Anyone using Comp's Mutha Thumpr?

[ne0fiend]

Swapping cams again, and I'd like to talk to Comp Mutha Thumpr owners speciffically.
-Driveability?
-Tune Necessary?
*Fuel Trim alterations
*Spark advance/retard
-Increases in exhaust temp?
-Braod increase in fuel comsumption?
etc.
Notes:
Heads are stock
Headers are long-tube (ceramic coat)
85mm TB
Summit brand MAF
Fast (r) Intake
MSD coils, etc.
*stock* Delphi PCM <- important



Thanks bros

[konigandy6]

What cam do you have in now?

It will definitely require a tune... 109 lsa will make it really lopey and hard to idle without a tune. The exhaust duration is bigger than normal, especially with the intake side of it.

Are you an M6 or A4? You'll need some support from the drivetrain if you are going with a larger cam. Rear gear ratio and if A4 a stall converter. What made you want to go with this cam?

[Firebirdjones]

I'm running it, but not in a fuel injected 4th gen.

[ne0fiend]

What cam do you have in now?

It will definitely require a tune... 109 lsa will make it really lopey and hard to idle without a tune. The exhaust duration is bigger than normal, especially with the intake side of it.

Are you an M6 or A4? You'll need some support from the drivetrain if you are going with a larger cam. Rear gear ratio and if A4 a stall converter. What made you want to go with this cam?

The cam I'm using now isn't as beefy as I want, I had a sour deal with ExoticPerformancePlus and was upsold a crappy grind with a really smooth LSA.
The Mutha Thumpr is exactly what I wanted in the first place, but I went with the easy deal - paying for it now.
Mine's an M6, so I'm not too worried about the gears in the short term.
I guess my only other question would be a Dyno tune. Do we know anyone in the Tampa, Florida area that can recomend a fair priced speed shop with a dyno service?

[snlrulez]

Havent ran the cam but I've read that a few people didnt care for it. Sounded mean but that was mainly it. Just from what I've read. Good Luck.

[Firebirdjones]

That's not really the case as far as carbed motors go. There have been several comparisons between these thumper cams and some of their more popular line of XE cams.
The thumpers only gave up a few ponies overall and they actually performed quite well. There is alot of thought that went into the design to give the sound without giving up much power or needing too much compression to make it work.

Fuel injection on the other hand I'm not so sure. Fuel injected motors tend to like wider LSA's of 110 or more it seems. And I've noticed the fuel injected versions of the thumpers only come with a 109 LSA compared to the carb versions of 107. How well they work in a fuelie LS motor I can't say.

[ne0fiend]

That's not really the case as far as carbed motors go. There have been several comparisons between these thumper cams and some of their more popular line of XE cams.
The thumpers only gave up a few ponies overall and they actually performed quite well. There is alot of thought that went into the design to give the sound without giving up much power or needing too much compression to make it work.

Fuel injection on the other hand I'm not so sure. Fuel injected motors tend to like wider LSA's of 110 or more it seems. And I've noticed the fuel injected versions of the thumpers only come with a 109 LSA compared to the carb versions of 107. How well they work in a fuelie LS motor I can't say.

Funny you mention the LSA, I am also concerned with that. I've taken the valves and springs into consideration and selected a slightly shorter rod to dampen the voilent open:shut cycle of the 109. The cam I am swapping now, is a symetrical 224/224 114 +1, and was just too laid back for me.
The plan is in the works and the Delphi PCM will be replaced by Pontiac Power's custom unit. The only thing holding me back now is finding a dependable speed shot that offers a dyno tune for a good price. It is VERY hard for me to allow other people to touch my cars, so leaving my Goat at some stranger's place for a few days SUCKS in my mind. But... I guess I've got to do it...

[TmaxicanA]

there is a camaro here in town by me that has that cam.
it sounds like a friggin rail car. dont think he has head work...runs like a bat outta hell cant hook for crapola though.(factory wheels w/ primewells lol

[ne0fiend]

there is a camaro here in town by me that has that cam.
it sounds like a friggin rail car. dont think he has head work...runs like a bat outta hell cant hook for crapola though.(factory wheels w/ primewells lol

Primewell.
The jewl of Chinese rubber... Vomit.

[Firebirdjones]

Funny you mention the LSA, I am also concerned with that. I've taken the valves and springs into consideration and selected a slightly shorter rod to dampen the voilent open:shut cycle of the 109. The cam I am swapping now, is a symetrical 224/224 114 +1, and was just too laid back for me.
The plan is in the works and the Delphi PCM will be replaced by Pontiac Power's custom unit. The only thing holding me back now is finding a dependable speed shot that offers a dyno tune for a good price. It is VERY hard for me to allow other people to touch my cars, so leaving my Goat at some stranger's place for a few days SUCKS in my mind. But... I guess I've got to do it...

I've been driving mine a bit now with the mutha thumper cam. Talking with Comp Cams, they based these designs off their roundy round dirt track cams they grind. I run mine in a 406 so it soaks up some of the sound compared to a 350, but I find it to be just about radical enough to turn heads. It's pretty choppy up to about 1,500 or so then finally smooths out a bit. I run a 4 speed behind it so torque converters aren't an issue, but it would need a loose one for sure
It only holds about 8 inches of vacuum Idling at 800-900 rpms in neutral so it could be a problem for someone with power brakes ( I don't have those either )

As far as power, this particular 406 made over 450 hp on the dyno a few years back with a different cam (230/240 at .050) on a 110 LSA. I have only switched to this Mutha Thumper cam because I wanted more sound, didn't care so much about output, but I can say seat of the pants feels no different, so I don't think I really gave up much if anything. Specs are 235/249 at .050 with split lift .490 intake and .475 exhaust. It's ground on a 107 LSA though, and they want it installed on an intake centerline of 102. So it has 5 degrees of advance ground in. I installed it and wound up with a 103 ICL though, my chain was a little stretched obviously after only 20,000 miles. I think it drives around great, raps up fast, and makes all the right sounds on cruise night. It lopes down the road at 30 mph. Again this is just their middle Mutha Thumper cam, they offer one that is even wilder than this one.
Just my experiences with it. I'm still not so sure I'd want to put one in a fuel injected car though.

[Mr. Luos]

Huge split.
I imagine it would also be a bitch to tune. But sound pretty mean.
I dislike picking a cam for sound....but I know it happens.

Personally....get something like the Torquer2 on a 112....should have plenty of power with decent sound.
I actually REALLY like the grind you have in there....would probably stay with it.

Don't want too much cam without gears and driveline for it.

[Firebirdjones]

Huge split.
I imagine it would also be a bitch to tune. But sound pretty mean.
I dislike picking a cam for sound....but I know it happens.

Personally....get something like the Torquer2 on a 112....should have plenty of power with decent sound.
I actually REALLY like the grind you have in there....would probably stay with it.

Don't want too much cam without gears and driveline for it.

Yep, they run the huge duration split to compensate for the reverse lift split of 490/475. It works well. The extra exhaust duration helps my combo anyway which is why I had a 230/240 in it from the beginning, because the exhaust flow on my World heads are a little weak, and my headers are small for the cubic inch I'm running 1 5/8" on a 406. The larger split made more power on the dyno for me. The engine really likes 1 3/4 headers but this is what I had laying around for this chassis.
It all works pretty well together though. Carbed motors like tight LSA's and this one has it (107) and right now I'm only currently running 3.08 gears out back (although only a 25 inch tall tire). Seems to work just fine with this cam. I can lug it down to about 1200 rpms in 4th (muncie 4 speed), and mat the throttle, it picks right up without so much as a buck or kick without having to downshift. The car only weighs 3,300 lbs.
Lights the tires up if I want to. So far after 100 miles logged it's really not that bad of a setup and seems to make good power right off idle up to 6,000 rpm where I'm shifting it at.
If I still had access to a dyno I'd love to stick it on there again just to see if there is a difference in power. But so far I find it drives on the street just as easy as the 230/240 cam on a 110 LSA I had in it before.

[Firebirdjones]

I'm trying to upload a short video of the car idling. Seems anything more than 25mb gives the computer problems so I had to shorten it down to 5-7 seconds. We'll see if it works shortly.

[Firebirdjones]

Hope this works. This is the Mutha Thumper in a 406. I built this motor about 5 years ago for my daily driver monza at the time, drove it daily for 2 years before the car rusted apart, pulled the motor and saved it till now. Went back through it just to check things after logging 20,000 miles.
10:1 with World cast iron heads, runs on pump gas. Back then with a somewhat less radical cam it made 458 HP if I remember right, (sheet is here somewhere) Just a mild build, I simply changed the cam to a mutha thumper before installing it in this car.

[Too Fast]

Video works fine, but the audio part is a bit distorted. Hey, nice Nova!

[Firebirdjones]

Always a bit windy up here, not much I can do with that

I had a ton more video pulling it outside, but I had to cut it short and keep in under 25 MB.

I could try it in the garage without the wind. I'm just so used to wind out here I didn't think much of it.

[Texas Jack]

Hope this works. This is the Mutha Thumper in a 406. I built this motor about 5 years ago for my daily driver monza at the time, drove it daily for 2 years before the car rusted apart, pulled the motor and saved it till now. Went back through it just to check things after logging 20,000 miles.
10:1 with World cast iron heads, runs on pump gas. Back then with a somewhat less radical cam it made 458 HP if I remember right, (sheet is here somewhere) Just a mild build, I simply changed the cam to a mutha thumper before installing it in this car.

Firebird, I haven't seen one of these in a very long time. Very nice is it a 69 or 70? Sounds nice also.

[Firebirdjones]

It's a 71.

Here is a better shot in the garage, hopefully the sound comes through better.

[Texas Jack]

It's a 71.

Here is a better shot in the garage, hopefully the sound comes through better.

Nice vid, sounds so good, had a 70 Nova SS back in the day but the Pontiac is a rare beast and I like!

[Firebirdjones]

Thanks, I had a bunch of novas over the years. This being a tad different makes for an interesting conversation piece. They are about extinct