2.5l 5cyl via diesel crank and smaller bore

[JShadzi at aol.com]

Sure, but all I5's make good tourqe, its a tourqey, oversqure motor, check out my dyno graph:

http://www.80tq.com/images/DynoRun090303.gif

The 291whp run ended at 6krpm, but you can use the 256whp graph to extrapolate it.  Once the turbo spools up by 3500rpm, you can see torque hits 250lbs by 3700rpm, and stays above 250 all teh way past 6krpm, peaking at 306 at about 4500.  Also notice that peak torque last for almost a 300rpm range.  Granted a stroker motor would spool this same turbo up sooner, and all the #'s would be a little higher, but you don't need a relative 2.6l to get good torque out of an I5, a 2.2 isn't a gutless, peaky motor by any means.

You'll find similar results with the HP curve as well, broad and flat, this is a LOT of power under the curve, compare this to your favorite NA dyno chart, whole different story, max power is at a very narrow peak quickly rising to it and dropping off from it almost immediately.

I don't want to come across as dis-agreeing with you, because I think we're both saying about the same thing, but a lot of people out there think they need either a big stroker motor or a 20v to make a lot of power, and its just not true, good flow and proper managment of fuel and ignition are the keys to making power in any motor, the size and # of valves are just relative.  Making 300 crank hp on a stock 10v motor is easy in light of the last statement, I'm making some 375crank hp on a stock 10v head and MC2 block and no where nearing a limit.

HTH,
Javad

>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.
>
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>-Cody
>
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>----- 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
>
>
>>This is a multi-part message in MIME format.
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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?
>>
>>
>>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.
>>
>>
>>
>>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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