land-speed
[Top] [All Lists]

An interesting study of bore and stroke

To: land-speed@autox.team.net
Subject: An interesting study of bore and stroke
From: Daniel Wright <daniel.wright@genetics.utah.edu>
Date: Wed, 30 Jun 2004 10:53:13 -0600
Hi
In selecting the unspecified components, such as heads, intake, carb, oil 
pan, and headers, I made very conservative choices from the basic default 
selections available.If I swap ONLY the heads I selected (canted stock 
valves, oval ports, mild pocket ported) for something more aggressive like 
canted large valve (2.04-1.95), rectangular ports, fully ported, with no 
other changes except to correct from the incorrect "hydraulic" cam choice 
to "Roller",  (I had missed the "Roller" part of the cam description) I get 
the following numbers.
SS torque peak 677 @ 5500
LS torque peak 698 @ 5500
SS HP peak    827@7500
LS HP peak      850 @ 7500

If I throw in a really radical Roller cam profile, Stepped Racing headers, 
a tunnel ram intake rather than the dual plane unit I had specified, and 
those numbers go to
torque 743 @ 6000
HP      991 @ 8000

I learned years ago, (from reading Hot Rod instead of doing my schoolwork) 
proper selection of heads, cam, intake and exhaust makes or breaks an 
engine build.
As always, I crave more information, what heads are you using? how much cam 
lift??
Dan



>Well, aside from the fact that it's only off by about 150 to 200 hp and 
>about the same lb-ft...
>DF



>Hi
>I ran this information thru the Desktop Dyno computer program.  I got the
>following information, which should be regarded as Desktop Dyno's Opinion.
>The Long Stroke (LS) version made slightly more torque from 2000-3500 RPM,
>then the Short Stroke (SS) version takes over and makes more power from
>3500 thru the rest of the rpm range.
>A few comparison points are
>SS torque peak 524 @ 5000
>LS torque peak 504 @    4500
>SS HP peak     567 @ 6500
>LS HP peak      520 @ 6000
>
>
>I don't intend this as an endorsement of Desktop Dyno Software, it is just
>one way of looking at this comparison.  This computer program makes many
>assumptions in order to simplify the task.  Those assumptions reduce it's
>effectiveness and accuracy, but it does offer some useful information,
>particularly in direct comparison of a single part change.  More
>information on the heads and cam would be helpful.
>If anyone would like a copy of these files to fool with in Desktop Dyno,
>email me off list and I would be glad to email them.
>Dan


Daniel Wright
University of Utah
20 S 2030 E
BPRB Rm 332
Salt Lake City, Ut 84112-9454
email daniel.wright@genetics.utah.edu
801-585-7863
FAX 801-585-7177






<Prev in Thread] Current Thread [Next in Thread>