My car can easily make 175! My speedo even said that! And It's mostly stock, see the pic of it!:



I was clocked officially at 244mph.

Oh, wait.. that's not my car...

clicky here for more info: http://www.mazdausa.com/MusaWeb/disp...eritageHistory

Sorry, this just seemed like the "end all" of any "HOW FAST CAN MY FC GO!!!11!!!11one????" thread

 

I want!!! I want!!! I want!!!

 

I want!

 

since its not closed, i'm going to argue!! okay, not really, more of an arguementative question..
sonicrat said his speedo was dead on until 90mph. how could something be off by a percentage if also dead on in a certain are? in this case, ~0-90. it seems as though the formula would need to be a bit more complex than just a "percentage." of course, thats assuming the speedo was, in fact, dead on. i trust sonic. i believe a monkey with a calculator and formula could figure the math out. its not hard, is it? just have to know the numbers and do some times'n an' divide'n.

 

here's out of Edelbrock's 2002 Performance Catalog; Technical Discussion section:

Formula for MPH:
MPH = Tire Radius / 168 x Engine RPM / Gear Ratio

Example: What MPH at 6500 RPM with a 4.9 rear axle and 14 inch radius tire in 4th (1:1) gear?
MPH = 14 / 168 x 6500 / 4.9 / 1 = 111 MPH

Note: Tire Radius is distance, in inches, from center of wheel to the top of the tire.
Note: Gear Ratio is Rear Axle ratio divided by Transmission Gear ratio.

have fun and drive safe. even if you're going slower than you think.

 

Basically yeah. Now, with that situation...Sonic's speedo being dead on until 90. Have you opened the guage pod up? I have! The speedo's in there are controlled by a coil spring. I am assuming that Sonics spring is getting hung up on these two little plastic stems poking out, pointlessly, from the back of the pod. My speedo was off by about 60% and I couldn't figure it out because once I hit 40mph is when it would go off. Before 40, it was dead on. Those springs are not the strongest types of metal, so, they are easily stretched and/or broken.

Did that answer your question...BTW, I don't see the arguement in your question...so, that whole first line wasn't needed. I let out a sigh of relief upon reading your post. I stand true to my previous statement.

 

haha, yea, it was a joke! i'm a dry humour jokester! no, i've never opened up the speedo, more just pointed out that, in the speed sense, it wouldnt be true to say its a percentage matter if something was 100% correct, then fell off at this number (speed in this sense). the situation could be, however, a variable percentage difference. haha, talk about numbers i wouldnt wanna get into!

this raises my next question. since i dont know, i'm going to assume that the miles counter is attached to the speedometer (am i right or, as usual!, wrong?). in this case, how off would the miles be on a car? may be impossible to ever know...

 

Actually, you are right...so, if you are travelling 100mph only reading 50 you are only marking down HALF of the actual travelled miles...That's jacked up, No?!


***Variable percentage...Sheesh...that is something that we will not get into here...But yeah...actually, you are absolutely correct...But, if a Speed-O is 100% on until a certain point, there is most likely an abstruction...as seen in MANY cases by my own two eyes!

 

Basically, mine is dead on with a GPS and radar proven up to about 90mph. After 90, it starts to increase almost expotentionally, 100mph is about 105-108mph on my speedo, by the time my speedo reads 120 i'm really doing about 111-113, 140 is around 123. 160 is around 133. It just keeps gettin off by more the higher I go past 90, all of my FC's follow the same general pattern.

 

same

 

wow.

i guess i'll have to buy a gps device of some sort.

 

I believe that.

But i think I have a legitimate question here...and i'm not trying to flame or anything.

I was thinking aout this thread. So i did a little test.
I redlined fourth gear to an indicated (and agreed semi-innacutare) 7400rpms. The speedomoter read a tick over 120mph.
I shifted into fifth and landed around 5200rpms.


So can someone tell me how tall 4th gear is? It seems to me that fourth must go over 111-113. Id imagine 120 would be fairly accurate?

 

rx7.com says that fourth gear at 7500 is 122mph.

 

Wow so my speedo was pretty close.

If it was that close i just cant believe i was only going 130 when it said 160 (and the rpms were around 6700-6900 i think.)

 

I raced a 95' Honda Accord EX with few mods from Fresno, Kali to Merced, Cali. Thats 45 miles. I kept beating him over and over and I reached 145mph and decided that was pretty scary when I looked at my rear view mirror and couldnt see **** cuzz it was vibrating. Besides the Accord couldnt even max out that high. O yea, my car is a stock 91 N/A soon to be 13BT cuzz it flooded after that night. Damn alcohol made me feel like the wind.

 

well honestly i don't know how rx7.com got that info. They may have just driven a car on the highway and looked at the tach and speedo...

 

Well you can figure it out with the gear ratios and tire size.

But if we agree that third ends around 90, it doesnt make sense for fourth to end before 120.

 

I think it is sad that no one has taken the time to fix the spelling error in the title...what is goten? Shouldn't it be, "Gotten" and isn't that a, "NOT REAL" word?! Sorry...

 

in fourth at around 6500 rpm i've gotten my fc to around 125

i've also got 215/45/zr17's, which may make a difference...

stock by the way...except for k&n filter

 

haha, if you wanna correct all the horrible type-os and bad grammar here, good luck ! sometimes i wish some people spoke another language and barely knew any english, much less knew its structure and how to spell. that would explain some of the crazy things we read. unfortunately, it seems as though someone swapped the keys on their keyboard around and hid all the punctuation marks.

 

I was on the interstate at 2:45 a.m. in my 1988 gxl and ended up racing a 2003 V6 mustang and smoking it and by the end of us racing i looked down and my m.p.h guage said 146 and climbing....talk about scary

 

So you don't have a second gen... you just have worse aerodynamics and less hp. And this argues your point how?
BTW... vehicle weight affects acceleration, not top speed. slap an extra 1000 lbs into a vehicle and it will have an identical top speed, it will just take longer to get there.
So having a 2000 lb FB car means your top speed won't be any faster than a 2600 lb FC, given equal hp. In fact, due to better aerodynamics, the FC will have a higher top speed.

 

In my old S5 TII, under dual stage nitrous, I managed to bury the needle.
My Nordskog GPS speedometer read 272 km/hr. (170 mph) I don't think nordskog makes it any more... I picked it up a couple years ago from summit racing for $399 USD and change. I wasn't even watching the speedo at that time, it has a peak recall.

This was on Toyo 225/50-16's. The tach read about halfway through redline. Actual engine rpms were closer to 7000-7100 from what I recall.
FYI: at 260 on the speedo, the speedo read 252 km/hr.

My all stock S5 N/A does 128 mph according to the nordskog.

And lastly... I have since done 276 km/hr according to the nordskog on another vehicle... Not rotary powered though.

 

What kind of GPS unit? Just curious.

 

Magellen something or other, I forgot which unit it is exactly, i was linked to 6 sats at the time, so I'm pretty sure the triangulation was pretty accurate (considering both radar and my speedo said I was at 90 while cruising as I went past the 'check your speed' police setup. Most of the time I have it datalogging and marking my position with MS's map software, and a couple of other programs that keep track of time spent actually moving/speed from point a to b/etc. I just have my passanger hit a button to monitor speed as i'm driving, and it's always been dead on with my speedo to about 90, after 90 the speedo goes downhill. It's also been verified within .3mph on a couple airplanes. Let me dig it out and figure out which model it is.