dat240z71 Posted September 1, 2017 Share #1 Posted September 1, 2017 (edited) I'm in need of someone that knows how to tune webers.I have a L28.20 over Ported and polished N42 head,Robello street cam.flat top piston 280zx distributor that I can't seam to get running correctly. The car has a slight bog at 2800 RPM. Bseam to hit a wall at 4k RPMS. My trimming is set to 20 degrees at idle vacuum advance disconnected. Distributor have not been re curved. Driving at highway speeds the car seams to bog when press down on the accelerator. The transition isn't smooth from idle circuit to main. If there anyone or a shop in N.E Indiana or the surrounding area that can help I will greatly appreciate it. I'm also willing to Compensate you. Jetting Idle jet 60 F9 Main jet 135 Air corrector 180 Emulsion tube F2 Pump jet 45 34mm Choke Edited September 1, 2017 by dat240z71 Link to comment Share on other sites More sharing options...
240260280 Posted September 1, 2017 Share #2 Posted September 1, 2017 There is a current thread on tuning DCOE's on L28. It may be helpful. Do you have 40's or 45's? Please measure your fuel height in all 3 carbs and make sure your linkage is synchronized. Link to comment Share on other sites More sharing options...
240260280 Posted September 1, 2017 Share #3 Posted September 1, 2017 Check this thread http://www.classiczcars.com/topic/56375-weber-selection-and-initial-jet-tuning/ Link to comment Share on other sites More sharing options...
dat240z71 Posted September 1, 2017 Author Share #4 Posted September 1, 2017 They are 45's Link to comment Share on other sites More sharing options...
Patcon Posted September 1, 2017 Share #5 Posted September 1, 2017 Do you have an O2 sensor or wideband set up? That would help a lot! Link to comment Share on other sites More sharing options...
dat240z71 Posted September 1, 2017 Author Share #6 Posted September 1, 2017 (edited) Just went out and looked at the carburetors after reading the post suggested. My throttle plate sits behind the 1st progression holes I'm going to adjust them as per the pictures will report back in a little bit what I found Edited September 2, 2017 by dat240z71 Link to comment Share on other sites More sharing options...
dat240z71 Posted September 1, 2017 Author Share #7 Posted September 1, 2017 (edited) I set the plat at the edge of the progression holes can't get the idle under 1500 RPMS at that setting . No ai don't have an 02 sensor no a wideband Edited September 1, 2017 by dat240z71 Link to comment Share on other sites More sharing options...
240260280 Posted September 2, 2017 Share #8 Posted September 2, 2017 plate should be as closed as possible. At first progression hole or closed even more is best. Link to comment Share on other sites More sharing options...
dat240z71 Posted September 2, 2017 Author Share #9 Posted September 2, 2017 I will go out today and play with the car and report back. One question I do have is do you guys think the problem I'm having in the high rpm range could be timing related. I do not have a digital readout timing light so I have set my idle at 20゚ but I have no idea what my total timing is do I need to look into that 1st. Link to comment Share on other sites More sharing options...
240260280 Posted September 2, 2017 Share #10 Posted September 2, 2017 Yes, 20 at idle is most likely too high. It depends on what distributor you have. You need to buy a timing light (preferably one with advance) to measure your timing at different rpms. The max timing you want is ~ 36 to 38 at 3000 rpm or above. Link to comment Share on other sites More sharing options...
dat240z71 Posted September 2, 2017 Author Share #11 Posted September 2, 2017 I have1979 280x distributor it haven't been re curved. Vacuum advance disconnect. When I get the new timing light do I want to set total advance. Link to comment Share on other sites More sharing options...
240260280 Posted September 2, 2017 Share #12 Posted September 2, 2017 I checked specs and all 280zx distributors gives 17 degrees of mechanical advance. If you put 20 degrees of initial advance in then you are 37 total so it would be in the ball park. Too much advance under load at higher rpms will reduce power and may ping. Link to comment Share on other sites More sharing options...
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