Okay I'm not sure how this is possible but I've hit 172. The only mods I had were drop in filters, a full exhaust, HFC and it was dropped quite a bit. I'm also at a very high altitude though...don't know if that has anything to do with it. I bought the car with 2k miles and it appeared stock inside and out...and I've never got a tune or removed the limiter. This makes me wonder if it was modified before I bought it.. :confused:

172 based on what? Speedometer?

FWIW HFC and CBE is a pretty big power bump... good for a couple-few mph on the top end.

Yes that was just off the speedo give or take a mph. So I don't understand, is it limited from the factory or not?

i hit 171 with a garmin for gps data. speedo said 175. it starts to get wobbly up there

fully load 2 200 lbs guys road trip cloths and a dog

Speedometer is wildly inaccurate. It could be off by 10% at high speed in some cases.

It is limited from the factory to 155 mph I believe. If you were truly going faster than 155 then yes, your car has had the limiter removed and might have a tune on it.

Are your current tires shorter than stock tire height? If they are then your speedometer is going to read faster than you are actually going... and at high speeds the margin of error is going to be even greater than when stock. So it's very possible that your 172mph indicated was under 155 actual.

So does the limiter cut you off based on what the speedometer says or what your actual speed is?

It can work a number of ways. Not exactly sure how it works in the Z, but it could just simply be a rev limiter in top gear, or based off of the wheel speed sensors.

I know for a fact I was going faster than 150, because I've been that fast in my last car and this felt way faster. Tires and wheels were stock with 20mm spacers all around, and the tpms were also removed. Awhile back I noticed it has a green bolt on the front of the engine.. looks like a ground. Thought maybe a grounding kit? I'll have to take a picture of it and see if you know what it could be. That was the only indication that it had be modified.

that's not really the most scientific way to establish speed

That's true. 100 MPH in a Buick LeSabre feels faster than 140 in a 370Z.

Well I'm assuming a 350 and 370 feel very similar at that speed. I'm not trying to be scientific. I'm just sayin..

they don't. the shorter wheelbase on the 370 is going to make it feel notably different, not to mention the fact that your car is slammed.

Oh..I see. Well my 350 was slammed as well...had a little more done to the engine too. I guess i'll get my friend to stand on the edge of the road and use my Hotwheels radar gun next time so I can get an accurate speed and prove myself.. :rofl2:

It's safer just to sit here and theorize. :icon17:

When I had my G37.. I saw 173 on the speedo and it was not tuned... Wondering if the governer is not always set from the factory? I have been in some BMWs that have blown past the governer as well untuned..