Carl Beck

ArnZ - what is the VIN on your Car? S30 or S31

While there is certainly a lot to admire about Prosche in general, and in view of their wonderful history, I wouldn't envy a 2002+ Porsche GT2 when compared to a 70/73 Datsun 240-Z. I mean, lets say; here you are - "PORSCHE" - and you've dominated the race tracks and rally circuits of the world though-out the 60's with your wonderful 911... evolving it to ever higher levels of performance...hyping air cooled rear engined, boxer six's... German Engineering, nose to the grind stone, constantly sharping that perfect blending of form following function. You even come up with a mid-engined example, said to have even better balance.. the 914/6... Then a cheap little tin can from Japan, loaded with great looks and good design blows you off the road courses first year it's out of the box.. and beats you at the worlds most watched international rally in Africa the following year... Yea GADS.. what happened here!! Quickly you up your engine displacement in the 911.. and move out of the class those pesky 240-Z's compete in on America's tracks... so long C-Production...... Then 32 years later... you have a $180,000.00+ model that can beat the 240-Z on an auto-cross course.. WOW.. that is something isn't it !! I can certainly understand why "Porsche People" love their cars... matter of fact I was/am one of them... to this day I do admire much about the company and their cars. I sold my 67 911S about six months after I bought my first 240Z in 1970. On the other hand, there is just something so efficient about that 240-Z that greatly appeals to me to this day (solid design and engineering?)... and I'd personally feel like "the fool and his money being separated" ... if I had that 35 year old, $25K, 240-Z right on my tail at any auto-cross... Matter of fact, I'd be embarrassed to be placed in the same class... what does that tell you about the two designs? but that's just me... efficiency vs effectiveness... we can put a man on the moon or a rover on Mars - if you don't care what it costs... both were very effective... FWIW, Carl B.

Jason must have a completely different mental picture of a car in mind... than I do, when it is described as "..a perfect one, with nice paint, nice interior and such.." For a 240-Z in far less than "perfect" condition - but still having nice paint, a nice interior and such I'd expect to pay closer to $7.5K..... might find a 260Z or 280Z in that condition for $5K somewhere West of the Mississippi here in the U.S. Unless they have been fully restored - I doubt you will find a 240Z with "no" rust, you might find a 280Z that hasn't rusted though yet..... for that price... but it is getting harder and harder to find them for sale. In my mind, a "nice" S30 in good running condition is in the $7,500.00 to $12,000.00 range.. I guess "nice" means different things to different people. If you buy an S30 for $5K, you can expect to put an additional $5K into it - before you are happy with it.... FWIW, Carl B. Carl Beck Clearwater, FL USA http://ZHome.com

How "mint" - How "original" and How MUCH? Where is middleburg Florida? and does your friend live near-by? Carl B.

Given the effectiveness we saw in the first wind tunnel tests, of blocking the air flow through the grill - and redirecting it elsewhere, we know that any 3D model would have to include a model of the engine bay so the air could flow virtually into and through it. (yes/no?). That is to say - we would need more than just the surface model of the exterior shape of the Z, if we wanted to compare results from the actual wind tunnel tests, to our virtual simulation or to a scale model in the physical world. With the Revell BRE Z Model Kit for example, you could build a fairly accurate engine bay, by scanning the individual component parts and merging them into the final 3D model. Building that model by hand in a 1:5 format of wood/clay, would be challenging at least. I would guess that an existing digital model could be easily scaled up to 1:5 then feed to a DNC and machined out of a block of relatively inexpensive plastic. That by itself wouldn't be cost prohibitive in todays world, once you have the 3D model. Lots of fairly accurate scale models of the Z's exist, and different component parts from those kits could also be scanned into a 3D digital format, then DNC'd and added to, or removed from, the 1:5 physical model. - the G-Nose itself exists in model kits - the Front and Rear Spooks and Spoilers are in Revells BRE 240-Z kit - the LeMans wheels/tires as well as the stock wheels/hubcaps With the above items scanned... you would have the 3D models for either CFD and/or DNC'd into the physical world - if you did both you would have at least a benchmark for validation of the results from either method. FWIW, Carl B. That desk top 3D scanner for $2,500.00 is looking better and better...

Anyone want to buy themselves a present? For $2500.00 you can scan your Franklin Mint Model into a 3D data base... Next Engine: https://www.nextengine.com/indexSecure.htm FWIW, Carl B.

Hi Bill: When it come to design, design simulation, analysis and verification the designers mentioned on "Futurecar" hold a huge advantage over us... They are paid to create the design in digital form from the beginning.... by the time they have a concept that has been moved forward to the development stages of design, they most likely have thousands of man-hours invested in that digital data base containing the 3D geometry of their creation. Yes, at that point they can simulate, analyze and then iterate the design in an extremely efficient manor. Taking an existing form from the physical world, and recreating it in digital form: ie. reverse engineering it if you will - can take hundreds of hours, using tens of thousands of dollars worth of software and computer hardware. That or it takes more advanced, large scale scanning technology like large laser scanners - or fixed point digital photo sessions. All relatively easy IF YOU HAVE THE EQUIPMENT... and knowledge of how to best use it. Contracting the work out can easily cost tens of thousands of dollars, because of the overhead costs of having that capital equipment... An alternative comes to my mind. The Franklin Mint already has a very detailed, three dimensional model of a pure stock S30. They used fixed point digital images to feed their software, to build that model. It is so fine that you can actually read the VIN tag on their model. 1) Get with Sport Z Magazine and approach the Franklin Mint - to see if they are willing to "donate" the use of that model for this group's simulation. In exchange for the publicity it could generate. 2) Use a smaller, and far less expensive 3D laser scanner - and scan a Franklin Mint Model. Then use the scan to feed the simulation and analysis programs. Past either of these alternatives - you still have to have someone with access to the software and hardware necessary to feed the 3D model into and then run the CFD programs. I think in the end, everyone involved in making all the above happen, would agree that they would rather have just paid the $3K of $5K themselves for the wind tunnel FWIW, Carl B.

If your going to pull and reinstall a first or second generation Z transmissions - the first thing you do is pull the two top bolts out of the transmission ... then you take them to the local hardware store. You buy two (I always get a couple extra, so I buy 4) matching bolts, only making them about two inches longer. You take the longer bolts home, and cut the head off them. Then set them aside until you are ready to reinstall the tranny. Prior to reinstalling the tranny, you lubricate them, and then screw them into the lower part of the engine block finger tight (but fully in)... and using them as alignment guides, you slide the tranny over them and into place, keeping equidistance between the engine and the bellhousing all around...(move the small jack as necessary to line things up)... then push the tranny in... The "Pressure Plate" has a huge hole - I think you had trouble getting the transmission input shaft through the clutch disc. You just have to make sure the transmission is in-gear, before you attempt to reinstall it, so you can rotate the input shaft slightly, by turning the output shaft - so you can align the splines between the input shaft and the clutch disc. FWIW, Carl B.

If you all ready had an L28 in the car, then chances were good that it also had a 280Z/ZX clutch assembly. In which case either the 4 spd. from a 260Z or the 5spd. from a 280Z/ZX would have had the matching throw-out bearing sleeve. Yes, it sounds like either the retainer spring on the clutch fork was bad, or you simply didn't have it pushed fully over the pivot ball. Or the retainer spring at the throw-out bearing sleeve gave way. The clutch forks for all the type "B" transmissions were the same, as are the throw-out bearings. There are really only two different clutch forks, one for the adjustable slave cylinder push rod, and another for the self adjusting slave cylinder push rods. The earlier type have a hole for the push rod to stick through. FWIW, Carl B.

I don't know about the CenterForce Clutch you used... but... Basically there are three different throw-out bearing collar (sleeve) lengths... Actually there are about five, but two of them are so close to the other three, they really don't matter a lot. So lets call it three.. 1. The shortest sleeve was found in the original 240-Z's - which had the thickest pressure plates. 2. The second shortest, or second longest came in the 280Z/ZX 2+2 3. The longest sleeve was found in the 280Z/ZX's... which had the thin'est pressure plates. "Thickest Pressure Plate": Lay the pressure plate on a flat surface, measure the distance from the pressure plate "fingers" to the flat surface. The 240Z pressure plates will be 43mm to 46mm (1.75" aprox). The 280Z pressure plates will measure 34mm to 36mm (1.33" aprox). For several years now - people have been ordering the 280Z/ZX pressure plates as replacements for the 240Z's anyway, as they provide slightly more clamping force than the original 240-Z's pressure plates. Likewise, many people swapped in the pressure plates and flywheels from the 280Z/ZX 2+2's - as they use larger diameter clutch disc and the machined surface in the 2+2 flywheel is a larger diameter. (so even more clamping force). Unless you have owned the car since new - you usually have no idea what you'll find when you pull the engine or tranny for the first time in your Z. The surest way to get it right the first time - is to simply buy a new 280Z/ZX OEM Clutch disc, pressure plate, throw-out bearing collar (sleeve) to begin with. A new throw-out bearing collar is about $18.00... Or use ALL the same parts from a known good set-up. If your clutch assembly etc was working fine with L28/5spd, and upon physical inspection it looks fine still - then just transfer the clutch disc and pressure plate from the L28 to the L24, and leave the existing throw-out bearing collar (sleeve) on the transmission. FWIW, Carl B. Carl Beck Clearwater, FL USA http://ZHome.com

Hi Erich: Type "B" 4spd. or 5spd. use the same case - The Type "A" or "B", 4spd or 5spd. used with the L24, L26, L28 is a direct bolt on to all. FWIW, Carl B.

Hi Mike: I can't seem to find this - has it been done? thanks, Carl B.

There were at least 3 different dashes for the HLS30 - 240-Z's. Series I and II for the 70/71 Model Year Cars Series III for the 72 Model Year Cars Series IV for the 73 Model Year Cars They differ in minor details... but that minor difference can be measured in dollars today. A NOS dash for a 69 to 71 Series I or Series II 240-Z could sell for $2000.00+ today. A NOS dash for a 72 240-Z would be in the $950.00 range... Serious "restorers" would demand having the fine details correct ... and they would most likely pay the most for an exact replica of the specific dash style they need. That however would represent a small market. If perfection of detail isn't the main desire - then any of the dashes could be re-manufactured by the companies mentioned earlier. They strip the old vinyl and padding and recover the original metal frame - the difference is only in the grain of the newer vinyl used. I believe that there would be very little demand for a more "universal" fit dash, that could be put in any 240, 260, 280Z - - that cost above $650.00... Indeed, they would have to cost less than that. The 240-Z dashes are not as deep as the later 260/280 dashes.. as Nissan allowed more room behind them for the Factory Air Units... so the center consoles have to be different to line up with the dash.. FWIW, Carl B.

Hi Guys: Actually the Left Hand Drive, Datsun 240Z's aka "HLS30" - VIN numbers started with the pre-production cars at HLS30 00001, however the first production car sold to the public, according to Nissan, was HLS30 00013. From 1969 into 1973 the VIN's on the Datsun 240Z's ran in order, within sequential blocks assigned from the same series. For example the 1972 Model Year 240Z VINs end around HLS30 100xxx, but then Nissan started the VIN sequence at HLS30 120xxx for the 1973 Model Year cars, skipping just less than 20,000 numbers in the series... that series ended around HLS30 172xxx The 1974, Datsun 260Z's had "RLS30" as their designation... and so started their VIN sequence at RLS30 00001. With the introduction of the Datsun 280Z for 1975... Nissan switched back to using the "H" to designate the new L28 for the North American market. However they started the VIN sequence for the 1975 Model Year 280Z at HLS30 200002, thus skipping about 25K numbers in the series where it dropped off with the 73 Model Year 240-Z's... According to Nissan - the VIN's for the 1972 Model Year HLS30 240-Z's started at HLS30 46000, however according to the cars we've inspected the earliest 72's here started with HLS30 43496...08/71 build date. Just some VIN trivia... FWIW, Carl B.

Hi John (everyone) Level pads or not ...your pretty close. I just measured two of my 72 240-Z's both equipped with the BRE Front Spook... both with more or less stock suspension/ride height. One is 7" off the floor and the other is 7.25" off the floor. "Plus-One" means that you increase the wheel diameter by 1" - but you also decrease the sidewall of the tire to offset that - resulting in the same, or very close to the same over-all diameter of the tire. So Plus-One setup's won't change the ride height very much if at all. Both of my 72's have 14" wheels with 195R70x14's - which are very close in overall diameter to the OEM 175R14's that came on the cars. According to the factory service manuals - the stock ride height on a US Spec. 240-Z was 6.3" measured from the front frame rail, where it meets the firewall/floorboards, to the ground. However after measuring about 50 different 240-Z's with stock springs and wheel/tire combinations - that measurement seems to be closer to 5.75". Measuring from the front and rear of the rocker panels - where the jacking points are indicated - Stock seems to be 8.5" That's to the bottom of the rocker panel - not the flange. As we have discussed before - installing the newer gas pressure shocks will raise the ride height of the 240-Z's between .75 and 1 inch. So you'll have to keep track of that... when you select the cars being brought into the tests. You would not want to change tunnels at this point. You would all but lose the baseline established during the first run. It's hard enough to normalize different runs on different days in the same tunnel - gets to be next to impossible if you are using different tunnels (from what I've been told). Just FYI... Carl B.

Thought I'd re-Post Michels answer here, since a new thread more specific to the Spreadsheet was started. Thanks for all the work on this 74_5.0L-Z regards, Carl B. "a jumper wire around the power supply switch" - - what do you expect for $20 Billion Dollars!! Must be some HybridZ guys up there....

It's an "improved" ZIP file compression ... actually it's the native format of the WinRAR archive. On Windows it's opened with the later versions of WinZIP on the Mac OS-X, it's opened with current versions of STUFFIT I had to "up-date" my Stuffit version... FWIW, Carl B.

Hi Dan: The spreadsheet "seems" to work fine - Great Job. At test #19 - With Speed adjusted to 70mph - on the Stock 240-Z the CD seems to be way off - 0.227, as well as Drag HP and Drag lbs. There is only one line of data from one run - so it looks like the avg. line is divided in half... Could be a download error... thanks, Carl

Hi Mike: Thanks for taking the time and expending the effort to bring me along. I fully understand what you are saying. You guys did a great job with a very difficult task at hand. Data Information Knowledge Wisdom I'm just trying to make the transition between Information and Knowledge here... Your Project adds a lot to the Knowledge Base on these 30+ year old Z's. Everything past the data input from the force pads on the floor and the known wind speed - would "seem" to be a calculation based on formulas - I would not be surprised to find that the formulas have been twick'ed and fine tuned with correction factors, developed by feedback loops from the real world over the years, by the guys at the Wind Tunnel. Design, model, simulate, build, test. Perform enough Design Verification Loops to fully dial in the models and simulations .... and somewhere along the way we wind up with a patchwork of code, incorporating undocumented correction factors and bug fixes... aka - Job Security for the old timers responsible for the software mess -vbg- and hence the phrase.... "if it ain't broke don't fix it". If the final output data consistently matches the real world - you are in good shape. Oh.. BTW - I don't often drive at 120mph - did you do a screen shot of the data tables at 80mph? That's about the speed at which I spend most of my Freeway time. thanks again, Carl

Hi Mike: I hope you'll forgive me if I'm asking questions that should go without saying, but your response above has left me puzzled to say the least. What is an unstable data format? Are you saying that 74_5.0L_Z is not allowed to build and publish a useful spreadsheet based on the released numbers in the tables; or are you saying that it is not possible to do, using the numbers published in the tables? Your reply above seems to be a way of saying that the numbers published in the tables aren't accurate and therefore not repeatable; nor could they be used to re-calculate the different variables, if plugged into a spread-sheet with the proper formulas. Sorry, but you lost me there - right when I thought I was beginning to gain a grasp of the process. Can you elaborate more on this? I really would like to understand what these results mean, and how they interrelate. thanks, Carl

Hi John / 74_5.0L_Z : Thanks for taking the time to respond. I hope you guys bear with me .... I think I have an inkling of what the coefficient of drag and lift represent, as well as how they are calculated. Now I know where the "area" for the profile of the G-Nose came from - and would I be safe to believe that the other three cars involved were also measured in the same manor? At this point however - I am still left wondering exactly what was measured in the wind tunnel. From our above discussion - once you knew the area of the profile of the car - everything from there was calculated as it related to Drag and Lift.... With the fans putting out a constant 80 mph - was it the actual velocity of the free stream of air - at the front and rear wheels that was actually measured in and by the wind tunnel - so that the Drag and Lift calculations could be made for each end of the car? My questions are somewhat aimed at the thought, that someone might be able to take some of the formulas, factors and now known input values surrounding all this - into a visual or graphical Mathematica Demonstrations Model.... that with the new free Mathematica Viewer - anyone could play with a graphic simulation model of the 240-Z - and thus gain a better conceptual understanding of cause and effects brought about by specific changes to the car. Looking through Mathematica's current library - I see no aerodynamics visual demonstrations models... http://demonstrations.wolfram.com/about.html Interesting to look at some of the existing demonstration models already there... Since I retired... I no longer have access to Mathematica, nor do I believe I will paying the $6K license fee for home use. Nonetheless I thought perhaps someone still working in an engineering field, or at a university - and with a younger better working mind than mine, - - could build a demonstration model or two - - - if they could be supplied with all the necessary data/information to build the graphical model. Sliders for Velocity, increased/decrease profile area (by raising or lowering the car - or by extending and air damn downward etc, wind speed over the front or rear of the car to recalculate front and rear lift ... and all the calculations would be made in real time, so anyone could more easily visualize all this. FWIW, Carl B.

Hi Guys: I'm not certain I understand what some of the numbers actualy indicate. For example, in the columns on the data sheets from the wind tunnel test # 1 in the CL (total lift) what dose the number .473 indicate? If the car is sitting on pressure pads - would that .473 number indicate that 0.473% of the starting weight, has been removed from the pressure pad via Lift ? For the column marked CD - how was that measured for the different cars tested. Does the wind tunnel have some way to scan the front profile of the car and then compute the total area involved? On the data sheet there is a "REQ'D INPUT" note that lists mph=120. Was the wind speed in the tunnel actually 120mph or something less, then using 120mph as an input to a computer program, were the numbers calculated at what they would have been if the wind speed was 120 mph? What do the numbers in the columns marked "Rad Top", "Rad Ctr." and "Rad Bot" mean? Is there a booklet that the wind tunnel gives out - that explains all the numbers, how they are measured or calculated, and how they are reported? Just trying to gain a better understanding of these numbers... thanks, Carl B.

Hi Mike: It's not really the same reason is it? The Whaletail exerts down-force on the rear only - thus causing the front to rotate upward. In the case of the G-Nose it seems that lift is increased at both the front and rear - and drag goes up as well. I think the question should be; why did the G-Nose increase front and rear lift as well as drag, compared to the stock 240-Z tested, when the G-Nose is supposed to do the opposite. In the Lift and Drag columns, lower numbers are an improvement - (yes/no?)... Carl B. Carl Beck Clearwater, FL USA

"Paulo's wing" looks a lot like the 7" by 30 degree rear spoiler that CD Tested. It added 120 lbs. down-force at 70 mph to offset the 20 lbs of lift in the stock Z. The BRE Rear Spoiler added 75 lbs of down-force, drag was the same for both - they increased gas mileage by 0.2 mpg at 70 mph. Increasing the angle of attack of the 7" spoiler to 50 degrees, resulted in 160 lbs of down-force, but increased drag to the tune of a loss of 0.6mpg at 70mph. That 160 lbs of downforce on the rear also lifted 40 lbs off the front... Maximum down-force might not be the best answer.... FWIW, Carl B.

I'm sure he would object!.. you have to drill holes in the lower finisher panels (right, center and left) to properly affix the Spook to the car!! Perhaps there is an owner in the area - with an otherwise stock bodied 240-Z, that has already added the BRE Spook, and which you could then use to swap rear hatches to measure the rear Spoilers as well. Given the front bumper on the 280Z's sticking out like it does - I'd think that comparing a stock 240-Z to a 280Z would be less than the ideal apples to apples comparisons we'd want to make. You know, make one change at a time and measure the results.. (unless the 280Z has been retro-fitted with 240-Z bumpers). When it comes to "downforce" none of the air dams that C&D tested resulted in the reduction of Lift that the BRE Spook generated. It would be a shame to not be able to include it... Everything is a trade off of some kind - the trade-off between Spooks and Air-dams would seem to be the trade off between reduced lift and increased drag... but if we can't measure both.. we'll never know to what extent or degree they vary. FWIW, Carl B.