So about these Pony Cars for ITR...

[lateapex911]

Travis, am i right in thinking that one of the goals here is to incorporate the torque into the output? So that we won't be adding it subjectively?

(Just stating the obvious....errrr...i think!)

 

[tnord]

Travis, am i right in thinking that one of the goals here is to incorporate the torque into the output? So that we won't be adding it subjectively?

(Just stating the obvious....errrr...i think!)

kindof. see my last post on the previous page. i think one of the biggest benefits of doing it this way is that this would eliminate the need for an adder, yes.

 

[Ron Earp]

also keep in mind that your 272 number does not necessarily have to represent HP, think of it as "output." i'm struggling with the methodoligy to make this work logically.....but the end result seems to be in line.

Ok, I see that now and agree and I think that is what Kirk was after. In that case we should eliminate units from the example calculations because the INTJ types will continue behaving as I am, going around in circles and pointing out impossibilities.

Yes, it would be possible to come up with a system that spits out numbers and those numbers are used to assign weights. But I still think you'll need to have a normalizer for engine type if you want to get it right. I bet that you'll have to have a engine type modifier to make the model fit our current class system the way it is now.

 

[Andy Bettencourt]

NOT FAIR, Andy. We don't apply the current system to the Rotaries and you know it. We reverse-derived the ITS RX7 13B multiplier to make it fit.

Bzzt. Wrong. Sorry.

K

Why do you say that Kirk? All we do is keep it simple. We take what we know and we apply it. The Wankel doesn't have it's own 'process'...it't no different that any other car that doesn't fit the standard 25% multiplier.

 

[Andy Bettencourt]

Lots of 'it looks right' and 'its wrong for this car' stuff that is all subjective. If it differs from the current weight and the poster thinks its a better weight from their persepctive, it's good. If it differs from the curent weight and the poster thinks it's 'off' based on their persepctive, it's bad.

Still trying to see what this is getting us - without trying to force something.

 

[tnord]

Ok, I see that now and agree and I think that is what Kirk was after. In that case we should eliminate units from the example calculations because the INTJ types will continue behaving as I am, going around in circles and pointing out impossibilities.

Yes, it would be possible to come up with a system that spits out numbers and those numbers are used to assign weights. But I still think you'll need to have a normalizer for engine type if you want to get it right. I bet that you'll have to have a engine type modifier to make the model fit our current class system the way it is now.

yeah, the whole "output" instead of HP is something I came up with only after starting to mess with the V8s.

i'm starting to think we may need one factor for OHC, and one for OHV......maybe. the current math seems to work if you can make the leap of faith that we can start the formula with HP, and spit out either HP or lb/ft. but i can't explain why, or justify why anyone should accept that.

 

[Ron Earp]

i'm starting to think we may need one factor for OHC, and one for OHV......maybe. the current math seems to work if you can make the leap of faith that we can start the formula with HP, and spit out either HP or lb/ft. but i can't explain why, or justify why anyone should accept that.

Well, no, the system can't spit out hp or lb/ft. All the calculations are done with hp and the system does not take into account torque. I can accept that we can drop the hp and go unitless, but to convert into lb/ft because "we want to" doesn't work well with me.

Seriously, there isn't a lot to it. It is simply normalizing the cars in the class to a bogey's specific output. Which is fine with me, it is what it is. One specific output is not going to work for the entire class in question and I'm not sure that you'll get away with a single OHC specific output target. We need to run the numbers on known engines like a 4 valve DOHC engine and a 2 valve SOHC engine, I imagine we'll find they don't jive well and each type of OHC engine will need a specific output.

A good 4V DOHC / 2V SOHC test case might be the BMW 325i and 240Z. Engine outputs of each are well known and I know right off the BMW 325i achieves a specific output the Datsun motor can't get to.

 

[tnord]

the datsun was another one i was having trouble with, but i don't have much knowledge about what it should make, so i just kinda left it alone. i think i'll let you guys run with this however you like. it seems to be in the ballpark, and pretty decent for a first effort, but not accurate enough to use across the entire IT listing.

 

[lateapex911]

A good 4V DOHC / 2V SOHC test case might be the BMW 325i and 240Z. Engine outputs of each are well known and I know right off the BMW 325i achieves a specific output the Datsun motor can't get to.

I agree, any output should be called a "Power factor" or some such.

I see the goals are to predict what engines that don't fit normally into the standard process will do, so that they can be classed appropriately. To that end, the S2000 is a good case study.

And sure it HAS to work for known targets, like the cars you mentioned Ron. But even there, we can get REALLY tripped up. The 325 that we "know" would actually DISprove the formula.... if the numbers 'seemed' right, because the stock HP rating is questionable/bogus.

It's back to the age old debate over "Predictive' formula vs. "what we know'

 

[JoshS]

Hey Ron, is there a reason why you are calling out 2V SOHC and 4V DOHCs, but not 4V SOHC (2nd-gen Neon), or 5V (Audi) motors? Are all of these different in your mind?

And the formula Travis is espousing doesn't take into account torque, but it takes into account displacement as a substitute, assuming that high displacement yields high torque.

Bottom line for me though, I'm with Andy ... it just seems to be another, more complicated, way to get to basically where we already are. I'm not sure it's helpful. Changing the process in this way FORCES another great realignment in my mind, so there better be a good reason to change the process.

 

[JeffYoung]

And if you start talking about accounting for peak torque you have to to start considering gearing and torque under the curve....

I'm with Josh. This system is appealing but seems fraught with danger and unneeded complexity since the "rough justice" we have right now works, mostly. Which is all you can ask for.

 

[Ron Earp]

Hey Ron, is there a reason why you are calling out 2V SOHC and 4V DOHCs, but not 4V SOHC (2nd-gen Neon), or 5V (Audi) motors? Are all of these different in your mind?
.

Yes, there is a reason, simplicity.

A 2V SOHC motor is distictly different from a 4V DOHC engine with respect to breathing characteristics. The 2V motor many times has the valves in a line and are not canted to the intake or exhaust port. A 4V DOHC design can have the banks of two valves canted which enhances port flow plus it has more valve area than the 2V engine.

The OHV engine is it's own unique case as you can imagine.

The others you mention are slightly different cases of the ones I defined. While the Audi is somewhat unique, I doubt the advantages were that great. Most of the five valve adopters have gone back to four valve designs. In particular is Yamaha in their Superbike race designs. They were a huge proponent of five valve motors but found just as much power with four valve designs.

I have to agree with Jake and Jeff. The system we have works pretty damn well, at least for ITS it does, the class which I know the most about. I understand from talking with others it works pretty well in A,B, and C.

 

[Bob Roth]

As a fly on the wall, might I suggest that the honda B and K VTEC motors with their essentially same vtec cams, head flow capability, and same specific power, be considered as essentially the same for a different multiplier?

 

[tnord]

As a fly on the wall, might I suggest that the honda B and K VTEC motors with their essentially same vtec cams, head flow capability, and same specific power, be considered as essentially the same for a different multiplier?

you really should have a prod car Bob.

 

[Knestis]

Why do you say that Kirk? All we do is keep it simple. We take what we know and we apply it. The Wankel doesn't have it's own 'process'...it't no different that any other car that doesn't fit the standard 25% multiplier.

But saying a new system is a "snafu" because it won't handle one of three oddball Wankel cases is completely disingenuous. I would NOT propose doing anything differently with the Wankels in any process we apply. They're "cases of one" so defy any effort to make them part of a repeatable process.

HOWEVER, that is most assuredly NOT enough of a reason to bail on any different way of dealing with the data.

Still trying to see what this is getting us - without trying to force something.

It's getting us away from picking power multipliers based on imprecise data. While I've long ago accepted that we need to do that with the rotaries, I've never been at all comfortable with the using "what we know," because - for about the zillionth time - we don't KNOW what we know.

This approach would quantify a theoretical assumption that I think there's pretty broad consensus on. And it would be REPEATABLE. And OBJECTIVE, if first principles are accepted...

K

 

[Knestis]

... It is simply normalizing the cars in the class to a bogey's specific output. Which is fine with me, it is what it is. One specific output is not going to work for the entire class in question and I'm not sure that you'll get away with a single OHC specific output target. ...

It's normalizing the outputs to our 1.25 multiplier standard. EVERY EXAMPLE has its own specific output, based on stock power, displacement, and number of cylinders.

Do we or do we not accept the first principles:

1. Not all engines respond to IT preparation the same way; they don't have the same "power potential"

2. We current adjust for this by using the 1.25 power factor multiplier, unless we "know otherwise" (I get hives just typing that)

3. We would LIKE to be able to take this step in the process, in a repeatable, objective way - we may not all agree on this point...?? Some of us may WANT to be able to adjust power factors subjectively more than others of us.

4. The "specific output" of an engine - the power per unit of displacement - is an indicator of how "maximized" it is. We made a big deal out of the 283hp 283CI Fuelie 'vette, and the S2000 gets cited as an example of engineering excellence because it's more than one hp/cc...

5. Therefore, it's REASONABLE (not perfect) to suggest considering specific output to predict how a car might be expected to respond to IT preparation.

Or have I fallen off my stool and am completely missing something...??

HELP?

K

 

[tnord]

It's normalizing the outputs to our 1.25 multiplier standard. EVERY EXAMPLE has its own specific output, based on stock power, displacement, and number of cylinders.

Do we or do we not accept the first principles:

1. Not all engines respond to IT preparation the same way; they don't have the same "power potential"

yup. without getting into what i feel is an overly complex process, and if you want a process other than what we currently have (which works well enough IMO), then you have to accept that whatever formula is used will be so with varying degrees of success. in other words.....any feasable formula used there will still be instances where people can say "HEY!!!! i don't make 175whp, i only make 165!!!!"

2. We current adjust for this by using the 1.25 power factor multiplier, unless we "know otherwise" (I get hives just typing that)

3. We would LIKE to be able to take this step in the process, in a repeatable, objective way - we may not all agree on this point...?? Some of us may WANT to be able to adjust power factors subjectively more than others of us.

i want it both ways. any formula will fail in some instances, i don't want "us" to be so rigid in the process that we won't move from it and creating another ITS BMW situation.

4. The "specific output" of an engine - the power per unit of displacement - is an indicator of how "maximized" it is. We made a big deal out of the 283hp 283CI Fuelie 'vette, and the S2000 gets cited as an example of engineering excellence because it's more than one hp/cc...

5. Therefore, it's REASONABLE (not perfect) to suggest considering specific output to predict how a car might be expected to respond to IT preparation.

Or have I fallen off my stool and am completely missing something...??

HELP?

K

of the entire post, 4 and 5 are the best points. you understand what i was trying to do perfectly, and if you want to run with it.....have at it. you have a lot more clout with people than i do, but i'm still happy to run numbers or help manipulate the formula however you want.

 

[Tristan Smith]

Having read this thread, and having raced in IT for 15 years, I can't help but think that creating new criteria for classifying cars, or adjusting cars is a slippery slope. It seems like the process currently works. why mess with it?
Now aside from the fact that I am building a 300zx for ITR, I am one of the those who feel that the Pony cars already have a place in AS, and there is no need to include them in ITR. It's not that I fear that they will become over dogs, but the cars have a place to race, and including them in IT is redundent. But I am all for the v6 Mustangs and camaros being included.

 

[Ron Earp]

but the cars have a place to race, and including them in IT is redundent. But I am all for the v6 Mustangs and camaros being included.

Tristan I highly respect your opinion as a long time IT racer. But that argument is akin to saying Miatas have a place to race in Spec Miata, Prod, and SS so they should not be allow to race in IT. Can a car only have one place to race? Should a car type only be limited to one engine option? If so there are numerous examples in IT that would be made redundant since they are already available in various configurations, including my own 260Z.

There are a lot of racers (the letters on the subject were heavily in favor of the Pony cars in ITR) who would like to race a Mustang or Camaro outside the AS ruleset and IT fits the level of modifications they wish to perform.

The discussion on this thread about another classification process was a digression from the Pony Car thread. There is no need to alter the ITR classification process. If you have a look at the proposal, which is around 1.5 years old, you'll find nothing new or rule changing was proposed to fit the V8 Ponys in ITR.

 

[lateapex911]

4. The "specific output" of an engine - the power per unit of displacement - is an indicator of how "maximized" it is. We made a big deal out of the 283hp 283CI Fuelie 'vette, and the S2000 gets cited as an example of engineering excellence because it's more than one hp/cc...

5. Therefore, it's REASONABLE (not perfect) to suggest considering specific output to predict how a car might be expected to respond to IT preparation.

Or have I fallen off my stool and am completely missing something...??

HELP?

K

Two big flys can fall into the ointment from my vantage point, assuming that we CAN find a predictive formula such as the one being discussed here that works:

1- Original specs from the manufacturers are under/overstated. Now, we already have issues dealing with that...so I would suggest that we need to continue to handle "special cases" in "special ways" (Of course I know THAT path is thick with thorns too....)

2- The basic assumption is that two factors will predict an outcome: Size and efficiency. It is assumed that motors that have high specific outputs just can't see large gains, (OK, I buy that), but the converse is assumed that low specific outputs WILL see bigger gains. We have to be careful there, as those low specific output motors are that way for a reason, and the reason could very well be something that can't be changed in IT, like a cam/intake manifold combo that just won't make power.

in the end, I think the current system is working, and anything we do needs to be a clear improvement. AND I can't see going to a system that doesn't allow, however strictly, some degree of "tuning" by humans.

It is very possible for a system to spit out the wrong output given the wrong input, and that can damage a class.

(Don't get me wrong...I like the idea, but I want to tread carefully)