question about speed
Thread Starter
|
Postmaster
Joined: Aug 2001
Posts: 4,532
Likes: 5
From: Trussville, Alabama
question about speed
Last night, on a very rural, deserted stretch of Alabama interstate, I realized I was being overtaken by a semi running at a "high rate of speed". My curiosity lead to action and I found myself running along with him for about a mile. Speed ranged from 96 - 98 mph. That is the fastest my truck has ever been (4.2 V6 w/ 5 speed). I slowed after about a mile and watched him motor on off. Then started thinking...I know my truck has a "speed limiter" but have no idea where it comes into play. I have been over 130 mph on both 2 wheels and 4 wheels and thought that - suprisingly enough - my truck actuall felt pretty "stable" at 95 - 100 mph.
Now, my question is NOT a techinical question about top speeds and where limits are set (although it would be interesting to know). Rather mine is a question of WHY. Is it just a matter of safety? There are plenty of cars that will top out way beyond what I figure my truck would be limited to. So, I wonder if the "powers that be" have determined that no truck has any business going over XXX mph, so they limit it to that.
Just curious..
Thanks in advance,
Brian A
Now, my question is NOT a techinical question about top speeds and where limits are set (although it would be interesting to know). Rather mine is a question of WHY. Is it just a matter of safety? There are plenty of cars that will top out way beyond what I figure my truck would be limited to. So, I wonder if the "powers that be" have determined that no truck has any business going over XXX mph, so they limit it to that.
Just curious..
Thanks in advance,
Brian A
Thread Starter
|
Postmaster
Joined: Aug 2001
Posts: 4,532
Likes: 5
From: Trussville, Alabama
question about speed
Thanks for the reply, but I gotta wonder about that one....I know my truck turns 32 rpm / mph in 5th gear. So that = 3200 rpm at 100 mph. I don't know what "redline" is, but 125 mph would equal 4000 rpm. Would that be damaging to my engine? Sure, a sustained 300 mile run at 4000 rpm might be detrimental, but that could be said of any motor. I'm still guessing it is safety.
Thanks again,
Brian A
Thanks again,
Brian A
Moderator
Joined: Nov 2001
Posts: 2,643
Likes: 35
From: Orange County, CA
question about speed
It's like the old rev limiters they ran on the 69-70 Boss 302's. It's to keep people from going a little nutty and revving their motors like they are getting ready to run down a 1/4 mile. It's mostly likely not a government thing, but rather as a way for the auto companies to help keep down warranty claims from people grenading their engines.
Gary
==============================
46 truck-6cyl now, 302/C4 soon
46 truck-flathead 8, 4spd
47 truck-getting a 429/C6
57 Ford FL 500-4 dr-312/AT
70 Mustang fastback-351W/FMX
72 Olds Vista Cruiser-350/AT
(for sale)
88 Bronco II, 500,000+ mi.
(for sale)
Gary
==============================
46 truck-6cyl now, 302/C4 soon
46 truck-flathead 8, 4spd
47 truck-getting a 429/C6
57 Ford FL 500-4 dr-312/AT
70 Mustang fastback-351W/FMX
72 Olds Vista Cruiser-350/AT
(for sale)
88 Bronco II, 500,000+ mi.
(for sale)
Sit. Stay.
Joined: Oct 2001
Posts: 18,308
Likes: 20
From: Washington State
question about speed
>>Sure, a sustained 300 mile run at 4000 rpm might be
>detrimental, but that could be said of any motor.
You can run an engine within the proper operating RPM (read:not above redline) indefinantly with no detrimental effects.
The speed rating on your tires (stock) may be one of the biggest limiting factors for factory set top speed.
>detrimental, but that could be said of any motor.
You can run an engine within the proper operating RPM (read:not above redline) indefinantly with no detrimental effects.
The speed rating on your tires (stock) may be one of the biggest limiting factors for factory set top speed.
Postmaster
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
question about speed
Car companies limit speed for several reasons.
1) Political correctness.
2) The tires on your model are not rated for higher speeds.
3) I had one car engine(SHO that was rated to 10,000RPM, yeeehaw), but was limited to 8,000 so the AC compressor wouldn't blow up.
4) Your engine or tranny just can't handle it.
5) Some countries or origin have regulations(formal or informal).
That's about all I know about why.
Jim Henderson
1) Political correctness.
2) The tires on your model are not rated for higher speeds.
3) I had one car engine(SHO that was rated to 10,000RPM, yeeehaw), but was limited to 8,000 so the AC compressor wouldn't blow up.
4) Your engine or tranny just can't handle it.
5) Some countries or origin have regulations(formal or informal).
That's about all I know about why.
Jim Henderson
Elder User
Joined: Jan 2002
Posts: 703
Likes: 0
From: Where they take the census by counting the appliances on the front porch and multiplying by five
question about speed
Monsta is right. Sustained RPM will not harm an engine for any length of time as long as it's not above it's redline. It's the up and down the rpm scale that is hard on them. I heard on the nascar circuit that the easiest track is Daytona because you stay at around 7500 rpm all day. The worst track on engines is pocono because you go from around 4400 on turn three up to around 8800 down the straights and back down.Think about it. 8800 RPM is 147 revolutions per second! Boggles the mind, huh?:-staun
Trending Topics
New User
Joined: Jan 2008
Posts: 0
Likes: 24
question about speed
That's about how fast my legs go when I have to go to the Bathroom real bad.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=3180&.jpg
http://community.webshots.com/user/mil1ion
[font color=green] Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [/font]
[font color=blue]78 F-150 429CJ,Silver,Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon [/font]
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
[i][font color=red]Calgary,Alberta,Canada[/font][i]
https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=3180&.jpg
http://community.webshots.com/user/mil1ion
[font color=green] Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's" [/font]
[font color=blue]78 F-150 429CJ,Silver,Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon [/font]
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread Starter
|
Postmaster
Joined: Aug 2001
Posts: 4,532
Likes: 5
From: Trussville, Alabama
question about speed
Thanks for the responses guys. I'd like to go further with the discussion, but it would go beyond the rules for this forum. Maybe later in some other forum.
Brian A
Brian A
Thread
Thread Starter
Forum
Replies
Last Post
thendrix
General NON-Automotive Conversation
48
Jun 16, 2008 05:36 PM
inline6ford
New Member Introductions
1
Apr 3, 2006 05:44 PM