Hondas NA engines

are we forgetting 5.0l touring car v8's that put out 500odd hp at 7500rpm or whatever they spin to??

i wouldn't be so quick to bag out the good old ls1 motor either, it's relatively light, compact and can make very, very good power. don't forget that gm actually switched from a twin cam per bank motor in the old zr1 corvette back to the pushrod setup in the z06.

have a look around for the picture of the modular 4.6l v8 from a mustang sitting next to an older 350ci gm motor... i'm guessing it was an LT1 or something. the pushrod motor was much smaller. so yes, in terms of output efficiency the pushrod motors are probably not going to be quite as sparkling as the ohc designs, but in my opinion they make up for that in terms of packaging and simplicity... i think pushrod v8's have a place in certain cars.

This is an awesome thread, I know this post may seem like spam, but I am just saying this should be made a sticky. You guys have taught me heaps I didn't know. Ahhh, the joys of knowledge :)

Ok seems i made a mistake about the S2000 not being oversquare, after doing some searching I found the following results:

S2000
Bore: 87mm
Stroke: 84

ITR (DC2R)
Bore: 81mm
Stroke: 87.2

ITR (DC5R)
Bore: 86mm
Stroke: 86

Civic Vti-R
Bore: 81mm
Stroke: 77.4

Prelude Vti-R
Bore: 87mm
Stroke: 91

Accord Type R
Bore: 87mm
Stroke: 90.7

Pulsar SSS (SR20DE)
Bore: 88mm
Stroke: 86


Thought it might be interesting just to compare (post info on some other good NA engines if you have it.

But still..........the DC2R is undersquare still turns out to 8,000rpm+ without any problems! :)

Quoted from "The Pursuit of Dreams" from the Engine First Chapter by Tamotsu Kawakami

In 1966, honda came up with another mighty machine in the RC 166, Dubbed an "extreme multi cylinder," its 250cc dohc six cylinder powerplant put out an all-conquering 60ps ans carried Mike "The bike " Hailwood to a perfect 10 out of 10 wins in the 1966 World GP Championship. Over the past 50 years, Honda has often looked at the high-revving world of motorcycles when developing new engines for its cars and vans. Its first sports car, the tiny S500 launched in 1963, had an exquisite four cylinder dohc four carburetor engine that was a natraul extension of experience gained from top level motorcycle making. The Highperformance dohc engine in the S500 caused a sensation in Japan where people marvelled at it, saying it ran like clickwork.
more dribble about F1 which I cant be ****ed typing then this
Recent Genetations Hondas with the Letter R after their name have taken Hondas egine development to even higher levels. Cars like the Integra and Civic Type R have brilliant, customed tuned four cylinder engines built for very high performance and from the outset you feel they were really ment for the track.
With a type R engine, Honda will have changed the piston shape, ligtened the conrod and valve springs , create a new oil supply line, reinforced the valve springs and balanced the crankshaft. The Intake ports and valves seats are handpolished by skilled veteran Honda technicians. this combination of high technology and hand craftwork results in a superb tuning standards. With the integra Type R, the 1797cc capacity stays the same as normal but the perfprmance level ( and sound ) are simply on a different plane. Power of 200ps at 8000 rpm means an outstanding 111ps per liter ! Maximum torque of 18.5 mkg also arrives at 7500rpm.

Nice info there. I think the heart of it lies in Honda's history starting off with motorbike engines and that is what has filtered down to the legendary B-series engines. Afterall that is where VTEC was developed :)

Ohh and for anyone who's doing more reading, you can't go past this article on the legendary B-series

Awesome thread :thumbsup:
i also do agree the theory behind the longer stroke and smaller bore is less resistance to force
having smaller componets eg , pistons and a longer throw would allow these small displacement motors to spin to high rpms with ease and less strain than a bigger bore , short throw motor

PS. was also thinking bigger bore pistons would mean more surface area touching clyinder sleeves = more friction ?

Quote:

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Originally Posted by wynode

......the S2000 not being oversquare......

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I don't get what you mean here Win.

Are you talking about the shape of a piston err...head? Or something else?

Any pics/diagrams to go along with what you have said? I understand better with illustrations. :o

Quote:

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Originally Posted by toE

I don't get what you mean here Win.

Are you talking about the shape of a piston err...head? Or something else?

Any pics/diagrams to go along with what you have said? I understand better with illustrations. :o

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An engine that is perfectly square has its bore=stroke
Over square --> Bore > Stroke
Under square --> Stroke > Bore
:)

i assume they gave the ITR engine a longer stroke because they figured it would be more reliable to stroke it to get more power than to raise the redline another 1.5krpm

-2ds

What tha?

they actually decreased the stroke, increased the rod length compared to the B18A/B motors. Increased rod length results in a more stable engine at high rpm.

Quote:

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Originally Posted by 2ds

i assume they gave the ITR engine a longer stroke because they figured it would be more reliable to stroke it to get more power than to raise the redline another 1.5krpm

-2ds

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Larger diameter doesnt always mean more surface area of contact between sleeves & pistons. Honda are known to alter the shape of the piston skirts and make use of a "ribbed" type design for the area above the ring lands on the piston. For those who have seen a type-R piston, Im sure they would concur.

Even without these design improvements, the increased friction would not be a major factor which would lead to motor failure.
The problem is with side force (thrust) of the rod/piston through the cylinder walls at an angle.
You often see cylinders crack mid-way, this is the reason.

Quote:

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Originally Posted by Mateoo

Awesome thread :thumbsup:
i also do agree the theory behind the longer stroke and smaller bore is less resistance to force
having smaller componets eg , pistons and a longer throw would allow these small displacement motors to spin to high rpms with ease and less strain than a bigger bore , short throw motor

PS. was also thinking bigger bore pistons would mean more surface area touching clyinder sleeves = more friction ?

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