Different Specifications. Why?

[fabianyee]

Actually, does the "HP = torque x RPM / 5252" equation works for all engines??? NA and FI.. hmmm..
too lazy to read that much or to do quantitative test to prove or disprove it..


Did a little brief calculation
Case A: HP = 200 , RPM = 3000
Torque = 350 (not sure whether it's Nm or lbft, should be Nm)

Case B : HP = 200, RPM = 6000
Torque = 175

what does it really mean?? hmmm...
Case A seem to be more like the characteristic of a diesel engine. and B is petrol..
So the lower the RPM, better torque u'll get with the same HP...
Better torque translate to better acceleration..
hmmm..

 

[turbology]

Diesel engine doesn't need to rev.. It's good enough as it is..

Yes, when I mean better car computer, I mean in fuel delivery part. 5 years ago, Direct Injection is nearly impossible within mass production car & price range. Computer is not fast enough to process too.
Of course Diesel car doesn't have spark plugs.
And pardon my selection of words: HP is proportionate to TORQUE is more correct, not equal.
Diesel engine doesn't need to rev: is not is good enough, is just because it cannot.
Is easier to utilize gear ratio with wider power curve of Gasoline, then narrow torque curve of Diesel.

Reference:
http://www.allpar.com/eek/hp-vs-torque.html
http://www.vettenet.org/torquehp.html

 

[fabianyee]

heheh.. I think we've somehow hijacked this thread with this petrol vs diesel discussion... Maybe should start a new thread for it..

 

[saat]

heheh.. I think we've somehow hijacked this thread with this petrol vs diesel discussion... Maybe should start a new thread for it..

Seconded.

cheers

 

[mizhan]

perhaps FI diesel shud be compared with FI petrol.. of equivalent cubic capacity, of equivalent boost pressure.