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Writing a letter to SCCA/PAC re: high comp. rotors !HELP!

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Writing a letter to SCCA/PAC re: high comp. rotors !HELP!

Old 07-22-04, 10:07 AM
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Exclamation Writing a letter to SCCA/PAC re: high comp. rotors !HELP!

I need some help here since I've never written a letter to the SCCA or the PAC (preppared advisory commitee).
I don't have a rule book, so I don't know the exact wording of the rules, but I thought it said something about not "changing the volume of the working chamber". I'd like to get that line removed. It's the piston equivelent of higher compression pistons, so I don't see what the problem is.
I have a friend on the PAC, and he brought it up during their meeting. Here's the minutes from the meeting:

"Alternate rotors for Rotary motors
Steve's friend is encouraged to write a letter. Be specific, its possible that rotor changes weren't allowed on purpose. That may or may not still apply today, but the PAC needs more information from the requestor as well as some history lessons as to why the rules read as they currently do."

Any help you guys can give me would be apreciated. I need to move fast if we want to get it into the books for 2005.
Thanks
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Old 07-22-04, 10:53 AM
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Ok. Here's the problem. If they allow high comprssion rotors where are you going to get them? It's not like Weisco makes a set. It's a moot point for turbo cars and for an NA you're only option is the RX-8 rotor. Last time I checked Mazdatrix was making less power with the RX-8 rotors in the EProd motor.
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Old 07-22-04, 11:04 AM
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You could modify the stock rotors for higher compression. Or fix the rx8 rotor situation with better sealing.
Why is it moot for turbo cars. If this rule were changed they could run 9.7:1 rotors and gain some low end torque (always a good thing for autocross).
I don't think availability is the reason they are illegal. The point is rotarys should be allowed equivalent mods as a piston motor.
cams = porting
pistons = rotors
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Old 07-26-04, 08:03 AM
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Does anyone know what the compression ratio would be if the pocket was completely filled in?
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Old 07-27-04, 12:30 PM
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YEARS ago Racing beat made and sold high compression rotors: "Didn't work, we don't make them anymore." is what they said afterwards.
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Old 07-27-04, 03:21 PM
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Originally Posted by Travis R
Does anyone know what the compression ratio would be if the pocket was completely filled in?

A good idea, except for one little itty bitty detail:
WHERE DO THE SPARK PLUGS GO!!!
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Old 07-27-04, 04:24 PM
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How is any one going to find out you have the 9.7 rotors, so how are they going to protest you?
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Old 07-27-04, 09:02 PM
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When you win constantly, LOL.

Hey Travis get a rulebook so you can quote the existing verbage and propose a well-worded modification to it, using phrases such as "in order to stay competitive..." etc.

I have been musing on high-compression concepts for my dead S5 NA which I plan to auto-x and therefore abide by some rules someday. I think it would take some very skilled welding and then tricky machining to modify the existing rotors, and then some very careful tuning to not kill them. According to Paul Yaw,

http://www.yawpower.com/febtech.html

a basic problem with the Wankel design is the long narrow combustion chamber. Making it smaller from the rotor side would make this worse. And don't forget, higher compression increases risk of detonation by it's very nature. But if it's done right it could be some screaming NA power...
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Old 07-27-04, 10:02 PM
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I have been thinking about this one a little more. The working volume of an engine is the maximum volume minus the minimum volume (this is usually called the displacement of the engine.) The combustion chamber volume is not the working chamber volume, so changes in compression ratio do not apply to this rule.

I joined SCCA back in 1979.
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Old 07-28-04, 07:44 AM
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I have a copy of the rule book. Here's the line:
17.10.R.2
The capacity of the working chambers shall not be changed.
speedturn, your interpretation might be correct. But I need to know for sure... If so, why didn't they just say "displacement"?
Most of the other rules are intended to keep the engine the same displacement, so I interpreted that rule to be about comp. ratio.
For grins here are the other rules:
R.1. No changes in the epitrochoidal curve of the motor are permitted.
2. (see above)
3.The eccentric shaft may be replaced with another of the same basic material, but no changes in the eccentricity or bearing journal dimensions may be changed.
4.Rotors are unrestricted, provided the material and number of lobes remains unchanged.
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