ah, roughly consistent with the ops manual. I can work with that. why didn't the type R get this? before other adders, from the math used when classified:
type R: 195*1.2*11.25 = 2635, tq = 131 lbft (factory) -> 20.1 lbs/lbft tq
S2000 (2.2L): 240*1.15*11.25 = 3105, tq = 162 lbft (factory) -> 19.17 lbs/lbft tq.
that means that the teg has less torque to weight than the S2000, and a smaller engine than is the norm. I'm sure a 100# deduct (after the FWD 6%) would be consistent:
see my next post, and andy's - got the math wrong here.
Corvette's numbers? 10.6 lbs/lbft and 12 lbs/hp at 3085# (205 hp, 290 lbft, 1.25 gain, +150tq/dipslacemnt, +50 DW)
certainly looks fair to me (small sample, but still) and it doesn't even take into account the torque gains in IT trim, which I'm betting the 'vette and other big-bore engines will get more of than the zing-bang hondas.
thoughts?
Last edited by Chip42; 03-01-2012 at 12:23 AM. Reason: added corvette and pwr/wt figures / Andy's post pointed out mistakes
Run those Vette numbers again?
205x1.25.11.25+150=3033--->3035
+50 for DW (that no other car in ITR gets) = 3085
I don't understand your other numbers. 'Adjusted crank hp'?
S2000 is 276hp estimated crank in IT trim / 3005 is 10.88
Vette is 256hp estimated crank in IT trim / 3085 is 12.05
Type R is 243hp estimate crank in IT trim / 2535 is 10.38
This is totally congruent with the extra 150 for torque not factored. Torque to weight can be done too. Your S2000 numbers need some freshening up.
Last edited by Andy Bettencourt; 02-29-2012 at 11:39 PM.
Sorry - 3085, just verified the number we recommended ans that's it.
My pwr/weight for the hondas was wrong and I fixed that (below). also, I used the ops manual process weights to prove a point, which remains valid.
don't know where the other numbers came from, didn't save the calcs. pwr/wt numbers for the vette stay the same (changes in the hundredths).
summing up:
teg R (195*1.2=234 process hp), 2425#, 10.4 lbs/hp, 18.5 lbs/lbft
S2000 2.0L (240*1.15=276 process hp), 3055#, 11.1 lbs/hp, 20.0 lbs/lbft
S2000 2.2L (240*1.15=276 process hp), 3055#, 11.1 lbs/hp, 18.9 lbs/lbft
84 Vette (205*1.25=256 process hp), 3085#, 12.0 lb/hp, 10.6 lbs/lbft
the point is that the ops manual numbers WORK here, and as expected the big torque cars are still strong in terms of weight/tq EVEN AT "HUGE" WEIGHTS. current classification for FWD puts many of them at a weight deficit, the low displacement/torque deduct is missing "randomly" (from the data I have), etc..
benefits: this system seems to work, well. members can understand it because its already published. reworking the cars will balance the field better (based on these numbers). consistent with the rest of IT processes. many cars lose weight.
down side: some classifications will change, some cars gain 50lbs.
we will be rerunning the numbers even if we don't end up recommending them. I will share my portion of that effort here and to anyone who asks.
Last edited by Chip42; 03-01-2012 at 01:00 AM. Reason: added summary
Watching the forums here and in STL the engineers are good at engineering the classes...I will pay you to get power to weight competitive Instead of the pro Porsche shops....light is better. I make the same power as the s2 cars and they run at 2810 vs 3055.
Who wants the retainer?
Last edited by benspeed; 03-01-2012 at 01:45 AM.
BenSpeed
#33 ITR Porsche 968
BigSpeed Racing
2013 ITR Pro IT Champion
2014 NE Division ITR Champion
Thanks Chip. I'll rustle up performance/dyno data on the S2 and the E36. Those cars are making the same power and weigh much less. Proud to submit my build sheet - been a very comprehensive process with top Porsche shops. My beef isn't about power, it's about weight.
Its very interesting to watch the experts work out how a car is classed on this thread, but it also makes me scratch my head and consider how poorly I can play this aspect of the game, hence my joke about paying an expert a retainer to help lobby my case :-)
BenSpeed
#33 ITR Porsche 968
BigSpeed Racing
2013 ITR Pro IT Champion
2014 NE Division ITR Champion
Why would you think we would NOT apply as consistently as we can?
C'mon now, some of this is getting silly.
We've had the DW discussion on the committee. I don't think the committee's opinion is going to change. In my opinion, we are starting with "doing it right" with the Vette. If we do it your way we are going to see the weight change on that car two times over a six month period or so, and the CRB is going to ask (rightfully so) what the hell we are doing.
Yes, there is a downside and yes, there is a bigger picture than this one car.
NC Region
1980 ITS Triumph TR8
Where does the RX8 fall in your new number crunch? Need to decide if I get new glass or lexan.
Steve Eckerich
ITS 18 Speedsource RX7
ITR RX8 (under construction)
And you can tell them the truth. That you went by the flawed Ops manual, didn't recall how cars were classed, and applied an adder when the class didn't currently call for it.
So you humbly admit this, bring the one car in line until the ITAC and the CRB align on a re-do of the whole class. Why? Because the simple fact is you should be considering a strut decuct at these weights instead of a DW adder. But that is just a time and committee thing, I don't so much care either way as long as the class is aligned.
It's really the most simple and fair thing to do. I can't see how you would see it any other way that to avoid a slightly embarrassing situation for the ITAC, unless the ITR redo was published in the next couple months, but that ain't how fast things can get done. ESPECIALLY considering the perceived desire of the ITAC to stabilize the rules for a time-period.
RX-8 is DW front.
Last edited by Andy Bettencourt; 03-01-2012 at 09:52 AM.
Bookmarks