Date: Sat, 3 Nov 2001 17:35:38 +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: <00ae01c163f9$01f5b150$035a5a5a@joe>
Content-Type: text/plain; charset="us-ascii" ; format="flowed"
> A diesel has compression ratioes in the neiborhood of 20 to 1 and a
>gasser seldom has more then 10 to 1. That puts a lot of stress on the
>engine. That's why they are less tolorant of higher revs. I've had na 1.5
>and 1.6 vw diesels and they didn't have a lot of power to say the least even
>for golfs and rabbits. However both my past 96 passat tdi wagon and current
>99.5 tdi jetta haves lotts of pep at a usable rpm. With my jetta, at 60 mph
>I turn around 2000 rpm's in 5th gear. I'm told these tdi's will do 145 mph!
>Highest I can confirm is 80 mph how ever as I don't need to go faster. I
>would think you would want around 3000 rpm's at the highest speed you would
>normally want to go, say 75 mph, and calculate from there. Like Frank, I
>would think the best would be a 1.9 TD IDI but don't know much about the
>gearing to comment on that. However I'm quite satisfied with my 84's 1.9
>gasser's preformance.
4-stroke bike engines are often 11:1 or more, and rev to 15000rpm or
more. Twostroke diesel model-aircreft engines rev to the stratosphere.
VW's 1.6 commercial diesels appear to be very low-geared, perhaps
because of the ridiculously small capacity (1.9TDi vans may be
taller-geared). The Japanese tend to go the other way. Tall gearing
is the norm here, and I've had 170kmh out of a Corona 2.0 diesel on
the flat, and 185 downhill in an old Corolla 1.8 diesel, with plenty
left before redline (5000rpm); given a long-enough hill, they'd
probably top 200 (125mph). My Corolla 1.8 van has considerably lower
gearing, accelerates and holds speed uphill better, is no less
economical or slower, but is more noisy. The Estima 2.2 TD will top
160kmh easily enough, and not revving hard (ours is probably out of
tune or worn, and won't reach this speed).
These cars, driven hard, get about 34-35mpg (our gallon is bigger, so
say maybe 40 US mpg). I cannot BELIEVE the claims for 40 US mpg for
diesel Vanagons which I keep seeing on the list!! Or that a Jetta TDi
can get anywhere near to 145mph.
--
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
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