Scottz

Aaron, Air flow calculation for carbs, using cubic centimeters as the units: - Engine Capacity x RPM/2 x Volumetric Efficiency. VE = 80 to 85% typically for 1970’s OEM spec carbs and engine. VE = 85 to 95% for performance enhanced. (Choose what you think is close to your engine spec). VE = 95 to 100% for competition spec. VE = >100% for extreme performance (blow'n). RPM/2 = Max rpm you expect to achieve divided by 2 revs per air intake stroke. That is; 4 strokes per cycle every 2 revolutions = intake / compression / power / exhaust. (2 revs every 4 strokes). So for every 2 revolutions there is only one intake stroke. Therefore air required is only once per 2 revolutions. Clear like mud Yes? Example: Performance stroker engine L series 6 cylinder, 3100cc capacity, mild head work & mid range cam, with expected max rpm of 7000. 3100cc x 7000/2 x 0.90 = 9,765,000 cc per minute air required. Now convert cc to cfm. Why? Because OEM's like to spec their carbs in cfm. cubic centimeters to cubic feet; 1,000,000 cc = 35.315 cf 9,765,000cc = 345 cfm Total. Using this website I got 365 cfm. http://www.carburetion.com/after.htm And using this website I got 346 cfm. http://www.csgnetwork.com/cfmcalc.html So I’m prity close to the mark. That's for all cylinders so divide by 6 and you get 57.5 cfm per cylinder. Or divide by 3 (because you are wanting 3 carbs to handle total air flow) = 345/3 = 115cfm per carb. The Stoichiometric ratio (AFR) for air to gasoline is 14.7:1, meaning that for each weight unit of gasoline, 14.7 units of air will be consumed. Stoichiometric ratio is different for different fuels (Av gas, methanol, ethanol, diesel, etc). 1kg of gasoline needs 14.7kgs of air. Considering you can fit a kilo of fuel into approx' 1.25liter container, how much volume do you think 14.7 kilos of air occupies. Answer - lots and lots and lots. Or about 12416 liters or 438.5 cubic feet. ( @ 1 atm and 25°C, air density = 1.184 kg/m³). Therefore 115 cfm of air flow does not need much fuel to achieve 100% burn, and remember that's at maximum revs for 1 minute, which hardly ever happens or never, on the street. Losses: Air density changes (altitude & temperature), friction (rough inlet passages, surface finish, material used), back pressure (exhaust restrictions & inlet restrictions), turbulence (velocity and size factor). All losses cause reduced air supply to the cylinder. Lots of owners reckon you should add 50cfm to the total cfm to compensate for losses, so 345cfm increases to 400cfm rounded off. Divide by 3 carbs=135 (rounded). RPM is the biggest number in the equation so think about what you want at the rpm you are going to use most. No point doing a spec for a high revving screamer if you use it mostly for cruising around at 4000 rpm with short bursts at 6000 rpm. You put the bigger carbs on and it runs great at the track day, but every other day it’s a de-tuned rough idle gas guzzler. :-\ I have ordered 40 DCOE triple Weber carbs. The USA Weber vendor's price was so much better than the OER price, I changed my mind and went for the Webers. Drop me a PM and I'll give you the vendors contact details if you are interested in a new set. Otherwise the network on this forum is best place to find a used set at the right price. What I’m interested to know is; Has anyone tried the SU’s on a triple setup for the L series engine. Like there are heaps of used SU’s around from old L series engines, surely there must be an inlet manifold that lets you bolt up 3 SU’s instead of 2. That's got to be a cheap alternative for an owner who already has the twin SU’s and wants to go triples, without the big $$ spend on triple OER’s, Weber’s, Mikuni’s, Dellorto’s etc? Scott.

Welcome Cable, Nice ride you got there. Hopefully more California zed owners introduce themselves to us Aussies. There are lots of zed goodies available in USA and having contacts on that side of the Pacific is a plus. Cheers, Scottz.

Go for it Mike. I'll buy some parts from you and you can tell your wife that you will be making a profit.

Forgot to ask - Have you got alternator with built in regulator, or external regulator?

Regulator. When they go you can get full charge to the battery which cooks it. When you found the battery was flat, were the cells also dry or low level? Overcharging overheats the cells and evaporates the liquid very fast. You can usually smell the acid vapour. The unregulated charge speeds up the clock and cooks everything. I melted a fuse box cover once with the same problem. The clip in fuses and tacky wire terminals are the weakest contacts and create the most heat. Good solid contacts have less heat. (One method used to find bad connections is IR thermography. Bad contacts are hotter). Run the engine and check output voltage from the regulator. From memory something like 14.4V. If it is the alternator, you have the opposite problem of not getting enough charge. The car runs on battery for a few days and then goes flat. If a cell or two drops in the battery, then it won't charge, and eventually flattens. This will not cause your clock to overspeed. Hydrometer test each cell. Funny story - Couple of years ago RACQ had a spat of new commodores with flat batteries. It was the new alternators that auto cutout when the car is running for long periods. Problem was they didn't always cut back in when they were suppose to. Ha ha. So after a very long drive the travelling salesman parks his car, sleeps the night, and couldn't get a restart in the morning. A bit of trivia told to me by some nice RACQ mechanics near Sarina, while they were replacing the alternator in my old '92 Landcruiser. Enjoy.

Have to agree with DJR. Also if you think volume is small here and that's why prices are high, I disagree. We are buying cars that are not made in Aus. They are made offshore for the Mass Produced Vehicle (MPV) market. That is, we are buying from makers who are supplying in big volumes all over the world, from strategic manufacturing locations. The manufacturers are moving into the global market and not staying close to their home shores. We are part of that large consumer volume. I do agree that Aus industry is protected and that's why prices have been so high, but they are slowly coming down now that import tariffs have been progressively cut. Just compare any capacity motor in any make with its new price tag from 1990 and its current 2010 price tag. Along with all the standard features that are now included in the package. That's what competition does. And if you think it is going to harm our home base manufacturers - Nope. They are also trying to move offshore and get into a global market. Commodores rebadged as Chevys and sold in the Middle East, just one example. JP – If local Aus cars are great, then they should be able to compete. Not just on our shores but in EU, North America and Asia as well. If they’re getting beaten, maybe it’s because they are still short of the mark. Aus cars might be made for longevity, but in every survey I read, they always got a flogging for safety and security. Easiest car to break into is an Aus car. Ask any 15 year old. Aus cars only improved safety features when they got hurt by the imports. Don’t get me wrong. I’d love to see lots of Aus cars’ cruising the autobahn or east west USA. Imagine landing in Milan and the Avis rental car sign has a picture of an Aus car instead of a VW. Hooray! Imagine if our auto makers were the envy of the soy latte iPod twats. Beauty! When you make a great product, it creates new markets and changes existing ones. Proof – zeds all over the world. As for high rego, insurances and safety inspection costs in other countries. Well we will soon see that in Aus. It’s just bulls*%t from slack governments raising revenue under the guise of road safety, de-congesting traffic and reducing emissions. (Safety, Infrastructure, Environment). Reality is those governments (including ours) are not prepared to fix the issues, so it is easier to slog the consumer. “Let’s push some big costs onto the consumer so he is forced to slow down, because we are to slack to catch up”. What we need to be a little careful of is raw material costs. As a big supplier of iron ore, aluminum, coal (energy) uranium (energy) gas (energy) and other raw materials, we directly affect prices for all the things we import into the country. Since most of our products are made offshore, from Aus raw materials, we pay the 'value added' margin. All costs roll down to the consumer. So if we keep pushing at this end, we pay at the other. It might just be that our greed changes the import market, so that we can keep buying cars! Think of it like this - If we double the price of the raw material, how much are we prepared to pay for a Nissan, Samsung, iPod, BMW, Westinghouse, or whatever? If prices were to soar upwards, would that break open the import doors? (Hung by our own rope).

Hi All, Check out this neat tyre/wheel calculator. http://www.rimsntires.com/specs.jsp Saves a lot of time measuring up your car, wheel arches, strut & spring perch, tyres and rims, etc... Also has anyone checked their speedo accuracy. Before and after changing tyres. My speedo reads 110kph when speed is actually 100kph. I used 2 different GPS's and got the same results. The error is 10% across the whole range. Sometimes an increase or decrease in tyre diameter is easier than trying to get the speedo right. Just match the tyre diameter to the speedo (so long as it's just a few percent). Scottz

Stevo, Thanks for the tip. I got in contact with the qld club. Jason and Peter have emailed back and I sent all the details, and a swag of photos. Hopefully will have the rego completed in a week or so. With 4 cars it gets a bit steep paying all that rego, so special interest is a big saving and living in a small town fits in with the restrictions. I also chatted with some Curtis Coast Cruiser club members locally. So there will be plenty of opportunities to use the car and be within the restrictions. Once it gets the Qld rego the current NSW plates 'ZZ7878' will come off. I am going to send them back to the previous owner, and if anyone is interested in buying them they can contact him. I can pass on his email if requested. Lynton, Z & Fuzzy, Soon as I can work out how to upload pictures into "my gallery" I'll share the photos around. Got any advice for a newbee on how to use the 'my gallery' mumbo? Zedback, I checked out the members project forum. You do nice work. Qld weather is cruel for old dattos. If you hadn't salvaged it from the yard it would now be scrap. It is definitely my old 240Z Scottz

Mike, Sounds like you do have my old 240. I bought it in June '87 from a guy who lived at Daisy Hill. I sold it in Nov '94 to a guy who worked at Stones Corner. I think his dad owned a car yard, and he worked at Westpac Bank. The L24 in it had been put together from bits and pieces. It blew up in '88, and when I stripped it down I found a dodgy and poor assembly (like every piston was from a different engine and 2 were facing the wrong way, one of which had blown its top off, and another split at the first compression ring groove). I used some parts for the L28, like carbies, intake and exhaust manifold, sold off what could be salvaged and scrapped the rest. Then thought..."why didn't I do this sooner" ! I guess some purists are cringing when they read that the L24 block is bye bye. However I doubt it was the original. From memory the chassis build date/month was April. Good luck with the Resurrection.

Mike, I can't recall the chassis number, and not able to find any old documents yet. I bought the L28 cheap because the fuel injection was trashed in transport, and swapped the twin hitachi SU's from the old L24 onto the L28. I bought the 280ZX gearbox from a guy in Gympie and had the tail shaft made in Brisbane. The rear stub axles I took from a 260Z. I replaced all the shocks with Pedders gas struts. All the front end cancer was stripped out, with plans to do the rear end later - Oh well! Yes - I had a fiberglass bonnet. Choke and throttle knobs (center console) were replced with s/s, same goes for fan & heater knobs. The plastic ones were busted so I made s/s ones. Easiest way to tell if it is my old 240, front rail has a welded section where I did a quick repair after taking out a post. That's when I replaced the original bonnet with fiberglass. ScottZ

Well I bought the GS31 after a bit of negotiating. It is now in my garage. RWC was completed yesterday but have a small glitch....No build date ??/1978. 100% original JDM with L20 6cyl fuel injected motor. Full instrumentation and electrics, including airconditioning, same layout as 280Z. Original alloy wheels, all 5. Even has the original owners log book and manual (In Japanese) and Australian owners service receipts. Only the radio has been changed ! Oh - and now has central locking, immobiliser + alarm. I added that since I had to park it out front for a week waiting for the concrete to set on my new driveway. Now I am looking for a good panel and paint guy since it previously sat out in the open directly opposite the beach. Engines I am still undecided on. RB26.....L28......oversize the original L20, add a turbo......dunno yet? Might even leave it original for the sake of it. Right now I want to register it as "special interest". It's a lot cheaper and convenient for me with 3 other Nissans already registered. Who can issue the car club document so I can apply for the 'special interest' rego? Any ideas how I can work out the month for the build date or does anyone know how to read Japanese? I can scan the original owners book and email it. ScottZ.

Good one mate. I just recently bought a 260Z having owned a 240Z years back. If the bonnet is fiberglass the torsion bars are sometimes removed (1 or both) to stop the bonnet bowing and having a humped look about it. I did the same with my old 240 after a little accident. I bought a fiberglass replacement from the Z car shop in Brisbane and took out the torsion bars. The fiberglass is so light you don't need the assistance. Enjoy the ride.

Hi all, I am a new member to the Z car club, and currently looking for a new ride. I previously owned a 240Z but sold it way back in 1994. I miss the fun and now looking for another zed. Spotted a 260Z with a 6 cylinder L20 engine and fuel injection Can anyone decipher the chassis and engine number for me please? GS31017650 L20749853 My old 240Z had Qld rego 055PIC. Dark blue colour (not original - Ford Ocean Blue) Original colour was silver. L28 motor and gearbox from a 280ZX. I guess it is landfill or recycled steel now, but maybe still out there? Regards, ScottZ.

There is a way to check when buying if the vehicle has been in a major ding or been written off, plus registration changes. It may give you some more data and narrow down the search. Try the checkitout website. Costs $30 to $50. https://www.checkitout.com.au/index.php?action=page&name=information_vcheck If your old mate can remember the UK rego number, you might be able to find the VIN on one of the UK websites for about 20-30 quid but I don't know how far back electronic records have been made for. And if the rego number went back into circulation it will be for another VIN. http://www.ukvehiclecheck.com/ Lastly, did the old mate buy the car himself from a UK dealer? Some of those old UK Jag dealers are still operating. Call and get the VIN by giving the original buyers name, address and date of purchase. Or get old mate to make the call. He can make a nice story like...oh my goodness my treasure has been stolen, and I have lost the old papers. I'm trying to find the VIN for my old Jag........It's a long shot but you would be amazed what data some companies actually keep. The tip about ringing the DOT and just keep ringing until you get the answer you like goes for all government offices. Including the ATO. Insurance companies keep all the data your looking for. Know anyone? Good luck.