How does cid make power?

[273]

I keep hearing displacement makes power but don't see how so my question Is how?

But let me clarify what I mean, I understand if you raise torque at any
Rpm at that rpm hp will also raise. Torque is obviously heavily related to displacement
If I was to say I'm gonna build a 440 without any other info you could ballpark guess how much Torque will be made. Because torque happens in a narrow range for an naturally aspirated engine 1-1.5:1 lbs-ft per cid and for most engines we deal with would be narrower, your not gonna get 550 lbs-ft NA out of a 100 cid engine but could get 550hp since there about 0.5-5.5:1 hp per cid range.

Torque is basically one powerstroke and hp is the sum of all the powerstrokes added up over time.
So obviously displacement has a huge impact on one powerstroke and only has one powerstroke to do it.
The limit on hp is mechanical limitations and ve% limits of rpm so as long you can keep spinning it higher while filling the cylinders you'll make more hp.


So question is how does displacement makes horsepower?

 

[RustyRatRod]

Cause I say it does.

 

[clementine]

 

[fishmens67]

 

[PRH]

You guys enjoy the popcorn........ I’m taking a nap......

 

[fishmens67]

The longer the stroke and the bigger the bore the engine is capable of pulling in more air and fuel at any given rpm. Thus, making more power.

 

[clementine]

The HP vs torque situation is visualized by me by looking at the whole as an air pump for starters. Then I look at the levers (stroke) and the volume of the air pump (liters per cylinder). The size of the air pump and the size of the internals affect how fast you can spin them. The faster you can spin em, the more horsepower POTENTIAL you have. Plenty of small displacement engines CAN make big power but you got to hold them together. I believe that you wont find many small blocks in dragsters.......but better brains will prevail....this is just me getting my head around it. simple man.

The search function will get you quicker results. This one has been talked about ad nauseum.

 

[Ironracer]

Cause there's "No Replacement for Displacement!" Lol

 

[RustyRatRod]

Cause there's "No Replacement for Displacement!" Lol

Another acceptable answer. lol

 

[Cheapsunglasses]

There’s a couple episodes of Engine Masters that discuss this very well.

But my understanding, engines are air pumps, of course there’s a lot of factors. But the more air you cram in, the more power. There’s ways to achieve this, by volume which is lots of C.I. And then there’s speed with smaller engines, the more you can take in and dump out quickly. That’s why “typically” smaller displacement engines make power at higher rpm, and need more rpm, and bigger engines “typically” operate at lower rpm, and tend to make more torque.

 

[fishmens67]

Cause there's "No Replacement for Displacement!" Lol

When all things are even.

 

[Projectile Dart]

out of a 100 cid engine but could get 550hp since there about 0.5-5.5:1 hp per cid range.

I think you just answered your own question here unless I am missing something. In theory, based on your math, if a 100 cid engine is capable of 550hp, then all things being equal, an engine that is 3x the size is capable of 3x the hp. 300 cid engine is capable of 1,650hp.
I want to see the 300cid engine that hold itself together while making 1,650hp N/A

 

[Ironracer]

Another acceptable answer. lol

Except when a Supercharger is cramming Hemi Heads with a Hillbourne Set up, up top of a Large CID mill....!!!!!

 

[33IMP]

Cause there's "No Replacement for Displacement!" Lol

...... if cylinder head flow and camshaft is compatible. (and boost and rpm are a perfectly adequate replacement! )Displacement ain't dick without a cam and cylinder heads to go with it.
Check out mid war years airplane engines. Land speed record holder- two 22 1/2 liter engines, that's almost 2800cu inches, 900hp total.
Or the Liberty aircraft engine. 1650 cubes, 400hp.
Land speed record holder with THREE of them ran only 207, and managed to kill the replacement driver.

 

[Rat Bastid]

The longer the stroke and the bigger the bore the engine is capable of pulling in more air and fuel at any given rpm. Thus, making more power.

Not exactly, but close. The longer stroke MAY be capable of pulling more air, but if you don’t consider RPM (time) and if the architecture of the engine in question is capable of supporting an induction system to feed it.

In most cases, we are dealing with early 1960’s architecture and they were never designed for huge displacement and RPM.

 

[Rat Bastid]

The HP vs torque situation is visualized by me by looking at the whole as an air pump for starters. Then I look at the levers (stroke) and the volume of the air pump (liters per cylinder). The size of the air pump and the size of the internals affect how fast you can spin them. The faster you can spin em, the more horsepower POTENTIAL you have. Plenty of small displacement engines CAN make big power but you got to hold them together. I believe that you wont find many small blocks in dragsters.......but better brains will prevail....this is just me getting my head around it. simple man.

The search function will get you quicker results. This one has been talked about ad nauseum.

This comes back to what I said about architecture. You can’t expect a small block with its bore centers to compete with a big block and it’s much more spacious bore centers can you?

If we are going to have this discussion (and we should) then there has to be some ground rules. Number one would be looking at the platform we are working with.

 

[273]

I think you just answered your own question here unless I am missing something. In theory, based on your math, if a 100 cid engine is capable of 550hp, then all things being equal, an engine that is 3x the size is capable of 3x the hp. 300 cid engine is capable of 1,650hp.
I want to see the 300cid engine that hold itself together while making 1,650hp N/A

Not really if you 3x the cid with same top end (heads cam etc..) theoretically just move the powerband down about a 3rd of what it was. You would need to triple the airflow.

 

[clementine]

My vote is a 400 smog motor, but Im not the OP. OP? What say you? I have to admit you have gotten more traction on this than I would have guessed.

 

[RAT ROD AL]

VW 1500 cc ( 91.5 CI )engine 53 HP, 78 tq.

426 CI 425 HP... figure it out !

CI = more better !

 

[273]

The longer the stroke and the bigger the bore the engine is capable of pulling in more air and fuel at any given rpm. Thus, making more power.

I wouldn't say at any given rpm, a 400 with run out of steam way before a 289 with similar top end but ya idle to where ever the rpm 289 starts to takes over.

 

[Projectile Dart]

Not really if you 3x the cid with same top end (heads cam etc..) theoretically just move the powerband down about a 3rd of what it was. You would need to triple the airflow.

I meant ALL things being equal, for lack of better wording, 3x the Cid + 3x the heads + 3x the cam.... 3x the airflow... etc

 

[273]

VW 1500 cc ( 91.5 CI )engine 53 HP, 78 tq.

426 CI 425 HP... figure it out !

CI = more better !

Yes cause manufactures don't want to turn high rpm most older engines we deal with
make peak hp between 4500-5500 rpm, so when rpm is kind of fixed idle-5500 ish displacement/torque is the only way NA.

 

[fishmens67]

Ford 7.3 liter 444CI 275 HP and 525 ft lb of torque.
A real powerhouse.
Should we compare it to the 302 Coyote engine. lol

 

[Ironracer]

Ford 7.3 liter 444CI 275 HP and 525 ft lb of torque.
A real powerhouse.
Should we compare it to the 302 Coyote engine. lol

That 7.3 ls a truck mill, ain't it?

 

[273]

I meant ALL things being equal, for lack of better wording, 3x the Cid + 3x the heads + 3x the cam.... 3x the airflow... etc

If you 3x the rpm with 3x airflow same thing, airflow the key component short block is just got to be able to handle it, same hp larger engine trades rpm for torque compared to smaller.