Ok, this may be a newb mechanical questions of some sort but if you will help enlighten me that would be greatly appreciated. What determines the redline of a car? and how does a high redline car feel, say in throttle or reving,benefits, and etc, when compared to a regular one?

I started pondering about this when i found out that the honda type R redlines at 8K and the S2000 redlines at 9k.

BTW: GO EVO!

GG GSR AERO & SSS

Moved to Evo X Engine.

There are a couple of things... but for starters, the valves springs have to have enough tension to support that high of a rev. Another thing that is considered is the piston speed... which the length of stroke is going to influence that also. I am not so sure on the other factors though.

Well, the term redline refers to the highest speed at which the engine and its components can run safely without causing any damage to other parts of the car or the engine itself. There are a couple of factors that can determine the redline of a car, but the main ones are generally stroke (length of the cylinders), the general mass of the engine's various components (their weight) and, displacement (volume of air/fuel mixture in the cylinder, or general volume swept by the pistons, i.e.: the size of the cylinder), what the components are made of and how well balance these components are. Generally, an engine with a shorter stroke (shorter cylinders) and lighter components (which will cause less inertia, thus a shorter resistance to the up and down movement) will have a higher redline. This is why the S2000 and RX-8 can safely rev up to 9000 rpm, and their small, light engines (2.0L and 1.8L respectively), with great power and performance, are proof to back what I've just explained.

It's important to note that the redline determines the rpm at which ALL of the car or machine's components can operate safely. It is to be noted that the engine can run at maybe 14,000 rpm, but that doesn't necessarily mean that the other components can follow.

Hope that explains it. :P

Very good explanation Evolve.

Very good explanation Evolve.

I ain't in pure & applied sciences for nuttin'!

hmm. i see what you mean now regarding what will help determine the redline. how does the redline come into play when designing a sports car? in other words, if i were head of design for mitsubishi or ferrari would it be important to have an extra high redline? how does a redline at 9k translate into power delivery and ride?

Yes. If you reread my explanation you will understand exactly why. If you cant figure that out on you own I will be elaborating tomorrow.

:amen: to the above but another factor is how strong the valve springs are and can they open and close in the available miliseconds and complete the intake and exhaust functions. Since I have an S2000 as well it will run on the redline all day but is sure sounds like it is going to grenade at any second. There is lots of voodo magic going on but 9000 is low compared to some motorcycle engines 13,000+ is not uncommon.

:amen: to the above but another factor is how strong the valve springs are and can they open and close in the available miliseconds and complete the intake and exhaust functions. Since I have an S2000 as well it will run on the redline all day but is sure sounds like it is going to grenade at any second. There is lots of voodo magic going on but 9000 is low compared to some motorcycle engines 13,000+ is not uncommon.

I mention balance and quality of overall components in there somewhere. :p

I had an '08 Acura CSX type S (Canada only), same as Civic type R in Japan. Redlined at 8... but gets to 8 RIGHT AWAY, goes nowhere... Fast, but not fast enough so traded it in!

Sorry but the Acura CSX Type-S is a Civic Si Sedan with leather and nav. :p

great point about the springs and rpms. the faster the rpms, the higher the spring rate needed to be able to react fast enough and open/close the valves. what's mind boggling are F1 motors, esp the prev gen ones that reved up to 19k (18 these days). that's almost 3 times the redline limit on most production cars, and just over twice our car. these engines use compressed air springs with pressures north of 150psi. ridiculous. just thought i'd share that tid bit not trying to go OT.

http://www.vettenet.org/torquehp.html

that link should make up for going ot. great info on torque, hp and engine speed.

Generally, an engine with a shorter stroke (shorter cylinders) and lighter components (which will cause less inertia, thus a shorter resistance to the up and down movement) will have a higher redline. This is why the S2000 and RX-8 can safely rev up to 9000 rpm, and their small, light engines (2.0L and 1.8L respectively)

Hate to be a dick, but the RX-8 part is completely irrelevant.

RX-8's (and RX-7's) have a rotary engine which uses the wankel cycle rather than cylinders or the otto cycle that typical engines use. EDIT: Also, its about 1.3L I believe :)

There are no "Cylinders", valves, or other typical components. Just a big rotor. That's why they can rev to the moon, no valvetrain to worry about.

But other than that, good explanation.