John, we started with pro engine builders and their ideas rather than the
other way around.
1915cc did not originally come from the Solo-Vees nor the MAC.
The idea of allowing a 1915cc low compression motor at the same valve size
and caburation as presently allowed was suggested to us by an engine builder
to economically provide our dual goals to both get actual peak HP into the
120 HP range AND to also to provide a wider useable HP operating range ( in
response to CVT envy :->).
The simple displacement-only approach also has the attribute of not
requiring race gas.
The current data we have is that all the legal 1600cc motors out there now
have between 90 and 100 HP under the present rules. We hear a few member
claims of 110 HP and then we have the the John MacDonald stories of 124 or
whatever HP.
There are NO engine builders so far that have said directly to us that they
have built a 120+ HP 1600cc motor with 9:1 compression, 39 mm intake and 32
mm exhaust, and single carb.
If one does simple proportional scaling for HP from increased displacement
with no other adjustments, the 1915cc vs 1600cc would take 100 HP to
119.7HP.
A usual by-product of increased displacement is increased compression, but
in this case, we are restricting it to the original 9:1. This is
accomplished by using the correct thickness shims between the head and
barrel to adjust the compression (just as can be done on a 1600cc motor)
In practice, with everything else remaiining the same, increased HP is
usually less than predicted by straight proportion due to the increased
frction.
Below are more references, if you are interested:
Primo (a top VW engine builder) has said said with a single two barrel carb,
stock exhaust valves and the rest of the package, the motor should be the
mid to upper 90 hp. He said if somebody did have 120 HP, they would easily
be blowing past a motor like this.
Primo also referred to the book he called the "VW hot rodder's
bible". In "How To Hot Rod Volkswagen Engines by Bill Fisher", go to the
dyno chart on page 36. The engine was 94 cc bigger than the Solo-Vee engine
with larger valves than what they have, 40 mm intake and 34 mm exhaust
(Solo-Vee is 39 mm and 32 mm). This dyno report engine also had dual (dual
port) carbs, Solo-Vee only have a single carb. The test shows the engine's
max hp was 109-110hp at 5,700rpm for only 300rpm then drops off. This is
definitely a better package than what the Vee's have and is still only
110hp.
Now, that said, this 1915cc concept can certainly still be disputed in the
input from the membership process.
I suggest providing your assumptions on the engine build-up and your engine
builder/book sources in your letters.
Chuck
From: John Whitling <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: Re: [F500] Re: FM alert, VEE engine magic
Date: Sun, 04 Mar 2007 09:44:35 -0500
Richard
I have yet to find any engine builder that subscribes to the notion that
adding 300cc to a 1600 cc motor (all else being equal) won't add peak
horsepower and torque, substantially across the range. Cubic inches is
very much like compression .. it increases not only some peak HP number
but bumps up the entire range. If you find that engine builder I would
like an email address or phone number so I can hear him say it.
The MAC's resident tech, Chuck, may want to weigh in on this claim you
make. Maybe he can clear up the conception that adding 300cc will not
make a substantially better motor.
________________________________
FormulaCar Magazine - A Proud Supporter of Formula 500
The Official Publication of Junior Formula Car Racing
Subscribe Today! www.formulacarmag.com or 519-624-2003
_________________________________
_______________________________________________
F500 mailing list - [email protected]
To unsubscribe or change options please visit:
http://f500.org/mailman/listinfo/f500
*** Please, DO NOT send unsubscribe requests to the mailing list! ***
