bjhines Posted November 22, 2005 Share Posted November 22, 2005 ok I have a set of these beauties....they are DCOE 45/late model 152s made in Spain..... They have 36mm chokes..and a middle of the line set of jets.... I intend to use them on an l24 with an agressive cam....It puts out 142 to the wheels at 6000RPM with SUs....I know it can make more power because only one third of the cylinders get the proper mixture with the little crappy stock manifolds.... anyway...a few questions.... It would appear that the original owner was not all that handy with carb tuning...and they are poorly assembled and set up they way he used them.....the throttle plates were all set to widly varying idle openings... the air bleed screws(#26) are all different heights... The jets all match.. thank god.... The bigest problem I see is that the "SOFT MOUNTS" between the carbys and the manifolds are significantly smaller than the 45mm trottle plates and carb bodies...they are actually forming a lip around the circumference of the manifolds that sticks out into the airstream several MM..... Tell me if I am wrong...but I think he mounted the silly carbs with a set of soft mounts for DCOE40mm... please tell me if the soft mount rings normally intrude into the airstream between the carbys and the manifolds. Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 22, 2005 Author Share Posted November 22, 2005 ohhhh... another request....I NEED 32mm chokes to fit the 45mm DCOEs....I can get them from Pegasus.... but I was hoping some Weber fanatics might have a set lying around for cheap. Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 22, 2005 Author Share Posted November 22, 2005 Is that crickets I hear..... Well...... I answered my own question today.... Pierce Manifolds came through...nice fella actually measured the soft mount rings for me....The Weber DCOE45 rings will not interfere with the airflow as they are 47mm inside diameter...The DCOE40 series had 40mm inside diameter rings...soo there is my problem... I dont know what kind of moron would have forced 40mm soft mounts onto 45mm carbys...but that explains why they are somewhat crooked on the manifold... I mean really..you just have to be retarded to do that... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 22, 2005 Share Posted November 22, 2005 I have a set of 44 Mikunis that the PO ran on a 40 manifold. There was a very good thread on Webers a few months back. Here it is: http://forums.hybridz.org/showthread.php?t=93343 If you read the stuff by NapaBill it may help out. There are a bunch of other Weber threads too. Search for Weber and just start reading. None of these are going to tell you what jets you need, but they should give you a good understanding of how the carbs work and what to try next. Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 22, 2005 Share Posted November 22, 2005 ohhhh... another request....I NEED 32mm chokes to fit the 45mm DCOEs....I can get them from Pegasus.... but I was hoping some Weber fanatics might have a set lying around for cheap. That's a really bad thing to do. 32 mm chokes on a 45 are not going to flow was much air as a similar choke on a 40. I did this test years ago on a flowbench. You need to stay above 35 mm to break even with 45s. For an agressive cam I'd think you'd be looking at 38 and still have decent mid and bottom. Cary Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 23, 2005 Author Share Posted November 23, 2005 I found the thread you reference earier... Very good info.... I purchased a 240Z Race car that was wrecked in the rear...recently...The carbs were functioning well enough for me to sell the engine for a good price...They were mounted on a 2.8 F54 flattop with the standard low compression head... there was a mild cam installed... Dyno said close to 200hp at the wheels...Which is respectable... considering I only get 142 HP to the wheels with my L24 and well tuned SUs.... The DCOE45s have 36mm chokes installed.... A handy carb refence webpage had a chart to determine choke sizes...Mine comes in at 31mm... 32 is the smallest I can get for the DCOE45s. They are available but they are $25 each...I checked on sizes too...36mm chokes are hard to find...apparently they are the most popular. If you look at the same chart I found...you will see that a 2.4litre engine is the biggest size they list for...it does indeed say that the chokes should be around 38mm.....BUT!!!! that is info for a dual carb 4 cylinder engine...you have to look at the info for a 1600cc 4 cylinder engine to match the same 400cc per cylinder volume as the 2.4L inline 6 cylinder.... Soo...I would say that a 38mm choke is wayyy too big... Most of the 2.4L triples are DCOE40mm with 29mm chokes.... I have run Mikuni/Solex carbs on Toyota 22R eninges...They can take big chokes because the cylinder volume is much bigger than the 400cc per that the Z L24 has. Quote Link to comment Share on other sites More sharing options...
Guest DoTheDrew888 Posted November 24, 2005 Share Posted November 24, 2005 John, Sorry I can't help you but I just wanted to say good luck. Im looking forward to seeing your car again once you get the Webers on there. -Andrew Quote Link to comment Share on other sites More sharing options...
Synlubes Posted November 24, 2005 Share Posted November 24, 2005 I have found on the 45`s that 32mm chokes with the right jetting works well with a mild build L-series motor. The 36mm choke sizing is good info for a well built L-series motor. I have some 36mm ckokes for 45 dcoe carbs if someone is interested. I am looking for six 34mm chokes for the 45 dcoe setup. Wanta trade? Quote Link to comment Share on other sites More sharing options...
RedNeckZ Posted November 24, 2005 Share Posted November 24, 2005 If you need 32mm chokes, I may be able to do some thing for you. Also have the jets for it. Need to know what you are planning to do with it. Road race or Solo II? I ran Solo II BSP with the L24. I have 6 of the chokes and all of the jets needed. I use to run them on my L24, before I went to the L28 w/E-31 head. If you are going road racing with it, you may want to go to a bigger choke. Your main jets should be 115 or 120. Idle jets should be around 45F9 or 40F9. Air corrector jets should be 180 or 200. The auxiliary venturis should be 4.5. Emulsion tube should be F16. I am going out into the garage to see what I still have, will get back with you shortly, Rich. Quote Link to comment Share on other sites More sharing options...
RedNeckZ Posted November 24, 2005 Share Posted November 24, 2005 Ok, went to the garage and got my box of parts. Main Venturis, I don't have 32mm main venturis, I have 6 each 30mm main venturis. Air correctors, I have 6 each 180mm and 190mm. The 200mm is in use at this time. Main Jets, I have 6 each 110mm, 115mm and 120mm. Emulsion Tube, I have 6 each, F16. Idle Jets, I have 6 each, 40F9, 45F9, 50F9, 60F9 and 40F11. If you are going Solo II go with the 30mm main venturis. For road racing go with 34mm or 36mm main venturis. The smaller the number on the venturis, the more grunt coming out of the corner. But you get less power at top end. I got my car with 180mm air correctors in it. Moved to the 190mm to make it run better. Ended up with the 200mm in it for the final running. It ran the best with the 200mm. Also had the main jets at 115mm for most of the time. Kept the idle jets at 45F9. The auxiliary venturis should be 4.5mm, still in use with the L28. I was running a L24/E-31 head with big valves and 3/4 cam. If you want to wheel and deal contact me at (910) 487-5972. Rich. Quote Link to comment Share on other sites More sharing options...
RedNeckZ Posted November 24, 2005 Share Posted November 24, 2005 Ok Synlubes, We may be able to do some thing with your need for 34mm chokes. I have two of them. Contact me at the number on the last thread. Rich. Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 24, 2005 Author Share Posted November 24, 2005 ok ... here are the numbers.... DCOE 45 152.. made in Spain... close set of serial numbers. TWM manifold and linkage...in good condition... 36mm chokes, 130 main, 175 air, F9?? E-tubes... L24 balanced and punched .020 over... polished crank... shot peened rods...new pistons and all Nissan internals. E-88 head...very slightly shaved...3 angle valve job...stock lift cam with aggressive timing... Currently running in HPDE events and TT.... I ran a minute 12seconds at "The Rock" in Rockingham NC...I never pushed the envelope with late braking there... so it is worth at least another second... Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 24, 2005 Author Share Posted November 24, 2005 Ok....things are starting to come together for me now... I managed to find a couple of Hybrid Z members who have some parts I need and have been VERY gracious about selling them to me cheap. The information I have found has been VERY helpful..... I really don't know what I would do without this site... Thank you EVERYONE!!! I think I have located a set of 30mm venturis for cheap... I was thinking I needed 32 mm chokes...but I will start with the 30s and move up if need to.... I have a huge list of parts on the way from all over the globe... correct 45mm soft mounts new studs and nuts for TWM manifold new studs and nuts for the E-88 head new Header style intake gasket one DCOE 45 152 rebuild kit...just to get gasket templates one fuel union tee..to allow return to tank Holley red pump screw on type fuel filter holley regulator carby fuel rail holley rail mount guage High quality hose hose insulation F.I. quality clamps I have 30mm chokes on the way I am adding a few O2 sensor bungs to my header I already have 2 A/F meters..I will add a third and move one existing I am adding an EGT gauge to the collector I am making up an equalizer/vacuum manifold. considering the TWM has a bung only on the #6 runner. I have a cold air box on the way...along with 4" tubing and a cone filter. I am making a heat shield in addition to the airbox The header is already jet coated and wrapped the TWM manifold will get insulated as well. I would like to know if anyone has ever found 5mm thread-vacuum ports/nipples to screw into the #48 vacuum cap hole on the DCOE bodies. This looks like a good place to plumb vacuum lines to a manifold block for dizzy vac signal...they may have enough flow to use for the brake booster and PCV as well... although I intended to make an equalizer tube for the TWM manifold anyway. Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 24, 2005 Share Posted November 24, 2005 I know you don't like my advice. But if you're going to use small chokes you should really put 40s on the car. It will work much better. If you decide to put a larger cam in this engine similar to the old datsun comp rally or slalom cam then you may find the larger chokes to work a lot better. We ran 32 mm chokes on a autox car for quite a few years. It wasn't until we started testing some of these pieces did we find these just don't work as well as you'd think in 45s. In our case the larger chokes were better across the board. This engne had a little over 11:1 compression. Cary Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 25, 2005 Author Share Posted November 25, 2005 I'm sorry Tube80Z... I have read a lot of your posts and found them very interesting...I like your web log about your fathers Z exploits and your continuation.. Well.... the carb size 45mm...They fell into my lap and thats what I have to use... as far as choke sizes...I am getting the 30s because they are available cheaply...and they are closer to the 29mm in DCOE40s used on most L24 engines... I really think that flow will be the same between the 40s and the 45s with similar chokes installed... therefore the 30mm chokes on DCOE45s are actually a step larger than the "normal" set ups for these engines... As far as what carby to use for what size chokes...I agree it seems silly to spend the extra cash on the 45mm bodies when the 40mm bodies will work just fine... but Weber made chokes all the way down to 28mm to fit the DCOE45s... I have em I'll use em...But I will indeed try tuning them at the track with the 36mm chokes installed...I may end up with 32mm or 34mm installed one day... BTW... if anyone has any 32 or 34mm chokes to use in DCOE45 bodies...I will buy or trade.. I also need to find jets of various sizes..I will request as I tune though... Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 25, 2005 Share Posted November 25, 2005 No need to be sorry. I can relate to using what you have or can get at a good deal on as I've done that many times myself. The issue with the carbs has to do with the changes in cross sectional area. The change caused by the smaller chokes on the larger carbs is greater than on the 40s. On the flowbench this shows as a reduction in flow when you test them back to back. I'm not really sure why Weber made such small chokes for the 45s when the 40s would have worked better. take care, Cary Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted November 26, 2005 Share Posted November 26, 2005 Well it sounds like you have sorted this out at least partially. I have spare jets, rebuild parts etc. for DCOE carbs if you need something, drop me an email and I'll see if I have what you need. I also understand about "using what you got" Get them up and running, and keep your eye out for someone who has 40's and wants 45's. I have run both the 40's and 45's on the same engine, and I have run from 34mm- 38mm chokes, and have come to a few conclusions about 45's on a Z. Yes 45's work pretty good on a Z. If you need to run anything under a 36mm choke, then run the 40's. (36mm is the largest you can run on a 40dcoe) The 45's are obviously needed if you are running larger than a 36mm choke, BUT. I would not recommend 45's for a street driven Z. Full race only. They are just not needed. Run some CFM calc's on a set of 36mm chokes on 40mm dcoe's, and I think you end up with 1100cfm (if my memory serves correctly) So if you think you need more than 1100cfm worth of carburation, then more power to you, but I highly doubt that your average Z needs that for the street. Like I said I ran the 45's on the street (38mm chokes), and the car was fast and strong. BUT it pulled harder when I swapped back my 40's with 36mm chokes. And this was on a overbored L28, 240 rods, 10.5:1 compression, 495/290 cam, nismo headers, FULL port polish job on an N42 that was done to rediculous extremes. The block was race prepped beyond rediculous. ie rods, crank, etc were almost mirror polished. The engine was built to shift at 8k, and I drove it that way. Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 6, 2005 Author Share Posted December 6, 2005 Well.... Webers are now installed....I got some tuning done to them before a rain storm cut my day short... I have installed 30mm chokes 115 main jet F16 E-tube 175 air corrector 60F9 Idle It pulls GREAT at low RPM...it has a much wider torque curve. and it idles rock steady... I have the idle speed screws out ~2/3 turn it varies from carb to carb... I used the air bleed screws unique to the 152 series to balance the bores The Idle mixture screws are out 3-3 1/2 turns..which is a bit too far out I think. There is a slight stumble when coasting...but it has perfect mixture at low speed part throttle. I can get it rolling without even using the gas pedal. My AF meters show very lean conditions when holding the throttle just enough to take all load off the engine in a level coast... This seems odd I think I have a huge idle jet size in there now...60F9...and the lean condition is only present when coasting with a TINY AMOUNT of pedal.. all other low speed conditions are perfect. anyone who has any ideas please chime in... anyone who has 32 or 34mm chokes...please PM me....I have your money in my hand... Quote Link to comment Share on other sites More sharing options...
Synlubes Posted December 7, 2005 Share Posted December 7, 2005 I have the idle speed screws out ~2/3 turn it varies from carb to carb... Did you set/sync the carbs with the car running and the throttle linkage loose? Setting the butterflies is the first thing to do, then start tuning. I have always found the idle screws to be about the same number of turns with little variance. Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 8, 2005 Author Share Posted December 8, 2005 Good thought on the linkage...But It did not escape me... The TWM linkage is very high quality...The best I have seen... And it is relatively easy to set by loosening the clamp screws on the arms. Before assembly I carefully checked the throttle shafts and plates to see that pairs worked evenly... I used a wire guage with them open enough to actually check clearances top and bottom...all 3 carbs had their pairs of plates in good order...variance ~.005.... Then I checked the idle speed set screws' contact points and position of throttle plates in relation to the transition holes... 1/2 turn past contact... there was some variance there...soo I set them just downwind of the 1st hole.. ~1/2 turn... The screws are not precision parts... niether are the throttle arms.... I thought that was a very accurate way to set them and I marked the heads of the screws at the same point on each one. If nothing else it makes it a little easier to count turns.. you dont get lost on half revolutions... The problem is that...all the screws are not turned the same to show equal flow with my unisyn meter..... they are up to 1/3 turn different from one another....I checked flow at 900 RPM and had trouble getting a decent reading with the unisyn set as low as it would go....I reset idle to 1100RPM and got a good reading from the unisyn. I was able to see a difference between bores on the same carby. The siamesed throttle bores would show slightly different flows at idle.... This was easy to make up for by opening the air bypass screw <1/2 turn on the low flowing bore. After dealing with this I have my doubts that the transition holes are accurately positioned in the carb body. A few of the idle mixture screws are F***** up...Inexperienced hands without a clue..screwing up far more than they ever fix. I expected them to be a little off...... With them over 3 turns out I think I need a bigger idle jet...60F9 seemed big to me..It is the biggest I have right now... I have dual air/fuel meters installed in the car..I welded bungs onto the rest of the runners and switch them out as I test... If the O2 sensors were less expensive I would put a rotary switch in the cockpit...and install all of the sensors...right now there are 4 spark plugs filling the unused holes. I used my ears to get the Idle mixtures close and tweaked them with the AF meters. part throttle and WOT conditions are very consistent....nice even mixture from all bores...The new spark plugs' deposits look much more even in all cylinders than when I was using the SUs. I used propane and a length of hose to check for vacuum leaks... I found one that I fixed before I started tuning. I believe my compression is very close on all cylinders. The engine has realtively low mileage... but I will check it. I will give the valvetrain a once over and see if that makes any difference...I have run one track event and played around on the street since I last checked lash... I doubt that is an issue... I would like to get a bigger idle jet in them and retune to see if that helps to even them out... Anyone have anything slightly richer than 60F9??? for cheap.. Quote Link to comment Share on other sites More sharing options...
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