Z rating is an old rating system that means 149+ because they figured no one would ever go 150 and beyond. They are good for much higher than 149mph.

Also, I want to know what's the deal with this speedo inaccuracy thing...anyone???

 

I was taking a friend home one night and he kept telling me how fast his old trans am was and he told me to see how fast we could go. I got up to 140 mph and said what the hell and hit 160 mph and he started to beg me to slow down. I still had more to go but backed off.

 

You should be scared going 150mph anyway, LOL. You'd probably get their quicker, but not as stable without the spoiler. The drag created by the spoiler would hinder you- more power would take care of this however. Either way, I'd rather have a stable car at speeds, and sacrifice a few mph, rather than the latter.

I read that the effects of a rear diffusor are minimal on street cars- because of our ride height- but they do add to downforce without the aero drag a spoiler creates. A flat underbelly like Ferraris have, w/ a diffusor and lower car would serve you better. As for the hood, I've seen videos where air gathers under it, causing the front of the car to raise some- a vented hood would assist in eliminating this problem.

 

cool thanks Shinobi-X

 

155mph and lost my driver's side headlight cover in the process..........racing one of the newer M3's

the 7 came out victorious

 

I wonder how the V-MIC and the Panspeed huge vented hood would fair at 180mph...

 

165mph.

 

170 with a weak motor and it was still pulling hard....that was back when i was running non-sequential stock twins

i started to think too hard about it and convinced myself that at any moment some sort of rabbit/armadillo/possum was going to pop out in the middle of that 2 lane TX road and cause me to go out of control and die.......so i slowed down

 

156 indicated.....146(4th gr redline)too many times....I get a little tight arsed about shifting over 120......4th gear is about it for spontaneous street racing. The 156 was an open stretch of road which ran out very quickly, however, I lost my nerve quicker than the road ran out tarmac......got a kid, wife, bills to pay can't do that ****.
Was still pulling at 156....good to know if I ever need it - not.

GEB.

 

175 Mph, on stock twins and motor.

In Germany It was running 7500 RPM. Calculated that with 8000 RPM you would be hitting 187.5 not calculating drag etc and inefficiency.

Only thing is that at these speeds your bonnet is moving.

 

What is up with all this talk about speedo inefficiency??? What causes this? Is there any way to calibrate it? Also, how does the bonnet move around?

 

I hit 160 the other night but my suspension scares me at that speed so I slowed to a stop with hit 180-200 hopefully when I get my single on her. they are right though 140 and up everything gets real scary at those speed.

 

155mph in my turbo II, it would of hit 160, i just got a little scared.

 

The speedometer (on my car, anyway) reading is off up to around 8 km/hr (5 MPH) both higher and lower up to about 120 kph (75 MPH for those ignorant of metric). It gets worse at higher speeds. Its' accuracy varies both plus and minus according to how fast you are going. As for how fast I've had mine I plea the fifth (in American lingo). I do know that an indicated 200 km/hr is actually 187 km/hr (that's about 145 MPH) in my car - my GPS (Garmin GPS III+) is accurate to 0.1 knot - better than 0.5 mph. That is what I used to determine the accuracy of the speedometer. At an indicated 200 km/hr the car is stable as though you were driving at 100 km/hr (62 mph) and when the accellerator is depressed, the car accellerates hard, firmly pressing the driver into the seat. Fortunately, as the driver gets older, he/she also develops a better appreciation of how painful (or dead) one can become at these kinds of speeds, if anything goes wrong, particularly without a roll cage and 5/6 point harness. The driver then quickly slows back down to speeds closer to legal ones ;-).

 

140mph and still pulling strong, i was shooting for 160... and then i heard an apex seal go through my engine, oops.

 

Damn! I wanna know what causes this inconsistancy in the speedo and how we can remedy it!

 

The inaccuracy in the speedometer is just caused by the cheap "automotive" instruments. The speedometer is just a poor quality analogue current meter, driven by pulses of current. All cars I've had my GPS in are pretty much as bad. Usually they are consistently above or below. My RX-7 is both, but not as much error as some cars. You could add a good quality meter and tap into the speedo output, and then calabrate your new meter. I suspect the input to the meter is quite accurate (not a cable, rather just pulses). You could even do a digital meter (like the RX-8), but it would take some circuitry to convert the pulse rate to an appropriate number. The easiest fix is just to get a GPS and make a calibration chart (affixed to the side of the pod like aircraft do - cool factor?). Or you could just leave the GPS in the car, like I do, and rely on it. Great for setting the cruise right at the limit (it's amazing how many drivers think I'm speeding when I do this - most car speedos are set to read a bit high to keep their operators legal).

 

110 but it was at the strip, (i stayed on the gas a little bit past the finish line) otherwise the fastest is 80 on I 95 flowing with traffic
-stephen

 

Ok lets say i'm hauling *** like around 150mph+ and i want to slow down. do i:

a) gently apply the brakes.
b) release the accelerator pedal until i've reached an x mph, then apply the brakes.
c) firmly apply brakes and risk accident and death.

given that i have stock brakes, pads, wheels and z rated tires.

 

b) as long as you can, then a)

 

what would be the x mph that i can safely use the brakes?

 

You can get on the brakes full down from 150 mph, people do it at the race track all the time....

Just don't jerkily close the throttle and jam on the brakes....just smoothly release the gas and smoothly apply the brakes.

Dubcaps: Live a little man, this car's hardly getting going by 80 mph.....

 

I've had my FD to 165mph before I had to back off before I ran out of straight road.
It was still pulling. I believe with enough road I can hit 180mph easy.

 

I'm finding the front end to get unreasonably twichy in my stock touring over 120 mph. For those of you who've transplanted the R1 lip, doest this mitigate the air buildup under the front end significantly, or just look real nice?

Girlfriend just looks over at me and smiles and says, "THAT'S why you bought it, right?" Good woman...

 

120mph...that's why you bought the FD?! Come on man, I do 110 in my beater...You bought that thing to do 150-160mph!!

In regards to the twitchy front end, I don't remember having that problem in my car at 140mph without the front lip spoiler, but my car is lowered to about 4" off the deck so maybe that has something to do with it. Anyone else wanna comment regarding the performance of the R1 front lip spoiler, I'm also anxious to know.