from Comp Cams website: 'The reason that the new Thumpr Camshafts have such an aggressive exhaust note is that the lobe profiles and grind characteristics chosen by the COMP Cams® engineers produce a combination of early exhaust valve opening, long exhaust duration and a generous amount of intake and exhaust overlap to maximize the rough-idling characteristics of the cams without negatively impacting the power output or streetability.'
you mean Thumpr.......it's made by Compe***ion Cams. i hate to say this, but do a search and you will find some threads on them..some love it and some hate it
I was just reading an ad about them yesturday and what ajmopar posted is pretty much what the ad says. Basically they have designed a cam shaft to sound like you have a whole lot more engine than you got. In my world that does not fly, but when it comes to engines and performance I am a purest. For a lot of the fellas sounding tough and being tough are one in the same. You either like the idea or you don't.
I agree, if you want a bad*** sounding motor, build a high compression big cam monster and have some power to back up the noise.
It's the, "my d!$& is bigger thAn yours" at***ude. The precieved horse power is all in their heads. Or maybe in the exhaust system sound. Sounds "cool" driving around in the car shows. As hinted at above, the cam specs. just don't add up to real power. Mike
the old adage "Power perceived is power achieved" does not always ring true. Thumpr® Cams sound really neat, but when Falfa pulls up to you at the light, what are you going to do? It's like wearing a karate gi out on the street. Some may give you a wide berth, but what's your move when a guy without one stands purposely in your way?
My neighbor had one in a 1985 chevy truck and he thought it was the best. I had to laugh every time he drove it because the truck couldn't get out of its own way.
So I`m going to do a cam swap and at the end come out with nothing but...noise? Thats like running a gear drive because it sounds cool. Why go to all that bother with no pay off?
I don't run one, so I can't speak from experience. However, if you want to know the engineering behind the Thumpr line, look at the Comp Cams presentation here: http://www.slideshare.net/COMPPerformanceGroup/thumpr-cam-2010-hrr-trade-show It talks about how they came up with the idea, what they did, and how it dyno'd against other similar cams. I have no link to them at all, but I thought it was interesting that a company would give out their engineering data and real dyno runs. Based on their data it appears they have promise in a properly built engine, but might not be suited for a stock low compression engine. Wait, that's true for any big cam. . .
It's 'BAD ***' like that term has been done to death. So be kool, be hip. be fast and run one in yer bad *** ride today. But you will make more of everything by going with a grind that is tailored to your complete package. Anyone put a thumper in LS motor? That would be double BAD ***.
Hell man my buddies 383 with a big mutha thumper sounds nasty and the tunnel ram works great on it, high compression motor, and the car is no slouch... I cant say that this cam is all sound and no bite... I personally think its a great cam for the price and it performs alot better than the specs made me think it would..
Which why I put a good double roller timing set in my 350 and a Weiand Supercharger on top. I prefer to have something to back up the sound.
Sounds like the modern day equivalent of taking a spark plug wire off and going cruising because most of the dumb *** kids on the side walk wouldn't know the difference anyway. Is that a sock in your tighty whighties?
Never tried the thumpr.I've got a extreme energy comp and it's fair.but my car has been a lot bigger pain in the *** since I installed it and I only gained a few ponies from what I can tell.it had decent specs but I. Running a low compression motor so I'm not expecting a whole lot.it did wake the car up a bit tho
Lots of exhaust duration with a 107 degree L.S.A. equals lots of overlap hence the sound. Lots of cams out there with better performance characteristics.
Or like "back in the day" pull out the choke cable so it idles rough when you cruise thru the Drive Inn then shove it back in when you hit the road,choke cable under $10
there was a thread on this a few days ago ----seems like dyno and race results agree they make plenty of power and are liked by their owners---me i'm running an old isky roller i've had for 20yrs ..i like it
Littleman commented on the other Thumpr cam thread and he used it and said it made good numbers. Original post here http://www.jalopyjournal.com/forum/showpost.php?p=8464524&postcount=10 Anybody that wants to call him poser obviously hasn't been on the Hamb very long. I've used older pre-thumpr cams in a 460 and a 351W and am going to put one in my current 351W. They make good power but are still streetable. I don't have the time to build the engine completely right now but since I am dropping it in a build I would like to have a nice exhaust note and I will reuse this cam when I pull it apart and throw 10.25s and AFR heads on it. I already have an Edelbrock intake and carb I snagged from a previous build and they are staying with the motor in it's next generation. Tell me, how many "poser cam" posters own or wish they owned a Harley Davidson? Quickest way to turn fuel into noise without the added nuisance of horsepower. I have been riding superbikes for over a decade and I can tell you 185 mph top speeds and 0-60 times in under 2.5 seconds are nice, and they don't wake the neighbors. Current bike is a 2011 BMW K1300S. (My own personal fastest speed was indicated 181 which corrects to ~176mph in a Honda Blackbird)
Gotta Isky cam, makes for a rough idle. Also got a Harley. Don't need to 'prove' anything or do 181mph to have fun on it. And it sounds way better than any crotch-rocket Blackbird!
I have a Thumpr cam in a 289 SBF. Funny reading the "poser" comments when there are of plenty of guys running 3 2's or 2 4's on their 350 that I could out run with a stock 289 with a 2 barrel.
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