TraviZ

iTrader: (2)

ok in my car, for example, i redline at 5grand, and it goes all the way to 7grand. im curious how they determine our redline ? that is all. i am clueless. thanks!

ShiftyCapone

iTrader: (7)

It depends on engine balance and what rpm range your motor makes peak power at. That is the simpilist way to look at it.

Petes 84Z28

Valve float.

TraviZ

iTrader: (2)

what is valve float? and if i go over redline, is that bad mechanic wise?

Stekman

Valve float is when the lifter actually leaves contact with the lobe and starts floating around int he bore until the spring pushes it against the lobe again.

TraviZ

iTrader: (2)

so for instance, if i dyno my car, and its still amking power after redline, is it safe to go into that redline zone?

dankhound

Its safe to go further if your valves arent floating. Another thing to look at with redline is the type of piston. They all have different max speeds.

TraviZ

iTrader: (2)

how can i tell when my valves are floating?

formularpm

Or the valve hits the seat and bounces back off. This is usually more common.

If it happens, youll know. It sounds kind of like a rev limiter, plus youll notice a big drop in power. What exactly are you hoping to accomplish by over-revving the engine? In your case, your power will peak well below your redline, theres no point to potentially damaging the engine just for the sake of revving it.

TraviZ

iTrader: (2)

actually ive gotten my best times shifting at 5grand, and i was curious if it was safe to try to shift at a higher rpm to see if i can lower my time even more. like 5500 or even 6000

jpk91rs

If your motor has been built to handle the stress of higher rpm's they by all means experiment changing shift points. Just listen to your motor, it will tell you when it is unhappy.

TraviZ

iTrader: (2)

only thing i did was put on the open element air filter and flowmaster muffler. and tbi injector riser.

jpk91rs

Just go easy and try it. Listen to the motor. Don't start by adding 600 or 700 rpms to your shift points, try 100 or 150 rpms and increase gradually. When the motor lays down you will know. Then use that as your new redline.

TraviZ

iTrader: (2)

read my sig if your more curious

dj haf

does anyone know the max speeds of each type of piston?

dankhound

Cast 3700 ft/min
Forged 4600 ft/min

Piston speed=Stroke * Rpm *1/6

So in your case 3700=3.48*Rpm*1/6

Max Rpm=6379

dj haf

how about hypereutectics?

dankhound

Hyperutectics are still cast.