Michael

Here’s an effort at clarification… Olie’s point, I think, is what might happen during the first few seconds upon starting a cold engine. Consider an average temperature over some number of cycles – large enough to smooth over intake-compression-combustion-exhaust variation, but small enough so that the engine block is still cold to the touch. Well, if the temperature in the combustion chamber somehow happens to be similar to the temperature in the water jacket, then things in the combustion chamber are happening at maybe 70 deg F – and if that were true, then hypothetically detonation would not be a problem even for a very high SCR and low octane. However, this condition does not exist! Immediately upon starting the engine, combustion chamber temperatures climb to something like 300 deg F (probably much more, but this is just guess for illustrative purposes; and note that this number is much lower than the flame temperature itself), while the water jacket and exterior of the block are still cold to the touch. When the engine “warms upâ€, the ratio of temperatures at the combustion chamber walls to those in the water jacket approach equilibrium. So, there are two points of confusion. First, one can not correlate the water temperature to the combustion chamber temperature until the engine warms up. And second, the combustion chamber temperature is what effects detonation, BMEP, etc. – and not the water jacket or block temperatures. But we measure water temperature, and hence the rules of thumb are based on water temperature.

The more important question is, what will this poor train do once it reaches the station in Los Angeles? I mean, that's going to be one harsh arrival!

And here I am chiming in!!! Cygnusx1 is absolutely right. And besides taxes, consider the maintenance, the insurance, and the transaction costs. And the depreciation, if you're in the Midwest. Let me put this in perspective: I own my house outright - no mortgage, no monthly payments. But between taxes, insurance and maintenance, it costs me more to live in my house than I used to pay for rent in my apartment! Purchasing a house is making an investment. But some investments are good, some are bad, some are indifferent. It's ludicrous to claim that ANY investment is a good move, just because you're finally making an investment!

I also wonder why the new Mustang is so heavy. We had a thread on this topic some months ago, actually. Probably the causes are (1) onboard gadgets that 80’s and even 90’s cars didn’t have, (2) safety equipment and safety-driven structural features that don’t improve chassis stiffness but do add weight, (3) insulation, sound-deadening equipment and other features to obtain the NVH (“noise, vibration and harshnessâ€) levels that modern consumers crave. It’s curious that today’s midsize sedans and coupes weigh as much as 19’ barges from the 1960’s. If they built a Chevelle in 2009, it would weigh 5000 lbs!

The component of horsepower needed to overcome aerodynamic drag is just P = D*V, where D is the drag given by Olie05’s equation. Assuming 30 ft^2 frontal area and the given Cd of 0.44, at 70 mph this comes out to around 30 hp. As a very rough approximation, the towed trailer and car will have about the same Cd and frontal area, so the required hp basically doubles. More difficult to approximate would be the rolling resistance and the internal losses in the drivetrain and engine (cooling, pumping, exhaust); of course, it is only the latter will change when you swap engines. The Jetta, meanwhile, with an assumed frontal area of 25 ft^2 would only need around 18 hp to overcome aerodynamic drag at 70 mph – and evidently it gets 49 mpg doing this. Presumably the gearing is such that the Jetta’s engine’s rpm at 70 mph is around 1800 (seems reasonable for a diesel?) – in which case it needs to make around 52 ft-lb of torque to produce the hp to overcome aerodynamic drag. Now assume, very roughly, that100% of the horsepower goes into overcoming aerodynamic drag. Putting the Jetta’s engine into the pickup towing the trailer, to produce 70 hp at 1800 rpm is no longer possible, as it would require around 205 ft-lbs, and only 177 ft-lbs are available. But that’s not far off. 150 ft-lbs @ 2450 rpm give about 70 hp. Assuming that volumetric efficiency at 2450 rpm isn’t much worse than at 1800 (the torque peak), the fuel flow per unit time should just scale as the hp required – meaning, in our crude approximation, that the mileage of the Jetta’s engine in the truck would be a straight reciprocal of the ratio of the horsepower levels required. That is, 49 mpg * (18/70) = 12.6 mpg. The actual mileage should be better, since the rolling resistance for the two vehicles doesn’t differ nearly as much as does the aerodynamic drag; so the total power required for the pickup isn’t as large as the ratio of drags predicts. If the pickup and trailer will cruise at only 55 mph, then the hp to overcome aerodynamic drag is only around 34 hp, and the mileage (same assumptions as above) becomes 26 mpg. But I highly doubt that the truck doubles its mileage by slowing down from 70 mph to 55 mph!

Good luck, Mike! May your real estate ventures turn out better than mine! (But that goes for EVERYONE on HybridZ!). Is this place in the Fredericksburg area?

The alternative option is to just use the T5 FOR NOW, get the car running, learn its manners, and later on upgrade to either a stouter variant of the T5, or to another transmission altogether. There are not many options in the world of manual transmissions that are both cost-effective and sufficiently strong. Each of the established solutions (T56, Tremec, Doug Nash/Richmond, G-force) have drawbacks, such as high cost, heavy weight, difficult installation, notchy shifts, or poor choice of gear ratios. Don’t let consternation over “will it be strong enough?†set your endeavors back by 6 months.

$400 for that shortblock IS a good deal, plain and simple. Yes, there could be hidden flaws. But a $3000 shortblock could also be suspect, with hairline cranks, mismatched bearing tolerances and all sorts of other ills. Paying top-dollar does not insulate you from potential trouble, but getting a low price definitely eases the pain if and when trouble comes. The tradeoff in quality vs. price is rife with risk at any price level. Nor does building the engine yourself necessarily help, unless you are an experienced mechanic, in which case the entire discussion is moot! Can you really measure bearing clearances down to accuracy of < 0.001â€? I can’t. I couldn’t, even if I had the right tools – and I don’t. I spent $1500 on a mild performance rebuild (stock block, crank and rods), not including the cam and oiling system. Yes, it was a very reputable machine shop that used modern tools and took their time, but in the end it’s still a gamble – I’m taking their word for the precision clearances. I’m taking their word that they really did use a torque-plate for honing the cylinders, and that they really did use the correct bob weights when balancing the crank. And there are still no guarantees that the engine won’t grenade 5 minutes after it’s started. That said, your biggest frustration will be trying to continue the low-price theme for the rest of the engine. I mean, “to do it right†you will end up with at least $500 (maybe $800 or more) for heads with the right machining and valves. Then there’s the oiling system, the intake tract, the exhaust tract, and the various engine externals like cooling and ignition. After spending another $2000 on these various parts, you’ll be wondering: “Maybe I should have spent another $300 on the shortblock – then I wouldn’t have to worry that the shortblock would be a weak linkâ€. But in truth, there is always a weak link! Spend more money on any particular part, and you’ve just transferred the weakness elsewhere.

Nagants are inexpensive, but most are really beaten up and impractical for a first rifle. Standard Red Army (USSR) issue for many years – and before that, used in Czarist Russia. I’ve never seen one with a scope, however. You would probably have to have the receiver casing drilled and tapped. Nagants, unless I’m mistaken, take a 54x7.62 cartridge, which is difficult to find, and is reputed to kick pretty hard. My advice would be to stay away from antiques and military surplus rifles, unless you happen to enjoy gunsmithing. For reasonable deals, check out a generic department store (as opposed to dedicated gun shop). For example, most Walmart gun counters have a photo album with reconditioned or returned rifles. I bought a Weatherby Vanguard for $250 (brand new) from our local Walmart, in 270 caliber. The Weatherby is a decent brand, with good machining quality and a good bolt. Its weak point is the trigger, which in my case required some lapping of the sear to improve trigger feel. The choice of caliber is a debate in its own right. If you have no plans for hunting, consider the 223 – ammo is cheap (for centerfire calibers) and recoil is very light. But in most states 223 is illegal for hunting. And stopping power – for a rifle, that is – is considered to be mediocre. For hunting or other general purposes, common choices are 243, 270 and 30-06. I’d definitely avoid a magnum or an oddball like 220 Swift – ammo is expensive and rare. For pursuit of accuracy, you might find that you’ll have more money in the scope than in the rifle itself. This happened to me ($350 scope). 1†groups at 100 yards are REALLY hard to achieve, by the way; it requires a good gun, a good scope, good sighting-in of the scope, good ammo, and most importantly – a good shooter

If you're a dealer, don't you have space on your lot to store your personal cars indefinitely? And if you are a dealer, most likely you would expect to pay wholesale. The wholesale-retail spread on these cars is huge! I'd say $1500 wholesale for the pair of them, tops.

Well, I'm an aerodynamicist, or at least I play one at work.... Automotive aerodynamics is very much a black art; or rather, it's much more of an art than a science. Airplane aerodynamics is in many regards much simpler. Over the years there have been several pages on the web describing why the S30 Z’s have such a high drag coefficient and so much front-end lift. While the gist of these explanations is generally correct, the technical arguments are at times fallacious. The complexity comes from the role of ground effect, rotating tires, radiator flow, sharp protuberances and flow separation from aft-sloped surfaces. These effects don’t scale well between tunnel models and real life, and are hard to reproduce in the lab. Computations are difficult and unreliable, too. I’ve done some testing in my water tunnel regarding the “smelly exhaust†problem, using a ~1:24 wooden model with a plexiglass ground plate. Dye injection gives sort-of the right picture, but that’s a very crude experiment. The problem gets much more complex in figuring what happens with air dams, radiator flows and underbody flows – so much so, that I’d trust the fingers-and-toes expertise of track testing much more than I would laboratory or computational predictions. That said, it is intuitively true that sealing off the area behind the air dam and underneath the engine compartment will improve downforce and reduce drag (slightly). If these areas are sealed completely, and the air dam extends close enough to the ground, then essentially what happens is that the low-pressure flow behind the car (it must be low pressure, because of overall vehicle drag!) bleeds forward underneath the car, and “piles up†(silly term, but gets the point across) behind the air dam. Hence, downforce. The reduced-drag effect is much smaller, but that’s not our primary concern, anyway. All of this will improve if you do something about rounding-out the sharp front lip of the S30 hood. .

I have Brodix aluminum heads, Hooker block-hugger headers and the standard (low-carbon steel?) bolts that came with the Hooker headers. And Fel-pro (?) copper exhaust gaskets. No loose header trouble yet, but then again the engine hasn't run yet. Slowly I've been drilling the header bolts with a #56 bit to accept safety wire. I use used motor oil as the cutting fluid. With my Harbor Freight drill press and drill bits, it's a slow, laborious process, but so far I haven't broken any bits. Point being, that if you have mild-steel header bolts, consider drilling them yourself, and using safety wire.

I think that it would be spectacular to see a diesel V8 from a full-size pickup (1-ton or larger) in a 240Z, backed up an old-school 4-speed with a granny gear!

I think that the point is that whereas the engine itself might be free, solving the various system integration issues (cooling, gearing, reliability, and so forth) would be very un-free - to the extent that it would be cheaper in the long run to avoid the free engine entirely.

One consideration regarding transmission torque-carrying capacity is whether you plan on regularly running the engine at WOT, or if the spirited jaunts will be rare. If the car will see a dozen passes down the quarter mile, every Saturday for six months a year for 10 years, then certainly a strong transmission is required. But if (as for example in my own case) the track would be visited once or twice a year, for a couple of time-trials just to collect a time-slip or two, then it stands to reason that even a gearbox that’s marginal at 300 hp should survive the occasional 500 hp. In that case, torque capacity really shouldn’t be a concern. The higher-rated transmission would be more expensive, heavier, harder to fit, harder to service, and harder to shift. But if you do plan on regular drag racing, then indeed the gearbox strength issue becomes moot, and the slushbox is the way to go.

On the S30, and to some extent on the S130, what accentuates the length of the hood is the pointed hood lip and “forward swept†grill. Rounding out the hood lip/grill/bumper area would reduce drag and front-end lift, besides accomplishing some cosmetic improvements (in the eye of the beholder, of course). If your seat is mounted far aft – either because you’re tall, or the car is otherwise modified to require a further aft seating position (as in my case), then the windshield actually feels too far forward already. However, if you do wish to move its lower lip forward, keep in mind that you’ve effectively shortened the engine bay. For the stock L6 this complicates the installation of the brake vacuum booster and removal of the engine. For a V8 Hybrid these problems become even more severe. An alternative might be to set the windshield upper lip further back, thus sloping the windshield more. This was, if I recall correctly, already done by a member on this site.

Bill, in the final iteration of pushrod length checking, how wide was the area on the valve stem swept by the rocker tip? Any pics?

Garbage in --> garbage out; true enough. But sometimes truth in --> garbage out, nonetheless. I’ve used DD2000 with very marginal success. DD2000 arrives at a higher torque curve at nearly every rpm, whenever a given component is replaced with a bigger one. Got a 650 cfm carb? Great – now replace it with a 850 cfm, and watch the torque curve rise magically. There is no penalty in throttle response and no discernable penalty in quasi steady-state torque. Nor is there a penalty for mismatch of components. The program is very sensitive to intake duration – for some reason, this one parameter has a completely magical effect. Now to change the topic somewhat, and consider for a moment what a good research code (in mechanical engineering, not in “practical†automotive mechanics) should do... A good computational model needs, first of all, the CORRECT GRID – that means full knowledge of the geometry of the air cleaner, carburetor, intake manifold, intake port, combustion chamber and cylinder, exhaust port, header and exhaust tract. It needs the right model for wall surface roughness, including the various bumps and protuberances along the way. Next, a good computational model needs to be solving the “right†set of equations. This is the full 3-D compressible Navier-Stokes, with the right constitutive laws for 2-phase flow, and the right equations for energy and entropy. Next, it needs the right boundary conditions, such as the piston and valve kinematics. And finally – this perhaps the most difficult part – it needs the “right†turbulence model, to “close†the expression for the viscous stress tensor in the momentum equation. This is the sort of computation that would be run in university graduate schools with connections to the OEMs. What I would like to see is a better connection between the research world and the practical applications world.

One specific instance that might call for a custom cam (or a semi-custom cam, as Jakeshoe points out), is when you want to run a mechanical roller, but happen to be interested in a low-rpm application, for which all of the cams in the catalog are too big.

Jon, it sounds like Boise is too much of a small town for some one used to L.A. and Seattle. Granted, small towns have their particular appeal, but I would opine that moving from big city to small town is far more traumatic than the reverse. One experiences a feeling of exile; you offend the authorities, and they send you to a small hamlet in Siberia.

Check to see if for purposes of your application it is required to obey NHRA rules for the intended 1/4 mile time. You only need to remain as legal as the letter of the rules, right? Depending on what’s not necessarily required, it might be feasible to gut everything aft of the crossmember supporting the rear links of the rear A-arms, and everything forward of the radiator. I removed the crash beams from the doors of my 1978 280Z, but retained the glass and window winding mechanism. This required quite a bit of contortion. Using tin snips, I cut as little of the inboard sheet metal as possible. Then, with a dremel, pliers and snips, I cut out the crash beams completely. Then I gathered the scraps of metal and weighed them. The result – for BOTH doors combined: 10 lbs! That was a lot of work for just ten pounds. And comparing, subjectively of course, how the doors feel now, when they’re opened and closed, vs. how they felt before the surgery, the difference in apparent weight is exceedingly minor.

Business isn’t for everyone. Depending on one’s personality, starting one’s own business could turn into an unmitigated disaster. And it’s especially hard to become a budding capitalist if you’re just 21. My recommendation would be to enroll at the local community college, either in Arts and Sciences (if you wish to transfer to a 4-year college into an academic program, such as Engineering), or in a technical trade. With a suitable degree, the job prospects should hopefully become better. My wife found herself without a career, despite her educational background. So now she’s a part-time student at the local community college, and a part-time waitress at a local chain restaurant. She had to suffer the particular ignominy of transferring credits from her Master’s degree to her community college – and “starting over†in her 30’s. The Midwest in general is declining. Offshoring, globalization, whatever – they’re hurting the Midwest especially acutely, as this region is beholden to traditional manufacturing for its economic mainstay. And if that’s weren’t enough, retiring baby boomers are moving south and west, the tax base is shrinking, and liabilities are rising. So it stands to reason that the job market would be tight.

One would think that faster flow of water through the radiator does NOT reduce cooling efficiency – in fact, quite the reverse. The engine/water pump/radiator/plumbing are a closed system. So, faster flow through the radiator means faster flow everywhere in the system (conservation of mass!) unless part of the coolant flow somehow bypasses the radiator. Water that flows quickly through the radiator will also return quickly; it will spend “more cycles per minute†in the radiator, even if each cycle is shorter. I’m sure that going through the heat transfer equations would confirm that assuming radiator fin surface area is kept constant, that faster water flow increases the heat flux from the coolant overall, into the radiator and into the ambient air.

That does sound intriguing! I have a 280Z which might perhaps be back on the road by the time that your autumn semester starts. Its condition is approximately of the type that you desribe (some rust in rocker panels, covered by POR-15 years ago, but otherwise generally rust-free). Where in Kentucky are you? I'm about 50 miles north of Cincinnati, Ohio.

I removed the reinforcements and related sheet metal from the doors of my 1978 280Z; net weight savings: 10 lbs. Certainly something to consider in the all-out effort for your specific purposes, but not a huge weight savings. Cutting out the front bumper supports and the associated bracing forward of the radiator support should be worth another 10 lbs or so. If you have enough time, consider cutting out the entire radiator support, including the transverse crossmember forming the power portion of the radiator support and connecting the frame rails. Replace with round or square tubes. What about replacing the radiator itself, with an aluminum universal-fit unit, such as Griffin?