How is the redline on a car figured out?

Question

I wanna know how do manufaturers figure out when and where the redline starts on cars.

Answer 1

If you have a car with a bigger bore than a stoke your redline will be higher and visa-versa(racing engines have big bore and big trucks have long stroke. Also they do it by your head. With certain cam applications you can go to a higher rev point for racing engines. They try to figure out what rpm your valves will start floating at and then they set the rev limiter. Valve float happens when you cam is not designed for that high of an RPM. And your engine will not be able to make any horse power past that RPM so they set it right there.

A simple answer is they set the RPM when they figure out they peak horsepower. If your peak HP is at 6,000 RPMs they will set it there.

Answer 2

Sorry, but most all of these answers are wrong.

They actually TRY to overbuild the assembly and set the redline based on the camshaft and gearing combination to make it perform economically and in its power band. The redline has a lot to do with when the engine stops producing power.

On many 4 cyl. engines the redline is past the power band so that when shifted the gear drops into the power band instead of below it bogging the engine and killing economy.

Most engines are not produced to run close to their fatigue point. Race cars are but are not very reliable.

KC

Answer 3

Through extensive destruction testing.
The mathematical number says that about 500 feet per second piston speed is about it with common materials.
So an engine with a 2 inch stroke can rev way higher to get to 500 F.P.S. than one with a 4 inch stroke.
So your saying wait a minute both crankshafts are operating at the same speed.
But remember that twice per revolution of the crankshaft the piston is doing zero F.P.S. , that 2 inch stroke will accelerate the piston along with the crank. axis reaching 90 degrees from top or bottom to its highest speed for a given RPM, so a 4 inch stroke at the same RPM will be accelerating the piston at twice the theoretical speed, at 90 degrees the piston will have moved twice as far as a 2 inch stroke.
Look at a high performance motorcycle with a stroke of about 1 inch, this bad boy will hit 14000 RPM, a 400 + cubic inch chunk of American iron will self destruct long before that, and I don't care what camshaft you have in it, just because you can grind a 8000 RPM cam. for a big block doesn't mean the materials are ever going to let you get there.

Answer 4

When the engine is under development, several factors are taken into consideration. Among these are valve float, clearances, rotating mass and desitred horsepower and torque ratings. When all of these are factored in, a "safe" engine speed is determined and a specified red line is established. The red line is a "guideline" and NOT a point at which the engine will self-destruct, although it is usually a safe maximum speed at which to operate the engine for a given period of time.

Answer 5

i ought to guage the gas performance (gas mileage). Do you've little ones? i ought to also evaluate how a lot leg area there is contained in the again seat. How tender the seats are, extremely in case you'd be doing any lengthy distance vacationing. I attempt drove the Saturn Vue and grow to be very uncomfortable in it because the seats were so difficult. solid success.

Answer 6

i own shop,and all the engines are tested at the manufacturer to see what they,ll take this is how they set this rate,they set it well below what they know the engine size will take,this way the consumer doesn't run it up to high,all engines will take more than they say they will,but staying below the red line will assure you,ll keep it from blowing up,as long as it has oil in it, but i have seen them red line them at the gm tech center in Detroit,to see if they would blow,and they will ,it takes a few minutes ,but they will give after a while, good luck i hope this help,s.

Answer 7

it's mostly guessamation they guess how much it'll take to redline and call it so after few hundred million testings they set it to what the testings shows, and based on the size and dimations of the engine, and all.