Top speed of AD's

[earl1951]

I'm trying to determine the top speed of our trucks before aerodynamics
become a safety issue. Anybody gone over 140?

[GreasyLikeaBurger]

Theres a lot of contributing factors to consider. Are you talking stock, lowered, slammed? Original frame, front and/or rear aftermarket crossmembers? Complete custom chassis? And then what drivetrain package are you considering. I think people on here have gone up to and probably past that. It just takes a lot of modifications to get up to that type of speed safely.

Then you need to consider if its a straight line or turning. Swaybars, coil overs. And how to slow down quickly at those speeds.

Technically just about anything can go over 200 mph, just look at all the vintage classes running on the salt flats. But those are far from stock or daily drivers.

[HUSSEY]

I don't know but at 88 mph time travel would be possible.

[1project2many]

Hmmm...

There are other limiting factors:

This limits top speed to 9.2mph:




This limits top speed to 30 or so:





This might get you to 125-135.




And this has potential to exceed 140 if the powertrain allows:

[b-mac]

Problem with that last picture...she's actually looking at the road.

[PDW HOTRODS]

140 and the wind pushes you around, even lowered with updated suspension.
The shape of the truck would need to be modified

[mongocanfly]

Image a brick..that's what these trucks are shaped like..not very aerodynamic...with my old stock suspension at 80 mine would be all over the road..I'm putting in vette front and 3 link rear...it'll help some..but they still aren't designed to run 140..

[1project2many]

I've actually been to 114 in mine. I thought it was 80 or so, following a friend in a Daytona. The wind is a huge factor at that speed. I wouldn't want to try 140.

[joedoh]

140? its not probable. wind load goes exponential and makes a big difference over about 60mph, and these have a lot of upright surfaces and even more "wetted area".

I had a pretty boxy older BMW with plenty of grunt and a tall gear and it topped out speed at around 123. that doesnt sound a lot more than the 114 1project mentions but you have to realize that the wind load difference (the resisting force the vehicle pushes against) in that 9mph was a lot more.

and I dont mean to say that wind load isnt exponential below 60mph, it is, thats actually the "squared" part of "velocity squared", just that for anything resembling a car it doesnt start getting to be a huge number till after about 60mph.

for example, say the wetted area A is 24 ft (total guess) and the coefficient of drag Cd is 0.45 (its probably not even that good) and the wind pressure of air is (0.0256*V^2), at 30mph the force the truck would need to push would be 24*(0.00256*30^2)= 24lbs, 60mph the force would be 24*(0.00256*60^2)*0.45 = 100lbs, at 114mph it would be 359 lbs, at 123 it would be 418lbs. so even though you are only traveling about 4 times as fast as 30mph the wind load is 17 times as high at 120mph, 4 times as much at 120 vs 60mph even though only twice as fast. even that 9mph difference, the load goes up as much as it did from 30-60.

this is why your top speed is not redline rpm x top gear, you run out of torque much sooner than rpm from pushing wind. its also why you can get better mpg by slowing down, pushing wind doesnt save you a penny.

cliff notes: going really fast in a brick takes a lot of torque

[Henry50]

A local guy here has a stock bodied 46 chevy pickup that runs 150+ in the quarter mile.
Here's an older video from about 6 years ago.

https://youtu.be/Rc_IeHY_b0Q

[Speedbumpauto]

Something bout that idle and the whine tells me he has a "torque multiplier".

[47 Fasttoys]

117 MPH flat out. Modern suspension/brakes/power train. Yep, that's all shes got. What surprises me at that speed is the visor is stable at that speed. But you should see the look on peoples faces when they see this beast moving at that speed.
Rob

[whitedog76]

I think you'll run out of horsepower before aero becomes an issue. On a 3000 lb vehicle, you'll need about 300 ponies at the wheels.
One at that speed is air being trapped under the hood. At a bare minimum, hood louvers would be necessary.

[_Ogre]

I was doing about 115 when this picture was taken.
The hood sheet metal was rippling back and forth
The wind noise was deafening
Truk had more in it but I was 1000 miles from home and didn't want to push it

[mr48chev]

Running stock suspension, a 283 with power pack heads 30-30 solid lifter cam and a 300 hp 327 intake and carb I cruised my 48 at 80 on a regular basis and it was doing an even 3K on the tach with N 50 14 firestone tires on it. The gears were around 3 something but I never checked them.

The truck handled great then.
With the Camaro front stub, coil spring rear with trailing arms and a 350 with M21 Muncie it top ended somewhere around 135 according to the guy in the Firebird that I was racing at the time. Didn't handle too well over 110 though as it got a little light in the back end.
There are a couple of AD drag trucks that run in the nines without problems.

[earl1951]

Originally Posted by earl1951

I'm trying to determine the top speed of our trucks before aerodynamics
become a safety issue. Anybody gone over 140?

hope to make Speed Sectors standing 1/2 mile at the Colinga CA. airport
in Oct for numbers,may not be ready until Feb. meet

[MARTINSR]

LOL, I just remember my truck did 95 in the quarter. I use to have to go to the second turn out lane that the top fuelers used because I was afraid I would roll the thing over on it's roof!

When I started dragging my Gran Sport I was running 100 mph and would take the first turn out without a thought. LOL

Brian

[earl1951]

Originally Posted by earl1951

hope to make Speed Sectors standing 1/2 mile at the Coalinga CA. airport
in Oct for numbers,may not be ready until Feb. meet

Correction: SHIFT S3CTOR