CKKrause Posted June 15, 2013 Share Posted June 15, 2013 So I have a Spec Boxster racer and am thinking about running in GTS2 when possible. In Spec Boxster, we are not allowed to touch the factory tune, so w/192 hp & 165 Ft/lbs it's hard to be competitive as weight would need to be about 2790 lbs... I know that if Torque is higher than HP you basically average the two, so why not always average the two. For example, in my case the divider in the power eq.... (192 + 167)*0.5= 179.5 vs 192.... The 179.5 being more representative of cars capability.... Just wondering.... -Chuck PS- By the way it's been good to see the positive changes made in the class by the GTS leadership..... Quote Link to comment Share on other sites More sharing options...
JSG1901 Posted June 17, 2013 Share Posted June 17, 2013 Hi Chuck, and thanks for the question. If you search around the GTS forum you'll find several long and passionate discussions about how the GTS power-to-weight formula ought to be modified. While you would like to see torque included for every computation (because that would be somewhat to your advantage), there are others who will passionately argue that torque should never be used. These, not surprisingly, are the folks with cars that make a lot more torque than horsepower, for whom that particular formula would be advantageous. Regardless, the formula we have is the formula we have and there are literally hundreds of GTS cars throughout North America built to take advantage of those rules as best they can. You're in a tough position shared by a number of our racers, guys and gals who have cars they're trying to make fit into multiple classes, whether that be Spec Boxster and GTS2 like you are, or classes from PCA, BMWCCA, SCCA, or some other sanctioning body. Unless you're running a class like Spec Miata that crosses directly over between sanctioning bodies, it's almost impossible to have a car that's ideal for two different classes using two different sets of rules. Unfortunately, in a situation like yours, something has to give. You have to compromise somewhere, and compromise almost always leaves you at some kind of disadvantage to the folks who have built their cars to a single set of rules. That's just kinda how it is. Now, having said that, at 192 hp and 167 ft-lbs, you could run in GTS2 on slicks at 3,072 lbs. That ought to be pretty achievable and, I would bet, be very competitive. Personally, I would gladly race that car in that configuration. A Spec Boxster on slicks (and ballast) won GTS2 at the 2010 Nationals at Miller Motorsports Park, FWIW. Quote Link to comment Share on other sites More sharing options...
JSG1901 Posted June 17, 2013 Share Posted June 17, 2013 Or...did I misunderstand the problem and is 2,790 lbs too high for what you normally run? Regardless, you're still back to the same place...it's hard to be highly competitive when you have to compromise. Quote Link to comment Share on other sites More sharing options...
ILIKETODRIVE Posted June 17, 2013 Share Posted June 17, 2013 Minimum weight for SB is 2650lbs (so +140lbs). Quote Link to comment Share on other sites More sharing options...
JSG1901 Posted June 17, 2013 Share Posted June 17, 2013 Minimum weight for SB is 2650lbs (so +140lbs). Roger that. Still, 140 lbs is not ideal, but it could be worse. My 944 S2 was for all intents and purposes unbeatable in GTS2 from 2008-2011 (35 wins, 3 seconds, 2 DNFs, and 1 DQ out of 41 starts) and the best it ever was, was when the power was down and I was running at ~194 hp (just a touch over 2,800 lbs). The Boxster has better weight distribution, (I would assume) better brakes, and a 20-year newer suspension. Sounds fair to me at 2,784 lbs. Quote Link to comment Share on other sites More sharing options...
CKKrause Posted June 18, 2013 Author Share Posted June 18, 2013 Scott- Thanks for all the feedback... Curious what your torque #'s were/are on the 944 S2? Quote Link to comment Share on other sites More sharing options...
Blitz128 Posted June 18, 2013 Share Posted June 18, 2013 If you have a SPB why not just run in the SPB class... in Texas the class is growing and folks run PCA SPB and also NASA SPB... the rules are the same like SM... Quote Link to comment Share on other sites More sharing options...
rabbit_diesel Posted June 18, 2013 Share Posted June 18, 2013 Hi Chuck, and thanks for the question. If you search around the GTS forum you'll find several long and passionate discussions about how the GTS power-to-weight formula ought to be modified. While you would like to see torque included for every computation (because that would be somewhat to your advantage), there are others who will passionately argue that torque should never be used. These, not surprisingly, are the folks with cars that make a lot more torque than horsepower, for whom that particular formula would be advantageous. Regardless, the formula we have is the formula we have and there are literally hundreds of GTS cars throughout North America built to take advantage of those rules as best they can. You're in a tough position shared by a number of our racers, guys and gals who have cars they're trying to make fit into multiple classes, whether that be Spec Boxster and GTS2 like you are, or classes from PCA, BMWCCA, SCCA, or some other sanctioning body. Unless you're running a class like Spec Miata that crosses directly over between sanctioning bodies, it's almost impossible to have a car that's ideal for two different classes using two different sets of rules. [snip] Yes, if one looks around this forum many words on "(HP+TQ)/2" can be found. At one time, classing in GTS was by WT/HP, later the "(HP+TQ)/2" component was added to the rules. The old forum/website that was in use back when the "(HP+TQ)/2" was first written is long gone, but I found copies on the 'way back machine' and read them. Back then, many GTS car owners were vehemently against the "(HP+TQ)/2" rule, but the rule was instituted anyway. (Some people from that period are still around on this new forum, if you wish to ask them.) The problem with the "(HP+TQ)/2" rule is that it is an error, and now this blunder is enshrined in the GTS rules. As I see it, the people that instituted the rule were trying to put a handicap on the engines with a broad powerband, so that the engines with a peaky powerband could be competitive. The rule they came up with, the "(HP+TQ)/2" rule, totally misses the broad-powerband engines that have their peak torque above 5252 RPM, and is a severe injustice for engines that have their peak horsepower below 5252 RPM --- and in between the amount of injustice varies. Personally, I think it reasonable that the classing rule include a component related to the breadth of the powerband, if it is done in a just manner. (The "(HP+TQ)/2" rule is an attempt at a component for breadth of powerband, but it is a gross injustice at both ends of the RPM spectrum.) Will Quote Link to comment Share on other sites More sharing options...
CKKrause Posted June 18, 2013 Author Share Posted June 18, 2013 If you have a SPB why not just run in the SPB class... in Texas the class is growing and folks run PCA SPB and also NASA SPB... the rules are the same like SM... I run SPB with NASA, (here in the SF Bay Area it's PRC), and with PCA... However, I used to run GTS2 exclusively with an E36 BMW and would like to race with those guys again... -Chuck Quote Link to comment Share on other sites More sharing options...
JSG1901 Posted June 19, 2013 Share Posted June 19, 2013 Scott- Thanks for all the feedback... Curious what your torque #'s were/are on the 944 S2? My torque was pretty close to the horsepower, which was ideal, but that's pretty unusual. A lot of the cars we see here have numbers a lot more like yours. Of course, the folks who concentrate mostly on GTS tend to try to do things to get there numbers more in line...once again the advantage of not trying to serve two masters. Quote Link to comment Share on other sites More sharing options...
Zach H. Posted June 30, 2013 Share Posted June 30, 2013 to be honest i think your current numbers are spot on! throw some ballast in there and bigger tires and you are good to go. also wont we all be done on power due to the alt. change? or is that just me due to my 1980's fuel injection..... Quote Link to comment Share on other sites More sharing options...
autodoctor911 Posted October 15, 2013 Share Posted October 15, 2013 It looks like adding 140lbs and maybe running some stickier DOT tires on some wide 15-16" wheels would make the SpecBoxster quite competitive in GTS-2. You might even consider running it on slicks, even heavier , since some Formula Atlantic radial slicks on some wide 15" wheels would make it fly through the corners. Are you getting 192hp at the wheels? that sounds like a good bit more than stock. Where did you pick up Horsepower? Did just removing the cats and mufflers get you 22HP at the wheels? I would use the Ballast to help balance the car, since it is probably left heavy if you're making weight in SPB without any. You could also limit the HP with something simple like a muffler, or a throttle stop, which may even out the torque and HP a little. I don't see a lower torque number being a disadvantage, except when you can't downshift to decent gear. For the 2.5 Boxster, this is when 1st is too low, but 2nd is too high on a slow corner. Usually only happens in Autocross. If you are at 192Hp at the crank(hopefully not, since stock should be around 200) you might be overweight already. Quote Link to comment Share on other sites More sharing options...
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