JMortensen Posted February 23, 2008 Share Posted February 23, 2008 That big one sounds about right to take advantage of the triples. Quote Link to comment Share on other sites More sharing options...
twistex Posted February 25, 2008 Share Posted February 25, 2008 I went from f11 emotion tubes to f15 and could feel a difference midrange. I really don't want to tune it without putting a header and the bigger cam because I will just have to retune it again! Quote Link to comment Share on other sites More sharing options...
twistex Posted February 28, 2008 Share Posted February 28, 2008 ok now, i looked into my carb's and can read a number saying 4532 .. only thing i can think is that it means 45mm carb, 32mm choke ? Anyways for me running a 3.2 I would think I need some 36 to 38mm chokes. I also cant get it to idle when i adjust my throttle plates so I have to change out my idle jets. I changed the f11 for f16 and it feels like it pulls harder. I also adjusted my timing from 10 deg lol to like 14 and it ran a lot better. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted February 28, 2008 Share Posted February 28, 2008 I found that my triple webers idled best with lots of advance. That's why many swap to the later 81-83 ZX distributors - they provide less mechanical advance which allows you start with more advance at idle without ending up with too much total advance. Did that make sense? Quote Link to comment Share on other sites More sharing options...
twistex Posted February 28, 2008 Share Posted February 28, 2008 I found that my triple webers idled best with lots of advance. That's why many swap to the later 81-83 ZX distributors - they provide less mechanical advance which allows you start with more advance at idle without ending up with too much total advance. Did that make sense? your probably talking about the 280zx non turbo obviously. Well I think i have the maxima one or the 280zx. how much does it advance ? i heard of one only advancing 14 deg ? so if you set your base at say 14 it would only get to 28 full advance ? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 28, 2008 Share Posted February 28, 2008 Get a timing light that does advance, set it at the total advance you want with the rpms over 3000 degrees and ignore what it is at idle. If that's not accurate enough, you can disassemble the distributor and look on the shaft near the weights and there is a number stamped on there. Double it and that gives your total mechanical advance. The ZX's come in either 8.5' s or 9's. Quote Link to comment Share on other sites More sharing options...
twistex Posted March 9, 2008 Share Posted March 9, 2008 ok my car was accelerating pretty good before I took out the 34mm chokes and bored them to 38mm. This increase in choke size obviously means i have to increase my mains correct ? I read on this thread that a good way to find your main size is X your choke size by 4. 38x4 = 152. I use to have 34 so 34x4 = 136! I have 135 mains right now. This is why its bogging badly when I get past 3k rpm I'm guessing. Anyone know what number drill bit will get me to a 150 on the main ? I'm Also going to go 200 on the air. Thanks. Quote Link to comment Share on other sites More sharing options...
twistex Posted March 9, 2008 Share Posted March 9, 2008 Well I searched around on google and found someone who talked about the jets being metric so like a 150 main would be a 1.50 metric drill bit thats one size under a number 53 drill. So 200 on mains would be a 2.00 metric bit. My idles must be to lean because it takes more then 2 turns to idle up. I have 55f8 and was thinking about drilling it out to a 60 or 65. .60 and .65 metric bits. Does this sound correct about the drill sizes ? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 9, 2008 Share Posted March 9, 2008 I'm not sure how the Weber jets are marked, but I wanted to give you a warning. I've got reams and drills, and I've quickly forgotten what is what. Best to buy the correct jets. Quote Link to comment Share on other sites More sharing options...
Administrators SuperDan Posted March 9, 2008 Administrators Share Posted March 9, 2008 I'm not sure how the Weber jets are marked, but I wanted to give you a warning. I've got reams and drills, and I've quickly forgotten what is what. Best to buy the correct jets. Same here, I bought this reamer set: http://www.cbperformance.com/catalog.asp?ProductID=525 And this gauge set: http://www.cbperformance.com/catalog.asp?ProductID=524 Fairly cheap as I recall and works great, unfortunately looks like they are out of stock right now. Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted March 22, 2008 Share Posted March 22, 2008 Well I have set mine up differently again. I put the stock dizzy internals back in and am running 11deg idle, 36deg all in. Carbs are 40DCOE18 33mm Main Venturis, 4.5 Aux Venturis, 60F8 Idle, 135 mains, 180 Airs, 45 Accell, F11 emulsion tubes. We'll see how she runs at the Auto-X this weekend, and I will fine tune the jetting on the dyno next week and post my numbers. Quote Link to comment Share on other sites More sharing options...
josh817 Posted April 10, 2008 Share Posted April 10, 2008 Here's a question for all you guys but I guess mainly Zredbaron. Building a 3.1L stroker, stageIV cam, headers, lightened flywheel, ported and polished P90. Power I'm looking for from 4k-7k RPM. Where to start? I'm seeing 45's but I can barely find them right now and when I do they're expensive. This isn't a race motor, jsut a hot street motor. Could I go with a large choke 40mm carb rather than 45's or will there be considerably less performance? My dad does the Triumph race cars so he has all sorts of gadgets but I'm still putting a narrow band in so it will make it MUCH easier to say "hey we're lean in the higher RPM's"... then again it is narrow band and I have heard/seen many horrors of them. Oh well. Quote Link to comment Share on other sites More sharing options...
zredbaron Posted April 19, 2008 Share Posted April 19, 2008 i have a high flowing 3.1L stroker with 36mm venturis in my 40mm DCOEs. i autocross, so i need my full power band. i have TONS of low end torque, and a hell of a pull above 3500rpm, despite the fact that my venturis dont look like venturis (theyre practically straight sheaths claiming to be venturis!). 36mm is the biggest venturi that will fit in the 40DCOE: unless you have a VERY aggressive cam and have invested A LOT of $$$ into your head, i'd bet that 36mm is too big for you. if the head cant support the flow, opening the venturis will only help up to point. lots of useful venturi selection charts in the weber carburetors book. check barnes and noble. they usually stock a couple. basically the bottom line is, *unless you plan on road racing exclusively,* in my opinion, no one NEEDS the 45mm, despite what people tell you. my car is trailered to racing events, but even still... i'm not sure if i'll ever go up to the 45mm. you open it up too much, and you loose that low end torque/wide power band/throttle response. cars driven on the street need all of these things, especially weekend warriors which mine was for years. you might sacrifice that peak horsepower number, but chances are, off the line to 80mph isn't as fast. average power (ie power band) matters more than a peak number! as far as where to get webers... i got mine new for $1000 from victoria british when they had a special offer in '97. no advice there. (i think they changed their name to black dragon or something ricer-oriented. boo.) i have a narrow band sensor in my car and it SUCKS! it's practially worthless. its too sensitive. for the beginning carb tuner, it's very easy to not register in the band at all and have no idea if you're rich or lean. *highly* recommend wide band for carbs! good luck! (you may also want to read this thread: http://forums.hybridz.org/showthread.php?t=89812) Quote Link to comment Share on other sites More sharing options...
josh817 Posted April 20, 2008 Share Posted April 20, 2008 Yah I read up in there. The only thing which keeps me from asking your current carb "settings" is that each setup is different. This is VERY good news as far as 40's go. I was looking into 45's and well... because of the price I was considering 6 Mikuni bike carbs but being only 17... I can't justify losing a college education over some sexy looking carbs. >_> As for head work... welll I don't even know. My dad does the Triumph race motors in our club and his head porting and polishing jobs go by all this literature he has collected for 20+ years from people like Kas Kasner who pretty much make diaries of their endless budget adventures. I'm still trying to look for porting numbers (how big the intake and exhaust ports should be measured afterwards or maybe how many mm to open up). When Dad showed me an example of how restricted a head could be he pulled one off the shelf and took a gasket out, it was clear that the ports were much smaller than the gasket opening. I'm tempted to do the same method, open the ports up to maybe 1-2mm gap from the gasket but I'm not sure how thats really going to work out. I really have to look at where water jackets are and stuff. I also want maybe a 3 angle or 5 angle valve job and is it a common thing to put even BIGGER valves into a P90 head or what? I know you can only port so much until you have to get bigger valves but like I said I don't know at what point this has to happen. I think my dad is a distributor for Weber not too sure, but I know he is for Moss Motorsport so jetting probably isn't and issue and he has lots of books that I snatched up to read along with gadgets. I think our best tools will be his synchronizer and then the narrow band. We can figure out jetting for summer and then for winter so when the seasons change I just change them out. Texas... its unpredictable until summer hits and everyday is sticky, sucky, and hot. 2 things I would like to ask though: What jetting would you predict for me right now? Noob question, rockers really have to be changed when changing cam? Thought the cam rides on the lash pad which you can take out of the rocker, so why not just change lash pad... My setup: 3.1L F54 block KA24E dished pistons L24 rods V07 crank .6mm X 91mm head gasket (or I can go with 1-2mm X 90mm) P90 ported and polished head 10LB's flywheel .495/.290 cam (stage IV) Headers Port matched intake 10.23:1 compression Couple of illustrations: Right or wrong? Port head out to match head gasket or is that WAY too much? PROBLEM: Charts don't represent large motors and lines aren't linear so you can't project the line really... My holy scripture. It teaches me the moral foundation of life itself. Thanks Redbaron you made my day by saying you don't need 45's. EDIT: And yes they did change their name to Black Dragon. Its very handy to have dealership pricing though. ! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 20, 2008 Share Posted April 20, 2008 i have a high flowing 3.1L stroker with 36mm venturis in my 40mm DCOEs. i autocross, so i need my full power band. i have TONS of low end torque, and a hell of a pull above 3500rpm, despite the fact that my venturis dont look like venturis (theyre practically straight sheaths claiming to be venturis!). 36mm is the biggest venturi that will fit in the 40DCOE: unless you have a VERY aggressive cam and have invested A LOT of $$$ into your head, i'd bet that 36mm is too big for you. if the head cant support the flow, opening the venturis will only help up to point. lots of useful venturi selection charts in the weber carburetors book. check barnes and noble. they usually stock a couple. basically the bottom line is, *unless you plan on road racing exclusively,* in my opinion, no one NEEDS the 45mm, despite what people tell you. my car is trailered to racing events, but even still... i'm not sure if i'll ever go up to the 45mm. you open it up too much, and you loose that low end torque/wide power band/throttle response. cars driven on the street need all of these things, especially weekend warriors which mine was for years. you might sacrifice that peak horsepower number, but chances are, off the line to 80mph isn't as fast. average power (ie power band) matters more than a peak number! as far as where to get webers... i got mine new for $1000 from victoria british when they had a special offer in '97. no advice there. (i think they changed their name to black dragon or something ricer-oriented. boo.) i have a narrow band sensor in my car and it SUCKS! it's practially worthless. its too sensitive. for the beginning carb tuner, it's very easy to not register in the band at all and have no idea if you're rich or lean. *highly* recommend wide band for carbs! good luck! (you may also want to read this thread: http://forums.hybridz.org/showthread.php?t=89812) Sounds like you've talked yourself into your 40s. I guess I've done the same with my 44s. By the way, you can get smaller venturis for the 44s too, so there is some overlap there. I changed my 34s out for 37s... Your O2 sounds like it is a cheap crappy one. I have a friend who got the Autometer A/F ratio gauge and was all pissed off that I had told him to get it. Then he changed the sensor and it worked great. Not as good as a wideband of course, but definitely better than what you describe and similar to my own results. I use a Bosch sensor for what it's worth. Quote Link to comment Share on other sites More sharing options...
zredbaron Posted April 20, 2008 Share Posted April 20, 2008 josh, most of your questions are outside the scope of this thread, but here are a few short answers. having a stroker won't give any noticable power (but you will have some torque) unless you allow its potential, even with triple webers. see my response to this thread: http://forums.hybridz.org/showthread.php?t=103763 as to your head, opening it up is a good thing. absolutely required to get power from the 3.1. in my book, if you've got it out, then you HAVE to do it. put the biggest valves in that will fit, and yes, port your head to match your gasket. if you didnt, you would have turbulent flow going into the cyls. like driving, smooth is fast. no offense, but the more experience i gain with carbs, the more i refuse to estimate jets for anyone. it varies between two different stock cars even. there are so many variables that you can only make it a science if you have the data (ie *exact* fuel flow rate (cfm), displacement, compression, rpm, etc. use your charts for a best guess starting point, then also buy a set of mains 10 above and a set of mains 10 below the charts. same with idles and air correctors, take your best guess +/- one size. (i'd vary the air correctors +/- 15 and the idles +/- 5) then go test. listen to the engine, test various throttle settings, not just full pedal, and pay attention to what your butt feels. you just gotta go do it. i bet my jet and venturi box cost me $750. just for mixture tuning. [and i still dont have it right!] [venturis are VERY expensive] dont forget that spark (spark power and timing) is just as important as fuel and air mixture. they depend on each other. just like flow and displacement. cant utilize one without the other. notice a trend? [yes! $$$!] Sounds like you've talked yourself into your 40s. Your O2 sounds like it is a cheap crappy one. I have a friend who got the Autometer A/F ratio gauge and was all pissed off that I had told him to get it. Then he changed the sensor and it worked great. Not as good as a wideband of course, but definitely better than what you describe and similar to my own results. I use a Bosch sensor for what it's worth. i think i have settled on my 40s, jon. although now i'm looking to upgrade my cam to more lift, so maybe i might open that door as a possibility again. for sure staying with carbs. no 3x2 TBs for this guy. speaking of which, if you'd chime in on this thread again, i'd appreciate it! http://forums.hybridz.org/showthread.php?t=89812 this is the first i've heard of the autometer O2 sensor. and yes, that's what i've got... thanks for the tip! Quote Link to comment Share on other sites More sharing options...
josh817 Posted April 20, 2008 Share Posted April 20, 2008 Redbaron you give some good responses thats all I'm going to say. >_> The guys over at Wolf Creek Racing said they can setup the carb to your application. I don't expect it to be right on (boy that would be luck if they were) butgetting in the general ball park is good. Yah, I realize I will have to sit down every once and a while and do some tuning but to me thats the fun part. I have barely any tools here at home and while I'm taking apart the car getting it ready for the next step I really really enjoy it. Go to bed each night and I'm excited for the next time to work on the car. Its funny how when Dad moved out so did the way our garage looked. It was filled with car parts and restoration things and tools, then it went empty, and now the Z is in there. The begings of the good old days. He's saying I need to start building up my tools now, even if they have to be crappy foreign quality things at least I will have them. So really some tuning doesn't bother me and all those FI people that say carbs are a pain in the ass don't scare me. I only view it as just another bond between driver and car. I'm setting the car up so it will always be like that. Forget the radio, the A/C, the heater, when I get in that car I get in to drive, not to enjoy luxuries. I'll use my moms Honda Civic for that. When all the kids at school say the car is so uncomfortable and this and that, screw them I have a well oiled machine ready to perform. Quote Link to comment Share on other sites More sharing options...
zredbaron Posted April 20, 2008 Share Posted April 20, 2008 glad to be of help. i don't know nearly as much as many of the senior members, but i've learned some lessons that could have been prevented with some very simple advice/experience. the things i've done right have been because of these senior members i speak of. it's good that you're asking questions. i fell in love with the 240 when i was 17 too, so i very much relate to your excitement. it's still with me 11 yrs later when i think about upgrades. and unfortunately the dollar amounts get higher and higher the farther along your car gets... best of luck. Quote Link to comment Share on other sites More sharing options...
1rad280 Posted April 20, 2008 Share Posted April 20, 2008 Does anyone want to buy another weber setup. I will sell for 1000obo. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 20, 2008 Share Posted April 20, 2008 Does anyone want to buy another weber setup. I will sell for 1000obo. Post a for sale ad please. It is not appropriate to post your carbs for sale here. Quote Link to comment Share on other sites More sharing options...
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