Previous in Forum: speed limiter for playground   Next in Forum: Equivalency testing good practice?
Close
Close
Close
6 comments
Rate Comments: Nested
Participant

Join Date: Feb 2008
Posts: 2

bhp of an engine

02/14/2008 2:00 PM

hi to

inetlligents....how the c.c of a engine and bhp of a engine differ from each other....is there any possibilities to beat 32bhp engine with 16 bhp engine????and how????guide me in this.......

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru

Join Date: Sep 2007
Location: Reno, NV (USA)
Posts: 608
Good Answers: 66
#1

Re: bhp of an engine

02/14/2008 2:58 PM

You ask a lot in just a few words!

First, there is no direct correlation between HP and engine displacement; factors like induction, valve timing, and head design play a huge part in HP generation - each one of which is an entire discussion in itself.

Second, what do you mean by beat? Is it possible to achieve a greater top speed than another engine with less HP? Sure, through gearing. If you're asking about in a drag race (the purest form of racing), I would say it is extremely unlikely that in a race between two cars properly set up and driven well, the car with 50% less HP will win, unless the more-powerful car were also much heavier. Just consider the basic definition of power (rate of doing work) and work (force times displacement) - if you can apply a greater force over the same distance at a much greater rate than your competitor, you will win.

__________________
Aequam memento rebus in arduis servare mentem.
Register to Reply
Guru
Popular Science - Cosmology - New Member United States - Member - New Member

Join Date: Apr 2007
Location: 33.49N, 84.19W
Posts: 1475
Good Answers: 3
#2
In reply to #1

Re: bhp of an engine

02/14/2008 3:16 PM

Hi CSM,

You're correct.

Given two identical vehicles, i.e, same weight, gearing, tires, aerodynamics, etc. the 32 bhp car will win. Conversely, the 16 bhp car with half the weight should theoretically tie the 32 bhp car.

In short, external factors aside, more hp, less weight = greater performance.

-John

__________________
All worthwhile programmers know that constants always vary.
Register to Reply
Anonymous Poster
#3
In reply to #2

Re: bhp of an engine

02/14/2008 3:28 PM

I'll disagree on a hp being the deciding factor in a drag race. Drage racing is all about torque, not horsepower. A engine that procuces 32 HP at 10,000 rpm and has only 16ft-lbs. A engine that produces 16 Hp at 1000 has 80ftlb torque so it will accelerate faster.

In drag racing torque is king, in road racing HP is king.

Register to Reply
Guru

Join Date: Sep 2007
Location: Reno, NV (USA)
Posts: 608
Good Answers: 66
#4
In reply to #3

Re: bhp of an engine

02/14/2008 4:15 PM

Figures lie and liars figure...HP & torque are two sides of the same coin.

First, it is highly unlikely that any two sensibly comparable engines would have power peaks 9000 rpm apart. Second, in your example, you do not consider what type of gearing is required to make a 1000 rpm engine competitive. Do the math all the way through and you'll find that after the effects of gearing are accounted for, running at peak power will allow the engine to pull longer and overcome any slight acceleration advantage you gain by running at peak torque. Best case is to generate peak torque at as high an RPM as possible, and to do that you need HP. This guy explains it better than I can.

__________________
Aequam memento rebus in arduis servare mentem.
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#5

Re: bhp of an engine

02/15/2008 6:07 AM
__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Power-User

Join Date: Feb 2007
Location: Aberdeen, Scotland
Posts: 393
Good Answers: 21
#6

Re: bhp of an engine

02/21/2008 9:13 AM

cc refers to the volume of the cylinders in the engine. bhp is a measure of the power produced. Usually the higher the cc the higher the bhp but this isn't a rule. As already pointed out the small engine can often produce more power than a larger one. One way is to increase the bore of the cylinders and decrease the stroke.

My very first car was a Fiat Uno. I know what you are thinking and yes there is a lot of street cred with one of those babies. It had a 1.3 ltr or 1300cc engine and produced about 65 bhp. My very first motorbike was a Honda Hornet with a 600 cc engine but this produced about 95 bhp.

When you say "beat" if you mean like in a race then there is another important fact you should be aware of. As you can see by my examples the power to weight ratio is important. The poor little Fiat wouldn't stand a chance of beating the bike even if the engine produced the same amount of power.

Register to Reply
Register to Reply 6 comments
Copy to Clipboard

Users who posted comments:

Anonymous Poster (1); CSM Engineer (2); Johnjohn (1); MACA (1); PWSlack (1)

Previous in Forum: speed limiter for playground   Next in Forum: Equivalency testing good practice?

Advertisement