zredbaron Posted June 5, 2017 Share Posted June 5, 2017 Hey guys. I’m getting ready to install my new 45 DCOEs and two of the three carburetors have “sticky” throttles. I uploaded a YouTube clip for demonstration purposes. My Weber book is in storage and I didn’t see any relevant hits in the search results. I’m hoping it’s just the bolts on the side of the butterfly valve, perhaps they are too tight or need some lubricant. Anyone have any experience or tips here? I’d prefer to not start tinkering randomly… Thanks! https://www.youtube.com/watch?v=jysf3Tbx4nw Quote Link to comment Share on other sites More sharing options...
steve260z Posted June 6, 2017 Share Posted June 6, 2017 I had the same issue. I loosened up the nuts on each side. You can run those pretty loose with the locking fold over ring. I would make sure you have plenty of grease inside..They look new... Quote Link to comment Share on other sites More sharing options...
zredbaron Posted June 6, 2017 Share Posted June 6, 2017 Perfect, that's what I was hoping to hear! Piece of cake. Thanks Steve. They're brand-new except for a few hours on the engine dyno back in October. Quote Link to comment Share on other sites More sharing options...
steve260z Posted June 6, 2017 Share Posted June 6, 2017 Also, I used a file to make sure a mating surfaces are flat. just fyi Quote Link to comment Share on other sites More sharing options...
zredbaron Posted June 7, 2017 Share Posted June 7, 2017 Interesting. Which surfaces did you find "not flat?" Quote Link to comment Share on other sites More sharing options...
steve260z Posted June 7, 2017 Share Posted June 7, 2017 The stamped steel washer that has the tab for the idle adjustment. Had some "high edges". Think the carb body had a casting mark as well. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted June 7, 2017 Share Posted June 7, 2017 I had the issue when doing some tuning for a friend. It happened the brackets holding the pushrods where too close to the carbs, they were rubbing against carb body. We had to add some washers between the carb and the brackets to get some extra clearance. It could also be because the nut of butterfly shaft is too tight. Try to remove the bracket/hardware to control carbs and check if they are still sticky. Your carbs are most likely fine. Quote Link to comment Share on other sites More sharing options...
zredbaron Posted April 17, 2018 Share Posted April 17, 2018 (edited) We're back online! Many thanks to the admins for restoring "Reply to Post" functionality. EDIT -- I mistakenly thought I was posting the below post to my engine thread. Oh well! It seems appropriate for this thread too. I have been kicking the "chassis dyno R&D" can down the road long enough. I have an appointment for Friday, May 4, 2018. Unfortunately, an air box will not be an option. However, I plan on doing intake volumetric efficiency research with regard to venturi diameters (38mm and 40mm) and the effects of various velocity stacks ("air horns" / "trumpets"). Here are my top air horn picks I am considering: For testing lengths, I like: http://www.emeraldm3d.com/throttle-body-kits/emerald-adjustable-length-intake.html Ideally, this would give us an idea how length of the air horns affects or doesn't affect performance Dyno will only be valuable for WOT. Butt-dyno runs will also be needed to confirm drivability. For testing shapes, I like: https://store.jenvey.co.uk/throttle-bodies-and-components/air-horns (currently awaiting their recommendation) http://www.palmside.co.nz/product_cid_10899.html (won't ship to USA) https://www.pegasusautoracing.com/productdetails.asp?RecID=1257 (currently awaiting confirmation from vendor) In my mind, a given length is best, and a given shape is best. These are not necessarily mutually exclusive. I predict the adjustable length will show a "good performance range," and choosing various shapes within this range would reveal optimal combination(s) for a given application. Again in my case I seek a wide, flat torque curve and not peak HP. Perhaps the data will be clear, but I predict a butt dyno / road test will likely have to confirm / deny the winner(s), especially if some combinations are comparable. WOT hp numbers are not what wins an autocross race. If anyone is interested in contributing their 45mm air horn shape to this shared research, please message me. I would be happy to return them to you after chassis dyno testing is complete. Alternatively, air horns, race fuel and dyno time are effing expensive. If anyone is feeling charitable and wishes to donate some coin, that would be appreciated. This project is financed by credit and cash loans; I'm "all-in" with this S30 project. Maybe some others relate? Some say gains won't be made here. Perhaps in peak hp this is true, but in terms of area under the curve, I defer to Ferrari and other performance companies who have engineered variable length intakes. If it was a gimmick, it wouldn't be on a supercar. We don't have this data publicly available for our L6s. Let's change that. Edited April 18, 2018 by zredbaron Quote Link to comment Share on other sites More sharing options...
GeniFx Posted September 4, 2018 Share Posted September 4, 2018 Maby some of you weber gurus can point me in the right derection her. I got a stock l2,6 with full z story exhaust. And i have 45mm webers on it. (Got Then with the car (new in box) ) What is a good starting point her? Any rule of tumb on This? My tuner recomeneded me now to order f11 tubes 55f6 idle and 30mm (36mm in Then now) chokes for them. Got alot of option on mains for it from 130-175 i think i was. Air is 170 if i dont remember wrong. Hope some one can point me to a start her. Having trubble making it run. Bogs AS soon AS we are trying to rev it if we are not carfull. Thank you. Quote Link to comment Share on other sites More sharing options...
Ereschkigal Posted April 4, 2019 Share Posted April 4, 2019 Hey to all the experts out there. I'm a total carb noob and I hope to get a starting point from you. I'm currently building the engine: L30 P90 Head (slightly ported) Something like this "Stage 2" Cam Lift(In/Ex): .480/.480 Duration(In/Ex): 274/274 123 Ignition distributor I currently have a set of DCOE40-151 on my L24 and want to keep using them but the question is, with which choke and jets should I start? Quote Link to comment Share on other sites More sharing options...
jonbill Posted April 5, 2019 Share Posted April 5, 2019 (edited) It rather depends what you'll do with it. I'd recommend getting this book or one of the others like it. How to Build and Power Tune Weber and Dellorto DCOE and DHLA Carburettors (Speedpro Series) https://www.amazon.co.uk/dp/1903706750/ref=cm_sw_r_cp_apa_i_Ah7PCb8WCD7AH They'll help you pick the parts you want for your use case. First thing I'd do with them is swap them for 45s. Edited April 5, 2019 by jonbill Quote Link to comment Share on other sites More sharing options...
Luzifer Posted November 16, 2023 Share Posted November 16, 2023 Hey guys, noob here. I just picked up a '74 260Z and I need some guidance. This is what I'm working with; L26 with E88 heads. Not sure of the internals of the engine but apparently it's been rebuilt (possibly upgraded, possibly stock - who knows). Canon intake and headers. Triple 40 DCOE 18 Main - 150 Air - 185 Emulsion tubes - F11 Idle - 50F9 Pump - 45 Aux Venturi - 45 Chokes - 35 Close enough to sea level for altitude. I balanced the triples and set the idle mixture and speed (to the best of my ability being new to carbs). Fuel pressure guage says it's getting good 4-5psi. It's got an AFR meter under the dash and what I'm seeing is that idle is ok and part throttle. Above about 3,500-4,000rpm with 3/4 throttle to WOT looks ok as well, perhaps a little lean. The trouble I am having is that anything below 3,500rpm if I step on the gas it bogs down a lot to the point it doesn't go anywhere. So I guess that's the transition from the idle to main circuit. I would really appreciate some guidance as to what I might try. Quote Link to comment Share on other sites More sharing options...
jonbill Posted November 16, 2023 Share Posted November 16, 2023 Will it get up to the higher revs ok if you don't give it so much throttle? If it can accelerate up at part throttle without any hiccups, then its probably the accelerator pump circuit. Quote Link to comment Share on other sites More sharing options...
Luzifer Posted November 17, 2023 Share Posted November 17, 2023 4 hours ago, jonbill said: Will it get up to the higher revs ok if you don't give it so much throttle? If it can accelerate up at part throttle without any hiccups, then its probably the accelerator pump circuit. Yes if I don't stomp on it and give it part throttle to 3,500-4,000 I can stomp on it there and it screams. Still a bit lean though. I don't know if the emulsion tubes are correct, or perhaps it could do with a slightly smaller choke? Quote Link to comment Share on other sites More sharing options...
jonbill Posted November 17, 2023 Share Posted November 17, 2023 I'd check that the accelerator pump is working correctly first. Take the carbs off and see if they squirt fuel out the back. Quote Link to comment Share on other sites More sharing options...
Luzifer Posted November 17, 2023 Share Posted November 17, 2023 9 hours ago, jonbill said: I'd check that the accelerator pump is working correctly first. Take the carbs off and see if they squirt fuel out the back. ok thanks. I'll try that first. Quote Link to comment Share on other sites More sharing options...
Luzifer Posted November 18, 2023 Share Posted November 18, 2023 On 11/17/2023 at 3:59 AM, jonbill said: I'd check that the accelerator pump is working correctly first. Take the carbs off and see if they squirt fuel out the back. Thanks. I did as you suggested and the pumps are all working. I pulled the accelerator jets and cleaned them with some B12, making sure it sprayed out the holes well. Put them back and it improved probably 90%. There is still a slight bog/hestitation but it's a hell of a lot better. Quote Link to comment Share on other sites More sharing options...
jonbill Posted November 19, 2023 Share Posted November 19, 2023 Maybe try the next size up idle jet, that might cover the transition hole, might richen it a little at wot too. Also check the float levels if you haven't already. Quote Link to comment Share on other sites More sharing options...
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