Chuck I wasn't questioning the rules settings in this case. I was commenting on Mr Hensley's idea that increasing cubic inches, with no other changes, wouldn't result in a better motor. My point was that on the contrary, it results in a better motor across all ranges, not just something like better peak HP or better peak torque.
Still, it's interesting to learn about the thought processes involved in engine aspects of the rules changes. Since the new rules have been published the Vee guys have stayed pretty tight lipped about the motor changes. Secretly they now smile when they go to sleep at night. Some are even openly giddy. Chuck Voboril wrote: > 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. [demime 1.01d removed an attachment of type text/x-vcard which had a name of jwhit.vcf] ________________________________ 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! ***
