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Re: 220hp? [All this carb crap]



At 08:04 AM 11/14/2001, Dan Bubb wrote:
>I'm with you on most of this post Jason, but (and I don't know why
>everybody seems to think this) the BMW and Honda engines are not "short
>stoke motors."
>The Acura Type R is in the range of 81mm bore and 87mm stroke, so it's
>pretty undersquare. Not as undersquare as a 2.0 VW, but not much
>different.

Really!?  That's shocking.  But you're right.
I just looked through lots of Specs.  It looks like Hondas once were very 
oversquare, but have gotten longer strokes in the last 15 years since 
multivalve technology has enabled them to breathe so much better.  Interesting.



>The BMW M3 is 3.43" bore x 3.58" stroke.

Yeah, I know that's true -- but if you look at the rest of the engines in 
BMW's stable, they're almost all oversquare:

Model           Bore x Stroke (mm)
E36 325i        84 x 75
E36 318i        84 x 81
E36 328i        84 x 84
E36 323i        84 x 75
E46 323i        84 x 75
E46 330i        84 x 89.6*
E36 M3 3.0      86 x 85.8
E36 M3 3.2      86.4 x 91*

* = undersquare

So really, the only engines that BMW has made for US consumption since 1992 
that were undersquare are the current 330i, the current M3, and the 
3.2-liter E36 M3.

Phew -- I thought I was nuts there for a minute. :)


While looking up Honda specs, I came up with an interesting page.. neat 
reading.
http://www.g-speed.com/pbh/bore-vs-stroke.html


Cool, Dan -- thanks for the info.

Jason



>So, it's not like they have massive valve area for their displacement.
>I'm willing to say that a 2.0 16V can get to 220 HP normally aspirated,
>but it's going to have NO guts below 4500 RPM. Is that "streetable"?
>Depends on how much the power rush will offset the irritation of driving
>an engine with this kind of power curve.
>Dan
>
>16V Jason wrote:
> >
> >Honda and BMW can produce engines
> > with that kind of specific power, but there are many differences.  First
> > and foremost, they have an almost 20-year advantage in technology compared
> > to the VW 16V, which was, remember, one of the first multivalve engines on
> > the market.  Secondly, and perhaps more important, they use 
> a >sophisticated engine management that, in one computer, has complete 
> control >over ignition timing, fuel injection timing (and quantity), and 
> valve >timing.  CIS-E (and Motronic) aren't even in the same league.  And 
> third, >also very important, they're very short-stroke motors.  The 16V isn't.
>
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