2.0 V10 goodness

[HAULN-SS]

That's not very sure at all

[Evan]

oops, those are actually only 3 liters. They must really suck then

[ultimagtrlover]

oops, those are actually only 3 liters. They must really suck then

This is exactly what I was thinking! We say that engine sucks, but look at the F1 engines...V-10 @ around 3 liters, with anywhere from 800-1000 horsepower, and up to 19,000rpms!!

[G.Irish]

Formula 1 3.5L V10 ~ 1000 hp

[.RJ]

Formula 1 1.5L Turbo ~1200-1400hp (on wastegate sealed shut qualifying laps)

[HAULN-SS]

[G.Irish]

Formula 1 1.5L Turbo ~1200-1400hp (on wastegate sealed shut qualifying laps)

Yeah but those were V6's fool

[.RJ]

Some were 4 cyl

[mpg9999]

i'd be curious to see the advantages of a 2.0 V10 versus a design with fewer cylinders.

as i understand it ususally low displacement engines of that many cylinders have the advantage of placing less stress on the main internal components like rods and cylinders compared to a 4 cylinder of the same size, because there are more cylinders to share the load.

There is less stress (and they can rev sky high) because they use very short strokes. The shorter the stroke the lower the piston speeds. Rod stroke ratio also has alot to do with it.

[Beej]

F-series fo life! most powerful na 2.0L in the worrrrrrld!

[CaptainHenreh]

There is less stress (and they can rev sky high) because they use very short strokes. The shorter the stroke the lower the piston speeds. Rod stroke ratio also has alot to do with it.

That reminds me...I've always wondered about Subarus, and why they don't rev to the ceiling.

Let's look at Jack's motor -- A lowly EJ25:
Bore: 99.6 mm
Stroke: 79mm
Redline: 7000rpm
Bore to stroke ratio: 1.2

Now, let's look at a HoMoCo K24:
Bore: 92mm
Stroke: 90mm (!!!)
Redline: 8000rpm
Bore to stroke ratio: 1.02

or a Nissan QR25
Bore: 88.9mm
Stroke: 100.1mm
Redline: 6000rpm
bore to stroke ratio: .888

On top of that, the H4 is naturally balanced!!! So what gives? Why aren't EJ25's (or NA EJ20's, for that matter) 9000rpm screamers from the factory? I mean, it has a better bore to stroke ratio than either of the two engines I gave examples of yet has the middle redline and the least horsepower!?! What gives?

(and don't even get me started on the st00ks. Undersquare what? No sense at all.)

[.RJ]

rod to stroke, not bore to stroke is important for higher end rev stability

I would ass-u-me the I4 has some inherent VE to it that the H4 does not have, in terms of cylinder filling (and evacuation).

[mpg9999]

rod to stroke, not bore to stroke is important for higher end rev stability

I would ass-u-me the I4 has some inherent VE to it that the H4 does not have, in terms of cylinder filling (and evacuation).

Yup, VE, rod stroke ratio, camshaft profile, and many other things all come into play.

[CaptainHenreh]

rod to stroke, not bore to stroke is important for higher end rev stability

I would ass-u-me the I4 has some inherent VE to it that the H4 does not have, in terms of cylinder filling (and evacuation).

Well yes, I understand that the rod to stroke ratio has more to do with it, but in a 10 minute post bore to stroke was a little easier to find. (Plus, people are always talking about the square of an engine, over under, etc)

Also, you may be correct with the cylinder filling, as the intake vacuum would have to fight for incoming air unless the intake manifolds were divided (which they aint, in the EJ motors...in the SVX's 3.3 they are...but I digress) but for evacuation I can only see H motors being *more* efficient, as there are only 2 cylinders fighting for exhaust space in the collector, not 4. (depending on header design, yaddayadda)

But again, I digress. In my K24 to EJ25 example, the EJ25 has 1.67:1 rod to stroke ratio and the K24 (by my calculation) has 1.68:1. Sooo....where did 1000rpm's go?

I was just curious. It always seemed strange the large amount of torque that the flat motors made, and the relatively low redlines, when on the surface they appear to be more apt to rev higher. Perhaps there's some other intrinsic nuance in the H design that prevents this kind of thing?

[mpg9999]

[mpg9999]

Perhaps there's some other intrinsic nuance in the H design that prevents this kind of thing?

First thing that comes to mind is the valvetrain. I have no idea what kind of valvetrain it has and what it can rev to, but the valvetrain is usually the limiting factor for the redline.

[.RJ]

but for evacuation I can only see H motors being *more* efficient, as there are only 2 cylinders fighting for exhaust space in the collector, not 4. (depending on header design, yaddayadda)

But you need those other 2 cylinders paired up to balance the exhaust pulses to help evacuate the exhaust gasses. I'm sure this could be accomplished with an H motor as well.

Maybe subaru doesnt like to build high revving motors?

4-2-1 ownz j00

[ScottyB]

First thing that comes to mind is the valvetrain. I have no idea what kind of valvetrain it has and what it can rev to, but the valvetrain is usually the limiting factor for the redline.

that brings me to another thought. what's the "real" redline on the ej25? for 1.8T's (since im familiar with them) with their hydro lifters and long stroke, the stock redline is something like 6800 rpm. realistically though, people have pushed the engine into 8000 rpm territory with no ill effects, even including teardowns to look for signs of engine failure at those speeds.

maybe some engines just have conservative redlines, plain and simple.

[ScottyB]

4-2-1 ownz j00

big pipe owns 4-2-1

[.RJ]

haha!