Re: 20V Torque, 2.5L

[Bruce Bell <bbell@csn.net>]

At 01:03 PM 9/29/95 PDT, you wrote:
>GTI Engineering of the UK as well as Oettinger and ABT
>offer a 2.5 L Conversion for the 20V.
>My understanding is they use the stock crank from the
>2.5 5Cyl in the Eurovan/Transporter, and relieve the head
>for the additional throw.  Can anybody comment on this?

Oettinger has had a 5 cyl. 94.5 mm crank for quite a few years. Don't know
what ABT is using. 

The Eurovan crank as I understand it, has a 95.5 mm throw and uses the same
main bearings as all the 2.22 & 2.31 motors. The rod bearings have a
different part number, and thoughts here are they use a bearing designed for
the 159mm rods which are rifle drilled to oil the wrist pin. The Eurovan 's
block is ~5/8" taller than our blocks to accomodate those long rods. My
thinking is that the rod journals are the same size as the Audi so our 144
mm rods would be usable. Pistons? those of you who read EC will remember all
those 2021 liter VW motors Darryl Vittone has made. 8V and 16V. Guess what,
those are the pistons you want. Since the crank is only 1 mm longer in
stroke, you only have to machine the piston by 0.5mm. On the 20 V you need
the 16V pistons Darryl used take the same 0.5 mm off the top THEN remember
to cut the valve recesses a little deaper. Watch your compression ratios
especially is you do not have a knock sensor. A 10 V built this way will end
up with a 10.5 - 10.8 CR. Haven't done the computations for a 20V. 

>It adds at least 30 FtLbs of Torque. Sounds good to me.

The above with 83mm pistons is 2583cc displacement. 185 ft/lbs should be no
problem with a 10v. Opening up the manifolds and head may get you to the 200
hp mark. 

>For the Turbo Fans out there, Oettinger has built 2.5l
>Turbo 20V's, and says the Torque was way over 350 FtLbs/2500rpm
>at street boost settings.
>How did he get that with a non-turbo Crank (reliably)?
>Food for fodder....

How does a forged crank for an Audi turbo differ from the forged NA crank?
VW and Audi cranks are almost impossible to break. 

Bruce

bbell@csn.net (Bruce Bell)