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View Full Version : Pwr to weight ratio



Racy-Stacey
07-19-2007, 11:19 PM
This a sort of continuation of the National IT class poll thread. As I was reading the last persons post. I was thinking it all comes down to leveling the field. How can people level the playing field.

My thought: Power to weight ratio.

So if we could set a Power to weight ratio to a class on top of its rules it might make the difference.
For the people who are write check racers or low budget racer, it would'nt matter. Cars found post race exceeding the Power to weight ratio would be disqualified. Figuring out what to set this golden number would be the biggest challenge.

The second big challenge would be getting all the regions to install dyno's at their location.

So whats your thought?

:024:

JLawton
07-20-2007, 06:47 AM
I think not only the cost of the dyno is an issue but the time it would take to run all the cars through the process. You'ld need an army in tech (and a lot of space because you would still be doing the previous run group when the next one comes in)

For the cost, are you talkin' purchase or rent?? Either way, at least at the tracks in the Northeast, the regions are losing money on the races as it is.............

joeg
07-20-2007, 09:01 AM
Too many other factors to consider. Power-to-weight may be too simplistic. For example, gearing and braking potential are also importatnt.

Knestis
07-20-2007, 09:09 AM
There's a big philosophical issue here, too: Which variables should we try to control, and which are we actually "testing" by racing?

One extreme is IROC, where the cars are prepared and maintained so as to be as close to identical as possible. Drivers don't even have very much latitude regarding set-up, as I understand it. This approach is intended to sort out the winners from the rest of them based only on driving skill.

MOST racing however takes into consideration engineering, preparation, etc., by providing mechanical parameters within which the competition takes place. In IT, you are racing a car and a driver (and a team organization, and budget).

If we have rules that limit/allow engine modifications, then power is an outcome of what you do within those parameters. BUT if we attempt to control for power - to take it out of the equation that we're testing by racing - then we've fundamentally changed what we're about. Spec tires attempt to do this but largely fail because the real variable influencing competitiveness is money. The dyno approach MIGHT not fall victim to that reality unless, I don't know ... someone buys a way to cheat their way around the dyno test?

Personally, I don't like the idea but some folks running NASA classes where this is standard practice think it's a good thing.

K

tnord
07-20-2007, 09:16 AM
especially with open ECU rules i can make that dyno say whatever the hell i want without too much problem.

this would be a gargantuan waste of time and money for all involved.

Racy-Stacey
07-26-2007, 11:01 PM
especially with open ECU rules i can make that dyno say whatever the hell i want without too much problem.

this would be a gargantuan waste of time and money for all involved.
[/b]

You can make it say whatever you want before a race but, a post race test would reveal what tune you just ran. And thats the catch.

Gearing and braking are important factors and already attended to in the current rules.

Concerning the amount of cars tested.
You would only need to test the winner.
If the winner failed you would test the 2nd place driver, if he/she failed you would then need to test the 3rd place finisher.

wrankin
07-27-2007, 10:16 AM
You can make it say whatever you want before a race but, a post race test would reveal what tune you just ran. And thats the catch.
[/b]

While I am not an ECU expert, I do seem to remember that some ECUs can store multiple fuel and ignition maps. What's to prevent me from changing from a "low power" to a "high power" setting and back at the flick of a switch?

Just a thought.

-bill

cmaclean
07-27-2007, 10:24 AM
I have personal knowledge of more than one ECU in professional racing today that will dyno 75% of the actual hp. If you don't start the car using a specific sequence it defaults to "dyno mode" Motorcycle guys use this trick also (since they are dynoed after racing)

gsbaker
07-27-2007, 11:10 AM
I have personal knowledge of more than one ECU in professional racing today that will dyno 75% of the actual hp. If you don't start the car using a specific sequence it defaults to "dyno mode" Motorcycle guys use this trick also (since they are dynoed after racing)
[/b]
This is why NASCAR loves them thar carbs.

chuck baader
07-27-2007, 12:10 PM
NASA works....sorta, kinda, maybe....with the hp/weight rule. But, when a low horsepower car outruns (GTS2) the 911 and Boxter in the first race...its awfully funny that they both can pull the Mustangs on the start of the second...and I can't stay in the same zip code. I would think there are many avenues through which to cheat the dyno numbers....just depends on how badly you want to win/cheat. :birra: Chuck

zracre
07-27-2007, 09:11 PM
SIR :o

MMiskoe
07-30-2007, 08:14 PM
Two things not already mentioned here.

You can't just dyno the top car. Dynos are all relative so to be fair it has to be open to everyone prior to the race so people can check where they stand against that dyno on that day. Same reason scales are open for weighing prior to going out racing. So then you're back to needing to dyno a lot of cars and chances are people would come, do a pull, be over their limit, then spend an hour tuning it back down.

Second thing is that peak HP or torque don't mean much if the power curve is a spike. So instead of building motors for max HP, you'd do everything in your power to make the motor have a dead flat torque curve, or one that slopes downward as RPM increase for a flat HP curve.

There is no magic answer.

Black91n/aRX-7
07-30-2007, 10:21 PM
IMO HP/weight comparisons are stupid. It's only one of many, many facotrs that determine what's fast around any particular track. At low speeds it does have a lot to do with what's fastest in a straight line, but at higher speeds hp/drag becomes more and more important. Then there's them turns...

Keep it the way it is, if one car's consistently outperforming others, then change the rules (weight, SIR). Lap times are the only real all inclusive measure of performance, and it's what matters in the end, so why wouldn't you use that?

shwah
07-31-2007, 09:46 AM
Because lap times introduce the single largest variable of the whole race car performance equation. Average driver to good driver can mean 4-5-6 seconds per lap. The combination of a good driver, and the fact that this good driver can set the car up better for each individual course is a HUGE variable that should not be factored into how cars are classed.

Compare that to the other two items that have the single biggest effect on lap performance: On my car we built a motor over the winter, and bought some Hoosiers in the spring. Going from Toyos to Hoosiers was 1.5s at Blackhawk, 2s at Road America (both times this comparison was on the same weekend or day with very similar conditions). Going from a stock to a full IT motor was about 1s at Blackhawk.

Modifications are limited enough in IT that the current process works well. Take specific parameters of the engine, driveline, suspension, brakes and use that to slot the cars into one of 5 classes with similar approx potential power to weight ratios, and adjustments for the other characteristics. How do we know this works? Well there seem to be a wide range of competitive cars in each class right now, there does not appear to be a single car to have in any IT class.