Re: Technical question: VANOS

["Allan Williams" <allanw@xxxxxxxxxx>]

It seems I should have though my answer out more thoroughly.

It may be superior, but it all depends on what you are trying to acheive. I
suggest you try a VTEC DOHC Honda... thaey are still not imensely tourquey
when compared to a "normal" Honda engine with the standard head on it. The
VTEC has amazing top end power, but you sound like a dickhead screaming
through town at 6K+ just to stay up there in the peaky power.

If you step into a Vanos 325i from a standard one, you'll immediatly notice
the difference at low rpms, while the high speed power feels the same. It is
VERY noticable in an auto 320i!!!

Anyway, BMW were not trying to get 100 bhp per litre with the 325i - that's
what the M3 was for.

I'm not sure if your models are the same as ours (Not sure where you are
anyway). We have the Euro model BMW's, and usually our Hondas are Jap spec,
or better (usually no emmisions, or speed limiters on NZ new models until
very recently, still not law though).

VTEC has three stages, low end boosts tourque and provides economy (slow),
midrange brings on the power, and loses some economy (drivable), the top end
provides full power, and forgets about economy(racy, peaky engine)

The BMW system allows the valve timing to be infinitely varaible between two
points. Porsche used a similar system on the 968 (It effectively changed the
length of the timing chain on either side of the cams.

They all work anyway :-)

Allan.

- ----- Original Message -----
From: Michael Ting <lupin@domain.elided>
To: Allan Williams <allanw@domain.elided>; BMW Digest <bmw-digest@domain.elided>
Sent: Thursday, August 17, 2000 6:55 AM
Subject: Re: Technical question: VANOS


- ----- Original Message -----
From: "Allan Williams" <allanw@domain.elided>
To: "Michael Ting" <lupin@domain.elided>; "BMW Digest" <bmw-digest@domain.elided>
Sent: Wednesday, August 16, 2000 2:55 AM
Subject: Re: Technical question: VANOS



> BMW's Vanos is to boost low rpm torque... that's why the *peak* figures
> don't really change. The engine has a *LOT* more low down torque.

So VANOS boosts low torque. Or I can say flatter torque curve.

> Honda uses the technology to turn a high revving gutless motor, with a
VERY
> high power figure, and insane RPM levels into a drivable motor. The Vtec
> makes it much more drivable -

Basically what you're saying is, Honda uses the technology to turn a high
revving-high power figure into a drivable motor. To make it a drivable
motor, it needs more low torque, or flatter torque curve. Right?


> Hondas system doesn't have extra cams, it has extra lobes on the current
> cams,

My mistake there.

> Vanos and Vtec acheive two different objectives. A broad torque curve, and
a
> high peak power level.

I'm confused here. What are you saying? VANOS is for broad torque curve, and
VTEC is for High peak power level? But didn't you say VTEC makes Honda's
high revving engine more drivable??

Anyway,
>From what I understand, VANOS only boost low end torque, and makes the
torque curve flatter. But max figure remains practically unchanged. Sorry if
I didn't make this clear in the first email.

On the other hand, VTEC provides low end torque, AND some high end torque
and higher HP.

The VTEC sounds superior to me.



Michael Ting
- --------------------

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