[doomsday]

Originally Posted by reignofchaos

I'm talking about cars coming out of the factory with warranty... not those tuned by tuners.

You must be aware that stock JDM cars are restricted by a gentleman's agreement not to advertise over 290 bhp. Hence, even though the Evo is capable to produce over 400 horses on stock turbos, the power is restricted to 286 bhp for the Japanese Market. Even the Nissan Skyline was advertised at 280 bhp from factory; but it was able to produce upto 500 horses on stock turbos (NISMO tuned) Although other stuff like intercoolers etc. needed upgrade; which is also the case with the Evo FQs.

Originally Posted by BUSA

Firstly what tech Honda uses of Vtec, same is used by Mitsu to extract more power and honda does not use FI but Mitsu does and a 2.0L engine from Mitsu tuned can go upto 1000whp

You can check this out a Evo which does a 1/4th mile less then 8 secs, now what you got to say about that.

Buschur Racing - Your source for Mitsubishi racing parts and accessories

Very true. Mitsubishi uses MIVEC. I'm sure that a 2.0 L FI engine can produce 1000 whp and run a <8 secs 1/4 mile. My only point is that it is easier to bump up the power on an FI engine rather than a NA engine. Not what the manufacturers claim and their statistics/warranties etc. I'm not biased towards Honda, if it appears to be the case.

[dustDevil]

Originally Posted by doomsday

2. Number of camshafts:Generally the rule of the thumb is, a DOHC engine will be more efficient than a SOHC engine. However, this efficiency may not just translate to more power being produced from the same engine, but may effect the torque or fuel efficiency as well, since the engine is able to burn fuel more efficiently than an equivalent SOHC engine.

Can you please elaborate!??

[doomsday]

Originally Posted by dustDevil

Can you please elaborate!??

I'll be happy to. Since a SOHC engine uses only one camshaft to control both inlet and exhaust valve operation; the number of valves per cylinder is usually limited to 2 or 3 valves per cylinder. It is also possible to have 4 valves per cylinder using SOHC but this translates into a complicated combination of rocker arms and cam lobe shapes. In a SOHC engine the camshaft is usually in the middle of the head because it has to drive both the intake and exhaust valves, which does not allow the spark plug to be placed in the middle of the combustion chamber (the ideal position).

However, a DOHC engine uses two camshafts, one dedicated to operating the inlet and the other for the exhaust valves. Thus it is easier to implement 4 and above valves per cylinder setup. Sometimes it also allows the engine to rev higher; which is an advantage if you want to extract more power out of a NA engine. A DOHC engine also allows the spark plug to be placed right in the middle of the combustion chamber which allows more efficient combustion.

A DOHC setup also allows for easier and more efficient implementation of Variable Valve Timing. Eg. VTEC, MIVEC, VVTi.

Hope this answers your query.

[ashutoshb]

Now i'm slightly getting to know what it is all about. So the engine size does matters, but a lot of other things as well.

cheers,
Ashutosh

[BUSA]

Now i'm slightly getting to know what it is all about. So the engine size does matters, but a lot of other things as well.

Nope size does not matter, case in point, Mitsubishi Lancer 1.5 produces 87 horses in India and a 1.6L Mivec from Mitsubishi produces 170bhp, all in NA form, bone stock.

[vabs78]

Originally Posted by BUSA

Nope size does not matter, case in point, Mitsubishi Lancer 1.5 produces 87 horses in India and a 1.6L Mivec from Mitsubishi produces 170bhp, all in NA form, bone stock.

The Mazda RX8 produces 220+bhp from a 1.3L engine. Its a Wnakel Rotary engine.

[BUSA]

But that Rotary engine is high on fuel and low on low end torque.

[vabs78]

Originally Posted by BUSA

But that Rotary engine is high on fuel and low on low end torque.

True.
Still 220+bhp reliable power from 1.3L engine is really exceptional.

[BUSA]

Wonder what that 1.3L will do with FI

[doomsday]

Originally Posted by BUSA

Wonder what that 1.3L will do with FI

Something like this:

YouTube - Abel Ibarra 1700 HP RX8 w/ Synchronic WG

and this

YouTube - Boosted rx8 @ 7psi

[sbasak]

Common thinking is that the bigger the engine the more power it makes

Bigger the engine size, usually more torque it produces. By revving engine more, you can get more power.

On a rough calculation, each 1000 cc of petrol engine produces 100 Nm of torque. Usually it is less than that because of some losses.

[arunphilip]

Originally Posted by sbasak

Bigger the engine size, usually more torque it produces.

I agree. The Cedia with a 2L engine puts out 185 Nm. Also compare it against the Sonata and Accord (both V6) which also have high torques.

[Venkatesh.C]

There is a lot of talk about the Means to the end.
It all boils down to this. I assume you know that the cylinder becomes a high pressure chamber of air-fuel mixture before it is lit.
Now, the simplest rule of thumb is,
MORE THE AIR_FUEL mIX, BIGGER THE BANG(WHen LIT) and MORE THE POWER

Now all of what everyone says.. valves, cams, turbos, super chargers, nitrous are only ways to get MORE A-F mix.
Of course there are other issues like thermal flashing, knocking etc to handle. Techies will put in half a dozen sensors to counter this etc etc.

NOW WHY DOES NOT EVERYONE DO IT?
its coz, if we make a 1000cc engine generate 100bhp, the engine will take heavy beating from all the super charged explosions happening in its tiny chamber.
It will result in reduced engine life.
Thats all of it in simple terms.

TOrque i have noticed is more a factor of the engine configuration and not just the CC.
A SQUARE engine (with similar bore and stroke) will have lesser torque than an engine with longer stroke even if they have same cubic capacities.
Lorries and Load Luggers are built to have more torque while bikes (racers) are built with slightly oversquare engines to have a good balance of torque and higher top speed.
engines with lesser torque generally tend to have a lighter flywheel to compensate the lesser power at bottom end and tend to be more free revving.

[diabloo]

2 more factors decide the torque:

1. Fuel type: Petrol or Diesel. Diesel produces more torque & comes fairly early in the rpm band.

2. Technology: For instance, Honda IDSI engine though petrol produces as much torque as a diesel engine and also comes fairly early in the rpm band, like a diesel engine.

Originally Posted by sbasak

Bigger the engine size, usually more torque it produces. By revving engine more, you can get more power.

On a rough calculation, each 1000 cc of petrol engine produces 100 Nm of torque. Usually it is less than that because of some losses.

[dustDevil]

@doomsday: The explanation was totally convincing... thanks!