So I’m looking at cars…older ones…and I want some help translating the lingo. A mopar pal of mine is helping but I want to increase my savviness if that makes sense.
My pal told me at inline 6 will have worse power than a V-6. True or false?
Also, what’s the ratio between size of engine and output?
I know this is basic stuff, but I’m having fun with it. Before this I’d simply been the guy who holds the tools while my pal rebuilt engines and such. So plug me in, people.
It varies.
It varies.
Really no other way to answer the questions. There are too many variables to make a blanket statement.
Unfortunately Telemark is correct.
There’s no easy answer.
I guess that’s better than “Unexpectedly **Telemark **is correct.” 
Just ask what is the rated horsepower of this engine at what RPM.
Don’t say anything else and you will seem to be pretty savvy. It will be up to him to find out the actual answer.
Does it really make a difference to your choice?
If you want ‘green’ or ‘good economy’ or ‘sporty with power’ or sporty with handling’ or it must be under a certain price, and on and on ad nauseam.
But you can have a lot of fun learning. Just be ready for a lot of arguments…
As was noted, there are a lot of variables involved. Mass-produced engines in the passenger car market all are subject to certain constraints of drivability, economy, durability, and emissions compliance, and so they tend to have similar power densities. But if you don’t mind having an engine that idles like shit and runs dirty and loud and doesn’t last long, you can achieve ridiculous power densities. Example, my 2013 G37 has a 3.7-liter engine that makes about 330 horsepower. In 2005, Formula 1 cars fitted with a 3-liter engine were making as much as 900 horsepower. The F1 engine revs about three times higher than my G37, and it’s fitted with a turbocharger, and it doesn’t have to comply with emissions or noise regulations. It also doesn’t have to survive for more than a few hours of run time, whereas mine should last for a few thousand hours.
For a 5.7-liter V8 (350 cubic inches), you might expect anywhere from a couple hundred horsepower (see 1984 Chevy Corvette) up to two or three times that, depending on what you’re willing to do to it.
It’s a nonsensical statement. It’s like saying “my dog is larger than your dog” without seeing either dog. The power output of an engine is a function of an insane number of variables, but there is little that is inherently different about a V6 and an inline 6 with the same, exact size, outfitting, and technology - except an inline six will run with less vibration due to having a better harmonic balance. This doesn’t really translate into better performance, but it can make an inline 6 appear smoother.
All other technology and variables equal, additional size generally means additional potential for power production. But as folks have said in here, it varies tremendously (as well as whether you are speaking of horsepower, torque, usable power potential at standard driving engine speeds, etc.) My Kawasaki Ninja has about 8.13 cubic centimeters required for every unit horsepower at peak. My Mustang needs 20.44 cubic centimeters for every unit of horsepower at peak. You could therefore say my bike can make horsepower 2.5 times as effectively as my Mustang. But in absolute power terms my Mustang makes almost 3 times the power due to having a much, much larger engine.
I don’t know what you consider to be an older car.
Generally-speaking -
Assuming equal displacement, an inline 6 is longer and narrower than a V6. The weight distribution could make a difference to overall vehicle design. Longer crankshafts and cams could be subjected to more stress if not properly supported.
A 2 liter inline 4 can produce 60hp or 600hp, depending on turbo chargers, maximized intake air flow, tuning the exhaust for low-end torque or high-end hp, compression ratio, rocker roller bearings, wet/dry sump, plus a bit of nitrous.
A wet sump engine (oil pan under the engine block) is taller than a dry sump engine with it’s separate oil tank, and it’s cheaper to mass produce. Sports cars and racing cars benefit by having a lower overall profile.
Overhead cam engines are taller than side valve designs. Overhead valves produce more HP due to its greater ability to flow more air/fuel into the cylinder.
Higher compression ratios produce more horsepower but may require a slower burning fuel to take advantage of the difference. Higher octane fuel burns slower than a lower octane, relatively-speaking.
Aluminum engine blocks are lighter than cast iron blocks but require a steel sleeve to take the abuse of piston travel and flame spread.
Sometimes, engine manufactures made crappy engines that didn’t stand the test of time. That didn’t mean that vehicle manufactures didn’t put those engines on the street to recover some of the R&D costs. Let the buyer beware.
If you’re talking about cars from the 1980s and before, there are lots and lots of old wives’ tales that now-balding guys in greasy t-shirts firmly believe. And almost all of which were wrong back then, and are certainly wrong when applied to cars from 2000 and newer.
A typical “muscle car” from the mid-late 1960s is slower in every way and handles less well than a family wagon from 2014.
etc.
Come back and tell us a bunch more details about what you’re really digging into and we can help get you started. Right now you’ve asked us the equivalent of: “explain animals to me.” Kinda matters if you’re interested in birds, pets, African big game, rodents, fish, spiders, or dinosaurs.
What **Telemark **said.
Find someone who can explain the difference between horsepower and torque. The two are related but tell you different things, and it’s difficult to explain. The way it was explained to me (and I’m still not certain if it’s accurate):
– more hp = shorter time from dead stop to top speed
– more torque = less difficult to make the wheels turn at a given speed, great for hauling and driving rough/sticky terrain because once you get to X mph, you can maintain it easier with less regard to resistance
You can put a Northstar V8 into a 1750 pound MR2 and it will haul ass. But day to day drivability is compromised.
Turbo = compresses fuel/air mixture so more can fit into the cylinder and go bang = more power. Turbo is operated by exhaust pressure and usually only engages when"asked" (you stomp on the gas). There can be a brief but notable delay between “stomp” and “WHAAAAA!” when moving from a stop.
Supercharger does the same thing as a turbo, but is operated by a belt just like the alternator or air conditioner compresor. It’s always “on” so there is no delay when you stomp the gas. However, the power output is not quite as good as a turbo. In a drag race, a super may beat a turbo off the line but the turbo will soon overtake it.
As noted previously, there’s not much you can do to an old car that will make it better than something new, affordable, and readily available. Which is not to say there is no value in tuning an older car. I know my 87 MR2 will never perform anything close to an Elise or Alfa Romeo 4C. But it is much faster and nimbler than stock, I enjoy it, and it’s a machine that I modified to be how I want it to be.
Higher compression ratio can increase the theoretical maximum efficiency of the engine, but the resultant higher peak pressures and temperatures will also produce greater tendency for detonation. This is when the mixure transitions from a “slow” flame front (a few tens of meters per second) to a supersonic flame front (a few thousands of meters per second). A transition to detonation near the end of a combustion event causes a light “pinging sound” from the engine, and isn’t a bad thing; indeed, it used to be regarded as “the sound of economy.” But heavy knock, occuring when the mixture transitions to detonation relatively early in the combustion event, can cause extremely high peak pressures and temperatures that erode the combustion chamber.
A fuel with a higher octane number is better able to resist this transition to detonation, allowing the mixture to burn at the normal rate. Higher octane number does not mean the fuel has more or less energy, and does not mean that it burns faster or slower, than a fuel with a lower octane number. It’s strictly a measure of how well the fuel resists detonation.
I’ll try.
Most people understand linear force well enough: you push on a thing, and you can make it move.
Less well understood is the fact that when you move or accelerate a thing by applying a force to it, you are doing mechanical work. The amount of work you do is equal to the force you apply multiplied by the distance the object moved while you pushed on it: W=F*D. Along with that, you might also consider how fast that whole thing happened. If the object moved very quickly (V = D/T), then you achieved a high power output: P = W/T, or P = F * D/T, or P = F * V.
Now take that linear understanding and think instead of rotation. Torque is a force applied in such a way as to cause rotation. The amount of mechanical work you do is equal to the torque you applied multiplied by how far the shaft rotated (W = T * #ofturns). The power you develop is related to how fast the shaft rotated while you were applying torque to it (P = T * #ofturnsperminute).
If you’ve ever heard of kinetic energy, it’s relevant here. A vehicle in motion possesses kinetic energy. This energy came from the engine. Want to accelerate rapidly? You need an engine that delivers energy (i.e. performs mechanical work) very rapidly. To say that an engine delivers energy rapidly is synonymous with saying that it has high power output.
That last equation (P = T * RPM) tells you that torque and power are intimately connected. If you have a plot showing torque versus RPM for an engine, then you can calculate what the plot of horsepower versus RPM should look like (or the other way around in reverse).
An engine that produces a lot of torque at very low RPM may have limited power output, but that huge torque at low RPM is very useful for getting heavy loads moving when the traffic light turns green. Diesel engines have this characteristic, and it’s part of why they’re used in large, heavy vehicles like trucks. Vehicles that are optimized for drag races may tune their engines to deliver high torque at some middling-to-low RPM, allowing them to accelerate quickly early on instead of later on.
An engine that produces high peak horsepower by delivering high torque at high RPM is useful for accelerating a vehicle rapidly anywhere except from a dead stop (since it’s hard to have an engine spinning at high RPM when the wheels aren’t moving). High-performance race cars may use engines that spin as fast as 20,000 RPM.
Well, you should start with an understanding of some basic terminology in regards to engine size, or as its usually called ‘displacement’. Measure the volume of one piston cylinder with the piston at the very bottom of travel, then multiply that by the number of cylinders. That’s the engine’s total displacement or ‘size’. Back in the good ole’ days that was kinda all that mattered. Because of complex & efficient computer control cars made in the last 25-30 years are not so cut and dry in regards to engine size equating power.
By the way, cc stands for cubic centimeters. When I was a kid only motorcycles were measured in cc’s (i.e. in metric units). This being because, except for Harley Davidson, there weren’t any US-made bikes. A Honda 750 meant its engine displaced 750 cubic centimeters. American car engine size was measured in imperial units, namely cubic inches (sometimes abbreviated CID for cubic inch displacement). Around the 80s US car makers switched to metric. Because car engines are much larger they use liters not cubic centimeters (one liter equals 1000cc)… And one liter is around 61 cubic inches. I say around (its 61.0237 actually) because since CID was more precise than liters car makers tend to round them off. A 5.0L engine could be 305 or 307 or 301 or 297 cubic inches. But again, because displacement is now only one factor this variance isn’t that important.
everything makes sense when it comes to learning something new.
impossible to predict without knowing the specific engines’ configurations. See, engines are measured for two things, horsepower and torque. horsepower is a measure of how much work the engine can do. Torque tells you what the engine’s best operating speed is, and in something like a car/truck tells you what gear ratios you should use in the transmission/axle.
Now, traditionally inline-6 engines have been used where an engine with a lot of low-RPM torque is desirable. Why? because “torquey” engines are typically “undersquare” (stroke length is greater than bore diameter.) It’s easy to make an inline engine more “undersquare” with a minor increase in height. A vee engine will get a lot wider. It’s one reason those big ass 18-wheel tractor-trailers (semi trucks) all have huge inline-6 engines. yes, they do. in North America, the most powerful heavy truck engine is the Cummins ISX; it’s a 16 liter inline-6-cylinder turbodiesel which puts out 600 hp.
impossible to tell with just those two parameters. You need to know things like bore, stroke, peak piston speed, pumping losses, BMEP, and a bunch of other stuff. I mean, I have a piston engine here which makes 450 horsepower per liter. Only thing is, the piston diameter is smaller than that of my pinky finger.
This has always confused me. Backyard mech that I am.
It would seem that torque and horsepower is simply power at different speeds. I’ve looked at the power curves on the engines that I have. The larger ones having more torque. And frankly, more mass and moving parts to get things going. Makes sense.
Then, from what I have read here, a longer stroke and less bore allows the engine to have more horsepower? Easier on the engine to produce more power at higher RPM? Easier for the engine to change speed at higher RPM?
I think I have it backwards. Longer stroke = more torque
Transmissions and the rear end differential ratio are also important in high performance cars.
Car guys buy and read a lot of magazines to learn this stuff. I bought the car magazines for awhile in high school but got more interested in my guitar and playing music.
The engine configurations that are inherently balanced are inline sixes, flat sixes, and V-twelves.
This is the best explanation of horsepower vs. torque that I have ever seen. I’ve learned a lot from the technical articles on this website, and the histories are well-written and informative.
Actually, this part I knew. Wanna know how I first learned that? When I was shopping for my Impala - 2011 bought used because I’m cheap - I saw several everyday cars rated at 250-300 hp. And in the pilot for “Adam-12” Malloy lectures Reed about the awesomeness of their patrol car and says it pulls 325hp. So I figure things have gotten exceedingly better, automotive technology-wise.
Man, I love Adam-12.
Let’s assume some facts that may be dangerous:
So my pal Tom - the mopar guy in the OP and the one who inspired this thread from 2007 - and I get to talking about cars and he’s telling me I need a hobby and - surprising no one - it should be his. I start tooling around on Classiccars.com.
I set my parameters thusly:
Years: 1958 - 1975
Price Range: 8000 - 15000 (The 8000 low end to weed out parts cars from the results, the 15000 high end because she #6 above)
Within 250 miles of my home city of Charleston, SC
Automatic (while I can drive manual its been a long time and I sucked at it even back then)
Bearing in mind that I want something to occasionally drive around in and to work on the engine and such and not something for heavy use I find myself please with some of the results. I’m semi-turned off by the convertibles because, much as it appeals to my SoCal sensibilities, it just seems to be one more thing that can break.
[ul][li]1965 Mustang $9000[/li][li]1975 Cadillac Coupe deVille $11,000[/li][li]1968 Mustang $12,000[/li][li]1969 Cadillac Coupe deVille $13,900[/li][li]1962 Studebaker Hawk $14,900[/li][li]1973 Lincoln Continental $14,995[/li][li]1963 Chevy Impala $15,000[/li][/ul]
Note that Mopar Tom reccos against the Studebaker as he believes parts will be difficult to find if needed. His choices - and he’s offered to go on the test drives and be a part of the inspection - are the 1963 Impala, the 1969 Caddy and the 1968 Mustang.
Note also that regardless I’m going to have to drop in a custom stereo with bluetooth capability due to work concerns. But I feel confident there are ways to do that without harming the appearance of the car.
Finally, note that this may simply be Tom wanting to expand the time he works on old cars while having me pay the cost. He’s tricky, he is.
OK, the internet ate my previous response that I spent a half-hour writing, and I am not going to repeat it, so here is the Readers Digest Version.
BMW 750iL E38 (1995-2001). Find a one- or two-owner one that was always serviced at the dealership. Get all records (any BMW dealership will have access to any service done by any BMW dealership). Target 150,000 miles. Should cost $6000-$8000. The catch? Maintenance is high. People who bought them new and always had them serviced at the dealer want to sell them because the dealership doesn’t want to service them. Find a independent mechanic who specializes in BMWs. Chances are this will be a guy who worked for a dealership when this car was new. He knows this car. If you maintain it, the maintenance should not cost more than $1500/yr, but in any one year, you may be hit with a $4000 repair. If you fix things as they go wrong, you can avoid major repairs.
The good? This is probably the best high-performance luxury sedan ever build, or ever will be built. The “750” indicates the BMW V12 engine, one of the smoothest, powerful engine put in a passenger vehicle. Don’t settle for a V8. The “L” is for “long”, meaning the back seat is roomier than the front. The 750iL was the Flagship BMW and sold for >$80,000 new, for a reason. It is a cruiser, built for the German Autobahn. Running at 70 MPH for 8 hours isn’t a problem (running at 100 for 12 hours is only a problem because you will have to stop for gas). It isn’t called the “ultimate driving machine” for nothing. I’ve owned Mopar, Chevy, and Ford, but the BMW is without a question the finest car I’ve ever driven.
Really, if a $4000 repair bill on a $8000 car isn’t something that would break you, take a look at it. Ask other BMW drivers, surf the 'net. It’s a fine car and a bargain for what they are selling for. You need to find a good one and a good mechanic, but if you can do that, you won’t be disappointed.
Honda is the world’s largest manufacturer of internal combustion engines. Neat bit of trivia.