determining carb jet/venturi sizes

I bought this to help me tune my carbs. Haven't installed it yet (been busy) but you can move it from car to car. Just weld in the threaded "bungs" into the exhaust after they merge and plug in the O2 sensor into it. There are plugs to close out the hole if you want to pull it out to tune another car. It's fairly inexpensive for this kit compared to others I have found on the net.... but again I haven't tried it yet so I can't really say that it's great.

Mac

I'm a Dumb-Ass..... here's the link I meant to post in the last message......

Right, it has a nifty little gauge to go with the kit. I have a few different types too.

But the gauge simply reads millivolts. You can do that with any decent VOM or multimeter that is capable of displaying millivolts. (Almost any cheap VOM at any auto parts store or electronics supply store). Many of us already HAVE such a meter, it's much more valuable with cars than just an O2 gauge ;)

Jan

Yeah Jan I found out that info on the net also but I figured thata guage would be alot easier (and safer for that matter) than trying to read a multi-meter that's jumping all over. I was hoping to be able to tune the accel pump also to optimize power and fuel economy and also making sure I don't fry an engine!!

Mac

very cool! just by reading the product description i'm starting to understand what this is all about. does indeed sound like something i might be able to manage myself. though i do have a decent vom and know how to use it, the included meter seems like a pretty good idea. still have two questions, though ...

2) how will i know when the o2 sensor in this kit needs to be replaced? does it just start reading "off" or does it die at once, causing the meter to read high/low?

thanks for your responses!

i think i kinda answered the first question myself:

To be SURE, you'd need to measure them. Or you can take your chances and trust the size markings on them. Jets are often drilled or reamed bigger, and the size marking will then be misleading.

It will start giving out very low voltage, in the 50-100 mV range or so. (Indicating super lean condition). Or none at all as you suggested. The heat is what is trying to keep it clean, and operational. If you run teh engine WAY rich, the sensor may get sooty and stop responding. Adjust accelerator pump close to minimum to avoid the sudden rush of extremely rich mixture (puff of black smoke when punching the gas pedal).

Measure the mixture at steady rpms, do not pump the pedal at all. If you do, the accelerator pump "squirt" will mess up the reading and you no longer see what the JETS flow through.

Jan

Right, that's it.

Jan

awesome, thanks for your responses. i've got the 1st and 2nd parts on order now - will see next week how rich/lean i'm running. i hope my jetting is lean; seems that rejetting would be an easy way to lower heat somewhat.