tailpipe.

No muss, no fuss, no bung.

gn

Thanks for all your replies.

My original post asked if a probe up the tailpipe would work.

It sounds like maybe it would.

Another thing I might be able to do is detach the muffler from the collector and substitute a straight pipe with a bung.

No maybe - That's how they work.

The brain trust is reporting in -- thanks guys. Seems a sniffer up the pipe and some tweaking would help a lot. What I was thinking was just setting the needle valves, and not going through a whole jet swapping maneuver to get things changed. Current jets are, as stated, a little on the rich side, I do believe and although mileage is kinda low (20 something +/-) the mill does scoot when asked. Hmmm, so now I got some thinking to do, and a few phone calls to make.

Double clicked and posted twice -?- how does one delete a post? Only edit, I guess.