Camshaft - High Lift and Duration - Increase Horsepower

Can you increase horsepower with a better camshaft? How can camshafts be optimized for maximum horsepower? What techniques do engineers use to design a camshaft? What is high lift and duration? This video explains several methods to keep in mind when purchasing or designing an aftermarket camshaft.

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[DanteTheAbyssalBeing]

I don't understand why most of his videos have dislikes. They're informative, well structured and well made. I'm guessing it's just the people who are too slow to understand basic mechanics.

[EngineeringExplained]

It's possible to increase your max hp and still get better fuel economy, but that doesn't necessarily mean that the two will happen simultaneously. For example, more hp typically means you'll need more air, and consequentially more fuel. But if your engine operates more efficiently at lower RPM, and creates higher power at higher RPM, you can have a combination of good fuel economy and HP. This is basically the principle behind VTEC/VVT/valve timing.

[stef]

As a car fanatic and a soon-to-be mechanical engineer, I gotta say u know ur stuff and ur really good at explaining it! Keep it up!

[TheFlacker]

Don't forget, changing a camshaft can change your cars sound!
Awesome explaining as usual sir!

[richardjensen]

One of the major limitations of stock engines, if you're trying to get higher revs is valve float. With stock valve springs, there is a designed limit to how quickly the valve can open and close. At higher rpms, the valve can't snap shut before the cam is opening it again, so the valve just "floats" there in a semi-open position.

Just putting in a more aggressive cam does not solve this problem. You must use stronger valve springs, so that the valve can snap shut more quickly than stock. Of course, stronger valve springs bring considerations of their own and cannot reliably be done in isolation. So, just a camshaft swap cannot produce magical results, and you'll invariably notice compromises like reduced fuel economy, rougher idle, worse emissions, and poorer power at lower rpms.

The moral of the story is that a camshaft swap in isolation doesn't produce a dramatic effect for the better, and there are invariably compromises for the worse. An engine is a very fine-tuned collection of parts that have been selected for their particular properties that contribute to a gigantic pile of chosen compromises. To "increase horsepower, " in a reliable way, you generally have to swap out entire "sub-systems, " so that, say, the entire valve train and timing set will cope with increased loads, etc.

But then you get into questions like, "Were your 6000 rpm wrist pins and rod bearings designed for 8000 rpms and 25% greater horsepower over stock? Your main bearings? Are you going to get adequate oil flow to critical components at the higher rpms?" Etc. There is no free lunch. You can't get something for nothing. Swap out certain parts, and you're just making other sorts of compromises, usually at the expense of reliability. At the outer end of the spectrum of compromises are top fuel dragsters that typically get an engine rebuild after every run (and an entire replacement clutch set)! That's "maximizing performance, " but you do not get something for nothing!

My best friend, who built racing engines for living, used to say to wannabes, "Speed costs money. How fast do you want to go?" A camshaft swap-out in isolation is pretty cheap and easy, and it doesn't net you very much at all.

[ercost]

So THIS is how you started! Great video, clear presentation. No CGI, no sponsors, just the facts!

[EngineeringExplained]

Thanks, they do go hand in hand, really. Increasing the amount of air/fuel etc means a greater pressure rise in the cylinder, meaning a greater torque, meaning greater power. You may want to check out my video "Horsepower vs torque."

[dennisw]

Someone finally explained how a camshaft works where the person can understand. You have a gift of making things easier to get. Thanks for that. Love your channel by the way

[arsukfjorden]

Great video as always, however this is not at all the whole story. Improving the breathing at higher revs will give you more power at those rpms but also lower the power at low rpms and often narrow the power band considerably. The more of a "race cam" you put in your engine the bigger the problem gets. Overdoing this can make the car almost unusable at low rpms. Great for a race car where you want full power most of the time, but bad for a street car where you also want to be able to cruise without reving the hell out of the engine at all time.

Who wants to have 200hp at 7000rpm but only 50hp at 6000rpm and below? I would much rather have only 150hp at 7000rpm but 100hp all the way down to 4000rpm. Would make for a greater street car and also a better race car.

So please do not go out an buy the most extreme cam you can find. Camshafts are a black art in itself and on top of that the camshaft need to match every other part of the engine and bigger is not always better.

With that said most engines, that are not already high performance engines, can almost always benefit from replacing the camshaft. You should easily be able to increase hp with 20% without loosing driveability. However depending on the engine you might need to replace other parts of the engine to take advantage of the new cam.

[EngineeringExplained]

I do not.. haven't gotten much into engine building, though I do plan on it eventually. Best of luck!

[EngineeringExplained]

I suppose it would yes. Especially if you're actually allowing in significantly more air/fuel. Hence when VTEC "kicks in" it is noticeably louder, from the change in cam lift.

[farzanasaheb]

I love the videos that this guy uploads, they're so useful and everything's just clearly explained. These videos are good for beginners and people who want to know about how each components function in cars.

[EBAIT]

I really learn a lot in a short period of time from watching your vids! thank you. I cant wait to get my gsc s2 cams installed in my 2007 sti

[dantheman]

I can't decide if you're 19 or 40 years old

[GTO]

I think you should also have mentioned the disadvantages, like low performance at low RPM :)

[EngineeringExplained]

Correct. If it was designed specifically for the stock engine, the stock cam is probably best. But if you have additional upgrades and need better airflow, this can help.

[deltas]

This channel is still the top recommendation I get for my search preferences. Thank you EE!

[worminator]

Man these schematics you drew are perfect. Just wanted to know what a high lift cam shaft does and just by looking at the whiteboard, I immediately got it

[jashepo]

More airflow nice!
Those drawings make easier to understand

[thomasish]

WHEN I FIRST OPENED THIS VIDEO I THOUGHT THIS WAS GOING TO BE SOMETHING FUNNY TO WATCH, LIKE A KID THAT DIDN'T KNOW WHAT HE WAS TALKING ABOUT. AND EVEN THOUGH HE DIDN'T GO IN DEPTH WITH MORE ASPECTS SUCH AS ICL AND LSA, FOR A BASIC EXPLANATION HE WAS VERY GOOD AT DESCRIBING THE MECHANICS OF A CAMSHAFT AND HOW IT OPERATES. MOST PEOPLE DO NOT FULLY UNDERSTAND DURATION AND LIFT AND HOW THEY AFFECT THE OPERATION OF THE VALVE, BUT MOST THAT ARE TRYING TO DO CAM SWAPS JUST LOOK AT LIFT AND DURATION BLINDLY OR LISTEN TO WHAT PEOPLE SAY HAS WORKED ON THEIR BUILDS NOT UNDERSTANDING THAT IT MAY NOT WORK ON OTHER BUILDS.

VERY GOOD BASIC INFORMATIVE VIDEO. THERE NEEDS TO BE MORE OUT THERE LIKE THIS FOR THE PEOPLE WANTING TO LEARN.