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goatman65 · 03-21-2010, 09:08 PM

What gives a cam it's idle 'sound'? I know a tight lsa does but does more duration? Any thing else? I like a really nasty,barely able to idle,idle that rocks the car.I know a nasty idling cam isn't always the best cam for the job.Just wanting to know if it's possible to have a street/strip combo run low 10s/hi 11s and 'sound' like it runs 8s-9s.My current cam is on a 106 lsa,sounds nasty but i could live with more 'nasty' from it.

Cliff R · 03-22-2010, 06:18 AM

Use a cam with a "tight" LSA with LOTS of overlap and low compression ratio. Best recipe I know of for a "rough" idle. Install a Comp 292H cam into a 400 engine about 7.7 to 1 compression ratio, it will give you the sound that you are looking for....but it woln't outrun a Dodge Neon with 2 plug wires pulled off!

Seriously, tight LSA grinds with big lobes make for a "choppy" idle. We like to put a lot of compression in those engines to keep power up at low speeds.

Low 10's on the motor requires a LOT of power. You'll need near 700hp at 3500lbs race weight. Mid to high 11's takes about 500-550hp, and is a lot more realistic for a pump gas street/strip type engine.....Cliff

ta man · 03-22-2010, 07:09 AM

You could also run ported advance instead of vacuum advance at idle.You will hear "more of the cam".I'm not into the sounds fast thing ......,I'd sooner pick a cam for power and streetability not for sound.

MescaBug · 03-22-2010, 09:25 AM

Check out the new Comp Thumpr cams. Not a lot of reviews so far, but apparently, they manage to get some power AND that choppy idle you're looking for. But...

You can get decent idle quality and nasty sound with better than 'off-the-shelf' cams. Any good shop, like SD for example, should be able to custom spec a cam for you.

http://www.thumprcams.com/

71 Ventura II · 03-22-2010, 11:46 AM

Quote:

Originally Posted by goatman65

What gives a cam it's idle 'sound'? I know a tight lsa does but does more duration? Any thing else? I like a really nasty,barely able to idle,idle that rocks the car.I know a nasty idling cam isn't always the best cam for the job.Just wanting to know if it's possible to have a street/strip combo run low 10s/hi 11s and 'sound' like it runs 8s-9s.My current cam is on a 106 lsa,sounds nasty but i could live with more 'nasty' from it.

A few questions: What size engine? Are you willing to pull the heads to swap the valvetrain? Compression? What octane fuel do you run? There are so many variables into selecting the cam, these are just the beginning. Vehicle weight, trans type, converter, rear gearing, and more. JD

goatman65 · 03-23-2010, 06:04 AM

Engine is a 467,6x heads by Butlers flow [email protected] comp,93 pump gas.I want upgrade to a roller,maybe solid and SD KRE heads.4 speed,3:90 rear.I'm running the CC 290b6 solid cam now.Sounds great,i get more compliments about how my car sounds more than anything else.I want to keep the sound of the 290b cam but use a roller.I kmow i should pick a cam to run hi 10/low 11s and accept whatever the idle will be.But,if a cam can be ground to give a 'nasty' pro/stock type idle and back it up with hi 10/lo 11 et's in a street/strip car AND outrun a Neon then that's what i want.Actually i like Cliff's combo running 11.30s on pump gas,but he says it idles almost stock.Give me his combo,performance with a 'nasty' idle,i'll be happy.....for a while..

Cliff R · 03-23-2010, 06:53 AM

"Actually i like Cliff's combo running 11.30s on pump gas,but he says it idles almost stock.Give me his combo,performance with a 'nasty' idle,i'll be happy.....for a while.."

I can turn the idle mixtures screws in half a turn and get a "nasty" idle out of it. I can also move the vacuum advance hose to a manifold source and have it idling like my neighbors 305 SBC powered pick-up truck!

My engine has a very good idle, but it has some "attitude", not completely smooth either. It's not setting off car alarms in parking lots or anything, but it does sound like there is a little something going on......Cliff

ta man · 03-23-2010, 07:34 AM

I almost used that 290b solid cam with my SD 290 KRE heads.The heads were initally set up for it.I had the cam at the time then my wife bought the heads for me for Xmas.I switched to a roller instead.With the 290b it would have made good power too....I thought maybe a little too high of revs for my engine though.Why not get the heads run 1.65 rollers and keep the cam since your cam is already broke in no worries or when you order the heads get Dave or Marcel to spec a cam for you if you wish to go roller.

goatman65 · 03-23-2010, 05:39 PM

I never thought about 1.65 rockers.I'm running HS 1.5 rollers now.On the chassis dyno my engine peaked at 4900 rpm,397rwhp,then nosedived.Similar to what Cliff sees with the XE lobes.I'll call SD about heads.I see guys on here running the 290b in the 10s/11s maybe i just need to tune and sort out my current combo to get the most from it.It's never really been dailed-in,just a dist.recurve.

BILTIT · 03-23-2010, 05:51 PM

http://www.youtube.com/watch?v=KvLwILhnkX8

Is this considered nasty?

performerrpm · 03-23-2010, 05:57 PM

im glad im not the only one, i had a perfectly good running motor that would burn the tires in all 4 gears, but sounded stock. now i got me a nasty 104 lsa cam for it. but i dont think i gave up anything but drivabilty and gained bit more power, i hope!!! if not im lookin at a 4k disaster lol

goatman65 · 03-23-2010, 06:11 PM

Quote:

Originally Posted by BILTIT

http://www.youtube.com/watch?v=KvLwILhnkX8

Is this considered nasty?

yeah,that's nasty nice.http://www.youtube.com/watch?v=zsl3XhHrs4s

Here's mine going on the dyno.

goatman65 · 03-23-2010, 06:16 PM

http://www.youtube.com/watch?v=EV5mOrODsAk Here's another for your viewing pleasure.

Sirrotica · 03-23-2010, 07:46 PM

They didn't chain it down or even chock the wheels, I've run my cars before on a chassis dyno and we had it chained and blocked. Nice car and the cam sounds fine to me, 65 is my favorite year. I've owned 2 hardtops and a convertible.

65gto69 · 03-23-2010, 08:38 PM

I don't know what you are talking about, that cam sounds pretty nasty to me.

Here is mine, this is through 3" exhaust to 3" super turbos that stop right at the rear axle, I am also idling at 1300 rpms.

http://www.youtube.com/watch?v=n3IWWqsIhzA

Mark

old66tiger · 03-23-2010, 08:41 PM

What did it make on the dyno?

BILTIT · 03-23-2010, 08:47 PM

Quote:

Originally Posted by goatman65

yeah,that's nasty nice.http://www.youtube.com/watch?v=zsl3XhHrs4s

Here's mine going on the dyno.

nice! Mine has a crossover and i know it gives it a smoother sound, i might take it out.

magnumea · 03-23-2010, 11:08 PM

watch those 1.65 rockers with stock heads. you will probably need to "waller out" the push rod holes through the head, because the 1.65s will bottom out the push rods in the head holes at the closed valve position and they will click, sounding like the valves clicking. i had to find a 1/4" grinding ball with a 6" long shaft to reach mine, and do them individually on a mocked up motor. i like that bad idle, too, but it can be a pain for the street.

lust4speed · 03-23-2010, 11:46 PM

The perfect cam and exhaust is the one that can set off alarms on cars parked across the street on a 4 lane boulevard while just poking along in the slow lane...

john5670 · 03-24-2010, 12:04 AM

I think a lot of people love the sound of a nasty, rough idle cam. But what causes this? In most cases your air and fuel are not properly mixing. This is fine and expected if you have a drag car that creates its power at high RPMs. I think its important to find that balance though for a street car. A rough idle creates cylinder wash at low RPMs until the motor start reaching the proper mixture. Cylinder wash will cause premature engine ware and poor street ability. My 2 cents is find the right balance between sound, power, and longevity.

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