2.5l 5cyl via diesel crank and smaller bore

[Cody Forbes]

Ok cool. I know its still small and wont be a mega torque v8 style, but I
was extremely impressed with the dyno chart on the motor in the article I
had mentioned. Torque came up quick and stayed level for most of the run,
above 300lb/ft from about 3000rpm (cant remeber exact number but it was
under 3500rpm for sure), and stayed above 300lb/ft until well past 6000rpm.
Peak torque was in the high 400s. I would think that good tuning was part of
this, but the extra stoke no doubt played a big role.


-Cody



----- Original Message -----
From: <JShadzi at aol.com>
To: ""John Cody Forbes"" <john at craincorporated.com>; ""Audifans Q-list""
<quattro at audifans.com>
Sent: Thursday, September 11, 2003 11:20 AM
Subject: Re: 2.5l 5cyl via diesel crank and smaller bore


Hey Cody, yes, Marc is correct in his info.  There is an idea that the
95.5mm crank is a diesel crank, but in the US the 95.5 crank is out of the
gas Eurovan motor, this fits quite well inside the "low-deck" I5 block (the
EV block deck was 1.6cm taller than the standard I5 block), you'll need to
clearance the block to get it to fit, and of course re-address the
piston-rod geometry (there are a lot of options, realistically you can use
stock rods and have custom pistons made to fit), but other than that its
quite straight forward.

Don't forget, even a mega stroker motor is still "only" 2.5-.6 liters, this
small motor is never gonna be a big tourqe monster, if anything you can use
the extra displacement to spool up a given turbo quicker than in a 2.2,
which works quite well.

Javad


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>I was reading an article the other day (for the 40th time) about a 500+hp
Dialynx 20v that used a diesel crank to bump up the stroke, then they
lowered the bore to get it to 2.5l. I was wondering about simmilar
combinations for my MC motors. Any BTDT with a diesel crank in an MC to get
some torque? I know of some diesel 5cyl cars arround that I can snag a crank
from, but what fits and what doesn't? Are there any OEM rods that go with
the combo to keep low compression, or do I have to go to Pauter/Carillo?
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>Thats one thing I really love about Porsche. Theres 4 katrillion
combonations of stuff from the parts bin that work to get you the exact
thing you want. My 914-6 2.5l race motor for example uses a 2.4l 911 crank,
2.0l 911 rods, top secret ;-) OEM Porsche heads, 904 oil pump, and it all
fits inside just about any 911 case from '69 through the '80s. How great is
that? If we go to a small track we build a motor with a longer stroke,
smaller bore, same displacement (+/- 25cc), to pull out of the corners
better, go to a big one like Sebring or Daytona and you build a big bore
short stroke so you can wind the tach clear off the dial up on the high
banking. All on OEM Porsche parts. Thats what I call a beautifull parts bin.
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>Cody Forbes
>2x '86 5ktq
>'87 5ktq - EFI is mostly on, gota touch up wiring and finish fuel lines
hope to run her by the end of the week.
>'88 80 4cyl - Awaits 5ks EFI so it can get out of daily driver status and
get some much needed attention.
>Hey wait the 914s count as VAG! I wont even get statred on that one (have
too many cars, but thats what you get having been raised at your fathers
Porsche shop/race team).
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