Chickfila? Try our nuggets? Now I'm really lost!

 

The only problem I have is that 5th gear won't go to 164MPH (might get up to 157 depending on when the rev limiter hits and tire inflation). But since he ran some in 6th I have no problem with his GPS reading 164MPH.

Stereodude

 

Don't worry I'm confused too.

Stereodude

 

I believe the top speed is 180 or so. In sixth gear at 2000rpm you are at 65. In 6th gear at 4000 rpm you are at 120. So then at 6000 rpm you should be at 180. The only problem is redlining 6th gear. Supercharger maybe?

 

Did you read the thread at all?

No?

Didn't think so.

The car could go 200MPH (redline in 6th) if it had the necessary HP to do so.

Stereodude

 

hey hey, but maybe he understands the chickfila thing...

95/2k2:6Maxima, what does this mean to you?

 

Don't worry Stereo I trust your math.
The way you put it in to form it all look very possible.

 

At least he's knocking someone else.

155 in 5th at 6550 RPM does equal 200 MPH in 6th at 6550 RPM.
With none of those unpredictable pesky tail winds it would take roughly 550 to 600hp at 6550 RPM.

http://www.rx7turboturbo.com/robrobinette/top_speed.htm

 

HAHA... this is just supposed to losen things up.
fil-a-Chik err Chik-fil-a doesn't make nuggets. Irony?

 

must be a regional thing??? What the hell is a chickfila?

Now, fil-a-chick, we know how to do that where I'm from!

 

just for the record...what i said on the first page about the speedo AND the GPS being wrong was meant to imply that I DO NOT think they could both possibly be wrong.

and what i said about trying it again didnt mean i was a doubter. i was just saying that doing it a second time with someone watching the speedo would just be one more thing to back it up.

 

My friends supra (at the time) had about 450HP at the wheels. He put it on the dyno to test that 450 and it ran out to 202 mph. wow that would be interesting.

 

Hey those numbers work for me. Besides, not every Maxima is the same anyways. But no more math! I'm getting flashbacks of Calc!

 

First of all, I'll play the responsible father figure here and say......

For the love of all that is good, do NOT feel obliged to perform your top speed experiment again. There is no sane reason this guy has to haul a passenger with him at 160+ mph to satisfy us *doubters*. Now, I've gotten mine up to 140mph or so, but at that point I was satisfied that it would, ahem, cruise comfortably at any speed I'd need to travel. If you are going 160+mph with passengers in the car just to satisfy us, please trade in your car, and get a moped. I understand the 'need for speed', but please dont endanger others to prove a point that many may not believe unless decreed from the Almighty himself. End rant.

 

and I can tell you that max speed can easily be skewed. for instance, if you go from 12ft accuracy to 50+ ft accuracy on next 1 sec polling interval, your max speed will be off. In fact, I've had a bad reading give me 275mph max speed. It only lasted for 1 sec when I went under an overpass. I know this is wrong because I cant get over 230mph in my 2k (with Jato packs )

WAAS is good and will keep the margin of error down.. but at those speeds, +/-30 ft in a reading will skew your speed. My WAAS keeps me locked at about 12ft *most* the time.. but it still varies at speed.

 

make sure your Legend is patched to the latest ROM. If you are running an older version, they recently changed some code to smooth out (via their algorithm) max and overall speeds.

 

Tim,

What you're neglecting to realize is that the error in a GPS signal is from the drift in the satellites orbit. The drift of the satellites doesn't change much if any in between sequential data points. That means the absolute position is off, but the the relative position (to the last data point) is not off. So yes, you may be 12 feet off towards 259 degrees, but your next point is also 12 feet off towards 259 degrees. That means it's speeds measurements are very accurate.

Stereodude

 

I have had a Garmin Street Pilot GPS and a Garmin Street Pilot Colormap in a Boening 727 / 737 on more than one occasion. They mantained pretty consistant speeds throughout from 500 to 600 MPH and made changes slowly that were consistant with pull of the plane. But I have seen blips or errors during normal driving that have swayed as much as 10mph when the sat. traking is bad. For the most part these things are VERY accurate. I have also sued one to confirm the speedometer in my max to be dea on ***** accurate from 20 all the way to 100mph. The meter in my 4th gen car was overly optimistic though.

 

E=MC2?

I read most of the math opinions and i have to say I dont understand...am i dumb?


Maybe not

 

Well, I gotta say, I expected a bit of a response when I posted the thread but never the type of response that I did get.

I think that this has been one of the best threads that I've read in a long time. The arguments that everyone made really made me think this thing over - big time -

I've come to the conclusion that the 2k2 Maxima 6spd is a very capable high speed car. Even if the run is out by 5-10 mph (I think most people agree that the Max will do 155 or so, stock), the adjusted number is very respectable. There are not too many vehicles in the Max's price/class that can claim to do even 150.

Thanks to Stereodude and SR20DEN for not letting this thread get out of hand. Both of you made good points that are well beyond my field of expertise.

In the end, all I know is that the Max surprised the heck out of me with the reading. No, I don't believe that I'm going to go find a friend to hop into the passenger seat and film the speedo. I may never wind the car out to that again. The entire time I was in the high speed run, my eyes were scanning the shoulders of the road for deer, unfriendlies with lights on the roof of their car, etc. Anything could have happened during the run, it turned out well - this time.

No, I'm not abandoning this thread, I just realize that things can only get much more theoretical than they are. Not sure how much I can contribute to a conversation that goes down the path of 'the wheel bearings in the Maxima are so good that resistance is 1/10th that of...' I hope you guys understand.

Again, thanks for a great thread. I hope it continues to be a productive thread.

Albert

 

I agree, I think this thread should be archived or stickied. Well at least the formulas and technical discussion in it anyway.

 

I'll chime in and add a few things. I don't believe he was going 164mph in his Maxima. I have a hard time believing a 255hp Maxima is going to match the topend of a stock LS1 F-Body. The F-Body makes substainlly more HP and TQ and as perfectly matched gearing (1-5 not 6).

GPS Error-
I'm an environmental engineer and my firm does environmental work for the Air Force. I use GPS units to survey in borings, excavations, fuel lines, underground storage tanks, etc. The accuracy of these over the counter GPS is "good", but not great. On an hourly basis, my vertical (elevation) readings can vary from 15-60' and horizontal readings can vary by 10-30'. What this means is that you can have roughly a 60' X 60' space in which the GPS estimates your location. This kind of estimated location is great for an over the counter GPS because most people use GPS's to find large areas like fishing spots, camp grounds, shopping areas, excavations, etc. By over the counter, I'm talking about the units available for cars and hand helds. The Government DOES dither GPS signals for civial use. If you don't want to believe me, fine, but I've got a document sent directly to me concerning the use of GPS units on their projects. The document clearly states that the government dithers GPS signals therefore the Air Force requests that I also manually survey in locations because of the inaccuracy of a civilian GPS. I cannot post this document due to the client privilage.

The amount of inaccuracy in readings is more than enough to throw off MPH wildly.


Dave

 

Hey Dave, I thought this stopped being the case as of 2000? Check out this link . I take it your saying that civilian GPS units are more accurate than before but still not as accurate as the military's?

 

I have to say I believe Dave in this case. I know they cleaned up the signal in 2000 but I doubt they took all the errors out of it.
Although the discussed reading may or may not have been thrown off from inaccuracy, in most cases they are accurate and consistent for speed readings. But for elevation they do plain suck. I have noticed you usually can't trust them to better than 200 to 300 feet.

 

Take video of it next time and silence all doubters. Impressive speed.

 

there is still a HUGE diff between consumer GPS and military/aviation GPS.

Stereodude, my point was that your accuracy can vary from point to point and skew the speed.\

if you watch, with 1 sec polling, you'll see 12 ft, 12ft, 15ft, 12ft, 20ft depending on atmospheric conditions.

 

SR2,
I agree that inaccuracies exist (and especially in elevation) longitudinally and latitude-wise at the second (") level (300ft is what I've seen as well) but that 300 ft variation is actually a constant when we are talking about speeds. As long as the frequency of hits from the sats is consistent during the run and the same # of satellites are in view to triangulate, etc., it should not matter as far as the cars position which is how they estimate the speed. That's not necessarily a linear adjustment of 300 ft, it could be perpendicular or any partial radian off the direction. But it is consistently so.

I imagine a calculation can be done for the permutations of possible positions read versus actual that COULD cause error, but I gotta think that it can't be more than 4 or 5 mph. Planes (non-military) use these same grade of GPS's to calculate descent times and turning plans. They can't be too inaccurate. Same with autopilot commercial shipping.
My opinion though.

Shaydz

 

So in a nutshell, you've just backed up everything I have said about cunsumer GPSs in this thread.

 

Damn people, I didn't know the org was full of scientists...
I read (more like skimmed, getting late and tired) the posts, but I noticed no mention of the fact that all the numbers/formulas/math/equations whatever didn't include a margin of error. I'm not a full fledged engineer, but in my lab class, we were always required to factor in error for real world numbers. Those equations work be accurate only if they were performed in a controlled enviornment.

I'm intrested in how elevation/altitude, and angle of incline would factor into the max speed obtained in the GPS.
I mean...other real world factors would probably affect the final number as well like wind. As to how much a degree it would affect it, that beats the hell outta me. I would assume at that high speed, wind (not resistance/drag) would have that much an effect.

And about the accuracy of the GPS...at those high speeds, would it matter? And wouldn't altitude affect the number as well? Interferance from surroundings? I dunno... but in the end wouldn't it still be pretty damn accurate?

damn....that was long.

But my final word, I think EVERYBODIES gonna get a different top speed in real world conditions, so why can't there be someone with a Maxima that performed expectionally well at a certain time and place? Call it a fluke. (good goin dude!)



woooord....after that said, I feel srmat now!

 

Frig!!! spelled smart wrong.

 

haha


btw, you can edit your posts.

 

HAHA.. weeyer all smrat heyere

 

oh hey, waddyaknow...I can edit! (spelled "spelled" wrong too...d'oh!)

 

Yes. Funny how that works, huh... I believe there is some margin of error - plus (haha) or minus, but not much because they are very accurate.

EDIT - Bottom Line - Awesome speed - It might be off a little, but geez, what does it matter! You're chewing up distance there in a short time - VERY IMPRESSIVE!

Shaydz

 

Stereodude........you're gonna win the Peace Prize with all those formulas ya know.

 

I have a stock 2k2 auto.
I was cruising down the interstate one day and decided to see what my car would come close to for top end.
So, I floored it!
Hit 6500 rpm in 3rd gear and then shifted to D.
It slowly was topping out in the low 130's. I didn't have the patience to see if it would go over 135mph. the interstate I was on is pretty flat here in IL too.
i had to know what it could do so I went home and put it up on jackstands. Hit the rev limiter in 'D' (drive) around 135mph. that sucked!!
I bought the car back in sept 01 and I think at that time I saw the new 2k2 max was supposed to do 153 mph top speed??

do you guys think my car has always topped out around 135mph cause it is an auto or do you think since the dealership replaced my gas pedal stopper and reprogrammed the computer that is why???

 

Anyone else picturing Ferris Bueller's Day Off in the making?

You put your car in drive and revved it up to 135 on jackstands??????????

I mentioned earlier in this thread that I'm psychic. My prediction for you: you will soon discover if your car can fly...








(and you will discover it CAN'T)

 

LMAO

 

Oh dear... here we go again.

 

I dont care what anyone says, that car is drag limited to WELLLLLL below that speed.

I aint starting a war, but it is not correct.

Dixit