Alright, I've been in a topic before about these Thumpr cams, but jegs is showing a new cam (maybe not new?) of a Comp Cams Thumpr Hydraulic Flat Tappet Cams, and this is what they say:

"Now available for hydraulic flat tappet applications, COMP Cams new Thumpr series of camshafts are the hottest cams to hit the streets in more than a decade. Applying a new camshaft design concept originally created for sports car endurance racing, the COMP Cams engineering team incorporated early exhaust valve opening, long exhaust duration and a generous amount of intake and exhaust overlap to maximize your engine's nasty-idling characteristics. Best of all, they won't negatively impact power output or streetability."

does that mean that they would work on street vehichles and wont kill the engine with the aggressive lobes (as what I was told before, the lobes of the cam would kill it and would need to be revved up pretty high so it wont die out, they were made for racing vehichles only)

(EDIT: I also forgot to mension the intake and exhaust do seem pretty high, and may be pretty aggressive and may even cut the gas milage down some, (which I dont like...) is that true?)

http://www.jegs.com/webapp/wcs/store...e&pos=sidebar4

Thanks,
Tim

 

Thumpr cams are made for show cars where the nasty lumpy idle is the only concern, and they don't get driven much more than on and off the trailer, with maybe a burnout or two in between.

 

Everyone is starting to use them, But i dont think they would be a very "comfortable" street ride.

 

yea but cam lope is sexy

 

Agreed

 

I'm sure thier not, and im pretty sure the town and police would start hating the person by the end of the month :-\

I was looking through which cam would be pretty good to get, by may, I hope to get my engine engine, and I was going to replace the cam in it, I guess for no reasons really, I kinda always had a thing for the rough idles, but having a rough ride would get annoying.
(Im thinking about getting a Comp Cam Xtreme Energy Hydraulic Flat Tappet Cam)

 

Give comp a call and tell them exactly what you have and what you want, they will give you the absolute best cam for your car. IMO

 

Sounds good to me

 

Not if it's all show and you haven't really got the power to back it up.

 

You can accomplish the same thing with a "bad tune" and save the time and money doing the cam swap.

 

Theres alot of cams that can give you a lopey idle and still within a streetable manner, like isky's split 280 theres some sound clips on www.youtube.com of it it sounds mean and i hear nothing but good things from isky (iskyndarian is the full name i think)

 

demon eater - pick up a copy of John Lingenfelters book "on modifying smaal-block chevy engines"...I got mine at Borders and it is the best book going...it will tell you what you need to consider before selecting a cam.....wish I had read it before building my engine........

 

Thanks,
I think I may go buy that,
I dont know much of engines all much yet, (course, im still 16) but im trying to learn as best as I can.
Im sure i'll be reading that and try remebering from front to back. haha thanks.

 

im only 17 (senior in high school) .. and i just finished up building my 91 camaro convertible .. did everything .. heads, cam, intake, pistons, headers, etc ..

all i can say is pick up a wrench and get to work .. the best way to learn if from actually doing it .. and get a haynes manual (i know there $hit) but they tell you how to take it apart and assemble it if you dont allready know the basics .. i just used it for torque / plastiguage specs

and i gotta say .. every penny is worth it .. and building it was the best part .. especially when you pop the hood in the high school parking lot and hear "damn that looks good" or "holy crap dude i bet that thing is fast" .. and then being able to say "i built that" ..

ive had people come up with brand new dodge daytona hemi trucks acting all tough untill i popped the hood and fired it up .. haha ..

save up the money .. do the research (dont just throw random parts together, they gotta work with each other .. not against) .. then go to town .. if you run into any trouble then im sure someone on here will be more than happy to help ..

 

---building it is the best part, get the info first to do it right.........somebody on this website has it right in the message on all their posts... "if you didnt build it, its not your car".................

 

What castings do you have btw? I was recommended the comp cams XE268H for my 305, i have the 416 casting heads though. take off a valve cover and youll see a six diget number if the last three are 602 or 416 then you got good stock heads. The stock 305 with those heads was rated at 190hp and 240trq so they are pretty torqey from the factory. The comp XE268H has a pretty rough sweet sounding idle http://youtube.com/watch?v=kukI2LnxrqY This corvette has one. Also what type of induction do you have? Get some headers an exhuast, intake manifold, get a XE268H and youll have a quick sweet sounding choppy idle 305. And for a 16 yr old still in high school that would be a sweet ride.

 

yea .. i put in the comp cams XR264HR-12 .. it sounds a little less lopey than that corvette .. yet has more than enough torque in the bottom end to stick it up in fifth gear as low as 35mph .. which helps on my gas bill ..

havent looked at the specs for that 268 cam .. but if you got a speed density (instead of maf) .. then i wouldnt go with it unless you can tune it .. ive heard of some pretty big cams being put in the maf camaros and running fine ..

just dont forget .. you can research stuff as many times as you want .. but you can only build it once ..

 

before it died and went to engine heaven, my old stock, crapped out LG4 had quite a nasty thumpy/rough idle.

 

Thanks,
I always wanted to build an engine from top to bottom, but I have saving problems so this is hard for me to do, haha. But the engine im looking at is either from jegs, or an engine my friend got here last summer from a place called PAW (Performance Automotive Warehouse) He gotten his engines from there, and loves them. and the haynes manual is also what my friend uses when he works on his engines,
As he told me that I should buy one, and make it become my bible, hahaha.
I would like the build an engine, but as what Adrians91Z28 said, I cant put just random parts together and expect it to work. that's pretty much the reason why Im afraid to build it up from block to the top.

but the new engine will be worth it, I still thinking about getting the Comp Cam 'High Energy' Hydrualic Flat tappet cam. and a new intake, and new disbutor, already got a pair of chrome vavle covers (the engine from PAW doesnt include vavle covers) im thinking to use the same throttle body, got a pair of new shorty headers I got for christmas, already got a new water pump, Im going to replace the starter for a 350 starter, get new hoses, new belt lines, oil, gonna need to buy a new oil pan. and I need to get the 350 chip, 350 specific knock sensor, 350 ESC module, and the 350 Injectors. does that sound all right?

 

Why would you pay someone else to build you an engine?? trust me you can do it, Buy a couple $20.00 books on rebuilding chevy small blocks. rent a hoist and engine stand (stands are like $60 a month and a hoist is like $30 for the day or weekend) Once you start taking everything apart just be extra careful don't force anything and use penetrating oil if theres a stubborn bolt or screw. Take down notes or better yet take a camera with you and document everything you take off and put tape on everything and label it, once you start tearing that engine apart youll understand how simple engines really are. Don't buy someone else's engine put your heart into it and build your own! youll be alot happier firing up your own creation than someone else's. I'ts basically idiot proof if you can follow directions and take your time. If you have any problems call a local mechanic or talk to us...
----------
Once you build one engine you'll always know how to do it.

 

building a motor isnt rocket science .. it just takes a little thinking of what you want to build it for (daily driver, drag car, strip and street, f1, etc)

and as he said .. i wouldnt get any satisfaction of just buying a mass produced motor that a thousand people could be using ..

i must say when i first started my camaro a couple weeks ago after building it for a month .. and it fired on the first turn of the key .. its an AMAZING feeling of satisfaction .. and you'll never get over the fact that YOU built it ..

i could have bought a "350 crate motor" and been done .. but instead a got a one of a kind custom built 305 tpi that will kick the crap out of a "350 crate motor"

and its alot more fun to unpack all the parts and assemble them .. kinda like christmas ..

read the engine section of your haynes manual and youve basically rebuilt a motor .. now do a little research on what you want to build it to do .. and then (re) build that motor with the new parts .. thats all there is to it ..

 

Thanks guys
I read your guy's posts over and over, I made my mind up on staying with my same engine block, but Im going to put all new parts in it (the engine is sorta beat up.. leaks dex cool, and that stuff isnt cheap... my oil pan has a big curve on it from hitting dips this winter, and the engine has about 170,000 miles on it, and im sure alot of the parts in the engine are pretty warn up. This helps alot, By may I hope I will have the money to start on rebuilding the engine

 

I used to think the whole Thumpr idea was pretty dumb... but if its really derived from real road racing style cams then that's pretty interesting. I just hope they didnt sacrifice any performance for the sake of vanity. The problem is, they're marketting this thing around vanity instead of the performance aspect which seems to be secondary. So my hopes of this thing being a good performance cam aren't so high.

But still... it's an interesting concept. A good example of racing technology trickling down, I'm betting this new design philosophy for cams wil lcatch on and get better over the next several years and maybe we'll all have a better idea of what they're capable of by then.

 

its just as apieron said .. there main purpose is for show .. if you want a lopey idle .. then just build a motor with a big cam, but build the rest of the motor to match so it will sound good and actaully GO ..

i think its stupid to make a normal motor "lope" over when it cant back it up with any power ..

 

Demon eater what kind of 305 do you have?

 

TBI, Im pretty sure its all stock (except the water pump and air cleaner, but I wouldnt really consider those :-\ ).

 

I'm trying the ***** thumpr in my 383 roller. Machine shop I used to assemble my bottom end said they weren't to sure about the cams, but a customer wanted to try one out and got good numbers. Now they try to use them whenver possible in higher cu motors. I can't tell yea anything about my personal build until the spring tho. The cam came from endurance racing.

 

I'd be looking for a new shop if I heard that.

 

Hey man, opinions are like...well you know what but dynos don't lie.

 

No they don't, so ask your shop to do a back-to-back dyno comparison with a properly suitable cam grind so you know how much power you're losing. While you're at it, get them to compare emissions levels and do a mileage comparison.

 

I'm not a big fan of the Thumpr cams at all. I finally ponied up the money and got a aggressive custom hyd. roller cam for my 406. Building this thing has been a blast. Once I fire it up come spring time I know I'll have on of those ear to ear smiles.

 

It's a marketing campaign that seems to be working. Think about all of the other names of groups of cams. ex; fireball, magnum, high energy, sat night special,etc. Whatever sounds cool at the time. You should be buying a cam based on specs and what your motor needs, not what you what it to have. Does this make sense to anyone else besides me?
immo

 

Ya it's really working! everyones hyped up about them even i was. I hear nothing in the mags about them though or on T.V.

 

Well it's a completely different cam design philosophy, no one knows what to make of it so if they wanted to sell any of them they had to hype it up with some sort of gimmick - hence marketting it based on vanity and a lopey idle as opposed to anything else.

If it makes for a nice, fat power band once you hit a certain RPM-range, then I'd say it's successful.

Just, like I said, it depends on whether these grinds are just slightly inspired by endurance racing and mostly tweaked for the sake of marketting, or whether they are truly very similar and with similar performance.

Im thinking if I want to autocross or open track with an auto (not my first choice, but T56 swaps aren't cheap) then a giant cam and a huge stall are going to really hold me back out of corners since the power just isnt going to be there with the nature of these loose stall converters.

So if these thumpr cams can get you into the power band sooner while maintaining similar peak power numbers as larger cams, or at least good numbers in the rev ranges that it works well, then they'd be a compelling option. The question is whether or not it works that well.

 

Look at the specs on the smallest SB with OE hyd roller. If I were to come on this board and ask if it will work with a computer controlled TPI, I would probably be laughed out of here. Too much duration, lobe sep is at 107 instead of the recommended 112+. I'm not saying that these cams don't have their place, I'm just saying each individual needs to pick a cam their motor needs based on how they will drive it, what trans, accessories etc.....but they do sound cool as $hit.
immo

 

They're just full of features you'd find in a real endurance racing cam, like 16 lobes, journals, a distributor gear, and provisions for mounting a timing set.

 

The tight LSA and EXTREMELY wide exhaust duration would make it an OK cam for a larger displacement carbed car with mech secondaries, narrow ratio gears (T-10 or T-56 with steep rear gears), and nitrous or a blower. Then again, the narrow LSA makes you wonder how well it'd do with a blower.


It has no place in an FI car, and naturally aspirated is dicey. I think one could do better.

 

 

Narrow ratio gears? I figured the whole endurance racing aspect would mean they'd try to keep the power band as wide as possible (even if it doesnt start until 2000 RPM or so) to reduce the amount of gear changes they'd have to do. That's the only reason I can imagine that it woudl be different from just "road racing" cams... because they do specifically say endurance racing...

But I'm just going to wait a few years and see how the reception/hype is then.

 

It doesnt have all those features! I want more! haha

Call Comp and see what they say I love my custom cam... .585/.599 lift 238*/248* @.050 and a 113LSA