your 93's 200hp V8 and a new 310hp V6 is not a fair comparison - your V8 is "de-tuned" - in other words - it COULD easily develop a lot more power than it does - the new V6 is "tuned" to the point that it would take a LOT more money and work to tweak a little more power out of it.

A better explanation to your question would be: compare 2 engines - both develop 300hp.

Engine 1 is a V6 that red-lines (highest RPM it can turn before it starts loosing power then blows up) at lets say 8500 RPM and hits it's 300hp at 8000 RPM. This is said to be a "high rev - low torque" motor.

Engine 2 is a V8 that red-lines at lets say 5500 RPM and hits it's 300hp at 5000 RPM. This would be a "low rev - high torque" motor.

Just for kicks - lets say both motors have the same displacement -

displacement is a measurement of piston diameter X stroke (how far the piston moves up and down) X number of cylinders.

A hi rev-motor would have a larger diameter piston with a short stroke - this allows high revs - remember - this engine doesn't develop 300hp until it hits 8000 RPM .

The high-torque motor would have a smaller diameter piston with a longer stroke - developing it's 300hp at 5000 RPM

Talk about a high-torque low RPM motor - how about a diesel 12 cylinder - 100,000hp at 102 RPM

http://www.boattest.com/resources/view_news.aspx?newsid=3055

 

Look up the FairbanksMorse 10 cylinder opposed piston (20 pistons - you figure it out) scavenging blower assisted diesels for WW-II submarines. 1680 hp at 550 rpm - each of the 4 engines turned a massive variable output generator which either/and fed the batteries/supplied power to the main (electric) motors wound on the propeller shafts. We had 2 batteries of 128 cells each - each cell weighed a ton.

EDIT: Go down to the Lounge for diesel submarine engines.

 

Like Basscatt said, a lot is in the tuning. An engine like yours, tuned properly, likely could crank out at least 300 hp itself. Additionaly, there's the massive technology difference as well. Gotta remember that your V8 is "merely" port injected. I believe (and correct me if I'm wrong) this means that there's an injector for each cylinder intake, at the beginning of each intake, and the fuel is squirted before the proper stroke. The CTS, on the other hand, has sequential multi-port direct injection. This means that each cylinder has its own injector near the spark plug, and the squirt of gas is timed precisely for the proper stroke in the engine cycle (mixing I think). One of my wild ideas is to see if I couldn't find an old Northstar and retrofit it with some direct injection heads If at all possible, imagine the power numbers! GM should totally bring back the ol' N* and fit it with direct injection.

 

Like Basscatt said, a lot is in the tuning. An engine like yours, tuned properly, likely could crank out at least 300 hp itself. Additionaly, there's the massive technology difference as well. Gotta remember that your V8 is "merely" port injected. I believe (and correct me if I'm wrong) this means that there's an injector for each cylinder intake, at the beginning of each intake, and the fuel is squirted before the proper stroke. The CTS, on the other hand, has sequential multi-port direct injection. This means that each cylinder has its own injector near the spark plug, and the squirt of gas is timed precisely for the proper stroke in the engine cycle (mixing I think). One of my wild ideas is to see if I couldn't find an old Northstar and retrofit it with some direct injection heads If at all possible, imagine the power numbers! GM should totally bring back the ol' N* and fit it with direct injection.

They are both "sequential " injected. That is, one injector for each cylinder (multi-port) and pulsed at the proper time for each intake stroke (sequential). The difference is the injector location. One is injected directly into the cylinder (Direct injection) and the other into the intake manifold just prior to the intake valve (port injected) as you mentioned. If I remember correctly the 4.9 was advertized as sequential multi-port injected.

johntaylorny
As you can see, there is no simple explanation. HP is achieved by a myriad of different things.

 

Also a lot of times you can't really judge just by numbers and looking on paper. I've driven a lot of different cars with various output numbers and cyls and each has it's own feel and power. I've driven Buick Park Avenues with the Supercharged 3800 and naturally aspirated which make 240/205HP and BOTH are phenominal. They feel like V8's until you get over 60, but the supercharger helps too. My family has a Jeep Liberty with the 3.7L, which makes numbers almost equal to the naturally aspirated 3800II, but the driving the Jeep is like a chore. :bonkers: My girl friends 2011 Malibu has a 2.4L I-4 with 170HP and it's pretty peppy surprisingly, but you can def feel the engine working harder and not as powerful at speeds above 50. I've driven Northstar cars from 275 to 300HP and they all feel like they have more power than 300 IMO. So smooth, and as you watch the RPM needle torque up to redline you can feel the car put you back in your seat. The "9" engine has rediculous power over 50MPH. It's called obsolete now but I would dissagree till death. Just how "fast" do people need to be going these days? Jeeze.

 

The V6 is probably higher compression. More compression = higher HP. You could rebuild your V8 identical to how it is now but increase compression (with popup pistons, for instance) and you'd have more HP.

It is what you do with those HP that matters. Gear ratios, engine rpms, intake systems all factor in. As some others have said, you are comparing apples to oranges.

 

Just for the record, increased compression does not of itself produce higher horsepower - there are quite a few other mechanical and design changes which must be made to use the increase to advantage.

 

Horsepower numbers are influenced most by air flow. When you get down to the simple basics, an engine is nothing more than an air pump - and the more air you can get in and out, the more power it will make. Period. Mechanical and thermodynamic efficiency, and compression ratio can alter things a little, but it really boils down to that air flow factor...

That said, an engine with more cylinders and higher displacement doesn't necessarily flow better than another engine at a displacement and cylinder disadvantage. Therefore, you can get everything from a poor performing displacement monster to a screaming miniature example.

 

Exactly, well, close. The only way that I know of on a naturally aspirated engine to increase airflow is to increase compression. Compression increases back in the late 50's and 60's (muscle car era) were the #1 reason for the exponential increase in horsepower over previous engines. So I disagree with the above and maintain that the primary factor for HP increases is compression increases.

 

All I can say is "There is no replacement for cubic displacement". I loved my Big Block Corvettes, lots of torque down low and able to twist parts in two at the touch of the throttle. Off idle burnouts, not a problem. Rapid acceleration, not a problem. Passing a gas station, big problem.

 

Another answer to the question "why some engines are higher HP but less cylinders?" is (as has been eluded to if not explained) that HP is not directly related to the number of cylinders.

 

Horsepower is calculated as a component of torque and RPM. So, less torque and a higher RPM would net similar horsepower as a high torque lower RPM motor. More often than not, smaller engines rev higher which is why it seems 6 cylinders seem to keep up but still go slower. After all, the amount of torque helps traverse the RPM range quicker. So, an 8 that hits solid torque under 2000 RPMs will get up and go better than a 6 that hits solid torque at 3500 RPMs. Of course, this can all be offset with gearing and launch capabilities.

 

Can someone explain to me in English the difference in power and torque and why some engines are higher HP but less cylinders? For example my 93 Deville is a V8 but only 200hp and the new CTS is only a V6 and has 310hp. So which engine would be bigger? Is the # of cylinders really irrelevant and you should just look at HP instead? I'm kinda confused. Any explanation would help thx.

I guess that depends on how you define "bigger". Usually, that means C.I.D., not HP or number of cylinders.