How do Honda engines make so much power?

[funnyfi]

I hope I don't get flames for this for being noob or whatever, I was wondering if anyone could explain why Honda have so much power from their b series engines (b16 and b18 civic type r and integra type r respectively) and the newer k series engines (k20, k24) . I tried googling about this but couldn't find anything.. Looking at engine specs I know that the Honda engines have a higher(?) compression ratio in regard to the 4b12.. Just wondering why our 4b12 has 125kw as opposed to say the k24a in the accord euro which has similar comp ratio but has 140kw..

People say increase displacement =power and torque but the b18c which is a 1.8 has like 150Kw?

I ask this as I'm wondering what the potential is of the 4b12/vrx as an allmotor car for track/circuit.. I haven't been able to find any timeattack/track builds of the VRX on other forums..

[shamrockshirts]

magic

[Graham]

Horsepower sells cars, torque wins races

[ofey]

First off the reason why you haven't seen 4B12s as circuit cars is that it is a relatively new engine. Give it time.

Now to try and add some thought to your considerations.

I would agree with shamrocks that it's a bit of Honda "magic"

You need quite abit more than just looking at numbers to understand all of this. The topic you're seeking to understand is engine tuning which is a dark art (i.e. requires alot of reading an understanding to grasp).

You are on the right track though questioning bore and stroke.

From first principles, the displacement of the engines are dependent on bore and stroke.

Displacement = Pi/4 X bore^2 X stroke X #of cylinders

So since all engines for the purpose of this discussion are inline 4s we can adjust this formula to read:

Displacement = Pi X bore^2 X stroke

If you do this for any of the 3 engines discussed (i.e. 4B12/B18/K24) you will find their displacements.

so the bore(diameter of each cylinder) and stroke (travel of the piston) directly affect the displacement.

The compression ratio increases the proportion of energy which can be extracted from the detonation. Too high and you get unwanted knocking, too low and you're being inefficient as the air/fuel mix is still burning when the piston reaches the bottom of the stroke and the exhaust valve opens.

Which finally takes us to the part the manufacturers don't always discuss i.e. the valving or air flow. Notice on all three engine description pages on Wikipedia, none of them give any "real" information of the valves nor manifolds (intake and exhaust). So it could well be the shape/form and dimensions of these which make the difference.

However, you have to understand that "tuning" these parameters involves manipulating a host of factors but primarily "timing" (MIVEC or VTEC) is the main factor which affects the final figure.

Depending on the drive train warranties and the Eco reporting of each engine, engines are tuned differently coming out of the factories. Remember that the 4B12 is the newest of the lot and has to meet the MOST stringent emission standards whilst the Honda B engine was released at a time when things weren't as bad. Furthermore, most Mitsu's tend to come with 5 yr warranties whilst the Hondas only go for 3yrs. From what we know now through hacking the factory ECUs, we know that the 4B11s and 4B12s were very severely detuned. So they're letting the engines not go as hard but they are certainly capable of going much harder.

Now with tuning, one seeks to optimise valve timing in order to improve burning efficiency. This however will increase the power within a certain range and drop off power at another. So even when you go to a tuner, it would be good to see where he is getting your power. It's much easier to tune for peak power at high REVs but how usable is that? Let's now go back to the specs:

The numbers game:
4B12=
Peak power 125 kW @ 6000 rpm
Peak torque 232 N·m (171 ft·lbf) @ 4100 rpm

K24=
Peak Power: 150kW @ 7000 rpm
Peak Torque: 222 N·m (164 lbft) @ 4500 rpm

B18=
Peak Power: 154kW @ 8000 rpm
Peak Torque: 181 N·m (133 lbft) @ 6200 rpm (98 spec)

Numbers may well be larger but where is all that usable power? Don't let the numbers like kW sucker you into believing higher is better.

Looking at the numbers though, you might also want to consider the track you're going to be driving on? Twisty bendy? or one with a couple of straights so the Honda has a chance to get up to those RPM levels?

I could go deeper into the underlying theory but I suspect this will suffice.

[BR14AN]

[Dire]

Probably a lay-mans version of ofey's post:
As seen here, you can get a fair bit more out of the 4b11/4b12 through a good tune without any major mods. Just because it comes with those power and torque figures that doesn't mean its as good as it can be. Engines are tuned to their requirements.
A lancer is a small-medium family car, its tuned for economy basically, with just enough power to be appropriate.
The first 2 engines you quoted are from cars that have been tuned to be closer to sports cars.
And, the reason an accord has more power than a lancer is tuning again. It is bigger, and probably typically carries more than a lancer, so it tuned to be more powerful.

The reason there is no high-revving powerful lancer type R isn't because the engines suck, its more about company philosophy.
Mitsu likes to use turbos to make their cars faster (evo).
Honda likes to use high-revs (type Rs).
This can amount to many differences in the way the engines are designed, even in economy cars.


Power in cars is a direct function of torque and revs.
So say you took the useless engine out of a smart car and (through magic) made it rev up to 50,000rpm, thereby giving it a crazy power figure. It still wouldn't be faster than anything, it would just change gears later in a drag and make the worst noise in the universe...

So as pointed out, power is quite deceptive.


Also another engine to consider: The F20C from the original S0000, 184kW and redline of 9000rpm, but only 218Nm (Jap spec, the most powerful one).

184kW is almost as powerful as a falcon v6, but because it is so torque-less, if you put it in anything heavier than the tiny S2000 it would be pretty slow (S2000's aren't necessarily very fast anyway which proves my point even more).
High revs and power figures in small cars is what Honda does.



At the same time, you can't judge a car just by its torque either. If the torque band is too small, it might have a high peak torque but none the rest of the time, making it fairly slow.


TL;DR engines are tuned for their applications.
Honda has different philosophies than Mitsu.
Power and torque are not the final say in an engine's ability, merely an indication.

[SAM-24A]

A 4B12 Engine is quite capable of developing Higher Power figures.
As some have already stated, its a case of Tune level, however other Build criteria such as: Build Specification & Induction Technology need to be considered.

The 4B** Range of Engine is not exclusive to Mitsubishi alone.
It is also used by Chrysler Dodge, KIA and Hyundai as part of the GEMA (Global Engine Manufacturing Alliance) which was concieved & established in 2004.
Unfortunately Suzuki was involved in the program in the beginning, but retreated brfore the Alliance was Contractually Arranged,
otherwise the 4B12 would be available in the current Kazashi.

Therefore:

Mitsubishi Lancer 4B12
Peak power 125 kW @ 6000 rpm
Peak torque 232 Nm @ 4100 rpm

KIA Optima 4B12
Peak power 148 kW @ 6300 rpm
Peak torque 250 Nm @ 4250 rpm

Hyundai i45 4B12
Peak power 148 kW @ 6300 rpm
Peak torque 250 Nm @ 4250 rpm

Dodge Caliber 4B12
Peak power 128 kW @ 6000 rpm
Peak torque 224 Nm @ 4400 rpm

Note: Hyundai has owned KIA since late 2007 and commenced fitting the 4B** engines in the KIA's in 2010.
That explains the identical Engine specs.

So why does the 4B12 (code-named "Theta") engines in the Hyundai & KIA's produce more than the Lancer.

Simple 3 Tier Answer:
1) The Compression Ratio:
Mitsubishi = 10.5:1
Hyundai/KIA = 11.3:1

2) Induction:
Mitsubishi = EFI (Electronically controlled Multi-Point Fuel Injection)
Huyndai/KIA = GDI (Gasoline Direct Injection)

3) ECU Tune
Mitsubishi = Conservative.
Hyundai/KIA = More Aggressive.

The Evident Differences & Combination of Higher Compression Ratios - Fuel Induction Method & ECU Tune Level yield more power.

Hope this Clarifies & Answers some of the Myths.

Regards: Sam....

[JaCe]

Are there any other differences between the 4B12's in the respective applications beyond the tune such as internal strengthening, other components, or the obvious less restrictive airflow/exhausts/etc?

[AUSSIECJ]

yeah if the 4b12s have strengthened internals i will be going to turbo town in a few years after my new car warranty is up. i cant be bothered waiting for the driveline warranty to be done

[milobob]

more poweh! less torque!!!

[SAM-24A]

Are there any other differences between the 4B12's in the respective applications beyond the tune such as internal strengthening, other components, or the obvious less restrictive airflow/exhausts/etc?

"NO"

The GEMA (Global Engine Manufacturing Alliance) Program was established to build 4 cyl engines only with displacements of 1.8L - 2.0L - 2.4L only.
All three share identical internal components differentiated by Bore / Stroke only.

The engines are Manufactured and Supplied as "Long Engines" (Rocker Cover to Sump Cover)

Mitsubishi, Chrysler, Hyundai & (KIA) apply their own External Components such as:
Intake Manifolds, Air Box & Intake Scoop.
Exhaust Manifold/Header.
Alternators & A/C Pump.
ECU & Air/Fuel Sensors.
etc, etc, etc.

Sam...

[funnyfi]

thanks very much for the responses! very informative

I have realized recently (maybe since 2 years ago) that KW isn't everything and that torque is important, I used to think it was cool to have a car (honda) that would have a redline of 10k but my cousin who owned a DC2R asked me one day "how often do you get up that high in the revs? daily driving doesn't include that" which made me change the way i think about the numbers.

guess everyone's right so far, still relatively early, guess we'll have to wait and see what the true potential of the 4b12 and NA lancer is!

[SAM-24A]

thanks very much for the responses! very informative

I have realized recently (maybe since 2 years ago) that KW isn't everything and that torque is important, I used to think it was cool to have a car (honda) that would have a redline of 10k but my cousin who owned a DC2R asked me one day "how often do you get up that high in the revs? daily driving doesn't include that" which made me change the way i think about the numbers.

guess everyone's right so far, still relatively early, guess we'll have to wait and see what the true potential of the 4b12 and NA lancer is!

That's why I often refer to Honda's as "Hiroshima Screamers"....

They boast big KW's....but the trade-off is extremely high RPM's which are totally impracticable for sensible street use.

Those high RPM's also promote a costly premature wear factor upon engine & transmission components.


Sam....