1927 Buick Standard on a Dyno test

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Results from a 1927 Buick Standard on a dyno.

"The horsepower peak was 29.97, while the torque number confirms the old notion that early engines were built for torque, with a peak of 89.10. Top speed on the rollers approached 50 mph, which seems about right for the vintage of the car."






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It must have been off song. The book says 63 hp @ 2,800 rpm. I would have expected it to go nearer 40 hp at the rear wheels. Torque peaking at a little over 1,000 rpm sounds right.

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That's awesome. About 20 years ago I was working at a company that had an in-house dyno for R&D purposes (they made various diagnostic tools that we all use regularly). One of their big sellers was timing lights, but I noticed they didn't really sell any 6V timing lights. One of the engineers said he thought that one of the lights would work on a 6V car but they didn't have any way to test it since they didn't have such a beast. Voila! I drove my father's 1925 Buick Standard touring car to work one day and we did all kinds of tests on it. Turns out that yes, the timing light would work on the old Buick. So would the spark plug tester and even the coil tester. Towards the end of the day when we were done with our real work, we put the Buick on the dyno, which was more or less the same Dynojet setup shown in that video although it was lab-grade and built into the floor in a test cell. I treated the car very gingerly, as I didn't really want to hurt it or break those wooden spokes, but in third gear it pulled pretty well from, say, 15 MPH to an indicated 60 MPH. I may still have the printouts somewhere, but from memory, it made about the same numbers they're showing up there. I think we saw just over 35 HP and about 105 pounds of torque at the wheels and both curves were practically flat across the range. I was surprised, thinking that both numbers would be a bit bigger, but this video pretty much confirms it. The tall wheels probably took some power to turn against the heavy drums, but everyone thought it was pretty cool. The engineers had never seen such flat torque curves, even though the RPM range was pretty limited (much like you can see up above--we aborted at 60 MPH, which was probably close to 3000 RPM).


The funny thing is that on a dyno, the engine sounds like it's screaming. The digital tach on the dyno said the engine was pulling around 2000 RPM but to me behind the wheel, it sounded like a rod was about to come through the block. A very strange sensation.


Thanks for reminding me of that--I'd totally forgotten that day!

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Hi All,


I'm the guilty owner of the 27 Standard that ran on the dyno. I say guilty, but then again, I would do it all over again in a heartbeat! ?


I've been reader of this forum for a while, but never really posted anything. I've been a fan of Buicks for a while and was lucky enough to acquire this well maintained car a few years back. The car has been a great driver and usually gets a fair amount of attention at shows in the area here as it usually is one of the oldest cars at the show. I have not done any work on the engine internals since I have gotten the car, however, I have switched to a Carter BB-1 carburetor as the Marvel was in really rough shape and performed general maintenance (valve lash, plugs, points, wires, condenser, etc...). 


I was at the Cars and Coffee and saw the dyno, and thought why not? I spoke with the guys sponsoring it, and they were very excited at the opportunity. The guy running the dyno was great, especially with helping a driver like me who has never run a car on a dyno before. All in all, it was a great experience.


As to the power level, I must admit that I was a bit surprised at how low it was, thinking the same thing as Terry and nzcarnerd, knowing that the BHP rating at the flywheel was 63Hp. Even assuming a 30% driveline loss (double the standard rule of thumb of 15%), to factor in thicker oils, and old style gear interfaces, plus tire to road wheel interface, the number should have been around 40Hp. However, when I look at a video of the run that my father took, on a few of the down transients from wide open throttle, the engine puffs a cloud of blue smoke, making me think that the rings might not be in the best of shape. That being said the car still runs great and I don't really plan on looking into this right now as I've got some other projects on my plate. A compression test might be in the future if I can sneak it in, but as the car runs and drives so well right now (great oil pressure, no overheating issues) I'm a bit hesitant to start looking into things.


I posted a video edited to the last run (where 29.97 was recorded) to youtube at:


In hitting approximately 50 miles an hour, my speedometer was showing more around 60, which is why I stopped the run where I did. If I had gotten to 60, I can't imagine how wound out the engine would have sounded, as she was screaming pretty good at least to my ears.


Thanks for reading everyone,


Respectfully submitted,





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Not too long ago, and perhaps someone has it, there was a good article published on early horsepower ratings.  What I don't know is what Buick was using in the 20's.  BTW, I work with Rusty.


Here are a couple of pastes to help better explain.  Nothing more than me rearranging the info posted in Wikipedia in a more logical order:


Early "SAE horsepower" (see RAC horsepower)[edit]

In the early twentieth century, a so-called "SAE horsepower" was sometimes quoted for U.S. automobiles. This long predates the Society of Automotive Engineers (SAE) horsepower measurement standards and was really just another term for the widely used ALAM or NACC horsepower figure, which was the same as the British RAC horsepower, used for tax purposes.


RAC horsepower (taxable horsepower)[edit]

See also: Tax horsepower

This measure was instituted by the Royal Automobile Club in Britain and was used to denote the power of early 20th-century British cars. (An identical measure, known as ALAM horsepower or NACC horsepower, was used for early U.S. automobiles.) Many cars took their names from this figure (hence the Austin Seven and Riley Nine), while others had names such as "40/50 hp", which indicated the RAC figure followed by the true measured power.

Taxable horsepower does not reflect developed horsepower; rather, it is a calculated figure based on the engine's bore size, number of cylinders, and a (now archaic) presumption of engine efficiency. As new engines were designed with ever-increasing efficiency, it was no longer a useful measure, but was kept in use by UK regulations which used the rating for tax purposes.

RAC h.p.=25D2n{\displaystyle {\text{RAC h.p.}}={\frac {2}{5}}D^{2}n}{\displaystyle {\text{RAC h.p.}}={\frac {2}{5}}D^{2}n}
D is the diameter (or bore) of the cylinder in inches
n is the number of cylinders[24]

This is equal to the engine displacement in cubic inches divided by 0.625π then divided again by the stroke in inches.

Since taxable horsepower was computed based on bore and number of cylinders, not based on actual displacement, it gave rise to engines with 'undersquare' dimensions (bore smaller than stroke) this tended to impose an artificially low limit on rotational speed (rpm), hampering the potential power output and efficiency of the engine.

The situation persisted for several generations of four- and six-cylinder British engines: for example, Jaguar's 3.4-litre XK engine of the 1950s had six cylinders with a bore of 83 mm (3.27 in) and a stroke of 106 mm (4.17 in),[25] where most American automakers had long since moved to oversquare (large bore, short stroke) V-8s (see, for example, the early Chrysler Hemi).


SAE gross power[edit]

Prior to the 1972 model year, American automakers rated and advertised their engines in brake horsepower, bhp, which was a version of brake horsepower called SAE gross horsepower because it was measured according to Society of Automotive Engineers (SAE) standards (J245 and J1995) that call for a stock test engine without accessories (such as dynamo/alternator, radiator fan, water pump),[31] and sometimes fitted with long tube test headers in lieu of the OEM exhaust manifolds. This contrasts with both SAE net power and DIN 70020 standards, which account for engine accessories (but not transmission losses). The atmospheric correction standards for barometric pressure, humidity and temperature for SAE gross power testing were relatively idealistic.

SAE net power[edit]

In the United States, the term bhp fell into disuse in 1971–1972, as automakers began to quote power in terms of SAE net horsepower in accord with SAE standard J1349. Like SAE gross and other brake horsepower protocols, SAE net hp is measured at the engine's crankshaft, and so does not account for transmission losses. However, similar to the DIN 70020 standard, SAE net power testing protocol calls for standard production-type belt-driven accessories, air cleaner, emission controls, exhaust system, and other power-consuming accessories. This produces ratings in closer alignment with the power produced by the engine as it is actually configured and sold.

SAE certified power[edit]

In 2005, the SAE introduced "SAE Certified Power" with SAE J2723.[32] This test is voluntary and is in itself not a separate engine test code but a certification of either J1349 or J1995 after which the manufacturer is allowed to advertise "Certified to SAE J1349" or "Certified to SAE J1995" depending on which test standard have been followed. To attain certification the test must follow the SAE standard in question, take place in an ISO 9000/9002 certified facility and be witnessed by an SAE approved third party.

A few manufacturers such as Honda and Toyota switched to the new ratings immediately, with multi-directional results; the rated output of Cadillac's supercharged Northstar V8 jumped from 440 to 469 hp (328 to 350 kW) under the new tests, while the rating for Toyota's Camry 3.0 L 1MZ-FE V6 fell from 210 to 190 hp (160 to 140 kW). The company's Lexus ES 330 and Camry SE V6 were previously rated at 225 hp (168 kW) but the ES 330 dropped to 218 hp (163 kW) while the Camry declined to 210 hp (160 kW). The first engine certified under the new program was the 7.0 L LS7 used in the 2006 Chevrolet Corvette Z06. Certified power rose slightly from 500 to 505 hp (373 to 377 kW).


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