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Motor bogs down alittle then cleans up


Sam1647545489

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Hesitation/Bucking is a lean condition, which is no surprise to me if this is what you're experiencing when you're starting to hit boost. I figure it probably clears up as you get into the main jets of the carbs and off the pump jets and through the progressive circuit which are probably on the lean side.

 

If it were a rich condition the motor would just react sluggishly and even sound loaded up.

 

Reading plugs is a good thing to learn, but I definitely suggest getting a wideband to figure out what you actually have going on.

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He said it was at cruise speed. If its lean or rich going into boost then pv. But the main circut should not control cruise rpm fuel. That's the ifr job. If its too rich at part throttle less ifr too lean more. Your main air bleeds should be set to slow the mains t not come in on cruise conditions. And I've went 8s on a carb for a few yrs. Built a homemade e85 carb id think my opinions should help. But fuck What Do I Know.
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He said it was at cruise speed. If its lean or rich going into boost then pv. But the main circut should not control cruise rpm fuel. That's the ifr job. If its too rich at part throttle less ifr too lean more. Your main air bleeds should be set to slow the mains t not come in on cruise conditions. And I've went 8s on a carb for a few yrs. Built a homemade e85 carb id think my opinions should help. But fuck What Do I Know.

 

Going 8s on carbs is different than setting up carbs that are going to be used for spirited cruising, I'm sure. You're getting pretty defensive about your answers, when nobody has said you're wrong in any way... we're just suggesting other things to consider.

 

Cruising is done on the main circuit, airs richen or lean the mains in the uppermost RPMs. Emulsion tubes and etc. will determine the richness on the main tubes at cruise as well as the choke size. To me his problem sounds like the changeover from the progressive circuit and main circuit has a lean spot. Obviously he's not cruising at the same RPM and then it suddenly bogs out and then goes back to normal. It's probably experienced when he's speeding UP TO a cruise speed, which he would go through the changeover in circuits. If the jetting was fine previously, and you're experiencing this condition randomly, I would definitely check the plugs and maybe even the fuel pressure. Bowl floats could be getting stuck and not filling the bowls correctly, as well.

http://www.tr3a.info/TR.images/DCOEchart.jpg

Edited by Farkas
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is it a holley 4150. If so it has 2 circuts. The only holley carb with 3 circuts are dominators to overcome the large butterfly. And some 1050s have 2 as well. The progresive circut ur refering to on a 4150 is in fact the idle feed restrictor. This can set cruise rpm all the way up to about 3000rpm. From there its the mains. Most if not all holleys come with the mains comming in way to early. And too large a ifr so too rich at cruise. My suggestion for accel pump is cause most blown cars go lean if u stab it untilll the powervalves open. I had a 6_71 blown 355 with 11.78:1 compresson. I know whatv blowers like his is dinky but I've tuned a few of them. Mine loved a big as shot on all 4 squirters but it only spun to 7800rpm. Proably was off on the tune some cause that was all tuned by ear and vac gauge. With a wideband I proably was a litte fat wot.
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Id get a innovate lm1 and auxbox recorf rpm afr egt boost and log it then make small changes. U can proably do a clamp on the hedder style if u didn't wana weld in a bung

 

I don't think the O2 would work with the water that come out the exhaust .

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Welp it ended up being 1 plug that I closed the gap to tight without opening it up when I was gapping them. Had it almost 100% closed. I regapped all them to .35 and now she runs great. :)

 

Idiot. Thats the last time I take your course on Carb Tuning and Engine 101

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Welp it ended up being 1 plug that I closed the gap to tight without opening it up when I was gapping them. Had it almost 100% closed. I regapped all them to .35 and now she runs great. :)

 

Do you remember setting it that low? Pre-ignition will close a plug in a hurry.

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