nynvolt

I've gotten it up to 140 and was smooth as silk, I was mostly worried about the law and hitting something, not by the stability.

I read the thread where a guy was saying he walked over a GT at high speeds, did he have the new 298HP or the older 265ish one? My boss kept gunning for me in his and finally gave up. He has the 04 or 05 G35 sedan. I didn't blow him away but he was obviously slower.

I read in motor trend the 05 GT is drag limited at 145ish, never got it over 140 so I wouldn't know for sure. The car pulls hard all the way up to 120, then you can feel the acceleration slowing a bit up to 140.

If I had to bet on it, 0-140 mph, my money would be on the GT.

2MFF

Without casting stones in any direction, I will just put up some "numbers".

A car with a Cd (coefficient of drag) of .30 (newer vettes have .28 or so) will use 230 hp just to overcome air resistance at 175 mph. This does not include the horse power required to overcome rolling resistance and drive train losses.

At a Cd of .35 it would require 257.25 hp just to overcome air resistance at 175 mph.

Given a theoretical test car that makes 312 rwhp (which we can assume accounts for driveline losses) that would leave 54.75 hp to overcome rolling resistance on the N. Vegas test strip.

Using 285/40-19 tires and a 5200 rpm point in 5th gear (.68) and 3.55:1 rear end ratio we would have:

Tire diam = 2 x [(285x40)/2540] + 18 = 26.98

mph = (5200 x 26.98)/(.68 x 3.55 x 336) = 172.97 (176.3 @ 5300 rpm)

Interpret as you wish

Shifty

I don't know who told you that but they are full of it. Maybe you're talking about 6 bangers?

max2000jp

There is no limiter on the C5 Z06, but its drag limited. Learn something about Vettes before making smart comments. Do a search on Corvetteforum and something should show up.

max2000jp

I like the effort, but that calcualtion leaves out weight. Two identical cars, but with differing weights(say 500 lbs), will not have the same top speed.

2MFF

As much as I would love to be a sarcastic azz at this point, I will merely point you back to my post for re-reading.

ben05

Well the other day I definately didn't go 145 on the beltway and my car definately didn't feel rock solid so I guess I really wouldn't know.

Purple Hayz

She's definitely NOT drag limited, at least not in stock form. *Maybe* if you had a helluva headwind. In any event, I've bounced her off the governor on several occasions, though it's hard to know how fast I was going precisely. The last "notch" on the speedo is at 145 m.p.h., though if you hit the 240 km/h mark your going just shy of 150 m.p.h. Obviously, at those speeds you don't spend too much time looking at anything but the road :nono: But judging by the needle, I believe the 143 mph top speed claim may be a few mph short of what she'll do (that or my speedo is a few mph generous!)

Incidently, I believe the gov chip chimed in when the tac was at about 4250 rpm. anyone know for sure?

SixtySix

I recall 4,300 last time I hit it before I got the tuner. I must say I like the way it hits the limiter, you don't feel it at all, it just stops pulling.

clockworks

It was a G35 Coupe with 298 HP and 6 speed manual transmission (6mt) in the thread.

My (then stock) GT easily pulled on my friend's auto G35 Coupe going 80 to 120 mph, but I think the argument on the thread was that a 6mt would beat an 05 GT at high speeds cuz of the closer gear ratios. When they say higher speeds, they mean like 120+.

I think the sedans are substantially slower than the coupes.

Sonic Brew

I had my car up to about 135 and it was as solid as a rock. I was trying to hit 145 but I saw another car comming the other direction on the road so I shut down.

RRRoamer

Vegasjay,

To make matters worse, motorcycle speedos (and particularly superbike speedos!) are WAY off! They usually read at least 5% fast and some are as high as 10% fast. The manufacturers do that on purpose to avoid lawsuits when some idiot losses it at 130 mph and claims he thought he was "only" going 125 mph. Lawsuits have been won on less in this stupid country (well, stupid tort system at least!).

As someone suggested, grab a GPS and see what it tells you (I would guess around 155 mph). GPS by it's nature is pretty good at relative positioning (telling you were you are on the globe), but it is VERY accurate with velocity and direction information (basically, the vectors).

There is a lot of math involved (most of which I have managed to forget since I ran the GPS Master station in Buenos Aires, Argentine back in 1990-1991), but it basically boils down to the simple fact that calculating velocity is basically (final position - initial postion) / time elapsed (and they are dead nuts ON with time! Time error for GPS is measured in billionths of a second!). The neat trick is that any position error for the initial is almost EXACTLY the same for the final position, so when you subtract the two, you cancel out (almost) all the error and end up with VERY accurate velocity data.

Oh, and just for fun: True * 1.05 = 175 indicated, so True = 166.7 mph. Or, True * 1.10 = 175 Indicated, so True = 159 mph. I bet your friends bike has closer to 11% error, or you have added a good bit of hp over stock...

sybidoc

Hey clockworks, I had my 05 GT M up to 145 indicated and the Stang felt fine, stable and tracked very well, just as good as my old 93 RX-7 Twin Turbo at that speed. By the way, Two weeks ago today I rolled and totaled the car. Was only going 30 at the time, no one hurt. The 05 Mustang got the highest rollover rating from the Govt and I have to say, the roof held up VERY well. My new 06 GT M Tungsten, red leather will be here in 4 more weeks. Doc

clockworks

Whoa!! How'd you roll it at 30 mph? Glad no one was hurt, but that sucks about the car. Do they flip easily?

Btw, good to hear that it felt solid at 145.

6505pony

Yeah how did you do that? When they test rollover ratings it is for the lack of tendency to roll over. Not how well they hold up during the roll over I thought.

Somebody in a vert (like me) should know.

245/45ZR-17

The G35 coupe and sedan I believe are very close in performance. If you compare specs for the two they weigh almost exactly the same and share the same wheelbase and overall length, which is surprising to me.

MT ran a 14.1 with an o5' 6MT sedan. Just some food for thought...

BTW Vegasjay, go get a GPS and put this 175mph matter to rest.

Shifty

The Speedo's last mark is 240 kph I believe and that's ~150.

Side note:

There is a reason for the ~147 mph speed limiter on the stock car. IT'S THE TIRES. They are only rated for 150 miles an hour. I would HIGHLY suggest not taking a stang over that speed with the stock perrellis. Very bad idea.

TehSLeeper

Well somehow the vortech mustang with such pooty aero did 198. So I still stand by what I said.

max2000jp

Jeez you can't win with some people. Actually read the article; it states that it put down 552 rwhp.

TehSLeeper

With no built engine. I'm sorry but a stock bottom end will not handle 552rwhp. That's at the crank. Regardless, I still don't buy your opinion that the Z06 is drag limited at 170 because I've seen the capabilities of a lightly modded Z06, CAI and short tube headers with exhaust, about 20 rwhp, destroying exotics from a roll.