Interesting! Have you all looked at my web site? I have an analysis of rod
ratio for lots of items there. My conclusion is that it really doesn't do an
awful lot for you unless you are a ProStock crew chief looking for the last
once of torque. Look at: http://www.teknett.com/pwp/drmayf/analyses.htm
mayf
----- Original Message -----
From: "Frank Marrone" <itswonderful@attbi.com>
To: <rpalmer@ucsd.edu>; "'Tiger List (Tiger List)'" <tigers@autox.team.net>
Sent: Monday, February 03, 2003 11:04 AM
Subject: RE: Desktop Dyno Fun
> Bob, actually the program does show that the long stroke combinations
> make more low end torque. The difference was small in the cases I tried
> last night but when I exaggerate the stroke spreads you can clearly see
> that the longer cases are best down low. I just tried these three
> bore/stroke combinations for a 306CID engine;
>
> Bore/stroke TQ@2000 TQ@2500 TQ@3000 TQ@3500 TQ@4000
> 4.414/2.5 357 365 381
> 396 406
> 4.030/3.0 364 370 385
> 398 407
> 3.730/3.5 367 372 385
> 397 405
>
> It is interesting to note that the long stroke did not really make
> significantly more TQ than the medium stroke but both the medium and the
> long made a few percent more TQ than the short case.
>
> If you graph the IMEP (indicated mean effective pressure, cylinder) you
> can see the longer stroke configurations making more cylinder pressure
> up to a point between the TQ and HP peaks, then the IMEP converges for
> all three cases and the configurations are basically equal with respect
> to IMEP. The BMEP (brake mean effective pressure, cylinder) looks to be
> mostly a result of subtracting FMEP (friction mean effective pressure,
> cylinder) from IMEP, the BMEP looks to be directly related to TQ. The
> FMEP component seems to be responsible for reducing the difference in TQ
> of the long and short stroke cases in the low RPM end of the plots and
> also for creating a divergence in the TQ curves in the high end of the
> plot where the short stroke configurations are shown to make more TQ.
>
> Frank
>
> > -----Original Message-----
> > From: Bob Palmer [mailto:rpalmer@ucsd.edu]
> > It's interesting too that the
> > program puts the lie to the old notion that long stroke
> > engines produce more low-end torque.
> > Bob Palmer
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