Yes, it is physics, but your physics appears to be wrong. I know for a fact that the tire distortion causes lower than indicated speeds, and that the gear calculator we're using is surprisingly accurate. How can I know that? Same way you can. Put a GPS in the car and compare the GPS readings to the corrected values you get from the gear calculator. They won't be exact, but the gear calculator, after correction for tire formation, will be closer than your speedometer. I know, because I've done it myself. Try it and see for yourself.

Tire slip is the dominent factor. That's the part of the physics you're either getting wrong or overlooking. I *think* you are also greatly over estimating the amount of tire expansion we experience, given the tire construcion we have on the S2000. A 1/2 inch expansion would reduce the contact patch enough to GREATLY increase the amount of slip, so the speedo error would be even larger (ie: car would be slower still).

 

i got to 138 a couple of times when the freeway was empty... still pulled pretty strong but i backed out. i wouldn't doubt it could touch 155, but i was consuming too much road and i had the top down...

 

everyday on my way to work i would run through 3rd to 5th on the service road all the way to redline, 125 everytime, not scary at all if the roads in good condition

 

the indicated top speed on the car is high by 2-3%, so subtract 4mph from the 159 and you get 155, which is what the calculator spits out.

and if the ap1 can do 155, drag is the same on an ap2 with roughly the same power to weight ratio (a few more whp and a few more pounds, slightly to the ap2's advantage on top speed i'd expect). why wouldn't the ap2 top out at the same speed? gearing will help more if the car is closer to redline, as power will be closer to peak and add more to the ap2's case.

i've gotten into the mid-130s a few times on a particular, low traffic, downhill interstate stretch, but that's about it. the stretch is less then a mile, and the car feels like it hits 125 there faster than it gets to 100 on flat ground. it was fun

 

my ap2 164mph with 100 rpm left.

 

i hit 140 with top down on a two lane road late at night, i thought it was really smooth and could go faster. but i really dont see the point anything could go wrong at that speed. i dont think i will ever go that fast again, i just wanted to see 140 on the tack.

 

On a flat road with no wind, top up, both AP1 and AP2 are drag limited to *about* 150 MPH. You have to look at the power/drag ratio rather than the power/weight ratio, because at high speeds, drag is the dominant factor. Since the AP2 makes a little more power, the top speed is a little higher, but not by much. When you add FI, the car is no longer drag limited, and with stock gearing I *think* the AP1 is a little faster. The difference still isn't very large though.

There is a thread somewhere here on S2kI where one of our members did some excellent simulations, comparing AP1/AP2/stock/FI, and so on, in terms of acceleration and top speed. If you can locate the thread (I don't have time to search for it this evening) you might find it interesting.

EDIT: I did have time to find the simulation thread after all. Click here.

 

yea they sure are limiters are right

 

Yeh, this was after alignment and tire balanced. Something about the car though. It could be the suspension being overtly sensitive.

it tend to lift on the front and too light on the rear for my taste.

But the wider tires and wider and larger rims really helped out.

 

you guys are crazy, i went 120 once and thats the fastest ive ever gone on a car and I freaked but then again im not used to that kinda speed so i guess i can understand where your coming from none the less i wouldn't go that fast if i wanted to see "150" on the dash ill just put it on KPH