 Weber 44 idf flat spot |
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| tornik550 |
 Jul 4 2013, 11:59 AM
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#1
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Senior Member  Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None  |
So I recently purchased new weber 44 idf's. They didn't work out well so I went back to an old set of weber 44 idf's that I had. I thoroughly cleaned the carbs, sprayed carb cleaner through all jets, tubes, etc. I have also balanced the linkage. Set the floats, etc.
The car starts well. Idle's well. When I drive the car I get a major flat spot between 1500 and 3000 rpm's. Below and above the car accelerates normally. What changes should I make? My current setup for my 2258 (dual webers, big cam) -idle 55 -main 160 -et F11 -ac 200 -vents 36 Are there other issues that can cause this type of problem (timing,etc?) |
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| tornik550 |
Jul 12 2013, 08:15 AM
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#2
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
I have worked out my flat spot. I found that the accelerator pumps on one carb were partially plugged.
I have ordered several sets of venturis in different sizes. Although my engine is running very well right now, would there be any reason for me to change to a different size venturi? I have weber 44 idf's with 36mm vents. I get decent low end torque and excellent high end power. I ordered 34 and 32 vents. |
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| ChrisFoley |
Jul 12 2013, 08:28 AM
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#3
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I am Tangerine Racing Group: Members Posts: 7,967 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None 
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QUOTE(tornik550 @ Jul 12 2013, 09:15 AM)  I have worked out my flat spot. I found that the accelerator pumps on one carb were partially plugged. I have ordered several sets of venturis in different sizes. Although my engine is running very well right now, would there be any reason for me to change to a different size venturi? I have weber 44 idf's with 36mm vents. I get decent low end torque and excellent high end power. I ordered 34 and 32 vents. I would leave it alone unless you have data from a wideband O2 which suggests otherwise. |
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| tornik550 |
Jul 12 2013, 08:31 AM
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#4
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Senior Member Group: Members Posts: 1,248 Joined: 29-January 07 From: Ohio Member No.: 7,486 Region Association: None |
QUOTE(Racer Chris @ Jul 12 2013, 10:28 AM) QUOTE(tornik550 @ Jul 12 2013, 09:15 AM) I have worked out my flat spot. I found that the accelerator pumps on one carb were partially plugged. I have ordered several sets of venturis in different sizes. Although my engine is running very well right now, would there be any reason for me to change to a different size venturi? I have weber 44 idf's with 36mm vents. I get decent low end torque and excellent high end power. I ordered 34 and 32 vents. I would leave it alone unless you have data from a wideband O2 which suggests otherwise. The only issue that I am having on the wideband is that I am very rich at idle, everywhere else is perfect. If I go down on idle jet size, then idle improves but screws up everything else. |
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Posts in this topic
tornik550 Weber 44 idf flat spot Jul 4 2013, 11:59 AM
ThePaintedMan
So I recently purchased new weber 44 idf's. ... Jul 4 2013, 01:36 PM Elliot Cannon
So I recently purchased new weber 44 idf's. ... Jul 4 2013, 01:36 PM r_towle f7 or turbo emulsion tubes help with flat spots, a... Jul 4 2013, 02:02 PM brant 28 vents. Perhaps 40 mm carbs Jul 4 2013, 02:24 PM Starlack Hello
This is the transition area from idle jet t... Jul 4 2013, 02:41 PM tornik550 The interesting thing is that my car ran great in ... Jul 4 2013, 02:57 PM tornik550 Thinking about this situation, I think the suggest... Jul 4 2013, 03:12 PM McMark The carbs weren't really flowing fuel when the... Jul 4 2013, 03:16 PM tornik550 Ok, I am getting a bit pissed off at weber now. ... Jul 4 2013, 03:45 PM
Racer Chris
So for the record- does the longer side of the se... Jul 5 2013, 06:55 AM sean_v8_914 good advice above
smaller vents
smaller main jets Jul 4 2013, 04:05 PM sean_v8_914 long side of taper down. spray hole down Jul 4 2013, 04:06 PM sean_v8_914 http://www.carburetion.com/diags/40IDFDiaginfo.asp Jul 4 2013, 04:07 PM sean_v8_914 a wide band O2 would be nice for selecting the tru... Jul 4 2013, 04:09 PM tornik550
a wide band O2 would be nice for selecting the tr... Jul 4 2013, 04:17 PM Mblizzard On my weber 44s, 28 vents made all the difference.... Jul 4 2013, 04:25 PM Woody I run 36 vents and the car runs great. I have a se... Jul 4 2013, 08:53 PM McMark If you take the vent out you'll see one side i... Jul 4 2013, 11:54 PM Jake Raby
The only issue that I am having on the wideband... Jul 12 2013, 06:31 PM tornik550
The only issue that I am having on the wideban... Jul 12 2013, 07:46 PM Racer Chris If you back off the nuts on the accel pump rods an... Jul 12 2013, 11:24 AM ThePaintedMan
I thought I read somewhere that smaller vents gi... Jul 13 2013, 02:01 PM Racer Chris
In theory, every form of the Type IV below about ... Jul 13 2013, 02:46 PM ThePaintedMan
That is absolutely false.
With wideband air/fuel... Jul 13 2013, 05:38 PM Racer Chris
But Chris, weren't you suspecting that the en... Jul 14 2013, 10:01 AM r_towle That motor in the red/ white race car had basicall... Jul 13 2013, 05:06 PM tornik550 Chris-
I followed your instructions on tuning my c... Jul 14 2013, 07:46 PM Racer Chris The true exhaust temp is a lot higher than that.
... Jul 14 2013, 10:29 PM |
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