Date:         Sun, 4 Nov 2001 11:59:55 +1200
Reply-To:     Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Subject:      Re: engine efficiency, I4s, subies, etc
In-Reply-To:  <ca.11f0507.2915899e@aol.com>
Content-Type: text/plain; charset="us-ascii" ; format="flowed"

>I would also agree that the TDi should not be squandered on the 5.86 ring and
>pinion of the regular N/A 1.6 diesel. Ideal case for a European or SA 5
>speed. If I were to do it, I'd probably go for a Porsche 915 trans and have
>top gear setup for 70 mph at 3000 rpm. Of course, if you are in about $3,000
>for the TDi you will probably match that amount for the trans, rebuild of
>trans and adapter hardware.

The Porsche G50 trans is MUCH stronger, and I just got an LSD G50 ex
Germany for $1200US, less than the US price for a good 915.

>The problem is the strength of the
>Vanagon transmission. As I have often said, the weak link in this vehicle is
>just forward of the flywheel!.... But the question remains, can the
>mainshaft and the 3/4 hub hold up to this. Sullivan either knows or will know
>at least an anecdotal answer (single data point).

Albins in Australia offers gears (customers' choice of custom ratios)
for any rear-engined VW trans; these are wider than stock gears and
are the strongest made anywhere; you won't break them. Their
mainshaft is also thicker than stock, and won't break either. A full
set of gears/mainshaft costs about $1200AUS for a 4-speed van. That's
a lot less than $1200US.

>As to why the torque curves go to hell after 4000 on most automotive diesels,
>I have always assumed that it was a fuel delivery problem. As the injector
>transfer pressure go up, and injectors go electrical, and injection is
>directly into the chamber, the torque curves keep going upward to higher
>values. In addition, the exhaust circuits in most turbo diesels and flow
>characteristics of the turbos are designed foe 1200 to 4400 rpm operation.
>Variable vane technology would enhance this range. So its just money!

Yep. What I want is a direct-injection common-rail DOHC 4-valve TDI
with an 8000rpm redline. They'll come... manufacturers are working on
these engines, and finally coupes and even sporties (don't make the
mistake of confusing the two) will soon be offered with diesel
option, eg the Audi TT. How about a diesel 911? (dunno if Porsche is
considering dieseling...). I can't see why a high-revving diesel
isn't possible, but I doubt the new diesels will be anything like
8000rpm. But they WILL offer AT LEAST as much performance as the gas
versions of the same models.


--
Andrew Grebneff
165 EvansSt, Dunedin 9001, New Zealand
<andrew.grebneff@stonebow.otago.ac.nz>
Ph: 0064 (3) 473-8863 fax: 0064 (3) 479-7527
1986 Toyota Corolla 1.8DX CE80 diesel sedan
1989 Toyota Corolla 1.8DX CE96 diesel van
1989 Toyota Corona 2.0D Select CT170 diesel sedan
1992 Toyota Estima Lucida 2.2 turbodiesel MPV (=narrow "Previa")
1984 VW Caravelle GL (to be fitted with 260hp Subaru SVX flat-6 &
Porsche G50 trans)
Seashell, Macintosh, VW & Toyota van nut