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This is the present set up for my engine. I have a backfire issue at idle and low throtle. Any suggestions from the guys that use webbers on what to do to minimize popping? I have to re-dyno due to dyno improperly set on last tune up.
347 Stroker Stroke: 3.400 Bore: 4.030 Connecting Rods: Scat I Beam 5.400" Pistons: J&E Forged Cam: Solid Roller 106 Degree LSA In Ck 104 Degree Dur. In 228@050 Lift .635 Inch Dur. EX 234@ .050 Lift .638 Inch Lifters: Comp Cams Solid Roller Heads: Ford Motor Sports Aluminium 1.94 X 1.6 Rocker Arms: Comp Cams 1.6 Weber: 44 IDF 18990.030 Compression: 10.25 to 1 44 IDF Webber Set Up Venturi ----------------36 mm Aux Venturi -------------4.50mm Main Jet ---------------145 mm Air Corrector----------- 180 mm Emulsion Tube---------- F-11 Idle Jet---------------- 55 mm Pump Jet --------------.50mm Needle Valve -----------1.75mm Pump Exhaust Valve----- 55mm Float Adjustment------- 32.5/10mm Idle Fuel Screw--------- one turn out |
Somehting isn't right. Or, as my kids say: "something's all jacked up dude".
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Increase Idle jet to 60.
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Rick, What does raising the idle jet size do to minimize popping. If the popping is caused by excess fuel entering sidepipes and igniting, wont that put more fule into the pipes??????
Jim |
You said it was backfiring, I understood that to mean back through the carbs? If this is at idle and part throttle up to about 2000 Rpm it's indicative of a lean condition in the idle circuit. If the side pipes are popping then its fat. The emulsion tubes work during light accleration and part throttle cruise.
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Thanks again for everyone's input. I went to the forum and read all the weber posts. I am using Champion 3025 plugs and have carbon fouling . Would you change to a hotter plug at this time, and if so, what plug would you recommend.
I changed my idle jets from 55 to 60. My idle mixture screw was one half turn out and I went to one full turn out. I also turned my puel presure regulator down from 4 to 3. Test drove car, Excessive backfiring through pipes on deceleration, far more than anyone would enjoy driving the car about every 5 seconds when you back off the throtle. I checked for leaks in headers but all bolts were tight and no signs of black marks around headers. Still some sneezing during acceleration. Bright side is I have more torque and during acceleration car feels strong. It is still that backfiring in exhaust pipes!!!!!!!!!! I'm thinking my S&W 45 would put some fine venturis in the darn thing!!!!!!!!!!!! I ordered the LM-1 Air /Fuel Ratio Meter. Not as though I know a rats a-- about that either! Someone should go into business tuning webers. May save guys like me more money to fly them to the car than waist time and money fiddle farting with something I know little about. I'm just a parts changer and that is expensive. Thank's Jim |
I like the NGK
It works for me :) |
Jim
I feel your pain, as I've been there and done that. My fix for my webers was to take them off install a Tunnel Wedge and sold the weber set up for one hell of a loss. Will be in the NW for a couple of days and then I'm heading to Alaska for a few weeks. I did bring my car back to the NW. Will be back in the area mid July so hope to get in some rides. Fred |
Fred will you be selling your Webers / what model how much
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Quote:
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Priobe
Sold them to another NWCC guy. |
In a close examination I found carbon coming from inside the four header pipes where they enter the collector on both sides. I will have to weld up all four pipes together up the sides to stop the leak. May be what is causing popping.
Fred, Nice to hear from you. Cant wait to see your car again. JayMac, You mean a heck of a swim!!!!!!!!!!!!!!!! Jim |
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