Why horsepower doesnt matter...

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badooy
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Why horsepower doesnt matter...

Post by badooy » Mon Aug 18, 2008 10:39 pm

keknya menarik.. ayo seseorang translate & simpulin dong ... hihihi..
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dari http://forums.evans-tuning.com/viewtopi ... 5cac84a9dc" onclick="window.open(this.href);return false;

For the last century, horsepower has been used to describe the power output of the internal combustion engine. The horsepower unit was created by James Watt in the 18th century. Its origin is based from how much power a horse could lift in foot pounds, 33,000 ft-lbs to be exact in one minute. The unit is derived from torque, which is the true measurement of the engine physical power production.

What is strange about the units of horsepower is that it has no physical meaning. Its an arbitrary unit that has no real signficance in describing the characterisitc of the engine. For those that are curious to calculate horsepower:

Horsepower=(rpm/5252)*torque

From this equation you can see that horsepower is nothing more than a contrived unit that is based purely from torque and rpm. You'll notice the number 5252 in the equation, this represents the point at which every dyno graph must intersect horsepower and torque. Its a mathematical relationship, both strange and interesting since horsepower is a function of torque and rpm.

There has been much confusion and rumors across the internet about gaining more horsepower. In essence, gaining more horsepower is gaining torque. If you are after "peak" horsepower, you are interesting in carrying the torque curve as high in the rpm range without falling as possible. You can see from the equation that as the rpm's increase, and the torque remains the same you get a higher horsepower number.

What phsycially is happening is that the engine is able to produce enough torque to overcome frictional forces through the air, tires, etc. As you are able to keep the torque from falling off on the top end, you are able to maintain a steady torque curve that will "pull" the car through the mph you are trying to reach. So people who are after "peak" horsepower really want to extend their torque curves as far towards redline as possible, without letting the torque fall off. Check out some dyno graphs and see what I mean. Horsepower doesnt describe the true nature of how the engine performs, its the torque curve.

From a tuners perspective, I dont tune off of the horsepower curves. The physical relevance towards the engine performance is arbitrary, since the torque is truely what is effected by the fuel, timing, breathing, etc of the engine. The horsepwer is merely a concocted unit of measure, showing no true characteristics of the engine power output. A good tuner will only make changes from the torque curves, see what increase/decrease the curves show from the changes. So next time you are thinking horsepower, think "what would I want my torque curve to be"?

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saitama
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Re: Why horsepower doesnt matter...

Post by saitama » Mon Aug 18, 2008 11:35 pm

wah kalo ini jagonya bang jendral nieehh

kalo HP ga terlalu penting trus yang penting apa dong???

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Re: Why horsepower doesnt matter...

Post by *jarno* » Tue Aug 19, 2008 11:27 am

yang penting, gimana HP itu bisa ditransfer dengan baik ke roda, sehingga handling masih tetap bisa dipertanggungjawabkan, huehue..

yang penting, torsi gede di putaran bawah, jadi ga perlu injek pedal dalem2 tapi mobil dah jalan, ujung2nya irit, weleh.. ini mah buat daily ya, hohoh!!
oldskool japanese warrior

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Re: Why horsepower doesnt matter...

Post by Nawee » Tue Aug 19, 2008 12:58 pm

hrgini di Jakarta ngomongin horsepower, mendingin efisiensi BBM...
hidup JArDM... :mrgreen: :mrgreen: :mrgreen:

General Lee

Re: Why horsepower doesnt matter...

Post by General Lee » Wed Aug 20, 2008 7:58 pm

saitama wrote:wah kalo ini jagonya bang jendral nieehh

kalo HP ga terlalu penting trus yang penting apa dong???
emangnya ane guru bhs inggris.

benar. semua tuner di dunia TIDAK pernah mencari horse power, melainkan torsi. rumus HP bukan itu boss HP=(5252xrpm)/torsi tapi HP=(T.n)/5252
T=torsi
n=rpm
5252=konstanta

rumusnya SALAH.

jadi begini tuner di jepang mulai motor sampai mobil balap selalu mengincar torsi flat. torsi naik pasti tenaga meningkat. tapi power naik blm tentu torsi naik. karena salah satu faktornya adalah rpm. bisa saja dengan torsi lebih kecil rpm ditinggikan, peak power meningkat drastis.
artinya begini sebuah diagram prestasi mesin selalu memunculkan tosi dan tenaga. jika sudah melakukan modifikasi engine kebanyakan yang dlihat adalah tenaga dulu. padahal tidak demikian. seharusnya justru torsi yang harus dilihat. lantas bandingkan dengan sblm melakukan modifikasi.
torsi rata naik smooth mulai putaran bawah hingga peak torque itu yang dibutuhkan.

torsi merupakan kemampuan kerja sebuah mesin sedangkan tenaga merulakan prestasi mesin itu. benar memang apalah artinya tenaga gede.

silahkan buktikan. misal sebuah mesin memiliki tenaga 200 dk dengan torsi 100 nm dan mesin kedua bertenaga 150 dk tp memiliki torsi 150 nm, pasti menang mesin dengan torsi gede. (tergantung settingan rasio juga).

selain dari torsi, mesin juga membutuhkan power to weight ratio yang bagus. sebuah mesin bertenaga 200 dk berbobot 2 ton (artinya 1 dk menghela 10 kg diadu dengan mesin bertenaga 100 dk berbobot hanya 500 kg. (PWR 1 dk membawa beban 5 kg saja). akselerasi hingga top speed pasti memang yang ringan.

makanya diregulasi balap batasan bobot selalu punya angka minimum. begichu.
mungkin ada masukan lain.

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Re: Why horsepower doesnt matter...

Post by meneer » Wed Aug 20, 2008 8:00 pm

ck...ck...ck...edun euy ilmuna :shock:
abiz baca buku apah om?


makanya si ijo bisa irit gitu :mrgreen:
adeindra wrote:wahahahahaha....dasar anak muda masih pada pacar2an...
udah tua....jadi berasa tua beneran nih gue
gara2 pacaran dari kampus ama die eh...langsung jadi istri, kaga ngerasain yang laen deh.... :(


heheheh.,...jadi curhat

General Lee

Re: Why horsepower doesnt matter...

Post by General Lee » Wed Aug 20, 2008 8:03 pm

rumus api, udara, bahan bakar saja. tanyain aja tuh saitama. he, he, he. tp tetap lah GC lebih irit boss. larinya jg dapet lagi.

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Re: Why horsepower doesnt matter...

Post by meneer » Wed Aug 20, 2008 8:06 pm

General Lee wrote:rumus api, udara, bahan bakar saja. tanyain aja tuh saitama. he, he, he. tp tetap lah GC lebih irit boss. larinya jg dapet lagi.
pengen sih maen2 ksono lagi...tapi lagi sibuk nih :)
ntar dah...sebelum puasa yah




OOT lagi nih gw :?
adeindra wrote:wahahahahaha....dasar anak muda masih pada pacar2an...
udah tua....jadi berasa tua beneran nih gue
gara2 pacaran dari kampus ama die eh...langsung jadi istri, kaga ngerasain yang laen deh.... :(


heheheh.,...jadi curhat

General Lee

Re: Why horsepower doesnt matter...

Post by General Lee » Wed Aug 20, 2008 8:09 pm

tak tunggu, deh bos. sekalian ngobrol2. apalagi kalau dibeliin ikan bakar ama saitama. tanbah mak nyoooos. he, he, he

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Re: Why horsepower doesnt matter...

Post by badooy » Wed Aug 20, 2008 11:04 pm

General Lee wrote: emangnya ane guru bhs inggris.

benar. semua tuner di dunia TIDAK pernah mencari horse power, melainkan torsi. rumus HP bukan itu boss HP=(5252xrpm)/torsi tapi HP=(T.n)/5252
T=torsi
n=rpm
5252=konstanta

rumusnya SALAH.

jadi begini tuner di jepang mulai motor sampai mobil balap selalu mengincar torsi flat. torsi naik pasti tenaga meningkat. tapi power naik blm tentu torsi naik. karena salah satu faktornya adalah rpm. bisa saja dengan torsi lebih kecil rpm ditinggikan, peak power meningkat drastis.
artinya begini sebuah diagram prestasi mesin selalu memunculkan tosi dan tenaga. jika sudah melakukan modifikasi engine kebanyakan yang dlihat adalah tenaga dulu. padahal tidak demikian. seharusnya justru torsi yang harus dilihat. lantas bandingkan dengan sblm melakukan modifikasi.
torsi rata naik smooth mulai putaran bawah hingga peak torque itu yang dibutuhkan.

torsi merupakan kemampuan kerja sebuah mesin sedangkan tenaga merulakan prestasi mesin itu. benar memang apalah artinya tenaga gede.

silahkan buktikan. misal sebuah mesin memiliki tenaga 200 dk dengan torsi 100 nm dan mesin kedua bertenaga 150 dk tp memiliki torsi 150 nm, pasti menang mesin dengan torsi gede. (tergantung settingan rasio juga).

selain dari torsi, mesin juga membutuhkan power to weight ratio yang bagus. sebuah mesin bertenaga 200 dk berbobot 2 ton (artinya 1 dk menghela 10 kg diadu dengan mesin bertenaga 100 dk berbobot hanya 500 kg. (PWR 1 dk membawa beban 5 kg saja). akselerasi hingga top speed pasti memang yang ringan.

makanya diregulasi balap batasan bobot selalu punya angka minimum. begichu.
mungkin ada masukan lain.
iyess anda betull.. !!
nih ada lengkap.. http://en.wikipedia.org/wiki/Horsepower" onclick="window.open(this.href);return false;
ayo rangkumin lagi.. :D :D
valkyrie wrote:bener tuh bung jendral, gue coba di simulasi emang gitu, kalo balapan yang paling penting (mesin) :
1. torsi
2. weight
3. rasio
4. HP
5. dll

ga ngeremehin juga handling, soalnya mesin hi tech kaya apa juga pecuma balapan kalo handling nya jelek.... tul ga om2? :mrgreen: :mrgreen:
no. 1 : doa restu ibu... hihihihi... :P

no. 3 : rasio opo to om... gigi? gusi? jam tangan rasio?? :P :P

oot mulu nih.. ayo dibanned aja om momod... :D

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