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Thread: Spec 911 rule change proposals for 2018

  1. #11
    Junior Member
    Join Date
    Mar 2010
    Posts
    12
    I ran the R7s with the 225 fronts for the first time at the last event, and they were fantastic. The brake balance was dead on with no adjustment from what I was running with the Toyos, and they were fast, predictable, and fun to race on. TVO, Ag, and the others who have been advocating for the Hoosiers were right.

    I support Brian's proposal to allow both sizes, for the reasons stated in Karen's post. We have a chance to try them out for the year in a competitive environment, and people can choose the size of front tire that exacts the least in cost and hassle for each racer. I am concerned about the significant cost attendant with going to a dual master cylinder setup, and would prefer not to have to do that where we have a no-cost option that would avoid that necessity before us already-- the 225. I have been given prices as high as $3500 in parts/$5,000 installed for that conversion.

    As far as I know, Brian and Mat are the only people to have raced the 205s with a conventional single-M/C setup, and they both reported an inability to obtain the proper bias using a proportioning valve. If someone else has run that setup, please weigh in! I do run a proportioning valve, and while I have found it works well to make minor adjustments to bias, it has a really detrimental effect on brake release if it is tuned in very far in pursuit of proper balance. I have tried two different valves, and that characteristic was common to both of them. I have also done a lot of experimentation with different pads, and have found that a very time-consuming and expensive way to try to achieve proper bias. I have a whole bunch of pads I used one day because I guessed wrong about what might work. At bottom, I don’t think a conventional brake system will be a competitive option if we mandate the 205s.

    Another of our members observed that we have several different engine packages, and different approaches to setup, yet we have really good competitive balance among our different cars. There is no reason we can't enjoy the same sort of parity with two optional sizes of what looks to be a great tire. Having a choice appears to offer the greatest good to the greatest number of our members, and would do the most toward getting our SP911 drivers back together again.

    I would oppose the 7000 rpm limit, for the reasons Brian stated.

    Allen

  2. #12
    Senior Member
    Join Date
    Dec 2002
    Posts
    169
    I have a rule change proposal to help address BOP issues.

    current rule:
    b) Minimum weight of cars with drivers is as follows: cars with 2.7 engines 2300 lbs, cars with 3.0 and 3.2 engines 2350 lbs. These weights are at the end of any qualifying or racing session.

    Proposed rule:

    b) Minimum weight of cars with drivers is as follows: cars with 2.7 and 3.0 engines 2425 lbs. Cars with 3.2 engines 2350 lbs. These weights are at the end of any qualifying or racing session.

    Reasoning: Traditionally we have adjusted weights to try to balance the performance of the various legal engine combinations. It's much easier to add weight than to lower weight. We have raced with weights up to 2550 in the days that we used rewards weights. The best 2.7 and 3.0 cars have similar performance and should therefor be the same weights as each other. The best 3.2 engines are currently at a disadvantage. We currently don't have accurate data as to how much less power the 3.2 makes, but we know it's substantial. A 75 lb weight advantage will make substantial progress toward leveling the playing field. The effect on acceleration should be equivalent of about 7.5 HP. The effect on braking an cornering will be minor but add somewhat to the correction of performance. I believe this will be somewhat less than the 3.2 drivers would wish for and somewhat more than the other cars would wish for. In other words it is a compromise and at least a good start. It could be quantified better during the 2018 season and adjusted as needed.

    -Andy

  3. #13
    Junior Member
    Join Date
    Mar 2010
    Posts
    12
    I propose an amendment to Brian Lowrance's proposal for including the 225 R7 Hoosier front tires, to set the maximum front track width at 65.0 instead of 64.5. Reason: with the 225s mounted on my car on Braid wheels with 2mm spacers to clear the 930 calipers and measured using Brian's proposed methodology, my track width is 64 7/8, and as narrow as I can get, I believe. As the author of the proposal, I confirmed Brian agrees with my amendment.

    Allen

  4. #14
    I would have commented sooner on the rules changes by I have been unable to log in up to now. So here goes:

    I shall start with my opinions (fwiw) and follow with my proposals.

    First, If you haven't already, buy Craig's book. It is fantastic. Anyone interested in Porsches or racing won't be able to put it down once they start reading.

    Regarding the engine balance of power. I have posted at length on this in the thread started by Craig so I will only summarize here. Compared to the 3.0, we (Rothsport) are able to make as much or more power with the 3.2 as the rules are now. It appears the scales have tipped to a highly modified 2.7 as the motor to have for the class.

    Next, I support the use of a 225 front tire. They are more fun to drive and will last longer. If you can't make it fit then your car is too low. We have run 225 front and 275 (yes, 275) rears on stock body work for years. I don't care about the brand. We have got the RR's working well up here in the PNW. Its all about alignment and pressure. The Hoosiers are great tires too.

    Keep the wings as they are. Yes, modifying them makes the cars faster. That is not the goal of the class. If we must change something, lets make everyone use the same wing. If you want to go faster try GT racing.

    We racers are always looking for the competitive edge. We always want to exploit the loophole and push the boundaries before someone else does. It is fun and challenging to do and it will always be that way. It is the job of the rules administrators to keep a tight lid on the "box" and to plug the holes as they become known. Our class has fractured because too much creep of the rules, and within the rules has occurred. We are at a tipping point, I believe, where some drastic measures need to be taken if the class is going to be saved. The class was designed and intended to be a relatively inexpensive Spec class where the rewards go to the drivers who performed best that day. It is turning into a GT class. GT classes are a constant arms race of mechanical improvement and operating costs. There are lots of ways to spend lots of money on Porsches. Avoiding that has always been the intention of this class. We all want cars that are fun to drive and fun to race. We want them to be fast, and they are. But, if we allow them to keep getting faster and faster we limit the ability of the class to attract new participants. If we don't have people racing, the class will die. Then what? Then we have expensive cars that we can't race anywhere else without more expensive alterations.

    So here come the proposals. They are all (IMHO) for the good of the class. I am not trying to punish or reward anyone. I really just want the class to succeed and for all of us to have fun racing together.

    1) I propose making ALL cars weigh 2350.

    2) I propose that front struts must be a Bilstein housing. Inserts are free but must be non-adjustable. Adjustable front shocks are very expensive, unnecessary and are an additional barrier to entry for new racers.

    3) I propose a minimum ride height. TBD. I think Andy had the numbers figured out a couple of years ago. Every major series and every spec series in the world has a minimum ride height. It is the easiest rule to enforce and provides the largest cost containment for the least effort.

    4) I propose bringing back the draw. Because it was fun.

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