Aerodynamics of Fbodys and their effect on High speeds - Top speed of Fbody's
02-21-2006, 05:03 AM
#21
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Originally Posted by Orange Terror
I hope this is the appropriate place to post this.
Ok, this started on a local board I am on about calling BS on a guy a work with that said he ran 160 MPH with his stock 1978 Z28. Anyway, it has progressed to a discussion about the aerodynamics of the fbody's and a little about the vette for comparison and that the factory speedometers and tachs are incorrect on these cars because one guy is posting this info That I think is totally bs and false.
Here are his posts:
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"the c4 vette in stock form didn't do that speed (was aero limited) around 130 the front tires leave the ground (the few f bodies that have doen it at bonneville are full race cars with a full belly pan)"
"top recorded correct speed in any factory f body is 125 (throw your worthless speedo in the trash over 55 that's the only time it's even close, it only has to be within 5 mph at 55 and can be off 40 at 100)"
"bear in mind the new vette is aero limited to 195 (that's the z06) the standard one can only muster 150 with testing equipment. The 4th gen is an aero brick over 100 mph. Look at bonneville you have to get a special license if you break 150, and it's not a common license to get, if factory cars did it frequently there wuldn't be as few awarded. I've gone over 150 (at Talledega in a stock car) and can tell you you have not gone that fast on the street a small pebble makes the car dance like it's on ice, and that's one that's designed for those speeds. When one of the magazines tested the new vette at 130 the front lifted almost 2 inches (at that speed you want it to go down not up)"
"when tested with electronics, and also at bonneville now basically stock f body of any generation has gone that fast the front lifts too much and it's like hitting a wall at 130 or so (I love watching the bonneville races)"
"factory speedos and tachs are way inaccurate, what you see at one speed has absolutely no bearing at another. My dad's dakota was fast under 55 but read slow over 70. Your factory tach can be off as much as 800 rpm at 4000rpm (even an autometer tach has some inaccuracy just becasue of electrical resistance).Trust me you would be scared on the street to go that fast (go to one of the petty schools once and you'll see what I mean)"
"the tests were done on either bonneville, or talledega, the front lifting is part of it, but at that point the car went no faster because the front got up in the air enough to cause drag"
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I'm curious, and just want to know if anybody has any evidence that what he's saying is true, cause I don't think much if anything he is stating is true. I'm sure I've been faster than 125 in my Z. Thanks for the help.
Ok, this started on a local board I am on about calling BS on a guy a work with that said he ran 160 MPH with his stock 1978 Z28. Anyway, it has progressed to a discussion about the aerodynamics of the fbody's and a little about the vette for comparison and that the factory speedometers and tachs are incorrect on these cars because one guy is posting this info That I think is totally bs and false.
Here are his posts:
------------------------------------------------------------------------
"the c4 vette in stock form didn't do that speed (was aero limited) around 130 the front tires leave the ground (the few f bodies that have doen it at bonneville are full race cars with a full belly pan)"
"top recorded correct speed in any factory f body is 125 (throw your worthless speedo in the trash over 55 that's the only time it's even close, it only has to be within 5 mph at 55 and can be off 40 at 100)"
"bear in mind the new vette is aero limited to 195 (that's the z06) the standard one can only muster 150 with testing equipment. The 4th gen is an aero brick over 100 mph. Look at bonneville you have to get a special license if you break 150, and it's not a common license to get, if factory cars did it frequently there wuldn't be as few awarded. I've gone over 150 (at Talledega in a stock car) and can tell you you have not gone that fast on the street a small pebble makes the car dance like it's on ice, and that's one that's designed for those speeds. When one of the magazines tested the new vette at 130 the front lifted almost 2 inches (at that speed you want it to go down not up)"
"when tested with electronics, and also at bonneville now basically stock f body of any generation has gone that fast the front lifts too much and it's like hitting a wall at 130 or so (I love watching the bonneville races)"
"factory speedos and tachs are way inaccurate, what you see at one speed has absolutely no bearing at another. My dad's dakota was fast under 55 but read slow over 70. Your factory tach can be off as much as 800 rpm at 4000rpm (even an autometer tach has some inaccuracy just becasue of electrical resistance).Trust me you would be scared on the street to go that fast (go to one of the petty schools once and you'll see what I mean)"
"the tests were done on either bonneville, or talledega, the front lifting is part of it, but at that point the car went no faster because the front got up in the air enough to cause drag"
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I'm curious, and just want to know if anybody has any evidence that what he's saying is true, cause I don't think much if anything he is stating is true. I'm sure I've been faster than 125 in my Z. Thanks for the help.
There's nothing but total crap posted there. If you want alternate ways of proving speed then GPS based system are some of the most accurate (many Satnav and hand helds can do this).
Or even drive a long a road with mile markers and time how long it takes to pass a marker.
At a constant 60mph you should pass one every 60 seconds, 120mph every 30 seconds and so on. Unless they claim that your stop watch is also not accurate and doesn't infact count seconds beyond 5 seconds then there's is no way of disrpoving it.
Last edited by 300bhp/ton; 02-21-2006 at 05:20 AM.
02-21-2006, 05:37 AM
#22
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I don't know where that guys gets his information...but um. He's a tool box. I've had the needle buried on mine for a good long while into 6th gear in the mojave desert. I've set the cruise control on 155 with the ttops off just for ***** and giggles.
02-21-2006, 08:09 AM
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Here were his statements last night. along with some other members.
Tool: "The tests were done by people with thousands of dollars in electronics designed exclusively for timing cars. So the SCTA is wrong (that's who runs the California top speed races) ?"
Other member: "Well I'm interested in getting this straight whos got gps?"
Other member: "I'll try it sometime. Last I checked with GPS, my speedo is exactly 10mph off, which means that it's 100% correct. It was 5mph off when I changed the gauges, and then when I got the rims it threw it off 5mph more. So it does seem as though my stock speedo is correct.. atleast at low speeds."
Tool: "keep in mind a commercial gps is also not accurate (which is why no timing association uses them) If it can't get your position within a foot it can't get speed that accurate (a military version would possibly work, but they don't sell them to the public)"
Other members: "lol Steve, you're starting to just sound paranoid."
"yeah I give up, my car only does 130 tops no matter what the speedo says, how depressing lol"
Tool: "the commercial ones have never been accurate, since everyone wants cheap (the military ones are 4-5 times what a commercial one is for the same features, just much better accuracy)"
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Now, here is some of what I posted after all this.
"This is starting to sound like desperation. Like the guy who tried to bluff and is now throwing in as much as he can to buy his way out of his bluff. Sorry, I gotta raise the bs flag (that we don't seem to have) on this one. I don't believe that modern speedo's are that far off. If so I don't see how they could legally hold us to speeding tickets and I've never heard anything about a conspiracy theory on that. Mechanical ones 20 years ago, maybe.
quote of tool: "top recorded correct speed in any factory f body is 125 (throw your worthless speedo in the trash over 55 that's the only time it's even close, it only has to be within 5 mph at 55 and can be off 40 at 100)"
Now if my math is right, and I may be off, I only use math daily and they pay me fairly well so I must know a little. So let's assume its only half that error instead of the max because, well 40 is a lot . So lets take that median error, if its between 52.5 and 57.5 mph when reading 55 (1/2 of within 5 or +or- 10 as I believe you meant) and 90-110 mph when reading 100. That's a 300% increase in error over 45 Mph. Wow, no wonder we only think we can break the 125 mph mark, when our speedo's read 145 we could only be doing 125, or, we could be going 165!!!! And that's only at half the error you are specifying!!!
Now, as for speedo accuracy, when my GPS reads 100 mph it has always correllated with my speedo. Not to mention I check it when I cross the finish line and go through the traps it almost always correllates to the speed on the slip at the track. If it doesn't, its never more than a couple MPH, not 40.
Even if GPS is off by a 1 foot radius, it can still track that 2 foot diameter circle as it moves pretty damn accurately, because it still knows where I am as I drive so I have to believe its going to measure speed pretty well.
Look, I'm sorry, but I think you are full of it on this. I mean you are saying that all of this equipment and technology is so far off that they are not even close to accurate? Cmon, give me a break. I'm going to bed.............."
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I appreciate all the input guys. Like I said, I was sure he was off his rocker, just wanted to be sure before I called him out on it. Thanks for the help.
Tool: "The tests were done by people with thousands of dollars in electronics designed exclusively for timing cars. So the SCTA is wrong (that's who runs the California top speed races) ?"
Other member: "Well I'm interested in getting this straight whos got gps?"
Other member: "I'll try it sometime. Last I checked with GPS, my speedo is exactly 10mph off, which means that it's 100% correct. It was 5mph off when I changed the gauges, and then when I got the rims it threw it off 5mph more. So it does seem as though my stock speedo is correct.. atleast at low speeds."
Tool: "keep in mind a commercial gps is also not accurate (which is why no timing association uses them) If it can't get your position within a foot it can't get speed that accurate (a military version would possibly work, but they don't sell them to the public)"
Other members: "lol Steve, you're starting to just sound paranoid."
"yeah I give up, my car only does 130 tops no matter what the speedo says, how depressing lol"
Tool: "the commercial ones have never been accurate, since everyone wants cheap (the military ones are 4-5 times what a commercial one is for the same features, just much better accuracy)"
---------------------------------------------------------------
Now, here is some of what I posted after all this.
"This is starting to sound like desperation. Like the guy who tried to bluff and is now throwing in as much as he can to buy his way out of his bluff. Sorry, I gotta raise the bs flag (that we don't seem to have) on this one. I don't believe that modern speedo's are that far off. If so I don't see how they could legally hold us to speeding tickets and I've never heard anything about a conspiracy theory on that. Mechanical ones 20 years ago, maybe.
quote of tool: "top recorded correct speed in any factory f body is 125 (throw your worthless speedo in the trash over 55 that's the only time it's even close, it only has to be within 5 mph at 55 and can be off 40 at 100)"
Now if my math is right, and I may be off, I only use math daily and they pay me fairly well so I must know a little. So let's assume its only half that error instead of the max because, well 40 is a lot . So lets take that median error, if its between 52.5 and 57.5 mph when reading 55 (1/2 of within 5 or +or- 10 as I believe you meant) and 90-110 mph when reading 100. That's a 300% increase in error over 45 Mph. Wow, no wonder we only think we can break the 125 mph mark, when our speedo's read 145 we could only be doing 125, or, we could be going 165!!!! And that's only at half the error you are specifying!!!
Now, as for speedo accuracy, when my GPS reads 100 mph it has always correllated with my speedo. Not to mention I check it when I cross the finish line and go through the traps it almost always correllates to the speed on the slip at the track. If it doesn't, its never more than a couple MPH, not 40.
Even if GPS is off by a 1 foot radius, it can still track that 2 foot diameter circle as it moves pretty damn accurately, because it still knows where I am as I drive so I have to believe its going to measure speed pretty well.
Look, I'm sorry, but I think you are full of it on this. I mean you are saying that all of this equipment and technology is so far off that they are not even close to accurate? Cmon, give me a break. I'm going to bed.............."
--------------------------------------------------------------------------
I appreciate all the input guys. Like I said, I was sure he was off his rocker, just wanted to be sure before I called him out on it. Thanks for the help.
02-23-2006, 06:23 PM
#25
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The guy is mostly on crack but the new ZO6 is aero limited with the HP it has now to 198. More power it will go faster my Grand Sport C4/LT4 did 162 MPH. My C5 did 189 redlined in 5th. Wheel were on the ground on both 
02-24-2006, 01:04 AM
#26
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Been 150 against multiple cars, who all said their speedometer was reading similar.
You go through the 1/4 mile in 105-109mph.. The speedometer is pretty accurate then.. so on the street.. you floor it to 105-109 then, somehow.. magically... from 105-109 to 125... the speedometer just goes up 50mph, while you only gain 15-20mph, and your speedometer inaccurately reads 150mph.
Why even bother talking to this guy.. he knows absolutely nothing about nothing, and he has serious issues to even argue the b.s. he is spouting.
Peace,
Josh
You go through the 1/4 mile in 105-109mph.. The speedometer is pretty accurate then.. so on the street.. you floor it to 105-109 then, somehow.. magically... from 105-109 to 125... the speedometer just goes up 50mph, while you only gain 15-20mph, and your speedometer inaccurately reads 150mph.
Why even bother talking to this guy.. he knows absolutely nothing about nothing, and he has serious issues to even argue the b.s. he is spouting.
Peace,
Josh
Last edited by distortion_69; 02-24-2006 at 01:11 AM.
02-26-2006, 05:48 PM
#27
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Originally Posted by 30th TA 0219
The Callaway 'Sledgehammer' didn't really have all that radical of a body kit when it ran 254.
04-01-2006, 02:32 PM
#29
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My 69 vert was clocked by the GA State Patrol at 143 with the top down. He was nice enough to share with me exactly how fast I was going!! So this guy is BS. I don't know how accurate my speedo was because it stops reading at 120.
04-03-2006, 01:19 AM
#30
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Originally Posted by s_harrison_jr
My 69 vert was clocked by the GA State Patrol at 143 with the top down. He was nice enough to share with me exactly how fast I was going!! So this guy is BS. I don't know how accurate my speedo was because it stops reading at 120.
04-04-2006, 11:17 PM
#33
Well in case you guys haven't read yet, my man intmd8 went to maxton and did 199mph in his turbo lt1 street car with no aerodynamic mods or belly pan. Running a 327 gear and did it in 5th. Of course you shouldn't pull in 6th like that anyway...
04-05-2006, 11:23 AM
#34
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Originally Posted by 5550racing
Factory speed is 125mph huh... 
I ran my nearley stock 2000 TA to 140mph... and have a speeding ticket to prove it .
I ran my nearley stock 2000 TA to 140mph... and have a speeding ticket to prove it .
04-08-2006, 10:02 AM
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[QUOTE=Orange Terror]Here were his statements last night. along with some other members.
Tool: "keep in mind a commercial gps is also not accurate (which is why no timing association uses them) If it can't get your position within a foot it can't get speed that accurate (a military version would possibly work, but they don't sell them to the public)"
Other members: "lol Steve, you're starting to just sound paranoid."
"yeah I give up, my car only does 130 tops no matter what the speedo says, how depressing lol"
Tool: "the commercial ones have never been accurate, since everyone wants cheap (the military ones are 4-5 times what a commercial one is for the same features, just much better accuracy)"
QUOTE]
Wow Umm I hate to brake it to this guy but I know for a fact that the civi GPS systems are a hell of a lot more accurate than the military ones. Infact the military since the start of this war has bought many civilian GPS's for that exact reason.
Tool: "keep in mind a commercial gps is also not accurate (which is why no timing association uses them) If it can't get your position within a foot it can't get speed that accurate (a military version would possibly work, but they don't sell them to the public)"
Other members: "lol Steve, you're starting to just sound paranoid."
"yeah I give up, my car only does 130 tops no matter what the speedo says, how depressing lol"
Tool: "the commercial ones have never been accurate, since everyone wants cheap (the military ones are 4-5 times what a commercial one is for the same features, just much better accuracy)"
QUOTE]
Wow Umm I hate to brake it to this guy but I know for a fact that the civi GPS systems are a hell of a lot more accurate than the military ones. Infact the military since the start of this war has bought many civilian GPS's for that exact reason.
04-08-2006, 03:26 PM
#36
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Originally Posted by 93formto98T/A
Well in case you guys haven't read yet, my man intmd8 went to maxton and did 199mph in his turbo lt1 street car with no aerodynamic mods or belly pan. Running a 327 gear and did it in 5th. Of course you shouldn't pull in 6th like that anyway...
Last edited by LTSpeed; 04-08-2006 at 05:18 PM.
04-11-2006, 03:52 PM
#37
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hahaha, that was the funniest, pulled it right out of his ***, bullshit I have ever heard. My little cousins tell better lies than that. Go get your coloring book and STFU.
04-22-2006, 11:08 PM
#38
Wheels up @ 130??? {Plausable deniability}
Not in my experience in the TA, seems like similar aerodynamics to a C4 Vette.
{/deniability}
According to the (lack of) logic of the Tool, we'd have to throw our tachs away also, since they also show more RPM with the higher road speed.
I know from owning a '97 Ram Air TA that Pontiac did put speed limiters on some cars that had lower speed tires.
This can happen, though- I did see a video of an RX7 configured as a streamliner spin on the salt flats and then get airborne & overturn several times at speed.
Not in my experience in the TA, seems like similar aerodynamics to a C4 Vette.
{/deniability}
According to the (lack of) logic of the Tool, we'd have to throw our tachs away also, since they also show more RPM with the higher road speed.
I know from owning a '97 Ram Air TA that Pontiac did put speed limiters on some cars that had lower speed tires.
This can happen, though- I did see a video of an RX7 configured as a streamliner spin on the salt flats and then get airborne & overturn several times at speed.
04-22-2006, 11:39 PM
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It must look pretty sick at the track when my car goes 0-60 mph in under 3 seconds considering the speedo error in my dash.
It would read something like this : 0-50 in reality (55 on my dash) 2.5 seconds. the other 10 real mph (from 55-100 on the dash) in the other .5 seconds.
He must be looking at the dash of a fast and furious car on NAWS.
What a F'in tool.
BTW GM advertising had the 85 TPI Vette at 151 MPH.
I have a poster of it captioned "Life Begins at 151".
Personally I have had my vette faster than that (not stock though).
It would read something like this : 0-50 in reality (55 on my dash) 2.5 seconds. the other 10 real mph (from 55-100 on the dash) in the other .5 seconds.
He must be looking at the dash of a fast and furious car on NAWS.
What a F'in tool.
BTW GM advertising had the 85 TPI Vette at 151 MPH.
I have a poster of it captioned "Life Begins at 151".
Personally I have had my vette faster than that (not stock though).
04-23-2006, 08:03 PM
#40
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What board is this turd on? Hell 130 will be done easily......in the 1/4 mile.lol I guess the commercial timers at the tracks are noy accurate. The military must keep the accurate ones.lol What a assclown!