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Thread: 2.4 with an SSD and a 45DCOE

  1. #61
    7,000 Post Club My location wrench459's Avatar
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    Quote Originally Posted by The Scifi Guy View Post


    So, guys, what combo from the list above would you suggest I try next? If I step up the size of a Main, aren't I supposed step down the size of the Air?

    When you step up the size of the main jet ...more fuel right?

    When you step up the size of the air correction jet..less fuel right?

    So when you increase the size of the main jet AND lower the air correction

    the mixture will swing rich.

    Ain't tuning fun?

    Btw when your rich you can kick the spark timing up a tad.

    Si vis pacem, para bellum "If you want peace, prepare for war"

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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    You're being unusually and understandably helpful Dan. I must have found the sweet spot that piques your interest!




    Okie-dokie, what you've said agrees with what we've observed and what others and various instructions have said: I seem to be too lean. I have the jets to step up the Mains to 155/160 and I could step down the Airs to 190/195, but if we're trying to eliminate the bog I have, isn't that part of the Idle Transition circuit and the 65 F9's I have?
    Last edited by The Scifi Guy; 02-18-2016 at 08:18 PM.

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    Quote Originally Posted by The Scifi Guy View Post
    Okie-dokie, what you've said agrees with what we've observed and what others and various instructions have said: I seem to be too lean. I have the jets to step up the Mains to 155/160 and I could step down the Airs to 190/195, but if we're trying to eliminate the bog I have, isn't that part of the Idle Transition circuit and the 65 F9's I have?
    Ok well lets look at the "F" tubes function.

    The F tube mixes the amount of air from the air correctors in the well.

    Heck yes they are a big influence with WHEN the fuel is picked up.

    Think of it this way..aerate the the fuel then its easier for the engine to ingest
    the only problem is your lean.

    Get it ?

    Si vis pacem, para bellum "If you want peace, prepare for war"

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    2000 Post Club Site Supporter My location P.J. Romano's Avatar
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    I would also try 36 chokes. While 38 are theoretically the right ones, you never know. Smaller chokes will give you better low end torque and improve the transition.
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    Quote Originally Posted by The Scifi Guy View Post
    Just for the record and to assist those of you who are helping me, here is the list of side drafts jets and stuff I currently have:


    MAIN JETS

    130 (1)
    150 (4)
    155 (2)
    170 (2)
    190 (2)
    195 (2)
    200 (2)
    205 (2)

    AIR CORRECTORS

    115 (6)
    135 (2)
    140 (1)
    145 (8)
    150 (1)
    155 (2)
    160 (2)

    IDLES

    45 F8 (2)
    55 F8 (4)
    55 F9 (2)
    60 F8 (2)
    60 F9 (2)
    65 F8 (2)
    65 F9 (2)

    Miscellaneous:

    Exhaust valves (2)
    F9 Emulsions (2)


    There are more jets and stuff in my remaining other two carbs. They should be in the low ranges listed above.


    And confirmation of my exact current jetting:

    38 Venturis
    150 Mains
    200 Air Correctors
    65 F9 Idles
    F16 Emulsions


    So, guys, what combo from the list above would you suggest I try next? If I step up the size of a Main, aren't I supposed step down the size of the Air?


    Should I order some additional sizes?


    FYI F7 emulsion tubes will give you a richer low end OR you can plug the holes (one at a time) in the F-16 to make it richer. You can drill holes to make it leaner at any point in the acceleration by scaling them down the tube from top to bottom. Plug holes to make it richer.
    Last edited by pinballace; 02-18-2016 at 09:55 PM. Reason: F16 edit
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    ggl
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    Stop complicating things, there's an incredibly easy way to test if your engine is running lean .....

    Use the choke !!!

    The DCOE carb uses a fuel enrichment system rather than choke plates so when you use the choke it simply runs richer ..... if it's better with the choke it's running too lean, if it gets worse you're running too rich.

    You can't even begin to test things like this until your engine is close to operating temp because it needs more fuel when it's cold, so a lean condition becomes worse when the engine isn't fully warmed up

    You can't test stuff like this properly until you can put a load on the engine, which means road testing or a dyno.

    Oh, and I'll promise this will be the last time I ask, have you checked that your acc pump is squirting fuel in both barrels ?
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    tomking My location tomking's Avatar
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    Gordo I had the same problem with my 2.4 stroker which also has a SSD 45 DCOE. I dont have mine 100% yet but the biggest step towards eliminating the bog was accomplished by changing the pump bleed valve to a 0(zero). It has been a while since I was on this but pretty sure that is what it is called. Jets helped but the big step was going to a 0 on bleed valve.
    TMK

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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    Goy, thanks for the great tip about using the choke function to test for leanness.

    I have no idea whether the acc pump is squirting in both barrels. It's a brand new carb, I just swapped the cover and a few chromy screws and external things over from the old chromed one. I guess I would have to use a mirror on a stick to check about the squirting.

    The engine runs much better now than my first time start up video. I don't think there's anything way out of whack, I just need to refine the preliminary, dual carb-based, jetting for the hungrier needs of an SSD set up.

    This weekend my plan is to try to get the A/F meter installed, get the engine warmed up, try the choke function test, probably try installing a bigger main jet/smaller air to see what happens, write down various readings from the A/F meter, look into the bleed thing that Tom mentioned. And I'll make some more poor quality videos with my non-movie camera camera.


    Tom, thanks for the tip, I'll look into that. Would you happen to have your current carb jetting set up written down and could you give it to us here?


    Pin-man, thanks also for the tip, that would be an interesting experiment, although I don't think I'm quite at the point yet where I've got the understanding and the balls to start drilling my emulsions...........yet. Let's see how a few of the above mentioned tasks play out and go from there.


    Thanks guys, you're great!






    Here's a link to a parallel thread I started on Air/Fuel exhaust readings. I figured it was topic specific enough to warrant it's own stand alone thread, but some of the early comments in it concern this thread's particular carb jetting questions:

    http://www.opelgt.com/forums/6c-fuel...io-change.html
    Last edited by The Scifi Guy; 02-19-2016 at 07:53 AM.

  11. #69
    ggl
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    Quote Originally Posted by The Scifi Guy View Post
    Goy, thanks for the great tip about using the choke function to test for leanness.

    I have no idea whether the acc pump is squirting in both barrels. It's a brand new carb, I just swapped the cover and a few chromy screws and external things over from the old chromed one. I guess I would have to use a mirror on a stick to check about the squirting.
    Yes you need to visually confirm that it's squirting in both barrels but if you pump the throttle and listen carefully you can hear if it's squirting at all.

    Brand new parts have problems, that's why we get a warranty, if they never had problems we wouldn't need one. Also, you've opened it, how do you know that something didn't fall into the fuel bowl ?

    My DSD equipped Ascona developed a misfire from one day to the next and it took me ages to figure it out with people suggesting everything under the sun including needing a new fuel pump, cracked head, skipped timing chain etc etc. After 3 days of trying everything I could think of I finally did the sensible thing and took a step back and started to retrace my steps, what if anything did I do in between the engine running perfectly to it misfiring ?

    Ding ding ding !

    I took off those little lids on top of the carbs, the ones fastened with a wing nut, and removed and blew compressed air though the jets/emulsion tubes just to make sure they were clean as it had been a while

    Turns out that while I went into the garage to blow them clean a piece of pollen or leaf or something had made it's way into the carb while the car was sitting outside with the carbs open, I could see it when using a flashlight, so despite me cleaning the tubes/jets several times over the previous couple of days that piece of debris was sitting in my carb blocking off a passage.

    No I didn't feel stupid at all, no really ......
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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    I warmed the car up with it's original jetting and made a video:

    https://youtu.be/emlZ4UWR4YY

    Then I activated the choke/enrichment circuit to see if a richer blend would reduce the bog and made a video:

    https://youtu.be/OnabnA3HYts

    I spent an hour swapping in what few choices of jets I had that would apply more fuel to the mix(160 main/205 air ; 160 main/190 air). I then swapped out the F16 emulsions and installed F8 emulsions and repeated the two previous jetting scenarios. Then I put the F16's with 160/190, main/airs, back in and made a video.

    https://youtu.be/boNRWS7S0mo

    The engine ran a hundred or two rpm faster with the F8's, but I can't say that having them in reduced the bog. I have to say, what I'm experiencing with the bog is almost EXACTLY how my 2.0 with a 38 on it behaved before I aggressively cut back the power valve spring to stop excessive fuel during throttle tip in. EXACTLY like that.

    I think on my next jetting attempt I am going to experiment with a leaner mix, just to see what happens. Unless you guys have other suggestions and observations to try something else. I'm out of choices for richier jetting, so a descision must be made about getting bigger ones or doing something else. Here's an interesting thing: I had a respected company in California called TEP send me jets for the 40DCOE I originally had on this engine when it was briefly on the Red Baron. They had a well known GTer on the staff who used to have an SSD set up and he chose the jets. I remember that the assortment had really small, below the suggested size, main or idle jets, I forget which. I'm not sure if I used that jetting scenario because it seemed so off target, but maybe I did. Here's another thing: The 40DCOE on the 2.4 didn't bog. Identical set up except that now the carb is a 45DCOE.

    So what does that tell us?

    PJ's idea of installing smaller venturis is starting to sound like a good idea.



    That tap is not good and there's a "miss" feeling to the way the engine runs. I've gotta drop tuning, after I try the smaller main jet and maybe a venturi swap, and deal with what's causing that tap. That means pulling the valve cover, which means I have to saw off that flange sticking up from the SSD manifold. Argh.


    On the good news front: The mod I did to the gas pedal worked as advertised and much improved the touchy throttle response. Acceleration from a stop isn't like a drag race anymore, it's more like when you're late for work. So, still some room for improvement. Maybe I'll have a custom gas pedal made!





    ...tick...tock......tick...tock.....


    I just went out and tried the next pair of smaller main jets I had, 135's, and I left the 190 airs in and gave it a go. The bog got worse than any of the previous combos. So I need to buy MUCH larger main jets, like 170-190, or try PJ's idea of smaller venturis.
    Last edited by The Scifi Guy; 02-20-2016 at 06:45 PM.

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    Gordon
    Please write up your steps by change the jets and other points you do.
    Otherwise after five steps you didn't know where was the base line

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    7,000 Post Club My location wrench459's Avatar
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    Quote Originally Posted by The Scifi Guy View Post


    So what does that tell us?

    PJ's idea of installing smaller venturis is starting to sound like a good idea.
    All your videos shows that the bog is a lean spot.
    A WB will confirm if it is true.
    At one point the engine likes when you pump the throttle aka accel pump squirts(extra fuel).

    Yep smaller chokes will help the carb pickup the fuel.

    As a test I guess you could cut a piece of cardboard with two 35mm holes over the stubs.
    Last edited by wrench459; 02-20-2016 at 06:08 PM.

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    What size is the acceleration jet.
    I know that a 40 or 45 is to small for a 45 weber.
    And go not under 34 Venturis on a 45 weber!
    How many bores have your bypass lines

    https://www.youtube.com/watch?v=l7S-gtV-vXQ

    https://www.youtube.com/watch?v=VLct6_XWOQE
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    Have you tried a stronger spring in your pump circuit? Or changing the jet in the pump? I know I'm not a "veteran" so take my tyro advice as you wish but it sounds like you're not getting enough gas on a quick throttle. Using a stronger spring will pump the gas faster.
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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    Alrighty, last video for the day. I went out and swapped in the 36mm venturis that the carb came with and that various charts said were the correct size. I put 135 mains and the 190 airs in place and that is about the recommended size mains and jets for 36mm venturis. I did initially leave things the way they were in the previous last video with 160 mains and 190 airs and the bog was bad. The 36 mains and the 135/190's virtually eliminated the bog. Tomorrow I'll try to fine tune around that 135/190 scenario and see if I can get rid of the bog entirely.


    https://youtu.be/tuIthvyOGYU


    Quote Originally Posted by norbertone.gt371 View Post
    Gordon
    Please write up your steps by change the jets and other points you do.
    Otherwise after five steps you didn't know where was the base line

    The reason that I didn't write down the results of each jet change is because none of the changes done to the carb with the 38mm venturis had any big, possitive, effect. I also only had enough jets for about 4-6 different set ups. None of them improved things. The swap to the 36mm venturis with 135 mains, not the 160's, is the only set up that has made a big impact on the bog problem. Now that I'm making progress and am on the right track I will start documenting my changes. At this point I just want to get the car to be drivable without stalling so that I can work on a few other things, then I'll return to fine tuning the jetting and getting the O2 sensor installed.
    Last edited by The Scifi Guy; 02-20-2016 at 08:39 PM.
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    7,000 Post Club My location wrench459's Avatar
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    Twin 45mm rockin

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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    I deduced where all this jetting was heading, so I decided this morning to cut to the chase and set the carb up the way PJ has his carb set up:

    36mm venturis
    140 Mains
    205 Airs
    55 F9 Idles
    F16 Emulsions

    I reduced my mixture screws to 2 1/4 turns out and I made a video:


    https://youtu.be/E11iLf4-2N4


    And then I went for a drive through the neighborhood flooring it after every stop sign and made a video:


    https://youtu.be/UEszms4og64


    Okay, I'm happy for now. I can get to Carlisle with the engine running like this.


    All in all, a GREAT weekend!


    Last edited by The Scifi Guy; 02-21-2016 at 12:50 PM.
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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    I took into account mentions by you guys of more fuel needed to get my engine running better and I studied the several books I bought about jetting side drafts and determined that I needed to change two things to make the SSD work better with my set up: Go huge on the emulsion tubes and install the biggest needle valve to keep the fuel bowl filled. I bought F8's and they improved the bog and I could tell that the overall power went up dramatically, but it still wasn't enough, so I just bought and received the biggest size e-tubes: F7's. I also received a 2.50 needle valve. We'll see how those work out:

    IMG_3326.jpg Emulsion tube selection (1).jpg Emulsion tube selection (2).jpg Emulsion tube selection (3).jpg Needle valve selection.jpg

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    7,000 Post Club My location wrench459's Avatar
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    How about trying to hit 9:1 AFR during rapid tip-in...then go from there.

    Most of the time 13.2:1 AFR will be max power...then turn her up a tad for every day driving.

    Eco-mode :-)
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    Just Some Dude in Jersey My location The Scifi Guy's Avatar
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    I had my car dyno tuned on a Mustang brand constant load dyno by a Greek side draft carb specialist in the Philadelphia, Pa. area. He drove an Opel GT in high school and he said all his relatives drove Opel Kadets at some point. I thought the car was running pretty good and just needed minor tweaking and that it was running rich. I had minor bog and hesitation issues, I couldn't spin tires from a stop, and it took 2-3 tries to get it to start, but it ran absolutely great otherwise. After the tune, I had 10% more HP and 40% more torque, no bog or hesitation, it spins the tires, it starts easily, and I swear to golly it feels like I drove home from the city in a brand new modern car. jetting Holy Cow!

    The guy said it was actually running dangerously lean and he had to take my jetting in a totally different direction. You guys with the dual side draft cars and lots of experience with dualies take note: This is a SINGLE side draft set up and it appears to totally break the rules of traditional jetting of dual carbs. There's very, very, little theory discussion and suggestions for single side draft set ups out there on the web. The one thing I was able to glean from my reading and searching is that you need to set up the carb to deliver a LOT of extra gas, in relation to the air. These results tell the tale:







    And for the record, here are all the specs of my engine set up, carb jetting and set up, and adjustments:

    Used internally stock 2.4 with stock jet-coated cast iron manifold to a custom RallyBob 2.25" jet coated headpipe to a 2" stainless steel OGTS muffler and exhaust system.
    Accu-Fire ignition trigger in a locked plates, advance deleted, 20* of mechanical advance, '68 dizzy with an MSD ignition system. A new Spanish Weber 45 DCOE 9 carb going to a hogged out, supported/ported/and flowed by RallyBob for a 2.4, Midikit SSD manifold(chromed). The car has a rebuilt, stock, Opel TH180 auto tranny and a 3:18 rear with 205/50 R15 tires(23.1" diameter)

    CARB JETTING and ADJUSTMENTS:
    65mm velocity stacks
    36mm venturies
    190 Mains(drilled out from a smaller size to approximately this size)
    180 Airs
    55 F9 idles
    F9 Emulsion tubes
    2.50 fuel bowl valve
    1/4 turn of the throttle screws, no more!(the guy said)
    Mixture screws out 3 turns

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