Weber jets??All who live for their triples please read this

[Lazeum]

Your carbs are not set up right if one is sticky... Most likely your throttle shaft is bent or twisted.

If some plugs are black (too rich) and some are white (too lean), it means you haven't set them up right. You should adjust them with what they need to make the engine runs good instead of having all the same adjustment. If cylinders 5 & 6 are showing lean mixture, open up a little idle adjustment screw, if other cylinders are too rich, turn the idle screw of the following carbs down.

 

Too rich could also be because of not proper timing, make sure it is also right at idle but once more, to fix properly your issue, you should fix carbs instead of adding stiffer spring than would make your issue worse in the long range.

 

btw, on spark plug, you forgot in the reference the heat range, that's what matters the most. It should 5 or 6 to run good.

Edited April 29, 2013 by Lazeum

[duragg]

My museum of intake leak hunting devices. They all have issues.

Sonic leak listening gun is neat but it gets blasted by spark plug noise and stops working.

 

Smoke machine is fine, but you end up with smoke everywhere 420 style.

 

A well aimed Garden hose has still been one of my top devices.

 

[Lazeum]

good point on leaks of course

[duragg]

I need those domed DCOE screens but dang / $50 per carb makes me want to find a DIY solution.

Mostly trying to keep the little ribbons of racing slicks from being consumed.

[AZGhost623]

Those domes you mention, I have wondered, we have a very small wire colander in the kitchen, I am almost tempted to see if its the right size, I think it may be... Have you looked in your kitchen to see what you might have?

 

Well after I had some head work done, and some other things... I think I finally found a good mix of parts. I have a lean stumble I need to work on, but  otherwise, I think I got some pretty good results on its first drive tonight. at about 6000 rpm, the AFR was 15. I can probably come down on the air jet a bit, and get that cleaned up some, but for the most part its right in the sweet spot at 13 cruising, and up to 15 at WOT. My lean stumble I think can be fixed with the progression fix, but we will see... This is on a DCOE 152. Idle AFR is pretty fat at 11, might need to make it a bit fatter to see if that might help with the lean stumble from stop.

 

With a P90 head, the thing I need to figure out is if I am limiting the head with the size choke. I may be under powering the head a bit. I dont know what the CFM is for the P90 head, and what the DCOE 152's with a 36 size choke CFM is. Anyone know this info? I assume a CAM also changes this quite drastically. With all the dynamics people change it might be hard to find that info out. My setup is a shave head .080 (10:1 compression), CAM .480 Lift 280 Duration, no other mods on head.

 

36 Choke

145 Main - may try 155 too

180 Air - may try 175 too

60F9 idle

F3 Tube

Edited June 2, 2013 by AZGhost623

[duragg]

I ended up buying the screens. They are made by "BBR Racing" fwiw and they have a good website.

I didn't take pics, sorry.

 

AZGhost: 15 at WOT is way lean (backside or power curve).

Fix that with MAIN jet first-is what I would do.

 

Cruise at 13 is fine and safe.

Fix ALL the jetting and setup related stuff first, prog ports very last .

I did buy the drilling fixture so we can do that someday.

[AZGhost623]

Once I get my throttle return problem fixed, I'll play with it some more today. I bought three different kinds of springs from ACE, so ill see which works best.

 

I do have a 140 main jet, but the air jet may need to be changed too. From previous testing it seems I can manipulate that main jet quite a bit by just changing the air jet around. Unfortunately the next size up that I have from the 180 air is 195 and 200. Dont have a 185 air jet. If I goto a bigger main jet those bigger air jets may help compensate and I have plenty of main jets. Looks like going through my inventory I do have a 165 air jet (smallest I got). I think I may have to go bigger main jet with bigger air jet to get the desired affect due to the parts I have. Or should I just get a 185 air jet and press my luck to see what happens? So many moving parts to this thing...

Edited June 2, 2013 by AZGhost623

[T-Bone028]

With a P90 head, the thing I need to figure out is if I am limiting the head with the size choke. I may be under powering the head a bit. I dont know what the CFM is for the P90 head, and what the DCOE 152's with a 36 size choke CFM is. Anyone know this info? I assume a CAM also changes this quite drastically. With all the dynamics people change it might be hard to find that info out. My setup is a shave head .080 (10:1 compression), CAM .480 Lift 280 Duration, no other mods on head.

 

Not sure if this helps you with the P90 CFM answer, but might be of some use to everyone following this thread.  I dont recall seeing this picture/graph in any of the other pages, but I came across it in a post on side draft central.  The graph compares 40's vs 45's CFM's for multiple venturi sizes.

 

 

According to the chart, 45 DCOE's with 36 venturis should be flowing roughly 205 CFM's @ 1.5 inches of mercury per barrel.

[T-Bone028]

Folks, joining this thread to consolidate notes/experiences.  Here's my install thread: http://forums.hybridz.org/topic/112810-weber-dcoes-installed-initial-impressions/

 

And here is my current jetting with 40 DCOE's on a 3.1L (I find my current jetting to be pretty fun, but still testing)

 

 

33 main venturi 

4.5 Aux

130 Main

170 Air

55F9 idle

F11 emulsion

45 pump jet, 50 exhaust valve

 

 

 

What sticky is the pdf from?

Regarding the Wideband, do you just hook it to a laptop? 

I looked it up on Summit but still not sure how you datalog with it. Says, no laptop needed.

ss

 

 

 

Steve, regarding W/B, maybe I'm not familiar with a W/B that doesnt require a laptop or some other tool to datalog, but with the AEM, you essentially have to wire in a 9-pin serial cable to one of the wires coming off the guage and then use a serial-to-USB adapter to record data onto a laptop.  If you do a google search on data-logging with the AEM UEGO, there should be a couple of hits on how to do it.  Never bothered to look it up for the Innovate.  However, with just the in-car W/B gauge and checking it as I drive, I still find it to be a pretty useful tool.  I will eventually wire in the serial cable though to study logs/runs once I finalize on what direction I want to go with upgrading my ignition.

[steve260z]

Thanks. Did you happen to find a gauge that replaces, say the clock or did you just mount the new gauge?

steve

[T-Bone028]

I mounted the AFR gauge on the clamshell cover in between the speedo/tach using one of the universal gauge mounts. I'll try to snap a pic tomorrow.

 

Edit: here is the picture.  I think you can buy the mount for like $10 (also from Amazon) and its just 2 small holes drilled into the top clamshell cover and barely "screwed" in (threads barely go through the cover and are basically flush to the underside).  I'm sure it could be mounted elsewhere.  Wiring was a breeze.  Just power and ground needed to get it running.

 

Edited June 4, 2013 by T-Bone028

[AZGhost623]

My first long ride in the car, if you would call it that since the head repair. 10 miles out and back on the freeway this evening. 

street cruise with rpms at 1500 is real good on the afr right on at 13, but when the cruise rpm is 2500-3000 afr is off the charts way to lean. it definately loves high rpm, WOT on the freeway its still right on the money 12.5-13 all the way up to 6000 rpm very solid. I was scared too go above that lol...

To fix this I need to go up in Idle size right? Idle jet controls the cruising idle right?

 

DCOE 45

36 choke

145 main

180 air

60F9

F3 tube

Edited June 5, 2013 by AZGhost623

[duragg]

The test;

Setup that lean cruise at 2500-3000 rpm and then push in the clutch and note the RPM at which the engines stabilizes without movng throttle:  5000, 6000, whatever.

Now when back in the garage in neutral you can recreate the position and identify the exact butterfly position which will tell you a lot about who is or isn't doing what or whatnot..

 

Often the last prog-port is a little reachy from the main giddyup.

Bigger idle jet, might help.  But we keep looking for the Super-soaker idle jet to fix problems related to less than perfect prog-port placement.

[steve260z]

For reference for a stoker:

 

I'm running the following:

34 chokes but have some 36s coming....

air corrector, 160

Main, 145

Pump Jet, 45

Idle Jet, 60F8

E Tubes, F2

Edited June 5, 2013 by steve260z

[AZGhost623]

Duragg, with the head working correctly now, I run into a problem with excessive RPM if I try to do the progression / butterfly trick. So much so that I cant even set idle just like the problem you were having. I think that drill jig you got from Keith helped you? I would hate to make modifications like that because they are semi permanent... the butterfly is setup just right before the first progression hole. I can tweak that by adjusting the idle rpm. of course moving it past the first one its excessive rpm for idle.

 

From what I have been reading, the F3 is very similar to the F11. It has all the same holes in the same places and same diameters. However, the only single difference is the F3 tube has a smaller orifice at the bottom by .5mm (7.5mm on F3 compared to 8mm on F11) Both F11 and F3 etubes are awesome at very high rpm but a little weak on transition. Now I have been researching and I hear that the F7 tube is great at low RPM quick pickups and slow acceleration including WOT, but not excessive high RPM. They have no air holes at the top only at the bottom. I have an F7 etube, but I haven't given it a go yet. The etubes only change the rpm range, and the rate (speed for lack of a better word) in which it affects the main circuit. 

 

A quick revving race motor has entirely different requirements than a slower reving street engine. Has anyone tried an F7 to know where it starts to lean out at in top RPM? Would love to know some F7 setups to start with.

Edited June 5, 2013 by AZGhost623

[AZGhost623]

Something else Im curious about, duragg and i are running stock pump jets at 45 (as far as I know). Since this is mechanically driven by your foot and gives the extra squirt, im wondering if a larger pump jet would be more beneficial for that initial transition rather than drilling??

Edited June 5, 2013 by AZGhost623

[T-Bone028]

AZGhost,  Larger pump jet should provide bigger shot, shorter duration...or smaller pump jet; smaller shot but longer duration.  Conversely, you can just change the exhaust valve at the bottom of the carb.  Only need to change 3 jets instead of 6 = less money.  Smaller bleed-back/exhaust valve should provide longer duration.  I currently have 45 pump jet with 55 exhaust valve installed, with a "0" exhaust valve that I still have yet to test.

 

I believe the pump jet circuit was intended to provide the extra gas needed at sudden throttle opening, not necessarily to tweak idle circuit AFR at cruise.  From what I recall when I was watching the pump jet arm on the bench, even at partial throttle plate movement, the pump jet would depress all the way to bottom (albeit slower than at sudden WOT).

 

So I would agree with Duragg, progression hole placement is contributing to the lean condition your experiencing at 2500-3000...and the common "fix" is to bump up the idle jet.  

 

FWIW, Im experiencing the opposite, with a 50F9 idle jet it gave me about 12 - 12.5 AFR at cruise.  However, I was experiencing a bog at sudden WOT at <2000 RPM.  I went to a 55F9 idle jet and that mostly fixed the stumble/bog, but it gave me a rich idle cruise of 11 AFR's.  Thinking back on it though, I could have gone with a bigger AND longer pump shot to reduce the stumble and could have kept the idle jet size the same to have better cruise AFR's.

 

Disclaimer: I'm new to DCOE's, and my rambling is based off some reading/research I've done over the past few weeks. I could be completely wrong, but as I write it out it seems to be correct in theory.

[AZGhost623]

Have you closed up all your idle screws and did equal turns on all of them until it shows around 13 AFR? You shouldnt have to open them very much.

 

The funny thing is I dont have a lean problem at stop to go, probably also why I dont have a problem at cruise on the street. I think Im pulling alot of vaccum when im driving on the freeway which is pulling in more air than what the idle can put out when in cruise.  Bigger idle for sure, which Im waiting on, i have 65F9 and 70F9 coming my way for this weekend to try out.

I also think the right ETUBE can help on that as well since the RPM is based around the TUBE for fuel delivery. The progression hole trick does work (i think from how it was on my previous head but it was pretty messed up), but now that my head is built right with these DCOE45's the idle RPM cant be adjusted when the butterflys are that far forward, 2000 rpm idle is just not cool with the set screw all the way out. Im pulling 7.5's across all carbs on the snail gauge sync tool at idle. Thats where the modification comes in to put in a 4th hole which im not sure how that affects the rest of the operation of the carb.

Edited June 5, 2013 by AZGhost623

[T-Bone028]

My idle screws are set 1 - 1.25 turns out from fully seated using the older style coarser screw.  What I found when I went leaner/turned-in was spitting/coughing from the front carb.  

 

I'm planning on spending saturday and sunday tuning and swapping jets and e-tubes to play around.  From a driveability standpoint, I find nothing wrong with how it feels running in idle, cruise, partial throttle, and WOT.  Just experimenting at this point and trying not to get caught up in "perfecting" my AFR's.  At the end of the day, as long as it drives well and consistently is all I'm really concerned about...until I bump up in size on the main venturi's...then I get to do it all over again!  

 

Speaking of which, if anyone has 34 - 36 chokes for 40's, let me know!

[AZGhost623]

Speaking of which, if anyone has 34 - 36 chokes for 40's, let me know!

 

Duragg may have some, he just went from DCOE 40's to 45's.