Unless i'm wrong, there was talk of the GT doing 212mph. It'll do atleast 205mph, that much i know.

As for coefficient drag, z06 > GT.

GT's Cd is 0.39 . Original GT40 was 0.43.

C6 z06 is listed as 0.34. The regular c6 on the other hand is listed as 0.28.

 

With only a 9% loss of power in the drivetrain, NHRA Pro Stock teams should start using the GT's drivetrain for their race cars.

(im being sarcastic, and doubting that there is less than a 10% loss from flywheel to wheel)

 

Because we don't really know what the flywheel HP is, and given that it is a street car with a street transmission on street tires with street gearing, I think a 50-60 HP loss through the drivetrain is reasonable - though I wouldn't at all be surprised if that is conservative and the actual flywheel HP is higher (and I'd rather be conservative...especially when discussing a Ford on this site).

I don't buy a generic percentage to convert from RWHP to flywheel HP. Never have. One reason is that I have shown a 15 RWHP (~5%) swing in my old 99 from one type of street tranny to another (300 RWHP vs 310 RWHP vs 315 RWHP - with only a tranny swap).

 

Well obviously different drivetrains will have different drivetrain losses, depending on the the setup. I wonder what kind of loss Ford's transaxle setup has in the GT. I guess the only way to know is to put the car on a chassis dyno, and then pull the engine and put it on an engine dyno. Does anyone have any links to any articles where any shops do this to any cars at all? I would be interested in reading the results.

 

That is the only way to know for sure. If I'm not mistaken, the GT uses a Tremec T56, similar to the Viper (and not much different than those found in the F-body, 03/04 Cobra, Vette, etc), though with different gearing.

The only real live numbers I've seen from the same car/engine on both a chassis and an engine dyno was from a racer friend of mine about 3 years ago. He was running in a Mustang Racing Organization (NMRA) in the "Factory Stock" class. His motor made ~390 HP on an engine dyno, and ~340 RWHP. I'm sure there are other examples out there (mostly from race cars), but I don't know of them.

 

I've learned in my aerospace classes here at school that aero has alot more to do with top speed than HP. Numbers like Cd have an exponential effect. I'd bet on the vette being faster. I wish I still had the book that compared aero to hp and how it effected top speeds.

 

drag=Cd*density*frontal area*0.5*velocity^2.

Nobody listed the reference areas for either the Z06 or the GT so you cannot say which one has "better" aerodynamics until you know that information.

The GT is faster than the Z06 by at least 7mph based on advertised numbers, so I don't know if that really leaves any room for speculation.

 

I know there is alot more to do with top speed than HP, my point was what does power-to-weight have to do with it? HAZ-Matt's equation makes no reference in regard to weight with it, so I am led to believe that it has very little bearing on a cars top speed, and therefore the Ford GT's portlyness will not be a disadvtantage when it comes to this.

Does anyone know the frontal area for the Vette and the GT?

 

The Ford GT does not use the T56, its transaxles are supplied by Ricardo. Here are its gear ratios for reference.

Gear Ratios
1 - 2.61
2 - 1.71
3 - 1.23
4 - 0.94
5 - 0.77
6 - 0.63
Reverse - 3.135
Final Drive Ratio 3.36:1

 

You beat me to it.

 

To answer your question Russ, drag is only one force that acts on the car. Simply put, you have the power to weight ratio of the car which gives you an estimate of the force it can use to accelerate itself if there was no drag. So take that force and subtract drag and you get a better idea of how fast the car can really accelerate. At low speeds, drag doesn't produce much of an effect, so power to weight ratio works well enough to compare the cars. But around the 200mph range, aero becomes very important such that small changes in aerodynamics can give you much greater increases in top speed than large changes in horsepower.

 

AFAIK, the ZO6 is gear limited, not drag-limited... Stick a ~3:1 rear gear in there, and it might be a match for the GT, but stock for stock, the ZO6 redlines 6th at a hair under 200mph, while the GT goes on to 210-212mph.

 

I understand power-to-weight always plays some degree of a role in acceleration, but at some point doesn't its importance start to greatly diminish compared to aero? How much of a difference is there actually in rolling resistance at 199 versus 200 mph? I think you are overall agreeing with what I said, and I am sorry if I oversimplified it. You seem to know more about it then I do. It just seems to me HP and Aero are primarly what are considered important in top speed runs.

 

The z06 is drag limited. It does not redline in sixth gear, if it did it would be doing very well over 200mph. Supposedly it hits its aerodynamic wall at around 5000 rpm, and will not pull any farther, which equates to about 198mph. Although I do agree, with a little lower gear in there, maybe 3.73s or 3.90s, by the time the z06 is at 198mph it may be in a better part of its powerband, and may pull past 200. I guess only time will tell, as there are still too few of these cars out there.

 

Ricardo or some such, I hear it is a very expensive transaxle,

oh,this is interesting when I went on a web search for the GT transaxle

http://montanafordstores.com/FordGT.pdf