found one

[Per Lindgren]

Michael Pederson wrote:

> Per -
> As someone who's playing around with an I5 2.5 - 2.6 liter conversion at the
> moment, (82mm bore, 95.5mm stroke) I'd certainly be interested in knowing if
> any of these 2.4 & 2.5 liter engines were in fact gas vs. diesel power
> plants; and if gas, what the bore & stroke dimensions were and/or a
> crankshaft part numbers.  The Audi/VW diesel engines that I know of were/are
> all 2 valve per cylinder, but I believe at least some of them were turbo
> charged.

Ok, what I can tell you about the Eurovan engines. No gas engines have ever been
turbo'ed by the factory. Almost all diesels are turbo'ed however. There are
three basic gas engines in the Euro-spec 4th generation Transporter (by VW
designated as the T4, which I from now on will use for simplicity). The gas
engines are:
2.0/85 hp (4-cyl)
2.5/110 hp (5-cyl) and
2.8/140 hp (VR6).
A new VR6 is out for 2001, this is the same unit as in Golf and Jetta V6 with
4-valve heads and 204 hp.

There are a lot more diesels out, as these are favoured by (my guess) 95% of the
customers. The diesels look to be:
1.9 D /60 hp (4-cyl)
1.9TD /68 hp (4-cyl)
2.4 D /78 hp (5-cyl)
2.5 TDI /88 hp (5-cyl)
2.5 TDI /102 hp (5-cyl)
2.5 TDI /150 hp (5-cyl)

The three TDIs are the only diesels out for 2001, the V6 is the only gas engine
left.

> I don't know why, but I would have thought +/- 1.5 CR between the AAF and
> ACU engines would have made for more of a power difference than the Bentley
> figures imply to me.  So far as I could determine the change in the CR was
> accomplished with the pistons.  The AAF are deeply dished, while the ACU is
> basically a flat top piston.

The effect of rasing the compression, but still keeping the output at the same
level is probably to lower fuel consumption. They first raise the power by
raising the compression, but after that the fuel managment system can be
adjusted to use less fuel, and stay at the output level they started with. It is
also a possibility that the entire managment system was replaced with the new
engine code. I found that there are 11 different ECUs for the two 2.5 gas
engines, all are Digifant's.

>
>
> I think someone once mentioned, or suggested that some of the 2.4 and/or 2.5
> gas motor info may have to do with a narrow V-5 engine that Audi &/or VW
> &/or ?? were at one time playing about with.  I guess the V-5 configuration
> has one bank of 2 cylinders offset between the 2nd bank of 3.

The V5 or rather VR5 that it really is, is very much alive and kicking! This
engine is a VR6 sans one cylinder which makes it into a 5-cyl. For 2001 it
receives a 4-valve head and now makes 170 hp vs. the previous 150. This engine
is primarly in use in the Golf, Bora (aka Jetta) and NBeetle, but also the
Passat. It is VW's answer to Audi's 2.4 V6. The V5 is not used in the T4.

>  I thought
> there was also an odd ball oval piston VW engine out there in somewhat the
> same displacement range?

I've never heard of a VW engine with oval pistons, but I do know that Honda had
a MC engine with oval pistons and 8 valves per cylinder.

HTH,

PerL