Be sure to test the top speed in Ontario, Canada. That way your car gets to be impounded for a week when you get caught.

 

6MT G37 will go 159 (at least) with no fuel cut off. So I was told by "a friend" who owns one and has access to a track for free occcasionally on the DL that someone lets him use while it is closed.

He said if he had the proper suspension and rubber it felt like it still had at least a little more. Maybe when he gets new tires and suspension he will be braver. However, he was pleased that it didn't get really twitchy on the smooth surface but the wall in turn 7 comes at you really fast.

 

Haha.. Nice. I was wondering if 147 was really it. I had my 2005 G35 up to 147 and was pretty sure that was all it would do.

 

At high speed I wouldn't trust what the speedometer says ... they tend to be a bit 'optimistic'.

 

ORLY? You think they are accurate at low speeds but "optimistic" at higher speeds or do you think it's just off in general? Do you mean just on the G or in cars as a general rule? How did you form this opinion?

 

All vehicles over report the speed the car is going. This is to prevent you from sueing the car company when you get a speeding ticket. The amount that is over reported is greater as your speed increases.

 

I've never heard of this before. Point me towards some reference to get in the loop on this.

 

Mine stops at about 145 (maybe 147) per the needle...

Have tested this numerous times......Doesn't matter how I have the transmission set...I have tried it paddle shifting, in the DS mode and in the normal mode. No matter what it does the following:

It will be in 4th gear but just as soon as it hits the 145 (happens fairly close to the redline in 4th) it will shift into 5th (no matter which mode the transmission is in) and just sit there. Will no climb any higher...

I've tried several times and had the exact same result every time....I do believe in stock form with no restrictions it should have the power to push 160.....If power was no issue it should run out of gearing somewhere in the 185ish range based on the rpms it's pulling in 5th at 145ish...

 

You have a 5AT. We are talking about manly cars.

On the 6MT the speedometer goes to 160. So does the car. Well, 159 so far. Unless it's innacurate as a couple of other posters claim. I don't think 185 is possible from this car with any gearing.

 

6mt Ftw!!

 

well tony from Fast intentions is trying to get an airfield soon for a few of his customers to do some High speed HD videos. if that happens i might go for this crazy record speed but if not then i think i have gone about 135 or 140 on my way to Vegas. Cars very smooth and felt as if it had more. Again my rims are pretty big so not sure if that would matter?

 

Just make sure you know how the far the strip is, don't wanna end up off the other end!

 

hmmm gonna have to speak to tony about that. lol and aznutz YOU NEED TO SLOW DOWN!

 

I know this from personal experience w/ cars & motorcycles. I would trust GPS calculated speed or a calibrated speed detector for top speed, but never a car's speedometer.

Due to a number of factors, most speedometers are only so accurate (see next paragraph), and it gets worse as speed increases. Simple example: If it shows 30 when I'm really going 29, then I am only going 58 when it shows 60, 116 when it shows 120, and 145 when it shows 150. The last rental car I had showed 80 when my GPS showed 74 (I haven't checked out my G because it already has nav). Back when I was into bikes most magazines would list the measured speed @ 60MPH indicated by the speedo for bikes they reviewed (54-56 MPH actual was common, which is ~15mph off at 180). They always measured their top speed using a speed detector, not the bike's speedometer.

If you dig into it, basically a speedometer infers speed by measuring something indirect like front wheel angular velocity (exact term escapes me right now) and then doing a simple linear calculation. They can't account for things like front wheel slippage (worse on a bike) and tire diameter changes (such as wear). As your tires wear, for a given speed displayed on your speedometer you are actually going slower than you were on fresh tires because your tires are slightly smaller (but you are quicker because your gearing is slightly better). The analog circuit used to move the MPH needle is functional but not what I would call 'precision' either.

 

I disagree with a lot of this reasoning. I do agree that the higher the speed that you go the more inaccurate the speedometer can become BUT it is relatively accurate up to a point. Good car review companies test this out by verifying the speedometer speed compared to actual speed. If memory serves me correctly they test between 60-100MPH. They will tell you how much the speedometer is off and most of the time it is correct. I also believe there are certain requirements as far as accuracy goes. GPS is not accurate compared to the speedometer. Calculation using the wheels can take in account correction factors which are easy to calculate especially for newer cars with a built in computer. If my TI-83 can do it then a car can do it. They can also calculate slip hence why we have LSD and the LSD light shows up. GPS is only accurate to point but GPS cannot give you exact positioning especially if it is a civilian GPS. How exact is GPS now? Within 10, 50, 100 feet? I will have to look that up. If it cannot pinpoint your exact location before and after then the calculation won't be exact either.