cylinders and displacement

Have you ever seen something like a 6cylinder with the displacement of a V8. Or a V8 with the displacement of a 6cylinder. So hears the question whats better to have, a car with less cylinders but the the displacement of a big engine? Or an engine with its appropriate displacement? Also what about an engine with less displacement but more cylinders? was that coherent at all?

ferrari 3.6L v8 in the 360modena...

there's some old straight 6's that are pretty big...

it's all about what you want it to do...

think about it...

viper v10... 8L, 10 cyls. do the math per cyl.

same with the ferrari 3.6L, 8 cyls.

it's all about tq, peak revs, and tuning.

one isn't better, it's all about application

"Back in the day" Honda had a 1.5L V-12 as a formula 1 engine.

"Back in the day" Curtiss Jenny four cylinder aero engines (12L in displacement unless I miss my guess) were used in LSR racers.

As far as I'm concerned, the layout isn't what make the power, it's the development of the layout. As for displacement, I'm partial to engines between 3.0L and 5.0L in size. They seem to be the best combination of weight, revs, strength, and packaging.

But then, you can talk rotaries and we throw the whole displacement theory out of the room.

TVR Tuscan 4.6L inline 6

More cylinders/small displacement means higher revs=more hp! less cylinders/big displacement means lower revs=more torque!

Cylinders don't limit how much displacement you have, for instance, the two cylinder engines used in older John Deer tractors are of a displacement larger than the 4-cylinder engines in my cars, and the Mazda Carol used a four cylinder engine but had a displacment of just under 360cc (yes I did just write 360cc!)

my 968 is a 3.0L 4-cyl.

Brabham made a 1.5L V-16 in 1955 (I think) for F1, but they never used it...too unreliable

Actually, I believe you might be thinking of the BRM V-16's which were used. In fact, a BRM V-16 won at Goodwood back when there was a Gran Prix on the old circuit.

Of course, I think that was a 3.0L car since it was back in the FR days of the 50's when the little Cooper-Climaxes were a big deal.

I'm sort of curious that if I were to make my 4.3L into a 4.6, use around the same compression as the Mustang GT (9.6:1 is it?), would the engine itself be faster in a Mustang, slower, around the same?

Originally posted by DeViL
I'm sort of curious that if I were to make my 4.3L into a 4.6, use around the same compression as the Mustang GT (9.6:1 is it?), would the engine itself be faster in a Mustang, slower, around the same?


Well... You can stroke it for sure.

Stroker 4.3l V6 (http://www.speedomotive.com/4.3%20chevy%20v-6%20street%20master.htm\)

Its not cheap, although this is a race bred V6 and wouldnt pass emissions for the life of it, but you can get the idea of stroking it.

It started off as a 262ci block, I believe its now a 272-276ci... around there. Or from 4.3 to 4.45... not much difference. But every bit helps. You could always get a bigger cam for your 4.3l and have the heads port and polished... then supercharge it!:D

way back in the day ferrari had a v-12 that was 1.6 liter that was one of the first cars (might be the first) from them. porshe has a 3.0 4 banger vovlo does a 1.9 5 cylinder

Originally posted by Octagon
Actually, I believe you might be thinking of the BRM V-16's which were used. In fact, a BRM V-16 won at Goodwood back when there was a Gran Prix on the old circuit.

Of course, I think that was a 3.0L car since it was back in the FR days of the 50's when the little Cooper-Climaxes were a big deal.

you're right, it was a BRM...but it was in the early fifties and I'm almost positive it was a 1.5L supercharged engine.

porshe has a 3.0 4 banger

my car:D if I ever take the head off I'll post picks.

Originally posted by Octagon
But then, you can talk rotaries and we throw the whole displacement theory out of the room.

MUA HA HA HAAA!!

Had a 1967 GMC Moving truck in the back yard when I was growing up. My dad disliked the neighbors, LOL. He painted some of it back to white with a paint brush and KILZ white primer after he was done priming the house.

Anyway, had a 401ci V-6. For those of you who aren't familiar with the math, that's a 6.6L V-6. RPMs? Not many, hehe.

Get into the sportbikes now. 4cyl 0.6L's. They make wicked power for their size too. About 100rwhp or right around 185hp/L. They have to crank over 12,000rpms to do it though.

Oversquare engines are generally superior for max rpm and peak power, while longer stroke engines generally have more low end torque. Doesn't always work that way though as there are a ton of factors around it.

Come to think of it, I think suzuki built a couple 50cc four-cylinder engines for racing, and they were 2-strokes too:)

Originally posted by DeViL: I'm sort of curious that if I were to make my 4.3L into a 4.6, use around the same compression as the Mustang GT (9.6:1 is it?), would the engine itself be faster in a Mustang, slower, around the same?

Ford lies a lot about compression ratios, and I'm not exactly sure why? The new GT's have a 44.75cc combustion chamber, and 18.5cc dish to the piston. The cylinder displacement is approximately 574.46cc. So 574.46+44.75+18.50 = 637.71cc/63.25 = 10.0:1 CR. At least that's the information I have on them.

The Gen I GT's had a I think a 57.5cc combustion chamber with a 10.5cc dish or long story short, 9.4:1 CR.

The 4.3L makes 160-180hp stock in the S-10, barring the Syclone. Adding the additional 18ci and the compression wouldn't get the same power the 4.6L SOHC engine has peak IMHO. The 4.3s torque might match the 4.6L though, at least the Gen I, but not the PI cars.

Well, Ford had an inline 6 that displaed 300cis even, or 4.9 liters... Isuzu makes a 4 liter 4 cylinder diesel, and a 6 liter 6 cylinder as well. GM now makes an 8.1 liter V8, don't they?

The 3.0 engine in the 968 is a beautiful little engine, I'd love to put one in a 924S one of these days :D Do you have pictures of your 968?

Still I'd be pretty interested to race to see. Chevy 4.6L V6 vs the 4.6L V8, both fitted in Mustangs. Thing is though the Chevy is a cast iron block with one camshaft where as the Ford is aluminum and two cams.

GT's have a cast iron block, aluminum heads. :)

Isn't the Caddy Northstar a 4.6L? It'd clean up the SOHC 4.6L Ford, but it'd have a real tough time with the 4V.

Originally posted by Cbass
Well, Ford had an inline 6 that displaed 300cis even, or 4.9 liters... Isuzu makes a 4 liter 4 cylinder diesel, and a 6 liter 6 cylinder as well. GM now makes an 8.1 liter V8, don't they?

The 3.0 engine in the 968 is a beautiful little engine, I'd love to put one in a 924S one of these days :D Do you have pictures of your 968?

Most interesting thing about the 300ci I-6 and it's 4.9L displacement is that technically the 302ci V-8 aka 5.0 also displaces 4.9L, though it was nicknamed the 5.0 to avoid confusion with the I-6 engine.

The 351W isn't a 351 either. It's technically a 352, but again, Ford didn't want it confused with the old FE 352 Y block from the 50s.

Really, didn't know that. Ok so even better both are cast iron blocks. Yeah I think Cadillac does a 4.6L V8. It puts out around the same as the GT.

The Northstar makes 275hp/300lbft or 300hp/295lbft depending on tune... It's a wonderful engine, the only downside is it's engine management system only works with the auto 4 speed.

Originally posted by erricer
More cylinders/small displacement means higher revs=more hp! less cylinders/big displacement means lower revs=more torque!

This isnt exactly right... The only thing that limits 'revs' is the stroke length and the ability of the valvetrain to handle the rpm's. F1 cars have 10-12 Cylinders and rev to 13k+.

Big displacement can be reached two ways, with a bigger bore, or a longer stroke. With a longer stroke you will increase power and displacement and the sacrifice of higher rpm's.

This topic is a lot more intricate then some of you are leading the others to believe. Please dont let the blind lead the blind.

Originally posted by V8Terror
The only thing that limits 'revs' is the stroke length and the ability of the valvetrain to handle the rpm's.

Big displacement can be reached two ways, with a bigger bore, or a longer stroke. With a longer stroke you will increase power and displacement and the sacrifice of higher rpm's.

Blang. A longer stroke will mean the rods will be moving a greater distance in each revolution, which obviously means if they're moving further in the same amount of time, they will move faster, which is more stressful. If you spin a short stroke engine and a long stroke engine of the same displacement up to the same RPM, the long stroke will have higher rod speeds.

Also a longer stroke will have more of an angle between rod and crank which makes the rod more likely to break when subjected to the same forces as a short stroke.

Originally posted by ldelaysionl


Also a longer stroke will have more of an angle between rod and crank which makes the rod more likely to break when subjected to the same forces as a short stroke.

Unless the rod itself is longer (for a more shallow angle)

Originally posted by Unit 5302
GT's have a cast iron block, aluminum heads. :)

Isn't the Caddy Northstar a 4.6L? It'd clean up the SOHC 4.6L Ford, but it'd have a real tough time with the 4V.

The new Caddy Northstar is a 4.6 4v 320hp.

The 4v Cobra engine is 320hp.

Of course it'd clean the SOHC the Caddy is a DOHC...

Originally posted by DeViL
Still I'd be pretty interested to race to see. Chevy 4.6L V6 vs the 4.6L V8, both fitted in Mustangs. Thing is though the Chevy is a cast iron block with one camshaft where as the Ford is aluminum and two cams.

the mustangs are sohc. the cobra is dohc. i think.

Yeah I'm talking about the GT not the Cobra.