2023 ST4 Section 7.2.3

[Alan_Wolfe]

Please tell me what game I'm supposed to be playing with my supercharged vehicle that Avg HP is calculated over 3 points plus Max HP instead of 7 points plus Max HP.

My Avg HP is calculated at 208.  But if I had used 7 points plus Max HP it would be 199.  So essentially I am carrying a bit over 100 lbs more ballast than an NA car with EXACTLY the same Dyno graph.  Why?

How can you tell from the Dyno graph that the car is supercharged?

Thanks,

Alan

 

[Alan_Wolfe]

Hey @Greg G., still noodling on this?

 

[Greg G.]

If I remember correctly, there are at least two or three different technologies that allow superchargers to be variable boost, like a turbo.  We write the rules for the best possible setups--trying to avoid loopholes that if just a few exploit, puts a huge dent in the entire program.  Of course I don't know your setup, or what your engine is capable of, but theoretically, someone could build a car with a supercharger with the same flat HP from 4k-8k, or one of the "Plateau" HP curves with much lower HP before/after the plateau that could potentially land the officials in the subjective landscape of determining if this rule applies:

Any Dyno curve resulting in aberrant data points that would otherwise be included in the Avg
HP calculation that are not consistent with the usable power band or flat tune power band can be
rejected by the Race Director/ TT Director at their discretion, and the Maximum HP will be used
to classify the vehicle.

[Alan_Wolfe]

Thanks for the info!

The MINI has no technology that would allow variable boost.

The MINI has a 1.6L four cylinder motor with a roots style supercharger - boost is a fixed function of RPM.  The supercharger allows a very small 4 cylinder motor to emulate a not so small 4 cylinder motor.

Since it does not use the supercharger to create a "torque monster" HP curve are you saying I am allowed to average over 8 data points instead of 4?

Thanks again,

Alan

 

[ssmith]

On 3/16/2023 at 11:26 PM, Greg G. said:

If I remember correctly, there are at least two or three different technologies that allow superchargers to be variable boost, like a turbo.  We write the rules for the best possible setups--trying to avoid loopholes that if just a few exploit, puts a huge dent in the entire program.  Of course I don't know your setup, or what your engine is capable of, but theoretically, someone could build a car with a supercharger with the same flat HP from 4k-8k, or one of the "Plateau" HP curves with much lower HP before/after the plateau that could potentially land the officials in the subjective landscape of determining if this rule applies:

Any Dyno curve resulting in aberrant data points that would otherwise be included in the Avg
HP calculation that are not consistent with the usable power band or flat tune power band can be
rejected by the Race Director/ TT Director at their discretion, and the Maximum HP will be used
to classify the vehicle.

The requirement to use only 3 data points for forced induction cars predates the rule that allows the race/tt director to use maximum HP for dyno charts that have clearly manipulated drops in power within the measured range.  The argument was forced induction cars can create these abhorrent graphs, but it was later shown that naturally aspirated engines can do that too.

Since the new rule now exists, can we drop the requirement that forced induction motors be limited to 3 data points?  The only people that rule is trying to catch would be caught by the rule you quoted.  Those that have normal or flat dyno curves are being unnecessarily penalized.

[Greg G.]

On 3/19/2023 at 9:37 PM, ssmith said:

The requirement to use only 3 data points for forced induction cars predates the rule that allows the race/tt director to use maximum HP for dyno charts that have clearly manipulated drops in power within the measured range.  The argument was forced induction cars can create these abhorrent graphs, but it was later shown that naturally aspirated engines can do that too.

Since the new rule now exists, can we drop the requirement that forced induction motors be limited to 3 data points?  The only people that rule is trying to catch would be caught by the rule you quoted.  Those that have normal or flat dyno curves are being unnecessarily penalized.

No.  The rule was put into place for the same reason that low RPM engines (high displacement) are not given a larger range of data points.   Both of those engines have the potential for very wide band flat HP curves that high revving, low displacement engines cannot. (In essence, the "torque" argument in a more practical application).  A car that can make a flat HP from 3K-7K RPM is not the same as one that can make a flat HP from 5200-6200 RPM.  At the very least, there are advantages in number of shifts/lap, and that is given a close ratio transmission.  But, in most cases, there are advantages in exiting the slower corners where it is difficult to keep the higher revving engine in the power band (again, without significant shifting).

[Alan_Wolfe]

@Greg G. , you missed the question I asked in my post above:

Since it does not use the supercharger to create a "torque monster" HP curve are you saying I am allowed to average over 8 data points instead of 4?

Alan

[Greg G.]

7 hours ago, Alan_Wolfe said:

@Greg G. , you missed the question I asked in my post above:

Since it does not use the supercharger to create a "torque monster" HP curve are you saying I am allowed to average over 8 data points instead of 4?

Alan

No, I didn't say that.  Rules are written for the potential that can be done (and has been done in the past).

[Alan_Wolfe]

15 hours ago, Greg G. said:

No, I didn't say that.  Rules are written for the potential that can be done (and has been done in the past).

Then how do I get this rule changed?

This rule penalizes me for what you perceive as something that could potentially be done by others, but that I am Not doing.  How is that fair?

[Greg G.]

Alan,

First, it is not what NASA perceives, it is something that can be done.   In terms of fair, there are many rules that allow something that drivers don't necessarily take advantage of.  If you take a look at all of the no Mod Factor modifications available, it is likely that you don't have some.  Then, as an example, someone may be taking the Mod Factor for spherical bearings due to an altered ball joint for bump steer, but not putting sphericals on every other possible site on the car--taking a Mod Factor for control arms, but not switching out all of them. 

The Avg HP rules are a very complex subject, and we have gotten to where we are by having rules like you would like in relation to superchargers.   However, if you can write a rule that will make things more fair for your situation, but not have either a subjective rule or one that leaves loopholes that others can/will take advantage of that will ultimately make things much less fair than your situation, please e-mail your request to me, and NASA will evaluate it for a possible rule revision. 

[Alan_Wolfe]

Great Greg!

I have an idea that can be quickly implemented to tighten up the Forced Induction penalty so it only applies to configurations using the SC or turbo to pump up low end torque.

I'll email you, but I am going to write it up here so we keep this process as transparent as possible.

Thanks,

Alan

 

Edited March 23, 2023 by Alan_Wolfe
Decided not to present 2nd idea, at lease not till this idea is hashed out.

[Alan_Wolfe]

Hey, @Firouz H., this is the first thread I mentioned in the email I sent you 2 days ago.