How can you raise your engine's redline?

[Armon]

Hey guys, I'm new here.. been reading for a while. I sorta wandered over here from the vintage-mustang forums. I've got a 68 so don't kick me out of here

Anyway, I was reading up on the formula 1 engines and I still can't get over how they rev past 18000 rpms. Alright, so they've got endless pits of money to dump into those cars. But how about motorcycles? I had a bike that reliably revved up to 15000, so it can't be that unreasonable to think that a normal v8 can have its redline raised at least a little.

So, regarding these 4.6s, or any engine in general: Which specific parts of the engine determine the redline? By specific I mean "pistons, lifters, etc" not just "internals". Have any of you done any mods to increase your engine's capability, and how far can it be taken? If you had $10000 could you make your 4.6 rev to 10000 safely? Just curious.

Going back off topic a little... I'm not sure if you guys pay much attention to f1 racing, but the cars themselves are absolutely amazing machines. Here's a link that talks about the technical aspects of the engine/suspension/aerodynamics, incase any of you are interested. http://www.formula1.com/insight/technicalinfo/11/467.html

 

[bdcardinal]

if you look at the F1 motors, they have a really small stroke. you are looking at a motor with no more than a 1" stroke, so they can spin them that fast. if you theoretically wanted to build a v8 that revved that high you would need some very strong internal components. generally the smaller a motor is the higher it revs. v8s, especially big block v8s dont usually rev high becaue of the combination of long stroke, and weight of the internal components. Ford does have v8s that rev over 15k, however they are built by cosworth and are 2.65litres. another problem to consider is airflow. many heads give up at a certain RPM. you would also need a camshaft that could provide enough valve opening and duration to let air in that fast. also above 13krpm normal valve springs tend float, so you would need pneumatic springs to close the valves, that requires carrying a tank of compressed air and having to refill that tank on a regular basis.

 

[Go HoTO!]

In simple terms, redline can be anything you want. It's really just the point before you hit your rev limiter. The rev limiter can be raised with a chip or programmer. It this safe? As already pointed out, depends on changes made to the motor. On a stock GT, you can raise it and still be safe by about 200 rpms.

 

[nickthegenius]

Cams and heads can also determine the "redline" to a point. You could have the bottom end built to the hilt and have a cam/head combo that wouldn't let it rev after a certain point. Porting and camshaft selection can cure that.

 

[bdcardinal]

also remember that race motors dont last that long of a time. this season they required formula 1 teams to make thier motors last the whole weekend. before that they had practice, qualifying, and race motors. even nascar uses one motor a weekend, but thats usually 700 miles at the most, then the motors get torn down and rebuilt. genrerally the higher you rev the motor and more abuse you give it, you have to rebuild it that more often. now to ferrari, thats no big deal, but to the average do it yourselfer, its a huge deal.

 

[Aaron 4.6]

More importantly, you need to remember that raising redline (or rather, building an engine that can safely rev higher) is only important if it helps the engine make power. A stock 2V 4.6L Ford engine is done making power by about 5500 RPM. Installing a trick valvetrain might allow you to spin it to 8500 RPM, but the engine can't use that additional RPM given the intake and head restrictions, so who cares.