Can someone explain to me the attraction of a lumpy cam?

[george graves]

I see all these American muscle cars (usually a LSx motor) with huge cams on them that make 'em sound like grandpa is coughing up his last lung, and about to keel over.

They can't idle worth a crap, and just sit and sputter.

What is up with that?

So this is cool? It sounds like the last Uhaul I rented after driving up the grapevine. I kid you not.



Am I the only one that prefers this?



I don't get it. Is the Harley sound what people are looking for? What gives?

[Smelser]

its all bout that rev bout that rev NO IDLE

[whodwho]

It is a sound of a built engine, like a supercharger whine or the whistle of a turbo.

You can always just turn up the idle and smooth it out some

[IronFreak]

WHAT GIVES??? MY PANTS...THAT'S WHAT GIVES.....

Mmmmmm, lope, it makes the pecker hard.


All that being said I appreciate a variety of exhaust tones and sounds. Whodwho nailed it. its kind of the staple for a built motor. Domestic N/A requires high lift and long duration for high hp.

[z31maniac]

^What these guys said.

Although on DOHC cars, like on the Coyote Mustangs, you can actually tune the stock cams to have a nasty idle like that just using overlap.

[flyboyx]

its all bout that rev bout that rev NO IDLE

lol

[BobombETA]

Sounds good on an inline 6 too ;)

[Exodus_2pt0]

It's dat overlap. Kills idle but makes it scream up top.

Buddy had a ls2 GTO with the ms4 cam. That car pulled like a huge turbo 4 banger. It has zero torque but once you hit 4k hold on tight.

A lopey idle that isn't caused by a misfire is one of the best boner makers out there.

[IronFreak]

^Brother from another mother.

[goarmy]

The sound has more to do with firing order and degrees of rotation between firings, their V8's fire at every 90 degrees.

[ForcedFirebird]

The sound has more to do with firing order and degrees of rotation between firings, their V8's fire at every 90 degrees.

It has more to do with the lack of vacuum and large overlap as mentioned above. A radical cam in a 6cyl still lopes like that.

[z31maniac]

The sound has more to do with firing order and degrees of rotation between firings, their V8's fire at every 90 degrees.

Shhhhh, let the adults talk.

[TheTacoMan]

Alot of big cams can be tuned to idle decently well I think. I think it can sound good, but after raising the idle up from this its has a bit better driveability.

[ForcedFirebird]

Alot of big cams can be tuned to idle decently well I think. I think it can sound good, but after raising the idle up from this its has a bit better driveability.

Tune has a huge amount to do with the sound. I have actually messed with idle tunes and made people's m20's sound like a v8 muscle car. Here's a video of my old m20 with a stock cam and lopy idle tune...



The video in the OP sounds almost as if the cam was installed and it's using stock maps.

[varg]

It's not just the murrican muscle boys, OP. Even the honda kids, who hate muscle like nobody else, are getting in on the action.


I have to admit, I find a perfect sewing machine idle is kind of boring to the ears, I like how high compression engines with aggressive cams idle. Sure you can tune most of the lope out by making it rich and increasing idle speed, but where's the fun in that?