# Modern engine innovations **URL:** \ **Category:** Factual Questions\ **Created:** [March 7, 2023, 7:21am UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823 "2023-03-07T07:21:07Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [April 20, 2023, 12:52pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/81 "2023-04-20T12:52:09Z")
> [@Machine\_Elf](#): > > Since you can’t use liquified H2, it’s hard to store enough fuel onboard to go very far, These folks > **[Universal Hydrogen | Fueling Carbon-Free Flight](https://hydrogen.aero/)** > > Universal Hydrogen makes a flexible and economical carbon-free future possible. We transport hydrogen in modular capsules over the existing intermodal container freight network. To accelerate market adoption, we’re also developing a conversion kit to... are working on liquid hydrogen storage for airplanes. They claim they have largely solved the boil-off problem, so storing rather dense LH2 in relatively lightweight tanks isn’t impossible. Yes, there are many hurdles to full-scale adoption and automotive applications are relatively more space-constrained than weight-constrained which is the opposite of commercial aircraft. But lots of smart folks backed by semi-smart money are pursuing all avenues. This will be a very interesting space to watch over the next 20 years. Vast fortunes will be made and lost. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 20, 2023, 1:18pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/82 "2023-04-20T13:18:32Z")
> [@LSLGuy](#): > > They claim they have largely solved the boil-off problem, so storing rather dense LH2 in relatively lightweight tanks isn’t impossible. I suspect fueling with LH2 works fine if you’re going to fill the tank from empty to full and then use it all at a rate that matches or exceeds the boil-off rate, as an airliner might do. But for a passenger car that may be driven only/mostly on short trips over a span of many days (while spending most of that time span parked), I’m wondering just how good their aircraft boil-off solution could be. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [April 20, 2023, 1:24pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/83 "2023-04-20T13:24:54Z")
> [@EinsteinsHund](#): > > > [@Saffer](#): > > > > I recently saw an add for a 1978 Camaro with a 5.7 litre engine. I was surprised to see it only produces 170 hp. > > The obscenely giant (and thirsty) 8 cylinder engines with rather low horsepower were almost exclusively an American phenomenon at that time. Wikipedia has an article about that: > **[Malaise era](https://en.wikipedia.org/wiki/Malaise_era)** > > Malaise era is a term used to describe the state of the U.S. automotive industry from roughly the early 1970s through the early to mid 1980s, characterized by malaise: poor products and a generalized industry unease. > Around this time, the U.S. federal government released in quick succession ever more strict and comprehensive automotive emissions, fuel efficiency and safety standards, — severely hindering the industry's ability to adapt and expediting a marked drop in vehicle performance and po... If you prefer a visual form, here’s Ed: https://www.youtube.com/embed/videoseries?list=PLdhHmHGywkTrWNulz207YaECu8T2ejDGS&wmode=transparent&rel=0&autohide=1&showinfo=1&enablejsapi=1 ---
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [April 20, 2023, 1:33pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/84 "2023-04-20T13:33:05Z")
A nitpick: that 350 Chevy only made 350 hp using the old and unrealistic gross hp rating. It’s not comparable with modern net hp ratings. As installed, the 1969 350 made around 260 net hp. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [April 20, 2023, 1:46pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/85 "2023-04-20T13:46:03Z")
> [@Machine\_Elf](#): > > I suspect fueling with LH2 works fine if you’re going to fill the tank from empty to full and then use it all at a rate that matches or exceeds the boil-off rate, as an airliner might do. But for a passenger car that may be driven only/mostly on short trips over a span of many days (while spending most of that time span parked), I’m wondering just how good their aircraft boil-off solution could be. An excellent question & concern. I’ve read several more in-depth articles in the aviation trade press about these folks. Part of their big idea is the tanks are interchangeable and rather than refueling an airplane, you unhook the empty-ish tanks, forklift them out, and slide other full tanks into place. The tanks are shuttled by truck back to a regional H2 factory / refinery / transfer station to be refilled. The tanks are expected to sit outdoors and full for two days before any boil-off occurs. They have some catalytic method to render the gaseous H2 inert as it does exhaust. The amount of boil off beyond the two days starting point is supposedly negligible for up to a couple of weeks. At least for aircraft-scale tanks. A smaller tank for an automobile would suffer more from the volume/surface area equation. Do I believe 100% of what they claim? Not exactly. But these folks are far past “artist’s conceptions”. It’s at the real full-scale, albeit prototype, hardware stage of development. is this model a good fit for personal automobiles? Probably not. For local-use fleet vehicles be they cars or trucks? Possibly / Probably. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [April 20, 2023, 2:58pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/86 "2023-04-20T14:58:52Z")
> [@kanicbird](#): > > As for supply limitations, we are just starting to mine lithium, Something I learnt in my time in the geophysics arena. Claimed resources always significantly lag behind the real quantities of a resource. Mining and oil companies have a baked in disincentive to find new resources quickly. Which sounds odd. The problem is that a permit to explore both costs money up front, and comes with significant additional costs and responsibilities once found. Typically a company will bid for and acquire an exploration license with a use by date. There is a use it or lose it build in. If they find a useful resource they will need to apply for production licenses, whihc include the royalty paid to the country/state. These also come with use by dates. The upshot is that the **proven reserves** of any mined commodity tends to sit at a pretty constant number of years of available resource. Say about 10-20. There are significant disincentives at play that keep it there. Whenever you hear that there is only 10 years of a mined (or drilled) commodity, you can be pretty sure it is quoting proven resources. The expectation of what there is to be found can be vastly higher, but more speculative. You can take a proven resource to the bank. ---
**Author:** ![EinsteinsHund](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/einsteinshund/32/8400_2.png) [@EinsteinsHund](https://boards.straightdope.com/u/EinsteinsHund)\ **Post date:** [April 20, 2023, 3:17pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/87 "2023-04-20T15:17:01Z")
> [@Skywatcher](#): > > > [@EinsteinsHund](#): > > > > > [@Saffer](#): > > > > > > I recently saw an add for a 1978 Camaro with a 5.7 litre engine. I was surprised to see it only produces 170 hp. > > > > The obscenely giant (and thirsty) 8 cylinder engines with rather low horsepower were almost exclusively an American phenomenon at that time. > > Wikipedia has an article about that: Ah, thanks, very interesting, but that makes me wonder: how did European brands of high powered cars like Mercedes Benz, Porsche or Volvo cope with the strict American emission laws? Did they have to cripple the power of their engines (a thing Porsche at least traditionally hates doing), too, or did they find other means? ---
**Author:** ![BrickBat](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@BrickBat](https://boards.straightdope.com/u/BrickBat)\ **Post date:** [April 20, 2023, 3:29pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/88 "2023-04-20T15:29:16Z")
> [@Capn\_Carl](#): > > A nitpick: that 350 Chevy only made 350 hp using the old and unrealistic gross hp rating. It’s not comparable with modern net hp ratings. As installed, the 1969 350 made around 260 net hp. A nitpick on your nitpick. 350 gross HP would come out to a hair under 300 HP. The difference between net and gross was 15 to 17 percent, as borne out by 1971 ratings published that published both ratings. The spread would also be larger if the engine is equipped with single exhaust. The top rated SBC 350 engine was 370 gross BTW, which translates to 314.5 net hp. ---
**Author:** ![BrickBat](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@BrickBat](https://boards.straightdope.com/u/BrickBat)\ **Post date:** [April 20, 2023, 3:32pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/89 "2023-04-20T15:32:41Z")
> [@EinsteinsHund](#): > > Ah, thanks, very interesting, but that makes me wonder: how did European brands of high powered cars like Mercedes Benz, Porsche or Volvo cope with the strict American emission laws? Did they have to cripple the power of their engines (a thing Porsche at least traditionally hates doing), too, or did they find other means? They did, but to a lesser degree. In some cases, for example, the European version with fuel injection would be specced out with carburetors, but yes, not at all uncommon to see the higher performance cars of Europe and Asia with detuned engines in US trim. ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [April 20, 2023, 3:33pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/90 "2023-04-20T15:33:26Z")
Those European “high powered” cars were anything but. Those late 70s Volvos barely cracked 100hp. A 1978 Mercedes 450 SL was about 180hp, as was the Porsche 911SC of that period. The European cars of the 50s, 60s and 70s made their marks by being lightweight with good handling. As a big fan of Lotus, let’s consider their late 70s ‘supercar’, the Lotus Esprit. 140hp. The Ferrari 308? 240hp given a very generous reading of the dynamometer figures. ---
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [April 20, 2023, 6:36pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/91 "2023-04-20T18:36:17Z")
The problem with the 15-17% rule of thumb is it implies accuracy that isn’t there. The gross numbers were not only unrealistic, they weren’t consistent either. Some engines were overrated, some underrated. So any calculation using the gross hp rating is suspect. The most accurate and most comprehensive means we have to determine the as-installed hp of an engine is to use the as-tested weight of the car and the 1/4 mile trap speed. The 1970 LT-1 Corvette hit 102 mph, possibly the highest trap speed for a stock small block of that era. It ran like you’d expect a 290hp car to run. ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [April 21, 2023, 9:14am UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/92 "2023-04-21T09:14:29Z")
Is gross hp basically equivalent to crank hp, while net hp is roughly wheel hp? I read the Wiki on hp but don’t have the mechanical knowledge to quite figure it out. Is the global standard for cars these days wheel hp, which is quoted as “bhp”? ---
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [April 21, 2023, 10:35am UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/93 "2023-04-21T10:35:10Z")
Gross hp was what the engine made, at the crank, on a dyno. Usually, the engine had no air filter, alternator, water pump, or exhaust beyond the exhaust manifolds. Sometimes the carb and ignition were tuned for max power. SAE net hp is the power at the crank, but with all accessories installed, tuned to stock specifications, run on pump gas, measured at standard temperature and humidity. Wheel hp is net hp minus drivetrain losses. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [April 21, 2023, 12:38pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/94 "2023-04-21T12:38:27Z")
> [@Machine\_Elf](#): > > But the article you linked to says that Toyota is specifically avoiding going electric on their H2 Corolla, so I wonder what kind of range it has. Wikipedia tells me their Murai gets 400 mi / 650 km on 5.65 kg\* of hydrogen. Although it seems capacity and range are improving, and those numbers may not all be from the same model year. Assuming the same capacity, I don’t know what kind of hit you take on losing the hybrid battery. \*The tanks weigh much more than that. ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [April 21, 2023, 4:46pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/95 "2023-04-21T16:46:11Z")
Thanks, that clears it up for me. ---
**Author:** ![BrickBat](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@BrickBat](https://boards.straightdope.com/u/BrickBat)\ **Post date:** [April 21, 2023, 5:04pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/96 "2023-04-21T17:04:56Z")
> [@Capn\_Carl](#): > > The problem with the 15-17% rule of thumb is it implies accuracy that isn’t there. That may well be so, but it wouldn’t lead me to summarily low-ball the numbers by assuming the rating **is** inaccurate. Over the years we get to see engine builds, many of them to stock specs by the owner’s desire for historical accuracy, on a dynomometer. The results were surprisingly accurate, though they seldom came out exactly to the rated number, since the manufacturer’s liked numbers like “300” or “285” more than “301.4” or “283.7” or the like. > [@Capn\_Carl](#): > > Some engines were overrated, some underrated. It’s nice with the passage of time to compare modern builds of stock classic engines and it’s been verified that one way of underrating engines was by half-truthing the dyno curves by publishing the rating at a point lower than the peak. > [@Capn\_Carl](#): > > The most accurate and most comprehensive means we have to determine the as-installed hp of an engine is to use the as-tested weight of the car and the 1/4 mile trap speed. Probably the best truth teller of output, especially in comparing cars of similar weights, and as long as the gearing isn’t profoundly disadvantageous. ( losing acceleration room due to a poor start or botched launch ) ---
**Author:** ![BrickBat](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@BrickBat](https://boards.straightdope.com/u/BrickBat)\ **Post date:** [April 21, 2023, 5:49pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/97 "2023-04-21T17:49:06Z")
> [@Capn\_Carl](#): > > The 1970 LT-1 Corvette hit 102 mph, possibly the highest trap speed for a stock small block of that era. It ran like you’d expect a 290hp car to run. ( Brain farted ( forgot ) and thus missed the edit ) I’d say a 3500 pound-ish C2 Corvette going through the traps at 102 mph is making _at least_ 290 _net_ hp for sure\*. - my “bench racing” wisdom Another factor seen is some of the highest performance versions of an engine were throttled by factory, or even indifferent tuning. Ram Air IV Pontiac GTOs ( and Firebirds ) were generally low 14 second 98 mph cars off the showroom floor, but given some fine tuning of timing and mixture, were 105, 106 mph cars. I’ve seen them run myself. Dwelling on it all further, it seems the generally crappy rubber of the day, compared to today, really hampered both traction…and handling. It doesn’t turn them into autocross machines, but makes them surprisingly competent and livable. ---
**Author:** ![WildaBeast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wildabeast/32/6_2.png) [@WildaBeast](https://boards.straightdope.com/u/WildaBeast)\ **Post date:** [April 21, 2023, 6:22pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/98 "2023-04-21T18:22:06Z")
> [@EnolaStraight](#): > > A hotter engine is a more efficient engine. In the early 1990s I checked out some science book from the library (think it might have been published by Popular Science) while doing research for a science fair project. I remember an article in that book about how scientists/engineers were working on building a ceramic engine, which could run much hotter than a traditional aluminum or iron one, and therefore run more efficiently. That evidently didn’t actually pan out, but it’s an interesting idea. ---
**Author:** ![Capn\_Carl](https://avatars.discourse-cdn.com/v4/letter/c/838e76/32.png) [@Capn\_Carl](https://boards.straightdope.com/u/Capn_Carl)\ **Post date:** [April 21, 2023, 7:58pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/99 "2023-04-21T19:58:03Z")
Jim Wangers at Pontiac did more than just fine tuning to get better numbers in a magazine. On one occasion, a Firebird or GTO ran so fast, the magazine editors suspected foul play. They found that the “400” was actually a 428! ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 21, 2023, 8:07pm UTC](https://boards.straightdope.com/t/modern-engine-innovations/980823/100 "2023-04-21T20:07:28Z")
> [@Capn\_Carl](#): > > The problem with the 15-17% rule of thumb is it implies accuracy that isn’t there. This should always be expected from a Rule of Thumb. If you could count on it to be accurate it would simply be called a Rule. [Previous page](https://boards.straightdope.com/t/modern-engine-innovations/980823.md?page=4) [Next page](https://boards.straightdope.com/t/modern-engine-innovations/980823.md?page=6)