[ryfrat]

Can you make a pump gas engine sound like this?

http://videos.streetfire.net/search/...5f014a00e4.htm

[bobj_70]

wow, really crackly, lol i like it

i'm guessing a ridiculously mean cam and glasspacks

[MaximumBrotitude]

Originally Posted by ryfrat

Can you make a pump gas engine sound like this?

http://videos.streetfire.net/search/...5f014a00e4.htm

[BillyGman]

That vid was posted on here in another thread about a year and a half ago. One guy who posted in the thread claimed that he had some info about that car, and that it has a camshaft with a 290 dur@.050 and a .800"+ lift at the valves, and a 15:1 static compression ratio, all in a 598 CID engine. Anyway, I sure don't doubt that claim, because it sounds about right. In the vid it sounds like the engine doesn't want to smooth out at all until he gets it to atleast three or four thousand RPM's, so the monster cam claim is probably truthful.

I don't know if your question is a serious one, or you've if you've posed it kind of "tongue-in cheek" as a joke, but assuming that you're asking a serious question here, I'll point out that you should keep in mind that the guy obviously has either open headers, or exhaust cut-outs. So unless you want to get pulled over almost every single time you drive your car, don't expect to have an actual street driven car that sounds like that.

[greg_moreira]

yeah, but not quite legally! It takes a healthy amount of compression, and definitely a rad camshaft......and uncapped headers(thats the illegal part). So if you wanted to push the limits of pump gas and build something as aggressive as that...you can do it. But, any muffler thats street legal would mellow out the crackle a good bit(chambered mufflers retain more of that pitchy sound though). The obvious lope will still be there...but not quite as ragged sounding with a muffler on it.


Edit: Billy beat me to the punch!

[BillyGman]

With a camshaft that radical, you can get away with a 12.0:1 static compression ratio, and still run on pump gas no problem, but forget about having any driveability for actual street use. And I don't doubt that you would need a 5,000 RPM stall speed, and an extreme rear gear ratio. Not exactly a vehicle combo that would be very fun to cruise in for very long. I mean, I bet it would get old pretty quick driving it on the street. Especially after you became very well known by the entire local PD, and your ticket expenses for making too much noise began to accumulate.

[Twins Fan]

That does sound wicked.

Last year when I did my cam break in I did it with open headers (exhaust pipes didn't match up with new headers, had to wait for cut and weld). At first I was like, this is awesome, but after 25 minutes, yeah, I was done with it. My build is nowhere near this Nova either. That's too much noise for a pump gas street car. Plus, have fun driving that Nova around town.

[ryfrat]

Not the loudness,but the crackle of the cam.

[Twins Fan]

The more overlap the better for the crackle. You can get a pump gas engine to crackle pretty good, but I don't think it's going to match this Nova.

[BillyGman]

Ray, you can have a lumpy cam, sure. And some of that crackle can still be heard through mufflers, but not all of it. Open headers will always sound more radical at idle than a muffled exhaust note will. The crackle is more with some camshafts, yes, but getting all of the crackle to come through and be heard at idle also requires that all the thunder comes with it via open headers. That is why some guys opt for exhaust cut-outs. So they can turn up the volume when and where they want in order to bring out the thunder and the crackle of the pipes.

Don;t get me wrong though. I'm just saying that you cannot expect a muffled street car exhaust to ever sound like the one in that video.

[BillyGman]

Originally Posted by Twins Fan

The more overlap the better for the crackle. You can get a pump gas engine to crackle pretty good, but I don't think it's going to match this Nova.

True, but overlap is NOT the only factor. There are other things in the valve timing dictated by cam design which can add to that crackle. Harold's cams for instance are well known for that among drag racers, but that sound of Harold's cams isn't just for show. It comes with increased performance and lower quartermile ET's. So there's a function to it with HIS race car cams. Not like those "Thumper" cam deals from Comp.

[Twins Fan]

Well, if you want to get all in depth.

I was just giving a simple answer, and please notice that I did not recommend a Thumper cam.

[BillyGman]

Originally Posted by Twins Fan

Well, if you want to get all in depth.

I was just giving a simple answer, and please notice that I did not recommend a Thumper cam.

Brad, I didn't mean to make it sound like I was implying that you were suggesting one of those "Thumper" thangs. I can tell by your posts that you know better. I was just making a comparison for Ray's benefit. But I was getting a little more "in depth" than you were, only because I've discussed these things in detail with Harold, and he gave me some pretty in-depth, and detailed answers about his cams. Answers that included explanations about cam design that I had tried to obtain from "tech" guys from various cam companies, but never could since they just don't have the knowledge that a veteran cam designer like Harold has.

So please don't think that I'm meaning to come across as a know-it-all, because i definitely am NOT. I'm just pretty fascinated with this stuff myself, so I tend to get a bit intense about it. Don't mind me.

[Twins Fan]

Originally Posted by BillyGman

So please don't think that I'm meaning to come across as a know-it-all, because i definitely am NOT. I'm just pretty fascinated with this stuff myself, so I tend to get a bit intense about it. Don't mind me.

I don't think that. Don't worry, I was just having a little fun.

Yeah, we definately get spoiled by having someone like Harold around.

[Highway Star]

That deuce sounded pretty firggin mean. My first guess was really high static compression, really high octane gas, really mean camshaft profile, and little or no exhaust. I am NO authority, but I think all of those things have to be present in order to make that kind of racket. They are all inter-related, and dependent on each other, right? So, you want that crackle, you need a giant, high compression BBC that runs on race fuel, with a wicked cam, and open headers. Oh, and unless it is tubbed out you're not going anywhere, all you'll do is spin even if you just goose the throttle.

Does the cam REALLY make the "crackle" or is it the compression? Curious.