how do you calculate the redline?

[maq]

How does one know what the redline of the engine is?

Correct me if i'm wrong, but are the valve springs the first thing to start going out of wack when say a B18A is reving at around 6500? And that can cause valve float?

If stronger springs and better valves are installed wouldn't that allow the motor to rev higher? And after that how do you find a redline thats safe for the engine?

I have had my B18B up to 7k before and didn't noticed a redline as i thought of one. Is there one on the stock ECUs?

 

[TeggyBear_Ls]

How does one know what the redline of the engine is?

Correct me if i'm wrong, but are the valve springs the first thing to start going out of wack when say a B18A is reving at around 6500? And that can cause valve float?

If stronger springs and better valves are installed wouldn't that allow the motor to rev higher? And after that how do you find a redline thats safe for the engine?

I have had my B18B up to 7k before and didn't noticed a redline as i thought of one. Is there one on the stock ECUs?

There should be. Normally cars fuel cut whenever you hit the preset redline. The main thing is the ECU. I've chipped my Jetta, and it raised the redline about 700rpms. From 6500 to 72-7300. The engine can go forever, but it will certainly blow up before reaching a high rpms unless you have the correct upgraded parts. I don't know exactly which parts it is you want that will allow you to run a higher rpm, but bottom-end reinforcements are probably a good place to start.

 

[Aussie]

Strength isn't the major reason for not revving high. It's how everything is balanced, vtec engines are built much better and balanced better then the non-vtec b18bs. You also have to worry about rod stretch. Stock ls rods are weaker and at a higher rpm they will stretch, not only the rod but the rod bolts. Valve-springs are another factor.

Really with a stock cammed/compression b18a/b there isn't a good reason to need to rev higher. Your actually going to start to loose power once you get to a certain point.

 

[maq]

So rods should be upgraded first? What about the crank? are stock cranks good enough to handle say, 8k?

What i was really asking is this: If somebody has a built motor, ballanced crank, rods, rod bolts, valve springs, valves, and cam. How do you know what a safe rpm limit it?

How does honda or even ferrari know what a safe redline is for a motor? Is it trial and error? or is there a set standard?

 

[Kuchtaboy]

stock crank should be able to handle 8k without problems.

I'm going to rev 9k on my stock crank. good idea? probably not, but it'll work. not a good idea because reving anything that high gets dangerous