Date:         Fri, 12 Oct 2001 12:37:57 EDT
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      Re: Torque Curves for Key Vanagon Swap Candidates
Content-Type: text/plain; charset="US-ASCII"

Damian,

Some quick comments below:

In a message dated 10/12/01 8:50:23 AM, dts@XMISSION.COM writes:

<< This isn't quite right.  The 3A is probably a good representation of the

Tiico because they probably have the same length connecting rods.  But

the ABA is a taller engine and has longer connecting rods moving the

torque further down the RPM range.  I think the ABA would launch a

Vanagon off the line better.  The ABA is prefered over the 3A for A1/A2

VW engine swaps because of that low-end torque.

While I have also heard this conventional wisdom, there are three other
significant differences here between the 3A and ABA engines. First, the 3A is
non-crossflow head as compared to the ABA. Torque is significantly enhanced
in the same side reversion geometry at low to mid-range. The real forte of
the cross-flow head comes in on the high rpm side where there are major
enhancements from the improved breathing. Second, the intake manifold for the
3A has a much better flow profile into the head, but the ABA has the long
intake runners that recover torque at low RPM. Finally, the Motronic fuel and
management system is significantly more precise than the CIS-E system of the
Audi, but the injector position in the intake manifold (further back in the
3A) seems to offer a better pattern. Note that the 3A is rated at 121 lbs.ft.
@3200, while the ABA is rated at 122@2600. The lower rpm max torque rating of
the ABA is an attribute of the flatness of the curve. In the end, I would say
that the two engines are within +/- 1.5 lbs.ft. of one another across the rpm
band.


My experience with my newly installed Tiico largely supports Frank's

claims.  I still haven't been allowed to run the Tiico over 4000rpms due

to engine break-in but under 4000rpms it is very similar to the 2.1

waterboxer in power.  It has more power, but not much.  Once I get it up

higher - and - also missing from Frank's analysis - OVER the boxer's

redline - the difference will be more pronounced.

Agreed, the high rpm performance of the I-4 is not to be touched by the boxer
engines. I have often spun my RV engine to 7000 rpm for exciting freeway on
ramp mergings! Even without additional balancing beyond the factory level,
these engines can run all day at 7000 rpm, so long as the oil temps stay in
line. Unfortunately too few of the sedentary listees enjoy the sweet refrain
of a would out four. Very smooth too!


I think the 2.1 waterboxer doesn't get its due:  it is a very well

suited engine.  I didn't do swap because of power I did it for the

reliability of the I-4, the superior fuel economy, and to get rid of

that curse VW called Digifant. >>

Agreed also! I was impressed with the 2.1 L power curve and the fuel
consumption maps. I'm not impressed with the exhaust or the cooling system
block technology. It appears that one more generation of development on this
engine could have resulted is a well matched powerplant. Unfortunately, the
sealing technology and a number of case metallurgy issues suggest that this
block is too marginal for long term reliability. Yeh, yeh, I know that there
are several anecdotal reports of stunning longevity, but the data shows ...

I remain concerned about the transmission as the weak link in all of this!

Frank Grunthaner