Whats with Ferrari and bogus HP numbers?

My apologies as I'm not trying to be negative.

Power = (force x distance)/ time
velocity = distance/time

I don't know your knowledge base on physics, mathematics or even James Watt and the steam engine so it makes it difficult to answer without assuming and coming across as an ass.

dv/dt can be read as "delta V over delta T" or the difference in velocity divided by the difference in time to calculate instantaneous points.

As to Ferrari and the published HP it would more then likely be engine dyno.

I hope that helps.

 

As I sit here thinking way too much about this thread I realize that HP has been distilled down to some holy grail of a number that means something other then what it really is. The numbers many mfg publish are peak HP, but that's just one data point that is relevant. Where in the operating range of the engine does this occur? How big is the power band? Then one gets into what the engine is stuffed into and those parameters. So in reality the single HP number is not that meaningful by itself.

 

I'm going to agree to disagree.

I'm looking at the formula for HP. Not power.

When torque T is in pound-foot units, rotational speed N is in rpm:
hp = (T * N) / 5252

We can look at power, velocity, speed, but the formula for HP is above and its what I believe Ferrari uses. My assumption was right. I jumped to Ferrari's web site and they measures SAE NET.

I believe 100% that Ferrari puts less power to the road then its competition. I believe they have more rolling resistance, more wind resistance. Maybe its downforce creates more resistance.

I think we are talking about two different things.

 

I agree 100%. If I could agree more than 100% I would.

 

One of the issues about manufacture statistics; ie., -0 to 60, 0 to 100, braking distance, lap times, horsepower, etc. is to show how superior their car is compared to other exotics when it comes to performance.

I'd say that some people in the real world buy it for those reasons and want to test it out for themselves. It is extremely important for a lot of people (myself included) that a car should perform as advertised. (f12, 675, huracan, aventador, etc.).

 

Every country has different sae measures of hp for the manufacture

I.m not sure whats changed to this day and age


Understanding Gross Versus Net Horsepower Ratings - Ate Up With Motor

 

I'm curious if Ferrari would tune the vehicle for you. My guess is they tune it for a particular driver.

Have you asked the dealer or Ferrari if it can be tune for better performance. Or find your own private mechanic to work on it. Might be fun to see how much difference you can make. How much of that engines power you can put to the road. How much rolling drag, wind drag you can reduce.

Who needs a butler when you can have a mechanic.

 

Ha ha. If it was really important to me then I'd give it a shot.

I'm definitely looking forward to the owners from SF Bay area who are going to mojave mile on October 1. They should have some good video, statistics, information for all of us.

I know that the particular f12 owner who is going is deeply competitive when it comes to this type of stuff and I believe he has had our local dealer at Ferrari look into his f12.

 

Power is to horsepower as an inch is to a mm. They are both a measurement of the rate of work but in different units. Definition and formulas are the same i.e. Torque x rotational velocity. Once you have your units right, you'll get the same number.

 

My understanding is the Bentley was not part of any wager. Proof of the lambo, 911, and 458 were the requirement. Title copies were provided for the lambo and 911 and insurance for all three. So more paperwork is being asked for on the 458 then the charity gets a donation? Hopefully 04 will get a copy of it when he can and the charity will get a donation, which is never a bad thing.

Also, what is the requirement these days for entry into the owners forum? I don't know any other fchat members in TN that can vouch for me and it seems Carbon is Mia.

 

I'll assume that the 458 is in a company/LLC name and wouldn't have his name on it. However, since his name is on the insurance then he would be the de facto owner.

I'd say he has proven it pretty definitively.

 

It's good article. Not sure I understand what you mean by every county uses different SAE measures. I did not read it that way. Different countries use different measurers, but SAE NET is SAE NET.

If you read Ferrari's PH for F12 you should know what SAE NET is to know what the HP means.

This article really helps understand why it has changed over time and what number is being advertised.

Thanks for sharing.

 

Agreed.

 

Right on so since dyno tests have little relevance to a cars road performance due to drag, weight, gear ratio, speed of DCT clutching/selecting etc, then IMO, the best way to distinguish one car from the other in absulute performance terms would be in straight line drag.

How fast from 0-60
How fast from 60-120
How fast from 120 to top speed
Speed at 1/4 mile
Speed at 1/2 mile

Now the only control factors become ambient conditions, tyre rating and road surface. Once you have those factors somewhat controlled, it would strictly come down to the cars performance. This is as objective as I can think and will allow the extra advertised horses to prove themselves. If they don't, then I would not blame anyone who:

1. Questions the OEMs validity
2. Asks where the hell the extra horses are going

So if this test still does not mean anything to you, then you should be ok with an OEM publishing numbers so ridiculously absurd as to never reflect thier real world performance. That was sort of the original argument, no?

 

I'll start with some basics.

1ft-lbf , this is foot-pound force, the application of one pound-force thru a displacement of one linear foot.

Why am I point this out? because when James Watt standardized the HP it was based on the amount of work a horse could do over time. For brevity it was 33,000 ft-lbf over one minute of time. Your 5252 in the equation is the rounded value of (33,000 ft·lbf/min)/(2π rad/rev).

Horse power is simply that, the power of a horse. James Watt in order to sell the steam engine had to make it relatable to the 'engines' of the day, namely the horse and that's how we got HP.

 

Hell if I know what the argument was at this point.

Your summation sounds right and is why many test mags would simply do that, round up a bunch of cars and hit the track, heck isn't it what is done in racing since the first wheel started rolling.

 

So after all of this ... does Ferrari overstate its HP ratings?

 

Well, nothing in this thread soundly supports the OP's original assertion.

Ringer cars supplied by Ferrari are a known thing.

But the reality of the situation is, Ferrari rates their engines using a known process (DIN 70020) and baring some kind of fraudulent dyno machine at the factory, the numbers are what they are.

Additionally, production engines are also dyno'ed and rated. Not sure how much deviation from the prime engine Ferrari allows. +- 3%?

Look, if a drag race winning Ferrari is what anyone is after, forget horsepower, start dropping weight. As in, 500+ lbs. worth.

-F

 

3% would be very good. On the electric motors I spec, I have about a 5% part to part variation in both Torque and RPM. Since they're not 100% inspected, I ask for a 1.33 short term capability (Cpk) and 1.0 long term (Ppk). All this means is that the 5% would be more likely close to 3% when the parts are actually checked just to keep an extra sigma variation for safety. If Ferrari dyno 100% and only allow +/- 3% total variation from nominal, then that's some pretty good quality control.

 

I don't know if this has been mentioned specifically, as I can't bear to read the whole thread to find out.

The flawed logic in determining the horsepower of a car from a drag race assumes all else is equal. Ferrari brags about the hundreds (yes, hundreds) of pounds of downforce that their cars generate. That's because they use Fiorano as their metric for performance. They value grip and speed in the corners. They are always raising both horsepower and downforce to accomplish this. To gloss over the impact of aero in passing by saying it is minimal, misses the whole point. The brick shaped cars that are faster may have more frontal area, but probably get much lighter as they go faster. There's a big difference between drag from air resistance and generated weight on the wheels. The only real way to back up a claim of bogus numbers in horsepower is to use a stationary dyno. The virtual dyno apps out there use acelerometers, but also use a constant weight figure for the vehicle it's being used on. The numbers they give can only be considered a crude approximation. Much like the crude thesis of the original assertion of this thread.

 

Honestly, I just pulled 3% off the top of my head based on some general information about various car companies. I have nothing solid to assert that is the actual variance in Ferrari engines across the production run. It could be 5%, it could be 10%. I really don't know.

Dyno tests of Ferrari engines conducted by outside shops are out there for review. Not sure if anyone has done it on engines from the current model lineup.

Oh, OK, you were just yanking chains all along. Good to know for future reference.

-F

 

On the subject of downforce and assuming straight line motion, apart from the added friction, does it also have an inertial effect (resistance to acceleration)?