doctorj77

Hello everyone. Need some input from people who have them or are familar with the Comp Thumpr cams.

I finally have the $$$ means to buy cams this time and I'm torn between FRPP Hot Rod cams and Comp Thumprs.

I've heard nothing but good reviews about both, but have heard the Comps will make more rwhp. That's not really my motivator, I just want the sound. So my question is, do the Comp's really require the phase limiters? Reason I ask, I'm getting conflicting information from two very reputable sources "names I'll keep anomynous" that we're all familar with.

I've been told by the tuner, that yes they are required, even Comp states that. Its not a performance requirement, but a safety measure essentially to prevent the valves from crashing into the pistons. Which I can understand.

But then a reputable mustang shop in Mich explains that its not required. Reason they state is when your mechanically locking/limiting the timing with phase limiters, the VCT struggles with the timing because its physically being restricted. Eventually the VCT gets into a learning curve, and the end result is the customer car doesn't sound or perform the way it did the day it was installed. They said that when someone says "they're required" that they probably are a tuner not a engine builder so they'll try to sell you more parts than you need.

I'm leaning to the FRPP cams because of this. Granted the Comps are about $50 more than the FRPP. But I can get a mail order tune for the Comps for free. Where as the FRPP I'll have to have it dyno tuned. I'm trying to save money on this and I'm inclined to do the install myself. But I want to to make sure I'm going into this blindly.

Does anyone have similar experience with this or heard anything along the same lines? Or people with the Comp + Limiters, have you had any troubles with the VCT?

Thanks in advance.

abarker8541

alright the age old question. comp vs. hot rods. really its a matter of personal opinion and what you want for your car. hot rods show nice gains throughout the rpm range or thumprs that make nice gains in higher rpms. now phasers, listen to the manufacturer. personally i would get phasers no matter what. i really dont want a piston and a valve doin the nasty together. personal opinion i would get comps. they have been doing nothing but cams cams cams for a long freakin time.

hammeron

from what i've read, there is no struggling
what so ever. the tune is modified, limiting
how many degrees the PCM can advance
or retard cam timing....

it's really a toss up, both cam sets will get
you where you want to be....

good luck and let us know which ones you
go with

SirKnightTG

The Ford engineers who designed the hot rod cam also designed the stock cam. They know what you can and can't do for cam profiles and the VCT system. So it would be not only a waste of money to use phasers on the hot rods but you'd get less performance, especially in the low end. I've gotten confirmation of not needing the phasers on the Hot Rods by many places, including JPC.

I prefer the Hot Rods since they make consistent power all the way from low end to high end. The Comps lose low end but gain a little more on the high end than the Hot Rods. So it really depends on where you want the gains.

GT Bob

One bit from a tuners perspective here:

The guys who are saying phasers are not needed are likely speaking from a standpoint that the PCM can control the amount of advance as well as the physical parts can. To a degree, they are right. However, if there is a hicup or something, and the cams over advance from where they are supposed to (which can and does happen more often than you would care to think) the chances of introducing your valve to the head of your pistion are pretty good and let me tell you, while they make good neighbors they should NEVER attend the same party. The Limiters are a physical protection against the cams over advancing. So the question comes down to... is spending the extra few $$ now on the limiters for the Comps worth rolling the dice on your valves and your pistions meeting up at a very bad time?

abarker8541

i would get the phasers man. spend that money to protect them. remember never put anything cheap in the engine. including not buying something you know you need. you will be happy with either brand of cams. i just think the comps sound a little better.

Fullsayl

Tell ya what, I have the Comp Cams ***** Thumpr on order and will have them installed in the coming week. I already have already Dyno'd my car in its current spec, so I will be able to tell you specifically what they sound like and give you exact HP increases.

Supporting Mods are listed in my Sig/My Garage.

Matt

hammeron

this isn't directed at any post in particular,
i'm just thinking out loud here.....

regarding the hot rods, the question i'd love to
know the answer to, is:

"did ford design the hot rods, to operate in
the event of complete VCT failure (in which
the cam angle can sweep from max retard to
max advance ***** nilly like), without the
possibility of valve to piston contact?"

if so, that's great, no need for limiters or lock outs.

if not, we are relying on the PCM and VCT to hold
up and continue to function, especially during an
event in which RPMs change extremely fast.

whew...glad it's happy hour...to much to
contemplate after a long day..

delstang

I had the Comp Thumpr's put in two weeks ago and they sound great. I would rather be safe than sorry and use the phase limiters. They were not that much more money.

SirKnightTG

This is what JPC (who basically "beta tested" these cams with Ford Racing) said to me: "Ford knows the requirements needed to use their cams on their heads. Basically the stock set up accept the specs of the cam. The lope and overlap do not make it an issue."

So I'd feel perfectly fine using the Hot Rods with out a limiter. Plus they have a crate engine (which is just a 4.6L GT engine) that comes with these cams. So I don't think they'd sell an engine with these cams if there was a chance of valve and pistons meeting. Ford is not going to take a dumb risk like that. Also, these cams are being used in their race trucks without issues. Remember that the specs of these and the Thumprs are very different regardless if they sound similar.