red986s
New member
Greg you've got a bunch of guys salivating, wrenches in hand waiting for the go ahead to start that build.
2011 Runoffs
- Thread starter Greg Amy
- Start date
Greg you've got a bunch of guys salivating, wrenches in hand waiting for the go ahead to start that build.
Well to be clear, the "serious topic of conversation" I'm referring to is general overall idea of how the Club is going to handle National classification and de-classification, not STL specifically.
Specifcally, if you want STL to be National, now is the time to be writing letters to your BoD and CRB reps.
GA
Matt93SE
New member
.... which is going to change in the next few weeks.
As Trey has mentioned, there's been lots of talk about STL around here, but nobody's jumping on that bandwagon because it's not a national class (yet).
I certainly wouldn't start building a car in hopes the class will be there when I'm done.
Sorry I'm late to the party.
tGA, so basically you're saying the stock turbo rules are very much written in pencil because it doesn't really matter what hairdryer you use on account of the TIR? if you look behind you you will see that slippery slope.
car or engine intake, VW in a porsche, now this? but no JDM / no other swaped or open intakes.
ST is going to wind up speclined to death, if it makes it that far. STO I think is fine as it has ben stringently controlled from the git-go, but U and to a lesser degree (now) L are crazy. I am super excited about this class, but I think it has become too many things to too many people. it's a 2 headed cow with stripes when it should be a thoroughbred.
the category makes less sense every time I open this page
Edit: I know this class is suppose dot be more open and creative, it's the unbalanced allowances I don't understand
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Generally speaking, yes, that's the theory. We have an FIA chart that specs the TIR vs max airflow, and thus implies max power; in theory, we should be able to get turbo cars pretty close regardless of equipment on the vacuum side of the TIR.
I don't know why you guys keep beating this JDM horse, without sending any letters to anyone (we've gotten zero - ZERO - letters from anyone on this board about this issue). If you want this, make a case for it.
Right now we really want to keep the STU rules consistent for a while (as royal "you" have requested). At the same time, there's a rumbling undercurrent that maybe the future of STU is to allow aftermarket turbo additions as well as placing some basic performance-limiting parameters on cars (such as throttle body size, displacement, compression ratio, cam lift, etc) and letting people have their way. But note this is not in process nor is it currently under serious consideration! It's just a general mindset about the future of the class.
The Runoffs should illustrate to you that STU ain't no "let's take our IT car and go National Racing" kinda thing, unless your "thing" is just to participate. It's a serious tuner class, and will require serious commitment to win. Let's see how things shake out.
(Your embedded videos are not working for me.)
Not at the moment. I spent most of my Runoffs week trying to get data acquisition on the top four cars in each class, and various issues with the hardware made it pretty much a flop. I have not yet reviewed the data I did manage to get (I'm still waiting to retrieve my laptop from its ride home from Wisconsin) but since I have so little it will NOT be used in any formal way for re-org of the cars.
GA
tyr them now, or cpy and paste the shortcut.
From what I have seen, the turbo and especially the turbo AWD cars are *rocketships* out of the corners.
FWIW, the Mits Evo was a T2 car with a smaller restrictor for STU. If that car was built to the limit of STU rules, I wouldn't be surprised if that car was capable of winning overall.
Weight definetely factors in as well - with the 3.2l cars being allowed next year, at 3500+ pounds, that will likely render them uncompetitive except for perhaps tracks like VIR or Watking Glen - the small wings (width and chord length) allowed will not create enough downforce to counteract the static weight forces.
Since aerodynamic resistance increses with the square of the the speed, and inertia/braking forces/stopping time and cornering forces also increases with the square of the speed - the weight plays a huge part in this. heavy cars aren;t going to make it, and cars that aren't powerful enough - Staal's Acura RSX for example - aren;t going to make it either.
A big NA engine will make power and torque, won't corner comparatively well, but can get up to high speed.
A small NA engine can make decent power, but no torque, and can handle quite well -see the RSX and the M3 for example - light weight can help with braking and ion the corners, but for the square ones, it takes torque to the ground to get out of them. the real small engines, say under 2.2 or 2.3L-ish - aren't going to make to power needed to get to the high speeds big tracks like RA, VIR, WGI or RdAm require.
Which brings us to the turbo cars. They make gobs of torque and enough power that it's a clear advantage. The AWD turbo cars can put it all down early, and in traffic, fighting/defending for position or on square corners, that's a huge advantage.
The reality is the class is built around a DISPL/WT and TIR/WT scale....but in the real world, it really is a torque curve to weight solution to win. The high revving NA cars that handle great can do well and be fast when they get a clean run through the corners -fast corners especially, but yousquare them off, add traffic or a position battle, and the lack of torque is a distinct disadvantage.
This is in the dry of course. In the wet, AWD will rule, especially sophisticated AWD systems like that on the EVO - which is not meant to take away anything from Marty Grand's accomplishments, who has shown to be an exceptional driver.
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Z3_GoCar
New member
Fixed it....
Marc's Miata is in it's first season, so I'm sure he's got more speed to find there. I understand your reluctance to changing the TIR size as it should limit peak hp as predicted.... but.... Then you add in AWD and distribute the power between four wheels, and the wheel size limits aren't as applicable. For reference look what the AWD "boost buggies" have done to the Solo ST classes, and now they've been taken out of some classes for two wheel drive chassis to have a shot.
Marc's Miata is in it's first season, so I'm sure he's got more speed to find there. I understand your reluctance to changing the TIR size as it should limit peak hp as predicted.... but.... Then you add in AWD and distribute the power between four wheels, and the wheel size limits aren't as applicable. For reference look what the AWD "boost buggies" have done to the Solo ST classes, and now they've been taken out of some classes for two wheel drive chassis to have a shot.
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These are all points worthy of consideration. If you've got something you'd like to put together for us to consider on how to manage this, do please put it in a letter and send it to us (as "JS154" has promised he would do.)
Speaking of which, in case you didn't know, "JS154" is none other than Eric Heinrich, driver of that sweet Gulf-liveried E30 M3 and our Runoffs STU Bronze Medal winner. - GA
Speaking of which, in case you didn't know, "JS154" is none other than Eric Heinrich, driver of that sweet Gulf-liveried E30 M3 and our Runoffs STU Bronze Medal winner. - GA
Limiting the AWD cars to a max tire width of 225 would help level that playing field. They were all running 245/40/17's at the Runoffs - on an 8" rim that's 1" more contact patch width per wheel on the ground compared to a 225.
Marc said many times he dropped that engine in just before the runoffs with no testing and had never been to RdAm before. Kudos to him for thinking up a brilliant combo of weight/shassis/engine/aero.... so fast through and out of the corners, but not enough top end to stay with the Audi at RdAm. Put that car at a track like Mid-O and he would have checked out.
edit:insert>
My understanding was (not 100% sure):
The Audi was running at 2935#/37mm
The Miata was running at 2200#/smallest resitrictor (i think 27mm?)
The Evo was running at 3400#+, 40mm restrictor
Nothing was touching the turbos through and out of the corners.
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I don't like the sound of that at all. The turbo cars need no help whatsoever. At the same time those limits - tb size, comp ratio,cam lift...without allowing non-USDM engines - will all have a significant impact on the NA cars.
if the ultimate goal is to have the class develop into a *turbo* class, then yes, those would be appropriate cahnges. But if the idea is to have a *varied* class, then it needs to go the other way around.
All that said, I do feel compelled to say that the STAC and the BOD so far has done a pretty darn good job of balancing the class, given how much there is to balance...RWD, FWD, AWD, combined with NA and FI, combined with small displacement/TIR/light weight vs large displacment/TIR/heavy weight.... no easy task by a long shot, and to be this close in only the second year of the class is a remarkably well done job. With the exception of the turbo and especially turbo AWD cars, there's not much that needs to be done, except perhaps make some allowances for the RSX-S and S2000 to be truly in the game, which IMHO they should be and I would support.
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I came across this forum while browsing the Internet 
. Couple thoughts after reading some comments on here. First the idea of my heavy Evo running on 225s is absolutely crazy. It would be lucky to score a top 10 finish in STU. The Evo weighs more than 500 pounds more than the BMWs, To put the Evo on 225 tires would be like putting the BMWs on 185mm tires. Also, RWD out handles AWD every time unless youre going slow enough that the rear tires will spin under acceleration.
Im not sure Ill run this class again since the rules are soley based on power to weight with no consideration for less weight= better handling and less weight=better braking and less weight=better tire and brake wear. My Evo was running a 39mm restrictor and was in basically a dead heat down the straight with the BMWs (watch laps 1 and 2). The only advantage I could see was tight corner exits like Turn 5 and 8 but I was getting eatin up in every other corner and brake zone on the track. And no, aero would not make up for 500 pounds of dead weight.
Greg, Ill repeat what I said at the RO's, I think there should be a curve to allow heavier, less handing and braking cars more power per pound. That said I think the only good race in STU was for 3rd place, we were running identical lap times fighting hard for the podium. If the top couple cars were pulled back 2 second per lap it would be an epic 6 car battle just how the cars sit.
Also keep in mind that in 09 I was on the T2 pole and set the track record in the race and reset the T2 track record in 2010 and yet was no faster than 2 first time drivers at RA in STU in their BMWs this year. Give Eric and Mike another year at RA and they will certainly pick up time just by learning the track.
It was suggested to me that the Audi is the "standard for STU" welllll there is no way that most of us can build a car to the level of the Stasis Audi. Thats like a 200k build. My car is a 40k build including the price of the car, cage, struts etc..
I realize my main class is T2 and only ran STU because I thought it was another class that my car could compete in, If I feel I cant compete than I will just stick to T2. If I were on the STU CRB I would be concentrating on figuring out a way to get the 3-6place cars closer to the 1st and 2nd place cars and not just picking on the "awd turbo" cars. To me this is like saying all NA cars should have X or all RWD cars should have X.
It was great racing with you Eric and congrats on your podium, you drove a really good race.
Marty
. Couple thoughts after reading some comments on here. First the idea of my heavy Evo running on 225s is absolutely crazy. It would be lucky to score a top 10 finish in STU. The Evo weighs more than 500 pounds more than the BMWs, To put the Evo on 225 tires would be like putting the BMWs on 185mm tires. Also, RWD out handles AWD every time unless youre going slow enough that the rear tires will spin under acceleration. Im not sure Ill run this class again since the rules are soley based on power to weight with no consideration for less weight= better handling and less weight=better braking and less weight=better tire and brake wear. My Evo was running a 39mm restrictor and was in basically a dead heat down the straight with the BMWs (watch laps 1 and 2). The only advantage I could see was tight corner exits like Turn 5 and 8 but I was getting eatin up in every other corner and brake zone on the track. And no, aero would not make up for 500 pounds of dead weight.
Greg, Ill repeat what I said at the RO's, I think there should be a curve to allow heavier, less handing and braking cars more power per pound. That said I think the only good race in STU was for 3rd place, we were running identical lap times fighting hard for the podium. If the top couple cars were pulled back 2 second per lap it would be an epic 6 car battle just how the cars sit.
Also keep in mind that in 09 I was on the T2 pole and set the track record in the race and reset the T2 track record in 2010 and yet was no faster than 2 first time drivers at RA in STU in their BMWs this year. Give Eric and Mike another year at RA and they will certainly pick up time just by learning the track.
It was suggested to me that the Audi is the "standard for STU" welllll there is no way that most of us can build a car to the level of the Stasis Audi. Thats like a 200k build. My car is a 40k build including the price of the car, cage, struts etc..
I realize my main class is T2 and only ran STU because I thought it was another class that my car could compete in, If I feel I cant compete than I will just stick to T2. If I were on the STU CRB I would be concentrating on figuring out a way to get the 3-6place cars closer to the 1st and 2nd place cars and not just picking on the "awd turbo" cars. To me this is like saying all NA cars should have X or all RWD cars should have X.
It was great racing with you Eric and congrats on your podium, you drove a really good race.
Marty
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Hey Marty, Eric here - here's a hearty congratulations to you on your win again in T2 and it was great to race with you - You're a heck of a driver and I'll race with you anywhere, anytime. Well maybe except for in the rain.
FWIW, this was not my first time at RdAm - I was there a year ago with the BMW Club and was able to get in a few hours of testing there, so I had some pretty good data and experience to start with. That said, RdAm isn;t the hardest track to learn, certinaly not like Mid-O, and Hoover said he had never been there, but he's got a *lot* of experience..... Also, I did have Seth Thomas (Bimmerworld Pro driver) co-drive my car then, and we were within hundredths of seconds witin each others sector times and 10ths of mph's in top and corner apex speeds.
So we built nearly to the limit of the rules - and went there with expectations of being able to win, not to be 2 seconds plus off the pace (Joel did a 27.2 IIRC in practice on Sat) in the race he was over 2 seconds faster than our whole group, and that was without serious pressure to push the limits. What little more we vould do would be astronomical in cost for fractional gains at best, to the point it would be better to sell and build a different car.
So my understanding is your car is a T2 car, with an STU restrictor....but what is the performance potential for and Evo (Or an STI, Or R32, or next years BMW Z4 x-drive 4cyl turbo) when built to the limit of the STU rules? we're talking full build, cams compression, exhaust, coatings, sequential, MoTeC/ADL/trans controller, relocated suspension geometry, full splitter and lower drag wing....
I think you are right, weight is a huge factor - next year when the 3.2l engines are allowed, the S54 BMW engine is easily capable of 400 hp, and stock revs to over 8000 rpm...but the car will have to run at over 3500# - that's appx 600# more than the STaSIS Audi.
I think the class is mostly close, but the following need addressing:
-the small displacement N/A cars I understand are having a hard time reaching their min weight, AND they don;t have the displacement to make the power to get to the high speeds needed at tracks like RA, RdAm, VIR, WGI etc
-The large displacement NA cars are going to have a weight issue next year already
-turbo AWD cars have a huge torque and traction advantage.
As for the budget - I think, as Dorsey mentioned in his broadcast - something should be done to cap outright expenditures - such as a heavier weight penalty for sequentials, but from what I understand, this class is not intended to be a low or even moderate budget class - it is Super Touring, and the rules allow building to a level along the lines of BTCC, WTCC, the old Euro Super Tourers and even the early Gruppe A cars from the late 80's - no small change by a long shot. And personlly I think that's a mistake. We already have those series in the US, it's called Speed World Challenge and GAC. I think it would be wise to submit a letter to the CRB about the costs, which if restrained, will enable more people to play, be competitive, and make for larger fields. That STaSIS Audi - there's a lot more into it than that, same for the Tindol Mazda.
Marty, in your case - a T2 car - perhaps an allowance such as the IT cars have - "T2 cars may enter under their T2 ruleset, with the exception of (? wheel size/rim width/TIR size/weight chart etc?)" dunno just brainstorming here, but maybe something like that.
Again, great racing with you and congrats on your second Runoffs Championship - to do it back to back, and with the weather/tire choice/driving gamble you had to make this year, that's pretty damn impressive.
EH
FWIW, this was not my first time at RdAm - I was there a year ago with the BMW Club and was able to get in a few hours of testing there, so I had some pretty good data and experience to start with. That said, RdAm isn;t the hardest track to learn, certinaly not like Mid-O, and Hoover said he had never been there, but he's got a *lot* of experience..... Also, I did have Seth Thomas (Bimmerworld Pro driver) co-drive my car then, and we were within hundredths of seconds witin each others sector times and 10ths of mph's in top and corner apex speeds.
So we built nearly to the limit of the rules - and went there with expectations of being able to win, not to be 2 seconds plus off the pace (Joel did a 27.2 IIRC in practice on Sat) in the race he was over 2 seconds faster than our whole group, and that was without serious pressure to push the limits. What little more we vould do would be astronomical in cost for fractional gains at best, to the point it would be better to sell and build a different car.
So my understanding is your car is a T2 car, with an STU restrictor....but what is the performance potential for and Evo (Or an STI, Or R32, or next years BMW Z4 x-drive 4cyl turbo) when built to the limit of the STU rules? we're talking full build, cams compression, exhaust, coatings, sequential, MoTeC/ADL/trans controller, relocated suspension geometry, full splitter and lower drag wing....
I think you are right, weight is a huge factor - next year when the 3.2l engines are allowed, the S54 BMW engine is easily capable of 400 hp, and stock revs to over 8000 rpm...but the car will have to run at over 3500# - that's appx 600# more than the STaSIS Audi.
I think the class is mostly close, but the following need addressing:
-the small displacement N/A cars I understand are having a hard time reaching their min weight, AND they don;t have the displacement to make the power to get to the high speeds needed at tracks like RA, RdAm, VIR, WGI etc
-The large displacement NA cars are going to have a weight issue next year already
-turbo AWD cars have a huge torque and traction advantage.
As for the budget - I think, as Dorsey mentioned in his broadcast - something should be done to cap outright expenditures - such as a heavier weight penalty for sequentials, but from what I understand, this class is not intended to be a low or even moderate budget class - it is Super Touring, and the rules allow building to a level along the lines of BTCC, WTCC, the old Euro Super Tourers and even the early Gruppe A cars from the late 80's - no small change by a long shot. And personlly I think that's a mistake. We already have those series in the US, it's called Speed World Challenge and GAC. I think it would be wise to submit a letter to the CRB about the costs, which if restrained, will enable more people to play, be competitive, and make for larger fields. That STaSIS Audi - there's a lot more into it than that, same for the Tindol Mazda.
Marty, in your case - a T2 car - perhaps an allowance such as the IT cars have - "T2 cars may enter under their T2 ruleset, with the exception of (? wheel size/rim width/TIR size/weight chart etc?)" dunno just brainstorming here, but maybe something like that.
Again, great racing with you and congrats on your second Runoffs Championship - to do it back to back, and with the weather/tire choice/driving gamble you had to make this year, that's pretty damn impressive.
EH
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Hey Eric,
The power increasers you mentioned would really do nothing to help me as long as I have a TIR. I have the best tuner in the US for Evo Tuning and even running Motec would do basically nothing for me as long as I run the TIR. I really lose so much power its crazy and it really chops off my top end (you can only get so much air though that hole no matter what you do and believe me, Im maxed out). BTW, the open turbo rule in STU wouldnt help me at all, I couldnt put a bigger turbo on since it would actually hurt my power, if anything Id go smaller to match the TIR.
From T2 to STU I put in the smaller restrictor (from 41mm to 39mm)and pull 210pounds out of the trunk and put on smaller wheels.
Only issue I have is that they have done a great job of equalizing the power to weight among the top 6 cars, I could be wrong but it sure looked like I would out accelerate you out of 14 but then you pulled me on the top end. So any Evo power advantage has been taken care of via the TIR. Watching me and Mike come out of 5 he was right on my heels the whole way up the hill, that is the sharpest corner on the track and my awd and turbo could not overcome his weight advantage, I actually thought Id pull him but was surprised I wasnt able to. There is no way my car can handle and brake with the light cars and if I dont have straight line speed advantage then the way I look at it is:
BMW vs Evo in braking = Advantage BMW
BMW vs Evo Handing = Advantage BMW
BWM vs Evo Speed = Draw
It's just tough when you dont have one advantage over your competitors in the 3 areas that count handling, braking, speed.
Would a Seq gear box help? yes but I will not pay 12k for a dogbox for my car.
Would aero help? Im not so sure at RA, its a high speed track and I actually took my wing off to gain a mph or two. I talked to my main sponsor who runs at RA often in a professionally set-up downforce equipped evo and they said with my power levels it would likely slow me down (increase my lap times) from the additional drag.
Id love to get down to the Audi's weight but Evo's are heavy rally cars and Ive stripped it to the bone. It has an alum roof, fenders and hood already, all lighter than carbon fiber. If I replaced the doors and trunk with carbon I could drop about 100 pounds-this would cost me roughly 10k and still I wouldnt be close to the Audi's weight.
But really although I think STU has great potential, this is an additional class for me and if the rules are favorable I will run with you guys, if not then Ill play exclusively in my T2 sandbox. But unless something is done to the Audi, everyone else is racing for second on down. If the CRB was taking my advice, Id ask for my 41mm restrictor back and run at 3300 pounds. Id still lose the braking and handling war, but atleast id have some poop down the straights
Take care and great racing with you Eric, it was good to see you up there on the podium! Oh and I very much appreciate the congrats on T2.
Greg or Eric, if you ever want to discuss; my email is [email protected] email me and Ill give you my number.
Marty
The power increasers you mentioned would really do nothing to help me as long as I have a TIR. I have the best tuner in the US for Evo Tuning and even running Motec would do basically nothing for me as long as I run the TIR. I really lose so much power its crazy and it really chops off my top end (you can only get so much air though that hole no matter what you do and believe me, Im maxed out). BTW, the open turbo rule in STU wouldnt help me at all, I couldnt put a bigger turbo on since it would actually hurt my power, if anything Id go smaller to match the TIR.
From T2 to STU I put in the smaller restrictor (from 41mm to 39mm)and pull 210pounds out of the trunk and put on smaller wheels.
Only issue I have is that they have done a great job of equalizing the power to weight among the top 6 cars, I could be wrong but it sure looked like I would out accelerate you out of 14 but then you pulled me on the top end. So any Evo power advantage has been taken care of via the TIR. Watching me and Mike come out of 5 he was right on my heels the whole way up the hill, that is the sharpest corner on the track and my awd and turbo could not overcome his weight advantage, I actually thought Id pull him but was surprised I wasnt able to. There is no way my car can handle and brake with the light cars and if I dont have straight line speed advantage then the way I look at it is:
BMW vs Evo in braking = Advantage BMW
BMW vs Evo Handing = Advantage BMW
BWM vs Evo Speed = Draw
It's just tough when you dont have one advantage over your competitors in the 3 areas that count handling, braking, speed.
Would a Seq gear box help? yes but I will not pay 12k for a dogbox for my car.
Would aero help? Im not so sure at RA, its a high speed track and I actually took my wing off to gain a mph or two. I talked to my main sponsor who runs at RA often in a professionally set-up downforce equipped evo and they said with my power levels it would likely slow me down (increase my lap times) from the additional drag.
Id love to get down to the Audi's weight but Evo's are heavy rally cars and Ive stripped it to the bone. It has an alum roof, fenders and hood already, all lighter than carbon fiber. If I replaced the doors and trunk with carbon I could drop about 100 pounds-this would cost me roughly 10k and still I wouldnt be close to the Audi's weight.
But really although I think STU has great potential, this is an additional class for me and if the rules are favorable I will run with you guys, if not then Ill play exclusively in my T2 sandbox. But unless something is done to the Audi, everyone else is racing for second on down. If the CRB was taking my advice, Id ask for my 41mm restrictor back and run at 3300 pounds. Id still lose the braking and handling war, but atleast id have some poop down the straights
Take care and great racing with you Eric, it was good to see you up there on the podium! Oh and I very much appreciate the congrats on T2.
Greg or Eric, if you ever want to discuss; my email is [email protected] email me and Ill give you my number.
Marty
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I was thinking about how to even a class with such open rules in comparison to the Touring rules. If the car is full of Pro cars why not have Pro type of rules such as penalty weight to even up the cars? The downside is that the Runoffs is a winner take all one race to decide the champion, unlike Pro series that accumulate points towards a championship. Basically, people could take it easy all season and unleash at the Runoffs. At least it would be a way to adjust cars from one Runoff to the next.
Just thinking out loud,
Marty
Just thinking out loud,
Marty
We, effectively, have that Marty: if someone wants to build a car to the World Challenge VTS, they get a 5% penalty. The reason we do that is because some of the specs in WC exceed the prep level of our STU rules (e.g., too much compression).
However, there's nothing to keep someone with deep pockets from spending the same amount of money to build an STU-spec car to the same level of prep. I can, for example, walk up to PD Cunningham, who would be glad to take my 6-figure check to me me a championship-winning Acura TSX that meets each and every point of the STU rules.
You just can't legislate how much people can spend.
On the other hand, if you think the prep level is too high, then the solution is to either reduce the prep level (unlikely, given the philosophy of the class) or convince the CRB to add higher weight penalties for specific allowances, like what we do for moving pickup points and for sequential gearboxes.
Exactly what happened last year. The 2010 STU champion qualified for the Runoffs in a BMW Z4 (SSB?) and then rented a RealTime Acura TSX for the Runoffs. Pretty smart strategy...
Mrsideways
New member
Greg, where can one find the FIA TIR chart? I tried Googleing it but came up with nothing.
Perhaps this? certainly not a linear 135# per 1mm TIR diameter increase, much more specific. Not being an engineer I'm not sure how it comapres to the current chart/grid being used but it may be worth considering.
Article 252 - 2011
Prescriptions Générales pour les
Voitures de Production (Groupe N), Voitures de Tourisme (Groupe A),
Voitures de Grand Tourisme (Groupe
General Prescriptions for
Production Cars (Group N), Touring Cars (Group A),
Prescriptions Générales pour les
Voitures de Production (Groupe N), Voitures de Tourisme (Groupe A),
Voitures de Grand Tourisme (Groupe
General Prescriptions for
Production Cars (Group N), Touring Cars (Group A),
Grand Touring Cars (Group
3.3 Equivalence formula between reciprocating piston and
turbine engines
turbine engines
The formula is the following:
S(3.10 x R) - 7.63
C = ---------------------------
0.09625
S = High pressure nozzle area - expressed in square centimetres
by which is meant the area of the airflow at the exit from the stator
blades (or at the exit from the first stage if the stator has several
stages).
Measurement is done by taking the area between the fixed blades
of the high-pressure turbine first stage.
In cases where the first stage turbine stator blades are adjustable,
they must be opened to their greatest extent.
The area of the high-pressure nozzle is thus the product of the
height (expressed in cm) by the width (expressed in cm) and by the
number of blades.
R = The pressure ratio is the ratio of the compressor of the turbine
engine.
It is obtained by multiplying together the value for each stage of the
compressor, as indicated hereafter:
Subsonic axial compressor: 1.15 per stage
Trans-sonic axial compressor: 1.5 per stage
Radial compressor: 4.25 per stage.
Thus a compressor with one radial and six axial subsonic stages
will be designated to have a pressure ratio of:
4.25 x 1.15 x 1.15 x 1.15 x 1.15 x 1.15 x 1.15 or 4.25 x (1.15)6.
C = Equivalent cubic capacity for reciprocating piston engines in
S(3.10 x R) - 7.63
C = ---------------------------
0.09625
S = High pressure nozzle area - expressed in square centimetres
by which is meant the area of the airflow at the exit from the stator
blades (or at the exit from the first stage if the stator has several
stages).
Measurement is done by taking the area between the fixed blades
of the high-pressure turbine first stage.
In cases where the first stage turbine stator blades are adjustable,
they must be opened to their greatest extent.
The area of the high-pressure nozzle is thus the product of the
height (expressed in cm) by the width (expressed in cm) and by the
number of blades.
R = The pressure ratio is the ratio of the compressor of the turbine
engine.
It is obtained by multiplying together the value for each stage of the
compressor, as indicated hereafter:
Subsonic axial compressor: 1.15 per stage
Trans-sonic axial compressor: 1.5 per stage
Radial compressor: 4.25 per stage.
Thus a compressor with one radial and six axial subsonic stages
will be designated to have a pressure ratio of:
4.25 x 1.15 x 1.15 x 1.15 x 1.15 x 1.15 x 1.15 or 4.25 x (1.15)6.
C = Equivalent cubic capacity for reciprocating piston engines in
cm3.
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