GEN3 Engine Requirements

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PostPosted: Thu Nov 14, 2013 4:10 pm
Weighing about 172 with gear, I would hope we don't end up adding 60# of plates to the lighter weight guys.
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PostPosted: Thu Nov 14, 2013 5:29 pm
Compute a statistical median and add in one standard deviation for the "driver" weight. :D
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PostPosted: Thu Nov 14, 2013 5:33 pm
SRF49 wrote:Compute a statistical median and add in one standard deviation for the "driver" weight. :D


I'd estimate that would give us about 80% to 85% of the drivers able to make weight.

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PostPosted: Thu Nov 14, 2013 11:52 pm
Some data and a couple of thoughts:

http://www.cdc.gov/nchs/data/series/sr_11/sr11_252.pdf

15th percentile weight for US women is 125 pounds.
85th percentile weight for US women is 210 pounds.

15th percentile weight for US men is 153 pounds.
85th percentile weight for US men is 236 pounds.

120# to 230# certainly is a range of drivers that are in the mainstream of the population.

1. If there is a safety issue with a combined weight of 230 of driver and ballast, a lower minimum car weight isn't going to make it any safer for the 230 lbs driver. Does there need to be a maximum car weight?

2. If the car is "ok" with 230 pounds total, but it is not safe to mount 90 lbs of ballast on the current posts, there needs to be an approved method to safely mount the ballast.

Those of you who know me, know that I'm a bit past the top end of that range. I got some work to do. For a scout trip next year I absolutely have to be under 239 or I can't participate. I plan to get down to 230, hopefully lower, back down to 215 like a few years ago, but even at that weight I didn't need ballast. I'd love to start using ballast plates for the first time.

I'm ok with a target in the 220 to 230 range, but a much lower weight would only generate a greater spread of car weights and increase potential speed differences, which I don't think is going to make it safer for anyone.

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PostPosted: Fri Nov 15, 2013 9:45 am
peterjank wrote:
Martinracing98 wrote:
Lee Spuhler wrote:The truth is out there and the solution is simple. Every driver has a physical with the SCCA and every physical has a weight, or more correctly a mass. Pick 100 active SRF drivers at random and averge their mass from their physicals and that is the number. (I am guessing 192#s.)


Average means that half the participants can not make weight. I do not think that is good for a class.


Sorry to be picky, but I think you are confusing average and median. The median would be the weight that exactly cuts a group in half. The average can be biased by outlying values. For example, imagine you have 2 drivers that weigh 140 pounds, one driver that weighs 150 pounds, and one driver that weighs 200 pounds. Their average weight is 157.5 and three of the four can make weight. The median of the sample would be 145 and only two drivers would make weight. My guess is that the distribution of weight for SRF drivers skews to the high side and that more than half of the drivers would make weight based on the average.



Yes, I recognize the difference. Without information otherwise, I was assuming normal distribution.

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PostPosted: Fri Nov 15, 2013 9:51 am
ICE CREAM!!
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PostPosted: Sat Nov 23, 2013 12:21 am
Hey as a 180# driver I'm perfectly happy to accept a new target weight for driver of 230ish and load up the weight plates. As long as the rules permit any drivers under 200# to place the weights anywhere on the chassis :twisted:

Seriously, I'd split the difference. If Gen3 average conversion shaves 100# from the current 1670, split the difference and lower the min 50# to 1620.

I've got reasonable (some repair, not new) body work, Chassis #308, with SCCA wheels and 2 gallons in the tank I need 20# to make 1670. No way should I have to load up and additional 50-60# to target a 230-240# drivers. Sorry guys :(
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PostPosted: Sat Nov 23, 2013 12:41 pm
What has made this class great is the fact that for the most part no one has been handicapped because the rules have been set-up that way. If the 1.9 was set-up to come in at 1670 then the Gen3 should be likewise set-up to reflect the total difference between the two. Do we really want this class to become the same as F1 where only the small guys can be competitive? I'm not sure but there probably isn't a 160 pounder among them and if there is there aren't many. I came into the class knowing I would not be handicapped by my size, just my talent. Now there is a gaggle of little guys asking for that advantage that they don't have now.

That aside I can live with whatever rules come down if I knew what the rules are. If I'm "lucky" in the next few months I may be ask to plunk down $2500, but as this discussion says I don't have a clue if it's a break even deal for me or if I'm going to be at a 50 pound disadvantage to all of you healthy guys!!

So Mike & Erik are you listening? I sure think it would only be fair that we actually know what the weight targets are before we are asked to plunk down our money and make a big commitment for the future. The 11 to 12K I will be investing to upgrade isn't going to break the bank but it's way more than a days wages. I would like to be able to make an informed decision on how much or how little a competitive disadvantage I will be at with the Gen3 before I put down my money.
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PostPosted: Sat Nov 23, 2013 2:00 pm
I don't believe anyone's asking for an additional advantage to be gained with the GEN3, but simply not use the Gen3 conversion as an excuse to make the cars any more ill-handling by over-ballasting the cars. If the Gen3 car is 100# lighter, than drop the current minimum by 100#. If the target is 230 lbs. then fine; but that should be with a car having new bodywork and current chassis (and 2 gallons in the tank) and not with 65 lb. noses and 45 lb. tails/midsections. I suspect that the current chassis, with good/new bodywork would already accommodate a 230 lb. driver without being overweight.

The Ford started out at 1,640 (Renault 1,590) and enough outcries caused the weight to be raised to 1,670, above the delta that would have maintained the same driver weight minimum as the Renault, resulting in a much more ill-handling car than the Renault (having driven a Renault against Fords in the early days I can say that the Ford in the beginning had marginal advantage over the Renault at any kind of handling track.) If the Gen3 upgrade is artificially "detuned" with additional weight, I would have the same argument about the value of the investment.

My vote, again, is to maintain the current minimum driver weight model by simply subtracting the delta between the current and Gen3 configurations from the current weight, or no more than a 230# target minimum weight (whichever is less.) Performance adjustments can always be made in the future, independent of the conversion.
Bob Breton - SRF 51 - San Francisco Region
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PostPosted: Sat Nov 23, 2013 4:11 pm
I'm inclined to agree. 1670 seems to work. Stand Todd Harris and Brian Schofield shoulder to shoulder. Then tell anyone who asks that those two guys are at the top of our class. Then ask that person if they think the weight requirements need to be modified. From that assessment, I think they'd say "sure doesn't look like it to me".
Safety of ballast location for very small drivers could, if deemed to be a big enough issue, be addressed with a supplemental (meaning secondary after the primary ballast spot is filled with x pounds) ballast location in the car designated by Enterprises.

I vote that the Gen3 weight requirements reflect the delta from Gen2 to Gen3. That way, to Bill's point,
no one is caught out by the change.

My .02.
Denny (a big guy)
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