eddy carb ?'s

Posted By: moparmandc

eddy carb ?'s - 02/13/09 04:41 PM

i am trying to figure out the best way to see what metering rods to put in. I think that it is running rich but not real sure is there any easy to tune it or is it trial and error. I am running a 650 cfm on a 360 with stock intake, headers, 9.0:1 compression and a purple shaft P4452757 mild comp and performance rv rpm band of 1000-5000. The heads are j heads with 2.02 intakes any input would be helpful cause i don't want to have to take the top off this carb a 100 times.

Posted By: Mr.Yuck

Re: eddy carb ?'s - 02/13/09 04:48 PM

Is that rich at idle or all the time? You might want to take a vacuum gauge and adjust your a/f mixtures. Especially if you haven't don it in a while.

Posted By: moparmandc

Re: eddy carb ?'s - 02/13/09 04:54 PM

sound's like a good place to start. just adjust till i have the best vacuum reading? not real sure about off idle but seems real boggy and not to good throttle response at times. i did put a overhaul kit in it about 2 years a go for the same reason but did not help much. other that that it is the same as it came out of the box.

Posted By: hooziewhatsit

Re: eddy carb ?'s - 02/13/09 05:17 PM

What jets & rods do you have in it now? How do the plugs look?
http://www.dragstuff.com/techarticles/how-to-read-plugs.html

Vacuum advance on driver or passenger side? Where's your timing at? Did you follow the guide in the manual to set the idle mixture screws?

Posted By: moparmandc

Re: eddy carb ?'s - 02/13/09 05:23 PM

timing is at 12 degreese base and i don't remember having a manual with the carb but that was about 5 or 6 years ago. vacuum advance is tied into the port on the passenger side of the carb. not sure of the size of the rods now.

Posted By: mickm

Re: eddy carb ?'s - 02/13/09 08:42 PM

it is trial and error, unless you can get an a/f ratio monitor. that will tell you exactly where you are. short of that, you just need to put something else in and try it out.

the metering rods are in 2 steps, cruise and power, so you need to know where you are rich. that is really important for finding the right rod. if you are only rich on cruise, and you end up leaning out power as well, that doesn't do any good.

keep in mind that 1 metering rod step is approximately equal to 2/3 of a jet size. that changes with the size of the metering rods, but it is a good rule of thumb. so the 650 thunder comes with a .068 X .047 metering rod, stock out of the box. .068 is cruise, and .047 is power. if you just needed to lean out the cruise, you could go for something like a .068 X .042. that would leave your power as it is, and lean your cruise out by almost 1 jet size.

it is a lot of trial and error, and i can tell you from experience that a few hundred $$ for a few hours on a dyno with an a/f monitor can save your hours upon hours of trial and error.

the other thing is that unless you have a local source for them, or get it right in one or two tries, buying metering rods pair by pair and paying for shipping each time really adds up. look at what you have in there now, and look at what is in the kit they sell.

note that if you are really rich for some reason, it may make sense to go down a jet size, and then play with metering rods.

good luck with it!

Posted By: Mr.Yuck

Re: eddy carb ?'s - 02/13/09 09:25 PM

Quote:

sound's like a good place to start. just adjust till i have the best vacuum reading? not real sure about off idle but seems real boggy and not to good throttle response at times. i did put a overhaul kit in it about 2 years a go for the same reason but did not help much. other that that it is the same as it came out of the box.

It will never be a holley.

Posted By: S/SSJOHN

Re: eddy carb ?'s - 02/13/09 10:01 PM

MickM, I believe you've got that backasswards, If you got a 68 cruise and a 47 power side , you would have to go to a 70 needle for the cruise with a 47 power, if you wanted to lean out the cruise! By the same token if you wanted to fatten up the cruise you would go to a 66 step ,and to fatten up the power side you would go to a 46 or lower #. You can only go a certain no of changes before you change jets, and go bigger in rods again! Have fun, John Lang (HEMIHEAD)

Posted By: moparmandc

Re: eddy carb ?'s - 02/13/09 10:16 PM

Quote:

Quote:

sound's like a good place to start. just adjust till i have the best vacuum reading? not real sure about off idle but seems real boggy and not to good throttle response at times. i did put a overhaul kit in it about 2 years a go for the same reason but did not help much. other that that it is the same as it came out of the box.

It will never be a holley.

sounds like i should just break down and buy a holley they seem easier to work on. do any of you have an opinion on a good street carb

Posted By: JohnRR

Re: eddy carb ?'s - 02/13/09 10:52 PM

Quote:

Quote:

sound's like a good place to start. just adjust till i have the best vacuum reading? not real sure about off idle but seems real boggy and not to good throttle response at times. i did put a overhaul kit in it about 2 years a go for the same reason but did not help much. other that that it is the same as it came out of the box.

It will never be a holley.

what took you so long ...

Posted By: JohnRR

Re: eddy carb ?'s - 02/13/09 10:53 PM

Quote:

Quote:

Quote:

sound's like a good place to start. just adjust till i have the best vacuum reading? not real sure about off idle but seems real boggy and not to good throttle response at times. i did put a overhaul kit in it about 2 years a go for the same reason but did not help much. other that that it is the same as it came out of the box.

It will never be a holley.

sounds like i should just break down and buy a holley they seem easier to work on. do any of you have an opinion on a good street carb

No , you'd still be on here asking what adjustments to make because it not calibrated to YOUR engine out of the box .

Posted By: moparmandc

Re: eddy carb ?'s - 02/13/09 11:08 PM

yea but it is slightly easier to have a box full of jets and try them. they are much easier to change than taking half the carb apart to change a metering rod. I think that i will use the 02 sensor in the header trick and see exactly where im at or just find an easier to work on holley. i just thought that some one might have close to the same set up i have and could give me an idea before i start to beat my head on the wall.

Posted By: mickm

Re: eddy carb ?'s - 02/14/09 02:44 AM

Quote:

MickM, I believe you've got that backasswards, If you got a 68 cruise and a 47 power side , you would have to go to a 70 needle for the cruise with a 47 power, if you wanted to lean out the cruise! By the same token if you wanted to fatten up the cruise you would go to a 66 step ,and to fatten up the power side you would go to a 46 or lower #. You can only go a certain no of changes before you change jets, and go bigger in rods again! Have fun, John Lang (HEMIHEAD)

yeah, you are right. i always do that, and then have to think it through again. going bigger on the jet makes it richer, going bigger on the rod makes it leaner, (as long as you only change one at a time). i always confuse the two.

thanks for pointing that out, would have been a bummer if he followed my advice, then he never would have got the damn thing tuned

Posted By: Greentween

Re: eddy carb ?'s - 02/14/09 03:02 AM

Quote:

yea but it is slightly easier to have a box full of jets and try them. they are much easier to change than taking half the carb apart to change a metering rod. I think that i will use the 02 sensor in the header trick and see exactly where im at or just find an easier to work on holley. i just thought that some one might have close to the same set up i have and could give me an idea before i start to beat my head on the wall.

To the Holley lovers: Changing the needles allows you to alter the A/F curve for both the power circuit and cruise. How EXACTLY can you do that with your average Holley? NOT POSSIBLE. The power valve circuit cannot be tuned for A/F ratio - only when it opens.

Once you put in an O2 sensor you will find out.

Posted By: volaredon

Re: eddy carb ?'s - 02/14/09 04:55 AM

for those that say an Eddy carb will never be a Holley; You got THAT right; it will never be a Holley for me either; I never have luck with those tempremental POS'. TQ AFB EDDY yeah; Holley or Q-junk-never.

Posted By: 451Mopar

Re: eddy carb ?'s - 02/14/09 05:24 AM

Quote:

Quote:

yea but it is slightly easier to have a box full of jets and try them. they are much easier to change than taking half the carb apart to change a metering rod. I think that i will use the 02 sensor in the header trick and see exactly where im at or just find an easier to work on holley. i just thought that some one might have close to the same set up i have and could give me an idea before i start to beat my head on the wall.

To the Holley lovers: Changing the needles allows you to alter the A/F curve for both the power circuit and cruise. How EXACTLY can you do that with your average Holley? NOT POSSIBLE. The power valve circuit cannot be tuned for A/F ratio - only when it opens.

Once you put in an O2 sensor you will find out.

It is possable to tune the PV on the Holley, just need to re-size the restriction in the metering block or use a metering block with screw-in restrictions.

If you live in the Denver area and need tuning help let me know, I have a fairly large selection of rods and jets you could try.

Posted By: Mopar73340

Re: eddy carb ?'s - 02/14/09 12:18 PM

Quote:

yea but it is slightly easier to have a box full of jets and try them. they are much easier to change than taking half the carb apart to change a metering rod.

You only have to take the top of the carb apart to change jets, two screws and the rods can be changed. Also there is no fuel spillage all over the engine. Try that with a Holley.

Posted By: fox

Re: eddy carb ?'s - 02/14/09 12:45 PM

On a holley, the main jet is the part throttle!
The main jet and power valve channel restriction in the power fuel flow.
Once a tuner understands that then they can tune it.

Posted By: Mr.Yuck

Re: eddy carb ?'s - 02/14/09 02:31 PM

you don't need an O2 sensor to tune a street car. A holley will require tuning as well. Both carbs have +'s and -'s. The holeey once tuned will give you much better throttle response. Easy way to tell is to buy a used Holley a 650DP should work fine. Order a rebuild kit, once inside install 28 squirters, a 6.5PV (should work w/ your cam) and start w/ 72 front 78 rear jets. Bolt it up and do you vacuum test to set the idle speeds and mixtures.