Just something thats been going through my head. Rule of thumb says 10hp per CR point. But what does it say for .1 liter?

Example...

B16A vs. B18C1

B16 has better flowing head and 10.2:1 CR
B18C1 has 10:1 CR

Both cams are about the same.

Not sure how the manifolds compare as I've never bothered to look.

The B16 has 160/111, the B18 has 170/128

The difference in power is small, but big in torque. Being both engines are about the same other than displacement, what are your thoughts on .1L being equal to 10/15?

 

Head flow is almost identical.

Bigger stroke for GSR.

 

i have a b20b4/vtec, built type r head w/ stock 9:1 cr and have 145 wheel tq w/ jdm gsr cams if that helps you any.

 

No, since its not stock it doesn't help much.

 

i think it's like comparing apples to oranges... there will be a lot of variables to consider to understand the correlation of these 2 engines... maybe if we compare a b16 to another bored or stroked b16 (with everything else equal) then there can be a predictable relationship... unfortunately hp is dependent upon the head as well as an increase in displacement and compression ratio...

 

if you had a 1.8l b16 and a 1.6l b16, the 1.8 is going to make more power.

can't really compare different engines though. gsr and b16 heads are way different, different r/s ratios, compression, etc.

"theres no replacement for displacement"

 

In General . . .

The more Liters you have for a particular engine, the more torque you have for a smiliarly designed engine.

HP = (Torque * RPM) / 5252


Therefore, in general HP should also be higher, as Torque and HP are directly proportional.

However, since engine designs are different, just because the engine has more torque doesn't mean it makes more horsepower.

Example is B16B vs. B18C.

B16B has more HP, but less torque compared to a B18C.

This is because the B16B can hold it's torque curve longer and because it holds it's torque at higher RPMS, the HP is higher in the HP = (Torque X High RPM) / 5252

With the B18C, the torque drops off sooner as the RPMs rise.

 

I know the differences in the engines and where power comes from.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">I know the differences in the engines and where power comes from. </TD></TR></TABLE>

than why did you make this post?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">The difference in power is small, but big in torque. Being both engines are about the same other than displacement, what are your thoughts on .1L being equal to 10/15?</TD></TR></TABLE>

 

thats just the thing, both engines are not the same. completely different head and intake manifold design on the b18c1 not to mention the difference in r/s ratio affecting the power curve.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">I know the differences in the engines and where power comes from. </TD></TR></TABLE>

the fact that you made this post and that you are trying to make a linear equation for how much power is gonna increase as displacement goes up shows that you indeed do not.

theres 2 ways to increase displacement and they are very different as far what they do to an engines power levels.

boring the motor makes more cranking power through the entire rpm range because the surface area that the combustion energy is being applied to is increased so theres more force pushign the piston down(same theory as hydraulics )

stroking the motor will make more power at the same rpm level because you are drawing more air into the engine sooner. you are also increasing the leverage on the crankshaft. this is a diminishing return though because the block will overspin the head sooner (pistons will draw air in faster on the intake stroke than the cams/valves/head port size will allow). in general the tq curve will be raised in value but shifted lower into the rpm range.

now both of these methods also have the law of diminishing returns in the head too. b series heads will only flow so much and when we start talking 87mm bore 95mm stroke deckplated engines the head starts to become a limiting factor for airflow (just cant flow enought through the head)

so you see you can just make a generic formula because

a. every engine package is different
b. gaining displacement is only half the story on what happened to the engine as a whole

edit BTW comparing the GSR to the b16 is the worst possible comparison. oh and dont just compare the peak power too look at the whole graph. and actually comparing the tq curve of the motor is actually a better motor/motor comparison than power.

motor to motor try comparing a b16b to a b18c5 or a b18b to a b20b/z b16a to b17a. you can learn alot about engines just by comparing similar honda models to eachother.

another great comparo is the b18c1 and compare EVERYTHING they changed when they made the b18c5. lots of good stuff relating to building a motor as an entire package there....

 

Like I said, I know where power comes from.

Fine, just use a B16B and B18C5 as an example then. All someone has to do is answer the question with their view (not you don't know this or that). The original question was not "construction differences and the power they make", but "how much power per .1L."

 

Confucious say's The only true answer you get is going to be nothing but an average guess.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">Like I said, I know where power comes from.

</TD></TR></TABLE>

fine since you know what your talking about make up a number then

b16a to b18c1 gain 10 hp so 5 hp/.1L
b16b to b18c5 gain 10 hp so again 5hp/.1L
b18b to b20z gain 4hp so 2hp/L

average it out and you get 4hp/.1l

what does this prove, NOTHING all those motors are totally different from eachother! you cant compare peak numbers and make a formula out of it to generalize things like this

 

Average guess was all I was looking for.

JCushing, the average you got from those engines is 3.3hp/.1L.

 

um 5+5+2=12 12/3=4

 

Where the hell did I mess up? Oh well.

 

maybe the ? should have been how much, if any hp do b series gain per .1 aditional liter?

 

That was the question.

 

except it doesnt work like that. its not that simple.

 

The word of the day is general, not exact.

 

Yeah well good luck putting the 'general' knowledge you gain to practical use because it wont happen. There are more factors in making power than just displacement. If youre at all a honda fan, you should know that.

 

Compression ratio, head, cam, intake, header do not have anything to do with making power.

 

compression ratio does have something to do with making power. so do cams and the head. the intake and header free up power thats already there, but the other 3 DEFINATELY make power. You have been officially mis-lead.