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Showing results for tags 'SU Carbs'.
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Hi guys, about a year ago i bought a 1974 260z that had an N54 l28 swapped in, it also was converted to 4 screw round top su carbs. I rebuilt the head and the carbs. I got it running last spring and it idled great but whenever i tried to accellerate hard it would hit around 3500 rpms and then start to stutter, cough and die, almost like it was hitting a limiter. I did some trouble shooting and ended up trying a couple pulls without air filters on, and the z ran great, I could pull way past 4k and more without any stuttering or coughing. I thought it was the stock air box restricting air for some reason, so i bought itg air cleaners off of MSA. Even with the performance cleaners the issue persists. I've checked ignition timing and it is around 10 degrees advanced, I'm really at a loss and have no clue what could be the issue any help would be greatly appreciated
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Anyone out there who can give me a performance review after installing SM needles to replace the stock needles in your SU carbs?? Would love to know if this was a good performance upgrade. Thanks! -Steve
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- SM Needles
- SU Carbs
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So I recently got a 260z last month and this problem has finally gotten to me. The infamous post emissions Flat top SUs are bogging when I lay the pedal to the metal. They will just begin to barf gasoline out the overflow valve if I start it up and rev it while the carbs are still cold. But this especially happens up in the hills (In Alaska) and no matter how slow I start up the carbs they will bog and puke up good gasoline. All I can do is floor it till what I assume is the floats go back up. Usually all it takes is flooring it till it touches off on 5k revs. But this problem is very persistant and when I come down from the hills after the carbs go cold all they wanna do is bog for the next 5 to 10 minutes. Now I'm just gonna guess this problem is from sticky floats and fouled up Emission carbs. (cept for all the emissions are taken off because Alaska)