porkbun

2.5 Turns is the starting point for getting the proper mixture. How far down or up depends on the carbs and your car

If the manifold isnt homemade then it will fit under the hood with an 8x2 air cleaner. Ive run both SU's and 4bbls on my car and their performance is very close if not identical. 4bbl setups are worth more than SU setups if it has an 8007 390cfm on it or 465cfm

No actual dyno, All my results have been from my butt dyno. BSR works and works alright but the opening on the sides is probably around the same size as one of the 4bbl butterflies. An SU butterfly dwarfs it and one of those openings is feeding 3 cylinders. The AZC has wider openings and it is very apparent. The taller divider makes way more low down torque and I believe the wider openings are to blame for it pulling harder than the BSR from any spot (same carb setup). My Rankings: 1. Azc manifold 2. Adapter with divider 3. Tie: Cartech adapter 4. Bsr manifold EDIT: Currently running a set of Roundtops with SM needles and the all around performance is VERY close. Fuel economy acceleration seem about the same as the AZC manifold but again thats just a butt dyno and no concrete evidence. ITBs in the spring hopefully!

I just learned it from tinkering around with my car. When I got the car it had a stock 390cfm but was also advanced as far as the distributor would go. When I went back to stock timing I noticed that the car was running really lean/barely at all. Another thing I noticed was that if you do end up advancing the timing more, try mid grade and premium fuel. When I got the car it ran best on premium. Not Im at ~20 degrees and it starts and runs better on 89 midgrade. Holleys youtube videos are great and will give you a pretty good idea of how your carb works and how to troubleshoot

The problem with advancing the timing is that it requires a leaner mixture. If you have a perfectly good running car and just advance the timing it will run very rich. Retarding the timing will make it run lean. Timing adjustments will require jetting changes. First figure out where your timing is supposed to be depending on your vac advance then after thats all set you can start jetting your car.

The way I understand it (which could be completely wrong), total timing should be around 34 so initial timing depends on how much your vacuum and mechanical advance advance. Ive heard people with L28's run ~#54 jets which is 3 steps up from a stock 390cfm, my cammed l24 ran best with 55 jets. Checking your jets is as easy as pulling off the primary fuel bowl (which is only a hassle if you dont have the blue non stick gaskets). Idle should be the same and dont forget about the idle mixture screws when trying to change the idle. You can adjust when you want the choke to open and close by rotating the black electric choke cover clockwise or counterclockwise after loosening the three screws. The preferred pump cam among Z's is the orange pump cam. Kurbycars order of operations is correct

Are you using a regular 1850 or one of the holleys modified for blowthrough? I was pricing out the blowthroughs and it seems like my money would be better spent doing an L28et swap especially if the blowthrough carb goes for ~$700 by itself. Interesting idea but im not sure if anything will happen on this car

Bob Sharp Manifold was less than satisfactory. Great when daily driving but no oomph when flooring it. I think its pretty hard to cram 195cfm let alone 300cfm through this tiny opening Didnt even try to film any acceleration runs since they were so slow. So far the best manifold has been this one that was on the car when I bought it But Ive got something else which im excited to try. According to Dave at Arizona Z car: "The divider in plenum makes a dramatic improvement in low end response, I also opened up the runners for improved top end. Overall performance is excellent." and something found its way to my door today High divider: check Wider opening : check BSR Honestly I dont know why there are those stupid little ribs before the 3 and 4 cylinders. In my mind it makes sense that the biggest opening would be the best(which is why the original manifold I had was the fastest) but as you can probably tell by my idea a few posts up, im nowhere close to an induction expert. Had a 600cfm on the car for a few months and finally got my hands on a 465cfm which I think will be my final Holley. AZC is on the car and running but I havent really tested it yet. All thats left Holley wise is to get my hands on that original manifold then triples? 6 motorcycle carbs? Who knows !:stupid:

Im hoping this is the ticket! My temporary pipes right now are thrush glasspacks and theres not really any rasp at all so ill try my hands at a different brand and double them up. Ill figure it all out with some exhaust shops but I was just making sure there isnt some secret supply of tiny glasspacks with fins in them that I didnt know about

Hmmm. That does sound pretty similar and maybe if I double up those twice pipe glasspacks I can get that extra rasp. At higher rpms the sound was really harsh. Going to get my friend to upload another video

Yup I think its part 99996-E1045? I think the header is salvageable as its pretty thick and the pipes probably could be saved but I feel like that woud cost more than getting them replaced. This is the style I have on my car You seriously need earplugs with straight pipes! After a 1/2 hour drive my ears were ringing and im sure my neighbors loved it. Ill try and get the videos off of facebook(theyre not public) on here but the camera cant do it any justice since you didnt just hear it, you felt it going by

I didnt install it, im guessing it was installed back in the day at some dealership along with the Racer Brown cam aka "Slalom camshaft" in the comp. catalog. I know 2" is probably too big and true duals make less power but if its made it 43 years like this I dont really see a reason to change it (plus ive got power to spare :stupid:). I think the small outlet helps a bit but I think whats making that raspy noise is the interior of the glasspack. Ive still never seen anything like those fins inside. A big issue I noticed coming from the straight pipes is the resonance at about 2k and im not sure a homemade glasspack would help with that (or honestly how that works). I know a bunch of people probably think im crazy for wanting my car to sound like a bees nest but after a while you really start to like it. Magical fins?

Burping out of the carbs is usually timing and if your timing is set properly then that means you are too lean. I dont know how much the "2.5 turns" applies to you since youre running a 2.9L stroker but IIRC 2.5 turns was a baseline setting that should get your car started so you can tune it further. I wouldnt get so hung up on the # of turns but keep turning out until the car runs properly and make sure you have no vacuum leaks ( which can lean out your mixture)

Definitely going to hard to find if anyone anywhere still makes them but the sound was like nothing youve ever heard and sounds completely different than every other car on the road. 2" is the smallest I can find and they sound alright but theyre nothing special. Probably going have to learn how to weld so I can cut them up and get that sound back. Here are a couple more short vids. This one is with the complete exhaust (2 glasspacks, 2 resonator/glasspacks) And this is one with top glasspack broken off. You can hear how different it sounds at idle while the new glasspacks sound like the green 260Z

Im replacing/refurbishing my Datsun Competition exhaust and im not sure I can replicate the exhaust sound. Old exhaust is rusting apart so I think its time to save what I can and replace what I dont think is worth the effort. Heres what the complete exhaust looks like: Then this happened Top glasspack broke off! Not only was the glasspack a 2in inlet to a 1.5in outlet(already impossible to find) but the interior looks completely different than the modern glasspacks. Modern: Original https://lh6.googleusercontent.com/-QtZ2x3NiWQw/UYunJpST29I/AAAAAAAALFA/2gjvkhMrIBM/w903-h677-no/IMG_1640.JPG Is there any way for me to get the hornets back in my car?

Sounds exactly like my 260Z with round tops when the valve lash was out of whack. You want to have your car completely tuned up before you try and tune your carbs. If your valve lash isnt set properly your car will run differently when cold and when fully warmed up. If youve got decent ears you can use a length of hose to sync the carbs up. Put one end to your year and the other end at the mouth(?) of the carb and adjust the vacuum screw until they sound identical. Personally I believe the 390cfm is a step up from stock hitachis but id definitely get the SU's running right first before you make that choice

With those fuel economy numbers I think I need to get a blowthrough setup! Here's a post off of hybridz from a guy who went from fuel injection to a 4bbl and dyno'd both and compared them: http://forums.hybridz.org/topic/52977-arazona-zcar-intake-vs-fuel-injection-long-pix/

Ahh yes the "other" brand which is sold by like 5 different companies. Even had the little nub at the end of my throttle cable pop off. I love spending hours outside trying to rig something up in 30 degree weather...on my birthday! Now I carry old G strings in my car just in case something goes wrong... G strings from a bass guitar! All carbs do pretty much the same thing, its just how well they can meter fuel at the right time. The blowthrough is a cool setup though, Ive heard from a few guys doing a blowthrough setup with a 4bbl and that may just have to be the next step . 600cfm is on the car now. Specifically I have an 80457 which is just the electric choke version of the 1850. Was a bit more work to get it setup properly but thats what happens when you have a big cam. Right now the stock jets are too lean so I cant go over 2.5k . Throttle response is different but not horrible. Initially it feels like "Oh, I didnt realize you touched the throttle" but once you get moving it feels the same as the 390. What this means is you have to blip the throttle before you get moving from a stop. Will give more details as I get them and look forward to doing some flat out runs!

But that post actually got me thinking. With SUs the air goes in through the grille and is pulled in at a 90* angle where it enters the intake and is distributed amongst the cylinders. With a 4bbl the air is also pulled downwards at a 90* angle before it enters the intake. From the base of the carb the atomized fuel and air are pulled directly where they need to go since the vacuum is coming from the runners/cylinders and not from underneath the carb. Not sure if I'm making sense since thought of this as I was falling asleep. Predictions for the 600cfm: Going to have a horrible idle since my cam doesn't pull much vacuum at idle. Throttle response shouldn't be great but it should have a great top end and perhaps an increase in fuel economy? The ribs in the BSR manifold might be restrict the flow too much if I can even open the secondaries

Went off the deep end and have a 600cfm on the way. Already have an idea of how it will perform but I still want to test it out. Will post results when its all setup

Dont tempt me! Im going to go back to SU's and try and get it setup using a throttle cable (also going to ask a guy I know who restores E-types if he has any 2" SUs). Ill probably go back to a 4bbl eventually but its time for a change and some experimentation now that the weather is nice!

Its been a while since I updated! Regarding the manifold design, I emailed Dave @ AZC. The BSR has a lower divider, narrower runners, and those ribs before the #3 and #4 runners. Dave said "...The divider in plenum makes a dramatic improvement in low end response, I also opened up the runners for improved top end. Overall performance is excellent." So the AZC appears to be better than the BSR. A couple months ago I realized that I was only getting ~11-12 mpg which didnt make any sense. I finally decided to get a vacuum gauge and hooked it up to the base of the carb: at idle I was pulling ~5mmhg (is that the right unit? I dont have the gauge in front of me and I just took a Chemistry final ). I had a 6.5 power valve in the car which means that the power valve was open as soon as I started the car (thanks a lot cam! My old carb had an 8.5 in it!). Went to a 2.0 power valve and #55 jets from #51 jets (each jet size is a 4% increase in fuel) and my fuel economy went up as well to ~14-15mpg city and but only 19mpg @80mph on the highway . I was getting decent fuel economy but the crazy speed was gone. I threw some #60 jets in got some oomph back but a big drop in fuel economy and the plugs were only the tiniest bit browner. Seems like I can jet wayy richer for performance but im learning that performance and fuel economy dont really go hand in hand. I would go out and get some 0-60 videos but I got wider tires and ruined my u joints after a couple of hard launches . Im interested to see the 0-60 times as is, with the pig rich setup (#51 jets, 6.5 power valve), and the ultra wealthy setup (#55, 6.5 power valve depending on how the plugs look after the first run). Thinking about switching back to SU's or maybe triples if a cheap set pops up. Nothing wrong with this setup but Id like to mess with SU's and see if I can get similar performance(and maybe pick up a wideband!). I just past the year anniversary of the day I got this car and ive done 5-6 carb swaps already :stupid: For some reason I just cant leave the car alone!

Ive seen some ads for NOS pumps for ~$90. Most annoying part is that the original pump was working fine but the diaphragm cracked while sitting in the back of my car. Maybe pouring some oil inside and capping off both ends will help it store better? Im pretty sure the updated part # for the 240Z/260Z diaphragm is 17053-W5301 and the cheapest I can find it online is ~$20 shipped.

Reviving this old thread to add some information to help those who are also looking to replace their mechanical pump. I pulled my Kyosan Denki pump in August with a Carter M60107. I bought it because it looked like the old pump in the online pictures but when it arrived it looked like one of the cheaper sealed pumps but I just assumed I bought the wrong part. A few months later my car is suddenly starves for fuel when going up a particular long but not very steep hill. I ordered another M60107 from Rockauto and sent the old one back as a warranty return but I got the same sealed pump. Noticed some markings on the body that read "1080 4513"....the Carter M60107 is now the airtex unit and ive asked a number of sources that all describe the M60107 as a pump with no screws and a yellow/gold finish. Dont bother buying the Carter since youre just getting the airtex. Now to find a diaphragm for my kyosan denki... "You will find it equal to or an improvement over the original pump"...ha!