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Discussion Starter · #1 ·
Funny thing, I haven't been running my Mazda on account that I just became a Dad and I have been driving my wife's Passatt. It's a V6 but it doesn't compare to my Mazda.
The Mazda has much more punch with that turbo. ANYWAYS, I haven't been able to run the Mazda and burn in that catalyctic converter.

Hey, what is the top speed you all have done???


I have taken my 88 MX-6 GT up to 135-140 MPH, but that was back in 1995. I was running against another Mazda (a 626 hatchback) on Loop 410 in San Antonio. Anybody from SA?
 

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200 KPH bouncing on a stock suspension towards upcoming turn = scary (really s****y roads/highways over here). Won't do that again any time soon. Engine had still some 1000-1500 RPM's to redline.
 

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bobgt let's see your ticket then. i call B.S. big time on this one. prove me wrong.

this subject has been discussed multiple times in the past. most people have an analog speedometer and estimate their top speed to be higher than it actually should be. digital dashes tell you exact speeds and there is no estamating... however that's assuming your speedo is accurate.

i thought the theroretical top speed of the 6 was 150mph. gearing, tiresize etc.
 

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Yeah, given 6000 rpm max engine speed and stock tires, the gearing limit is about 150 for MTX on either N/A or GT. In theory it would be higher on the ATX, because the overdrive is 0.700 instead of 0.711, but given the whole torque converter thing, yeah....

Of course, if you futz with the ECU, and you were willing to blow your engine, you could rev higher, you could also ride with bigger tires, but it is very unlikely that you could ever get over 160 or so without serious modifications to suspension, air dynamics, and engine. It takes a bit of power to travel at those speed, and an appropriately modified suspension.

That being said, I managed to get my speed limited DX up to ~120 on the speedo once going down hill, it's hard to beat continuing to accelerate after your fuel cuts. I think I had a tail wind too. :)

Also, a funny thing about my DX, for some reason, there is a lot of noise and vibration between 78-82 mph, but over 82, it is much smoother and quieter, such that I was driving at around 105 mph at one point, and a friend in my car didn't even realize it, he thought I was going slower, so I slowed down and he couldn't get over the difference in noise. Eh, whatever.
 

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I dont go past 120mph. I know I can hit 145 with ease and get there fast too.

I just dont trust my cars parts to hold up at 130+mph (not that I dont trust my car) its just that in the triple digits it gets scary.
 

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moebius. that's more of wat i was trying to say... but didn't quite know how to put it.

my max i have run (according to the digital dash) is 132mph. i ran outta road though. i bet i could have squeezed a few more mph out of it - but not much more than that. i've got more mods now & would love to try again but i must wait till my summer tires are on. wouldn't want to do that with winter tires on.

for you guys trying this... be safe!

1) nobody on the roads around you.
2) TOP mechanical shape.
3) tires at the correct pressures
4) AND tires rated for high speeds.

if you want to see how fast you can go like an idot (myself included) make sure not to take out a family in a minivan or your best friend in the passanger seat.

just look at dany heatley.
 

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Discussion Starter · #10 ·
Thanks for your comments, stories, and advice. I feel great knowing I bought such a great car. My car now has 230000 miles and I only take it up to 110.
I used to travel from San Antonio to El Paso on Interstate 10 and I would cruise for about 30-50 miles at 120 MPH. Of course you have to be aware of the following:
GOOD TIRES (high speed rating, balanced, good suspension)
NO ONE AHEAD of YOU
CLEAR STRETCH OF ROAD
HEADLIGHTS ON
However at anything beyond 100 MPH, you are at the mercy of GOD.
 

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God Shmod, you're at the mercy of your own abilities and cars ability to travel safely at that speed. Dont give a fairytale in the clouds credit for anything you do in the real world. Anyone traveling faster than their vehicle is capable of, is iching to follow Darwins theory of dumb die, smart live.
 

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indicated speeds vs ACTUAL speeds

drdemux said:
most people have an analog speedometer and estimate their top speed to be higher than it actually should be. digital dashes tell you exact speeds and there is no estamating... however that's assuming your speedo is accurate.
Your speedometer, whether analog or digital, has no idea what the circumference of your tire is, only what the stocker was when inflated properly.

I'v done 189 on Highway 40 between Canmore and Longview.

That's kph and that's REAL kph (recorded on a GPS). That's not even 120 in MPH, but I wouldn't wanna go any faster on a public road.

Stock speedo on mine is a bit ummm optimistic (again, checked against a GPS). With a shorter tire, the "optimism" will be further exaggerated.
 

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Scrubbo said:
235Km/h has been my top speed was reading with a G-Tech not my speedo. :cool:
While I have no personal experience with G-tech, the consensus hereabouts is that is about as accurate as butt-dynos (that is, not very).

I would trust my speedo more that G-tech.
 

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i have topped out at 150mph i know my speedo is off so i went over the guage. Going at that speed is a thrill. My car was smooth and had full control, didn't feel like it was lifting off the ground at all.
 

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i've done 120mph on the highway, but any slight "turns" felt like the car was leaning quite heavy. I still had some rpm's left, but i wouldn't go any faster anyway..... it was awsome but i could feel the front end lifting.
 

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I have hit 130 and it had a little more, I think I had the stock tire size on as well. If not it would have been 205/60R15. It was on a stretch of new wide open freeway, that was freedom.
 

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Discussion Starter · #18 ·
DUDE!!, that is fast...150mph.
What I am hearing is that the speedometer is not accurate at those high speeds, but I disagree. I do believe we (the car and I) went at 135-140 mph (217.26 - 225.31 KPH {HP-48GX}).
And thank you for the word of caution URETHANE.
I wouldn't take my car more than 90 at this time. It needs a lot of work, specially on the suspension.
 

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dreamx6 said:

What I am hearing is that the speedometer is not accurate at those high speeds, but I disagree.
The speedometer does not know what your tire circumference is AT ANY SPEED, not just at high speeds.

You're permitted to disagree, but without a GPS or radar gun or timing lights to check against, you just don't know, it's just your opinion.

My opinion was that I was doing 240 on Hwy 40, but the GPS said 189. I was wrong, GPS was right, no matter how much I disagreed.
 

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Well, as for accuracy on the stock speedo,
Depending on what has been done, it can be reasonably accurate(unlike my spelling today). In this case, I mean give or take 10 mph.

There are often side of the road radar speed traps which tell you how fast you are going, sure, when there is alot of traffic it isn't nearly accurate, but late at night when you are the only car, it should be pretty accurate.
Some speeds(mph) I remember (speedo on left, radar on right)
30 27
55 52
60 56
70 64

And of course, the last speeding ticket(more than a year ago), according to my speedo I was doing about 96 mph, but I got a ticket for 89, but I suspect that was a low number, or not entirely accurate, since the cop car was perpendicular to the road, and by the time she (yes, butch b*tch cop, sigh) pulled out, I had slowed down to less than 80, but still... 89 mph actual from a speedo of 96 is pretty close, and in line with the above numbers.

Point is, the speedo will be off, but you can get a good idea of what the real speed is based on the speed that the speedo is reading, so my one run of 120 mph, was probably more like 108 or so in real speed.
Granted, my car was in better shape when I did that, a couple years ago, but still, just a little commentary from my paying attention to the side of road radar speed traps.

Furthermore, the accuracy of your speedo is affected by the wear on your tires, it can be significant. I have done a number of long distance (~340 miles) drives between pittsburgh and Virginia, and I have gotten a variety of distances, between 340 and 365 miles based on the level of wear on my tires, granted that's only like a 7% difference, but 7% differance at 70 mph, is between 65 and 75 mph, and of course there is also the inaccuracy of reading a speedometer, just because of the limitation of what it says.

Point being, it is very likely that the GT's can do 130 mph when un governed, and they are theoretically limited by gearing, stock tires, and engine rpms' to 150, but except on the people running FE-DOHC (because of higher rpm limit). Given the inherent inaccuracy of our speedos, I really doubt that, inspite of the 150 mph speedo listing, that anyone here has gone more than about 130 mph in real speed.

As for sleepcounter's speed(speedo said 240, gps said 189), geez, his speedo was off by more than 25% -- that's really bad. Either you are running way off stock tires, or something is wrong, because that much of a difference is ridiculous.

I think a safe estimate for most people is around 10% high, (so that 200,000 miles on the odo, is reall only 183K, sigh!), so just remember, if it says 110, it's really only 100 (or less even!)

But this is all just my opinion.
 
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