most JDM cars have speed limiter at 180kph.

 

My speedometer doesn't work so I can't tell how fast I'm going. Oh and my emergency brake like won't turn off. Is that bad?

-Max

 

1. Check the speedo cable at the tranny. Look at the FSM for location.

2. There's a sensor for the brake lever, again check the FSM and test it.

 

Pull out the instrument cluster. On the printed circuit board on the back there is a little screw with 180 printed next to it. Removing this screw disables the speed signal sent to the ECU, and hence disables the 180km/h speed limiter. Enjoy.

 

in my street ported 90 vert I hit 157. I then topped a hill and nearly **** myself, the whole car left the ground, I knew cause we found four seperate marks where I landed. about a 25 foot flight. At 145 the whole top kinda sucked out and the car tucked down even tighter than usual, it felt really weird. I had a pic of the speedo at about 153 but the little memory card got erased.

 

Since a stock S5 Turbo needed 200hp to get to 145mph, you'd need ~250hp to get to 157mph (power required increases to the cube of speed). That's not really streetport territory. I'm not saying you're lying, just that the speedo was way out.

When will you guys realise that you can't trust the speedo at high speed. Bragging about your top speed is like bragging bout the size of your dick while looking at it through a magnifying glass.

 

Whats wrong with a magnifying glass?? J/K

Anyway haw far off does the speedo get? I guess mazda figured if you were goin that fast accuracy didn't really matter cause you were goin to jail anyway. But the speedo did say 157, my buddy was behind me in his eclipse and his saye 147 when I gunned on it and I was leavin him behind pretty quickly. And he has one of these G-tech things or whatever that tels you your speed and all and it said 148 tops for him and I was faster, and I was on a slope when i hit 157 and the next hill is the one that put me in the Flyin FC

 

I have no idea how fast you were going or how accurate the speedo is at that speed; I just know the physics relating power and speed. Most people don't appreciate how much more power is needed to increase a car's top speed. For example, doubling power only increases speed by 26%. Gearing obviously plays a big part too, since engines make different power at different speeds.

The speed reading on G-Tech's can't be trusted at high speed (this has been proven). It measures acceleration, and at that speed your acceleration is tiny so accuracy suffers.

Do you know what revs you were pulling? You'd need 6400rpm in 5th to do 157mph in a NA.

 

you wont hit 150 if you don't have the power

 

it was about that, I think about 6300 to 6400, I think.

I've also got the rear end out of a automatic so I could hold gears longer, so that might contribute to it.

 

Um, your story's getting worse. With a 3.9:1 rear, 6400rpm would be ~165mph...

 

This is what makes Jason such a fantastic forum member.

******** like me just post the BS flag, no beating around the bush.

 

On flat ground with a **** pot load of ground covered, when my car was stock, I got it to 140mph in 4th... dont remember rpms... Its a skinny road, I was more consintrating on where the **** I was going!
It'd be interesting to see what it would do now, because 3rd and 4th pull alot harder now!

 

Thats why I said "I think" it might have been in the 5k rpm range. It was a while back when I just got everything fixed on the car, so I don't remember exactly.

 

tell me ways that when i get my car working i can do something or get something that will more acurately tell me my real top speed

 

Factory tolerances are typically within +5% at under 100km/hr and within +8 % at 200Km/Hr

So at factory calibration, the speed could be off as much as 3 MPH at 60 MPH and report you were doing 63 MPH or at 90MPH be reporting that you were doing 95 MPH and still be within factory specs

If you have changed gearing/ trannys, or rear ends or tire size, or even have a speedo gear that chipped a tooth or two, that could go considerably further off than that. And its not uncommon to see a speedo off as much as 10% at 135MPH (so the reported speed would be 148 at 135 MPH).

 

Take the car to a speedo shop and tell that that you need it calibrated to 100+

 

Check your brake fluid level - chances are it's low.


Really though - why would you want to do 150 mph +? Am I the only one who thinks that doing this on public roads is kind of stupid?

 

In my buddies S4 N/A, he got it to 135, i've only taken it to 125...it was exhilerating.

 

So I take it that if you have a j-spec ECU in an A-spec car there is no speed limiter?

 

mine does opposite, it increases the speed smoothly. It probably needs more air in 5th

 

that's funny......lol

 

OMG, I totally forgot about that untill you said something. I still had the transmission end of the speed cable for the manual gear ratio, instead of for the Auto geared rear end. I switched it a few minutes ago. Thanks, and feel free to call me an idiot. and a tooth on the gear was a little chipped but not horrible.

 

I tried to max out my car one day driving through north california. I was racing with a AMG E55 (i have part of it on tape .. until we started racing). We both took off, neck and neck until about 130ish is when i assume he either let off or speed gov. kicked in. Well I figured it was a straight road for as far as i could see, with NO cars in front of me. So i continued to see when my car would top out. It was having problems that day also, and i had already been driving from seattle washington non stop. I took it past redline in 4th, then went to 5th ... expecting not much pull, i was very surprised. I shifted right into the powerband of 5th and it was still pinning me in my seat. At around 6500 rpm i pegged my speedo. The car was still pulling and i got scared and let off. Not to mention i have a little taller tires on. Either way, it was REALLY fast to me ... and i was happy with the performance i got out of my little t2 i'll try again once i finish a few things

stock block/turbo/fuel inj

fmic/walbro/some other little things

 

The US cars don't have a speed signal from the speedo to the ECU, so the speed limiter shouldn't work.