N1XRR Posted June 16, 2009 Posted June 16, 2009 Just starting to get track time after several years of working. Pretty exciting stuff, and although I'm a ways off I started playing with the classification of my car. Something isn't working out right. The issue I see is with the base classing. The TT rules have a stock 13B RX7 listed as 2800lbs comp weight. I weighed my car at the track a several weeks ago, 2635 lbs...with me in it and ~10 gallons of fuel. Came out to 2425 all alone. A few stats: '86 Base model A/C removed (35 lbs of weight) Custom exhaust (30 lbs less than stock exhaust) 4-point roll bar (additional weight, not sure how much) No rear carpet or spare tire A few other cars for comparison: Model - Weight, power, power/weight (factory power output, comp weight) MR2 (2nd gen, NA) - 2657, 130hp, 20.4:1 944 (83-87) - 2779, 150hp, 18.5:1 E30 325 - 2855, 168hp, 17:1 280Z - 2800, 150hp, 18.6:1 240SX - 2700, 155hp, 17.4:1 RX7 (NA) - 2800, 146hp, 19.1:1 Those are all RWD strut cars, so what's the difference? They are all TTF**, except the RX7 which is TTE. Am I missing something here? Shouldn't there be a separation between the '86-88 and 89-91 RX7's? 86-88 N/A RX7's had a 146hp engine, 89-91 had 160hp. The heaviest N/A RX7 was the '91 base model...power everything, rear wiper, adjustable suspension and its rated at 2787 curb weight. The '86-88 base models where lighter. Quote
mbuskuhl Posted June 16, 2009 Posted June 16, 2009 Shouldn't there be a separation between the '86-88 and 89-91 RX7's? 86-88 N/A RX7's had a 146hp engine, 89-91 had 160hp. No. While your facts are correct, the rules allow for updating/backdating within the spec line for no points. There is no separation in other race series either. You can add the S5 intake, rotors or the whole motor if you want. If you are still running the S4 intake, at least swap to the S5 intake. It can be done in a weekend and cheap. It will get you up to 15rwhp depending on the rest of your setup. I agree the RX-7 is not classed that well in PT, it is not given any favors. You have to really think to make it work. The car kicked butt in other series and I think NASA wanted to make sure that didn't happen here. I also get the feeling they don't trust/like the rotary by the way the rules read, last years porting points were absurd with low max HP levels. This year, any and all porting makes for an automatic dyno class. I will say the regular classing and dyno classing of a stock port NA RX-7 were similar in one test case, a car with regular points in the 50 point range did also class out the same by dyno. Base weight at 2800 is a beating, ITS weight is 2680 and EP 2400 +....lots of weight points you take if you have a real race car. At 2635lbs, you'll take 165lbs of weight points. Remember, it's what the car weighs after the race with you in it minus the base weight. Know your weight as if you are under, you get DQ'd. Don't forget to take +2 for the calipers. The 4 pots are not on the base model, neither is the LSD. There is specific info on the 5th/6th ports and VDI, see the rules (I fought to get those). FWIW, if you don't have 180rwhp it's not built to the max. You can get this on a stock port NA which does not require dyno classing. Quote
Members Shawn M. Posted June 16, 2009 Members Posted June 16, 2009 FWIW the car that should have won PTE last years championship was a first gen, RX7. (TTE too if he would hav ran TT.) The classing for that car is perfect. Choose your mods wisely. Quote
N1XRR Posted June 16, 2009 Author Posted June 16, 2009 FWIW the car that should have won PTE last years championship was a first gen, RX7. (TTE too if he would hav ran TT.) The classing for that car is perfect. Choose your mods wisely. I understand, but 1st gen and 2nd car RX7's are very different. 12A RX7's start out in TTG** with a comp weight of 2345 lbs. 13B 1st gen's, which have basically the same engine, are TTF** and have a comp weight of 2512. Is there something magical about the FC chassis that I'm missing? Is the 2800 weight to compensate for a great chassis? It just seems odd because it seems that nearly every car I look at in TTF and TTE, the comp weight is almost always curb weight, except the FC. Quote
N1XRR Posted June 16, 2009 Author Posted June 16, 2009 Shouldn't there be a separation between the '86-88 and 89-91 RX7's? 86-88 N/A RX7's had a 146hp engine, 89-91 had 160hp. No. While your facts are correct, the rules allow for updating/backdating within the spec line for no points. There is no separation in other race series either. You can add the S5 intake, rotors or the whole motor if you want. If you are still running the S4 intake, at least swap to the S5 intake. It can be done in a weekend and cheap. It will get you up to 15rwhp depending on the rest of your setup. I agree the RX-7 is not classed that well in PT, it is not given any favors. You have to really think to make it work. The car kicked butt in other series and I think NASA wanted to make sure that didn't happen here. I also get the feeling they don't trust/like the rotary by the way the rules read, last years porting points were absurd with low max HP levels. This year, any and all porting makes for an automatic dyno class. I will say the regular classing and dyno classing of a stock port NA RX-7 were similar in one test case, a car with regular points in the 50 point range did also class out the same by dyno. Base weight at 2800 is a beating, ITS weight is 2680 and EP 2400 +....lots of weight points you take if you have a real race car. At 2635lbs, you'll take 165lbs of weight points. Remember, it's what the car weighs after the race with you in it minus the base weight. Know your weight as if you are under, you get DQ'd. Don't forget to take +2 for the calipers. The 4 pots are not on the base model, neither is the LSD. There is specific info on the 5th/6th ports and VDI, see the rules (I fought to get those). FWIW, if you don't have 180rwhp it's not built to the max. You can get this on a stock port NA which does not require dyno classing. See, that makes a lot of sense. I have not swapped out my rear end for an LSD unit yet. At this point its all academic, I'm still a ways off to applying for my TT license (still need lots and lots of track time), but I don't want to put a car together and automatically be in TTD where I have no hope of contending without some serious upgrades. Keeping it in E is the logic choice, but that weight...oh boy. Quote
kbrew8991 Posted June 16, 2009 Posted June 16, 2009 the weight does look out of line compared to other similar cars, I'd be curious to see the logic behind it. If we knew what factors were considered when assigning base classes and weights I'm sure this is something we could answer ourselves... or at least make more intelligent inquires about and at Shawn getting the generations confused Quote
mbuskuhl Posted June 16, 2009 Posted June 16, 2009 At this point its all academic, I'm still a ways off to applying for my TT license (still need lots and lots of track time), but I don't want to put a car together and automatically be in TTD where I have no hope of contending without some serious upgrades. Keeping it in E is the logic choice, but that weight...oh boy. I have worked the points on this car over and over and over. It is very difficult to even make D with the car with ITS type mods unless you undo some things. It's a C car in ITS trim. An EP car is probably going to be A, it has to be dyno classed. If it was to run in E, you'd have a very stock car. Base class is PTE, 19 points for mods is nothing. Search the PT forum for RX-7 and you'll find some posts on this car and the questions you are raising, it's been discussed. Here's one thread - viewtopic.php?f=16&t=23572 The 2nd Gen has a stock hp/base weight of 17.5 (2800/160). The '99 Miata has a stock hp/base weight of 17.24 (2299/130). Both are PTE. Quote
N1XRR Posted June 16, 2009 Author Posted June 16, 2009 At this point its all academic, I'm still a ways off to applying for my TT license (still need lots and lots of track time), but I don't want to put a car together and automatically be in TTD where I have no hope of contending without some serious upgrades. Keeping it in E is the logic choice, but that weight...oh boy. I have worked the points on this car over and over and over. It is very difficult to even make D with the car with ITS type mods unless you undo some things. It's a C car in ITS trim. An EP car is probably going to be A, it has to be dyno classed. If it was to run in E, you'd have a very stock car. Base class is PTE, 19 points for mods is nothing. Search the PT forum for RX-7 and you'll find some posts on this car and the questions you are raising, it's been discussed. Here's one thread - viewtopic.php?f=16&t=23572 The 2nd Gen has a stock hp/base weight of 17.5 (2800/160). The '99 Miata has a stock hp/base weight of 17.24 (2299/130). Both are PTE. I did a bit of reading through that thread. Here's what I gather (if I'm understanding correctly): The RX7 classing is based off of the heaviest of the 2nd gen coupe's (nearly 2800lbs). That model/year has the 160hp engine with a 2800lb chassis. But, since I've got a '86, I'm down on power and seriously handicapped because of weight. The brakes are another point. The RX7 specified in the rules has 4-piston brakes, but I have to take points because the base model came with single-piston brakes. So, out of the box, none of the RX7's are 0-point cars. The early cars need to take points because of weight, the later cars need to take points because of other things (like brakes). Weird. Quote
Members Shawn M. Posted June 16, 2009 Members Posted June 16, 2009 and at Shawn getting the generations confused No confusion there. (how could I be confused since ive competed in all 3 gens..... ) The hint was, he has the wrong car. 1st gen FTW. and at Ken for being confuse that someone is confused. Quote
mbuskuhl Posted June 16, 2009 Posted June 16, 2009 [quote name="N1XRR I did a bit of reading through that thread. Here's what I gather (if I'm understanding correctly): The RX7 classing is based off of the heaviest of the 2nd gen coupe's (nearly 2800lbs). That model/year has the 160hp engine with a 2800lb chassis. But' date=' since I've got a '86, I'm down on power and seriously handicapped because of weight. The brakes are another point. The RX7 specified in the rules has 4-piston brakes, but I have to take points because the base model came with single-piston brakes. So, out of the box, none of the RX7's are 0-point cars. The early cars need to take points because of weight, the later cars need to take points because of other things (like brakes). Weird.[/quote] One would assume it is classed off an S5 model, as that only makes sense. My shell is an '86 as well, they are light and one of the better shells to start with, of course you'd never know it was an '86 as the S5 intakes are obviously different as well as bumpers/tail lights. Change your intake to an S5, you can do it without pulling the motor, probably for less than $150 and in one weekend all for 0 points...that solves alot of your "down on power" problem. I have dyno proven before 15rwhp from switching from an S4 to S5 intake. Results are typically 10-15rwhp improvement depending on other mods. As you probably know S5 rotors are better than S4 and will give you a litte more as well. The RX-7 spec'd is a "RX-7 13B" (unless you have a 1st Gen). Never between 86-91 did it come with 4 pots on the base model, I've researched heavily. To say the one spec'd in the rules has 4 pots, I don't understand. Don't forget you can add up to 250lbs of ballast, so it is possible to run a 0 point RX-7. Quote
N1XRR Posted June 16, 2009 Author Posted June 16, 2009 and at Shawn getting the generations confused No confusion there. (how could I be confused since ive competed in all 3 gens..... ) The hint was, he has the wrong car. 1st gen FTW. and at Ken for being confuse that someone is confused. Haha. Good ol' Sparkle Pony. Quote
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