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Michael

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Everything posted by Michael

  1. I would spend the $200 on sufficient quantities of intoxicating fluids, such that the paint job and condition of the body would begin to resemble that of a championship-winning hot rod. If genuine reality is intractably out of reach, compensate through solipsistic surrogates. The keenest satisfaction is not in the production of a beautiful machine, but in the reorientation of one's sensibilities to obviate the need for great effort towards ultimately unsatisfying pursuits.
  2. Big blocks have their advantages, and these are not merely originality or the appeal of exotica. However, don't bother with a 396, unless it's a mock-up for engine installation. Build at least an overbored 454 (ideally with a stroker crank), or go with an aftermarket block. The complexity and cost of a big-block swap are only borne by aggressive displacement and concomitant power levels. Definitely use high-end aftermarket heads, a mechanical roller cam, good bottom-end components and the appropriate intake and exhaust systems. Plan on $10K+ for a suitable engine, and driveline components to match.
  3. A mismatched combination with an unknown history sold by a neophyte (or cagy) seller... Maybe 5000 rpm usable redline and 5500 rpm never-exceed redline. Figure on 220 ft-lb torque and 170 hp.
  4. Try "Engineering Statics", by Merriam and Kraige. That was our textbook 20+ years ago - it was very clear, almost pedantically clear.
  5. Indeed, Problem 3.81 is incorrectly worded, and that would confuse students. But resolving vectors into their components, finding magnitudes and directions, etc., is essential for mechanical/aerospace engineers. Something else to note... as you become more senior as an engineer, you'll be doing far less calculation and far more writing and speaking. So after enough time on the job, the primary skill set is supplanted by more of a humanities-type of skill set. The math however continues to be important, not through direct calculation, but in understanding the equations and how to simplify them for making quick estimates. One route to consider is to switch to a "mechanical engineering technology" major at community-college. Get an associates degree that qualifies you to operate CNC machines and the like. Old-timer machinists are losing their jobs because they can't program the new machines. Get into that niche, get some practical experience, and a few years in the future you can decide whether to return to 4-year college for your BSE. Your employer might even offset the tuition.
  6. To be pedantic, this probably belongs in the "drivetrain" subforum. The "world class" T5 is probably adequate for most applications, as the limiting factor will likely first be rear-wheel traction, rather than driveline stresses. The disadvantage of most domestic 4-speeds is the narrow spread between 1st and 4th gear. For a torquey engine in a light car, all of that shifting will be superfluous. And the highest gear is still too deep for comfortable highway cruising. A good example is my own mistake: I went with a Doug Nash 5-speed. Yes, it's a 5-speed, but 5th gear is 1:1. First gear is 3.27:1. So the highest to lowest ratio, 3.27 to 1, is quite narrow. The 4-speeds are even worse... some of them have a 2.2:1 first gear and 1:1 fifth. Unfortunately manual transmission options have not been improving over the years with anything close to the vigor that we've seen on the engine side. When the JTR manual first became popular, in the late 1990s, the LS engine series was just starting to hit the market, and the Datsun swap of choice was the traditional carbureted 350. The manual transmission choices were T5, the then-cumbersome T56, and the 4-speeds. Well, the T56 is still cumbersome. Just about the only change in the past dozen+ years has been the aftermarket support for the T5 (Forte's, G-force) - which is substantial and very good, but also very pricey ($2500 for a G-Force T5 upgrade).
  7. Replacing the pistons likely means rebalancing the rotating assembly, and buying new rings. You'll need to confirm piston-valve clearance using a mockup installation with clay. Even if everything fits mechanically without interference, as Pyro and others have mentioned, the performance gain is incremental at best. And if you currently have a fairly well sorted combination, changing one component tends to trigger a cascade of requisite changes to keep the overall combination consistent. That of course raises costs and promotes risk. My recommendation would be to do nothing, assuming that you have a reasonably well-running engine, until you are ready for a significant upgrade in power. Then get the latest fancy aluminum heads, mechanical roller cam, forged pistons with the right compression ratio, rods, and so forth. The cost advantage of a Chevy small-block is in the low price of the as-is combo. Adding individual components to any engine, no matter how common, quickly gets to be expensive.
  8. I'm all in favor of lightweight 2-seater sports cars rolling on 14" or even 13" wheels... something like my 1991 Mazda, only even lighter due to use of modern materials and chassis engineering. Say 120 hp from a 1.6L 4-cylinder (perhaps horizontally-opposed) in a 1800-lb car... decent performance and good fuel economy simultaneously. I don't believe that crash standards would be a problem, if bumpers are properly integrated into the chassis and the proper analysis (validated by testing) is done on crumple-zones and the like. The problem is market acceptance. People who crave this type of car tend to be ones who buy >20-year-old cars, not the latest models.
  9. One possibility is to run bracing-tubes along the transmission tunnel. Triangulated bracing would be welded in between the front strut towers and the firewall (piercing the firewall), then continue along the transmission tunnel, and then kick up again to meet the bracing connecting the rear strut towers.
  10. It's going to be a tough sell, considering that even economy cars in the current market are leaving the factory floor with 15" wheels. About the only market for 14" wheels is muscle-car restorations - and those probably are more for appearance than for handling prowess. I recently had a similar problem with my 1991 Mazda Miata, which is still on its stock 14" aluminum wheels. Its factory tire size is 185-60R14, which is becoming quite rare. As with S30 Zs, most NA Miata owners are "upgrading" their wheels to larger size... and this is on a car with maybe 90 hp to the rear wheels! My solution was to "downgrade" to 185-55R14 tires (Yokohama S-drive), which are somewhat smaller diameter and therefore throw off the speedometer, but have excellent grip. The lighter weight of the smaller tire carcass is also a bonus. On a brighter note, 15" wheel diameter is very popular for drag racing. So just a 1" increase greatly opens up the tire selection.
  11. The fellow at in the link [http://www.dragtimes...slip-21234.html] is making his Hp numbers with 415 cubic inches, aftermarket heads and relatively sophisticated engine management, intake and exhaust. That engine has nearly a 1.5L displacement advantage over the 327. The point is not to disparage the 327 or to insinuate that the displacement is too small to be useful. That is not the case. Rather, the point is that more cubic inches offers a route that's likely to be simpler. Not guaranteed to be simpler, but widely regarded as likely. Alternatively, how about an incremental approach... shoot for a reliable car with no power-adders that comfortably runs 13.0 without breaking parts or displaying any ill manners. Establish that as a baseline. Then incrementally improve, experimenting with exhaust mods, cylinder head porting, and so forth. The advantage is the gaining of experience with a running vehicle, and the testament of personal evidence for what does and does not work.
  12. The trouble with Hp-weight-mph calculators is that they assume constant-power applied during the entire run, and then multiply by a fudge factor in attempt to account for aerodynamic drag, slippage, gear shifts and so forth. For a pro car with a pro driver, these assumptions are reasonable and the fudge factor is stable. But for an all-purpose car (street car, road-race car, and part-time drag car) the assumptions break down. I recall some advice from Marlin Davis, the tech-guru at Hot Rod Magazine, on much the same question. He said, if I remember correctly: for an amateur car intended to achieve a speed in the 10-second to 12-second range, go ahead and use the calculators, but calculate an Hp figure for a car that would be 1-second faster. In other words, if your goal is 11.00 seconds, then look up the Hp number for 10.00 seconds, given the estimated weight, and use that value for required Hp. My Z weighs in the neighborhood of 2600 lbs (completely stripped, lots of stock sheet metal removed, but heavy mild-steel roll cage and big block (aluminum heads etc.). It makes maybe 400 hp in present state of tune, but would be lucky to run 14s with the present suspension, tires, transmission etc.
  13. Randy - would it be possible for you to share the price and parts-list for the 555" big-block that you mentioned? There's another thread currently running, where there's a discussion on "price of a 800 hp big block". I'm curious about actual numbers for an actual engine.
  14. $2600 is an excellent price for that combo IF you have reliable evidence that it's complete, present-as-advertised, running, and properly assembled. Otherwise if could be a $2600 paperweight. It is emphatically not the case that a "600-800 hp big block" can be built for $2600! At that power level, you'll have $2600 in the cylinder heads alone. Stock rods would be questionable, and a decent aftermarket set of rods ($600) plus forged pistons ($500), balancing the rotating assembling ($250), and you've already blown more than half of your $2600 budget. Roller cam ($250+), good roller lifters ($400), pushrods ($100) and rockers ($300), high-quality timing chain ($100)... you get the picture. A properly assembled big block with the requisite machining and the components needed to reliably produce that level of power will run around $8000 using mail-order parts (Summit, Jegs) bought individually, if assembled at home, and if you already have a usable block. Crate engines will be cheaper, but components will be inferior and you have no control over tolerances or other details of assembly. A good crate big block from a reputable builder at the 600 hp level would run around $10000, with proper aluminum heads (AFR, Brodix) and mechanical roller camshaft. Adding another 200 hp means some serious CNC machining on the heads, probably an aftermarket forged crank and top-shelf valvetrain components... try $12000+. If I could interview the builder and have reliable information about that $2600 engine, I'd be all over it! Actually, even if I had no use for such an engine, at that price level, it would be a worthwhile acquisition just in case. But a few things bother me. For example, 0.630" lift in a 355 is an awful lot. What was done to the valvetrain to accommodate that much lift? How much valvespring pressure, and how will that affect camshaft life? Do we have dyno data... in other words, is that 485-500 hp an evanescent blip on the dyno at 6700 rpm? The big risk with "screaming deals" is truth-in-advertising. For peace of mind, and not for personal arrogance or cost-cutting, it is more attractive to build one's own engine.
  15. Some years ago I had the fortuitous experience of attending "professional military education" with a class full of USAF pilots. They were captains, most with 6-8 years of military experience, most from ROTC but a few from the USAF Academy and a few from Officer Training School. Very few were engineers! The most popular major was political science. Why? Evidently, what counted most was their GPA, and secondarily their extra-curricular activities and "leadership skills". If you kept a 3.9 majoring in English while captaining the lacrosse team and excelling in your ROTC unit, you were pilot material. While the poor schmuck who studied mechanical engineering, got similar grades but didn't play sports or "lead" any student groups - well, he ends up as Acquisition or Maintenance. In other words, knowledge does not matter; raw numerical outcomes (such as GPA) matter.
  16. "Calculating the flow in an channel" is NOT a basic equation, unless one makes sweeping assumptions (laminar flow, circular pipe or usage of hydraulic diameter, etc.). But then the crucial piece of knowledge is knowing when to make those assumptions, how to defend/refute them, what they mean, and what are the error-bars. The groundwork for receiving that knowledge comes from formal education. The actual information comprising the knowledge comes from practical experience. It is however largely true for a plethora of reasons that the BSE is the new "high school diploma", and graduate school is the new "college".
  17. Here's a little dose of reality to all of you professor-hating kids out there: 1. Ever wonder why so many of your engineering professors are foreign-born and speak with funny accents? It's because native-born U.S. citizens are either too lazy/stupid to get a Ph.D. in engineering, or because having obtained one, they DO find greener pastures in industry. Now imagine that you are a foreign-national graduate student getting his Ph.D. in the US. How can you stay in the US after graduation? H1-B? Good luck! You can marry an American girl (again, good luck!) or get a professorship. 2. So why does your freshman-calculus professor ignore you? Because (1) he's probably a graduate student or post-doc and not even a professor, and (2) his performance evaluation has very, very little to do with how well he teaches freshman. Plus, most freshmen are obnoxious louts anyway, so why bother paying attention to them? But in all fairness to professors: yes, they waste a good 2-3 hours daily in stupid faculty meetings, chatting with colleagues on the phone, or just piddling away in their offices. But you know, besides giving lecture and preparing lecture notes, there are another 9-10 hours in their workday (typically 6 days a week) devoted to writing proposals, reviewing papers, advising graduate students, dealing with government program managers and otherwise whoring for funding. 3. Subtracting polynomials counts as engineering mathematics these days??? 4. An engineering education is mostly self-education. The professor's role is to apprise you of the requirements. It's your own responsibility to meet them. 5. There are dorks and cretins in every field, including professorship. It is quite surprising how many fools manage to graduate with a Ph.D. 6. Salary in most technical fields tops out at around $150K. Beyond that's management, owning your own business, executing various deals, etc. - not really engineering anymore. You can get to that salary in private industry, in academia or in government. The point is that there's convergence at the top of the engineering salary scale. So it's rubbish to claim that professorship is the consolation-prize after failing in industry. 7. The older edition of the textbook is generally more rigorous and is better written. Wise professors encourage students to buy the older addition, and hand out the new homework problems by photocopied pages in class.
  18. It will take some work to get the 305 to produce 210 hp at the rear wheels. It ought to be possible with the stock heads, but would require some head-work (valve guides/seats, new springs, port-work), intake/carb, exhaust, cam/lifters/springs, and various other bits - assuming that the bottom end is healthy. Even if it is healthy, you will likely need new pistons to achieve a reasonable compression ratio... and that means balancing the rotating assembly, even if you do no machine-work on the block. The point is not that 305 are woefully useless, but that return on investment is inferior to that of a 350-383 class of engine. Since the original poster sounds like a person with preference for the turbo approach, it would likely make sense to persist in the turbo-refinement vein, if the objective is incremental improvements in power. But if the desire is to go from 210 hp to say 350 hp, then indeed the V8 approach becomes attractive. Do however please note that proper building of a V8 is more involved than the Datsun V8 swap itself. Or to rephrase: fear not performing the swap from L6 to V8; instead fear the proper building of the engine.
  19. A full backhalf treatment would be pretty radical, and remains rare on Zs. And it would only be consistent to do a full cage and to deal with the consequences. What are the performance goals for this car (forecast/desired 1/4-mile time)? How aggressive is the powerplant?
  20. That's a pretty healthy cam (247/254 @0.050") for a 327, especially if you install it 2 deg retarded, with 10.4:1 compression. Desired RPM range? Resulting dynamic compression ratio? Will the rods hold up at that piston speed? Carb is borderline too large (but should be OK if you will be spending lots of time above 5000 rpm and off-idle response is not important). Is this intended for nostalgia-type of hot rod, or any particular form of competition, or mostly a fun street car? This sort of combo enjoyed some popularity here in Z's about 10 years ago. The result was a decently peppy car, which did however require lots of aggression with the throttle to keep the engine happily revving. Gear ratio and transmission type?
  21. This is a big block, correct? What cylinder head casting number? I am surprised that the two heads are not exactly identical, down to the drilled/tapped accessory holes. And accessory holes should all be 3/8-16. If not, then likely a bolt got stuck somewhere, was drilled out, and an oversized hole was drilled. Any more details of your engine build? And welcome to HybridZ!
  22. If you "drive like a grandpa" then you'll likely be happiest with the C5. It is remarkably tolerant to low rpm/high gears. All of the others require attention to being in the power-band that the engine most prefers. My M3 (the regular E36, not the 2-seater) has a 3.7 rear, whereas stock is something like 3.15. This definitely helps with apparent feel at low rpms, but the price is high highway rpms (3500 rpm at 70 mph), the hit in mileage, and the need for a very early 1st-->2nd upshift. The C5 Z06 is geared more deeply than the regular C5, so that's another reason to opt for the Z06.
  23. No first-hand experience on the S2000, but a few days ago I drove a Z3 M (that's the convertible version of the M3 Coupe), and had about a week's seat time in a friend's 2001 Corvette (stick-shift, hardtop, but not Z06). My former daily driver (now occasional weekend car) is an E36 M3. The Z3M feels much more nimble airy and purposeful than the "conventional" M3. The M3 is quieter, has higher-quality interior and has the obvious advantage (to some) of a commodious rear seat. But it's just not as lively as the Z3 M. The base-model C5 is remarkably quiet, has impeccable highway manners, and gets superb gas mileage on highway drives in 6th gear (~30 mpg). The torque delivery is very predictable and linear (the BMW S52 engine is lethargic below 2500 rpm, even with properly functioning VANOS). But the steering is numb and the overall feel is that of a muscle car: large, brawny, commanding, but lacking litheness or poise. I would not worry about E36 BMW reliability. It is not outstanding, but repairs are relatively straightforward. That said, spending some time underneath a C5 Corvette for basic maintenance (fluids, belts, etc.), I'm surprised how well-built and competently engineered it is. I still can't figure out why it feels like it's 700 lbs heavier than an M3, while in reality the weight difference is maybe 100 lbs. For pure highway cruising, I would recommend the C5. For overall driver-feel and nimbleness, I recommend the Z3-based M-cars (convertible or hatchback). The M3 sedan or coupe are bargains; moderately-worn examples can be found for under $5000. But it's just not as satisfying to drive as the Z3-M.
  24. Somewhat off-topic, but perhaps a useful data point.... A fairly close friend of mine was a professor at the U of Mississippi. Originally he's from upstate NY. He reports that the environment was very insular and unaccommodating of "yankees" - even around the university. Even though he was awarded tenure at the university (he started on the ground floor, as an assistant professor), he eventually moved; the environment was just too toxic. Datsuns and foreign cars in general may not receive a warm welcome.
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