Scalpel

iTrader: (4)

Yep, very good info to have. It always irritated me when others I have read would post that stock pushrods were sufficient with stiffer/heavier valvetrains and aftermarket (more aggressive) cam shafts.

J-Rod

Here are the lobe charts from Bret Thanks Bret!

2002Z06yellow

very interesting read... i just want to make sure i got this right

1- your saying that there is a lot left on the table when it comes to cams and the LS1/6?
2- lopey idle is one thing and idle quality and driveabilty is another thing? usually they are linked together the meaner the lope the worse the idle quality and dirveability...
3- we can make(or at least 93pony) cams at 220/220 580~ @114 that would outperform the current TR224 and MTI 224 cams but with even better idle qualities and driveabilty?
4- are the aussies light years ahead of us in cams?(i thought LG's cams were big)

DenzSS

Not necessarily. Their cams are just big.

As stated, it is very easy to "over-cam" an engine. Unless you can keep the engine in its increasingly narrow power band, you will go slower.

Too much cam, carb, and manifold are the #1 mistakes made by beginners. "Too much cam" is so prevalent on this board it is frightening. That is one of the big reasons we see so many 450rwhp 12.5s 1/4 cars.

Cstraub

iTrader: (1)

"one of the big reasons we see so many 450rwhp 12.5s 1/4 cars"

DenzSS,
I agree. I have a customer's son with a '72 Chevy Camper Special pickup with a stock iron 882 headed flat top 350 with a .500" hyd cam that runs 13.50's at Beech Bend Park on ET streets. 3000 stall. Tailgate down. Combination, Combination, Combination. I preach it till I am blue in the face.

Chris
Oh yeah, I forgot 4600Lbs.

black_knight

iTrader: (1)

DenzSS, your posts support a position that most people "over-cam" on this board. It seems like you mean not just the question of "will this cam idle/work," but more along the lines of "is the powerband of this cam useful at all?" Do I get your jist correctly?

So, I guess the natural question is:

What cam specs or cam would you recommend for someone who wanted to make maximum power from 2000RPM to the stock rev limiter, without any particular concern for idle quality or gas mileage or spring life or pretty much anything else? (I assume you would have two differant answers for stock heads and aftermarket heads) This is without Nitrous or any power adders, and for stock cubes.

I'm talking about the cam that would get such a car down the 1/4 as quickly as possible, whether that's with a good peak # or with power "under the curve."

~230-240 duration, high lift, is what I assume you mean when you say "over-cammed." If not, please do specify what you mean.

Basically, I'm asking that if you are going to trash the cams on this board, then please offer what your idea is of what people SHOULD be running.

critter

iTrader: (9)

Someone mentioned non-symetrical lobes earlier in this threaed. I finally got my cam degreed and "doctored" last night. The Comp 3719 and 3726 lobes are both symetrical, and the cam is ground to the specifications as well as I can tell (+/- 0.5 degree) with a manual "cam doctor" (degree wheel and dial indicator).

Oh yeah ... the Cloyes hex adjust rocks!!

CHRISPY

I dont agree with the statement that a lot of cars are overcammed

You should see what some of the racing small blocks use and a lot of them are setup to shift at 6500rpm.

The rest of the cars combo is probably not built around the rpm range of a cam.

If I have a cam that has a powerband of 4000-7000rpm and makes 450RWHP at 6400rpm I can setup the car to run faster than a car with 400RWHP peak @6400rpm every single time. (Provided same tranny, same raceweight)

The missing links are suspension, gear and converter (if auto)

I am not going to get into the streetability or manners of a particular cam, I am talking from a racing standpoint only.

You pick the powerband you are looking for and setup the car accordingly.

I think that is why we see so many 12.5 450RWHP cars.

DenzSS

That is exactly my point. People are "over-camming" their cars because they do not have the necessary suspension, gear, or converter. People are choosing cams as if their cars are are race cars, when 99% are not. They are street/strip at best.

CHRISPY

But overcamming in my opinion refers to a cam that moves the rev range out of the physical limits of the rotating or oiling system OR prevents the car from idling or running even with proper tuning. (complete loss of power brakes etc)

People that do not setup the car properly based on a cam selection are just being foolish IMO it isnt in any way the cams fault

DenzSS

Well, there is where our definitions split.

To me, "over-camming" refers to a choice of camshaft that is too large for your application. People obsess on peak HP numbers without regard to what is required to access and use that power.

In my opinion, this whole board focuses too much on "race cams" when in fact that is far from what the average guy should actually be using. People focus on how much "power" they can make without understanding the differences between street, street/strip, and race configurations.

We are doing them a great disservice by discussing "race cams" as if they are the best choice for most people.


In my opinion, that is the incorrect way of going about things for most people. You match the cam to the setup, not the setup to the cam. Most do not have the money, time, or knowledge to do it the way you suggest.

My biggest concern is that we are giving people the wrong impression and we are paying for it. People read the "big cam" threads, put one in their car, and run slower than bolt-on cars. I don't know how many threads I've read that say "It sounds like a monster, pulls incredibly hard, and sounds like a super stock car." "How'd it do at the track?" "12.5". Then they go through the rounds of mods trying to figure out what is wrong and saying "I need more power." If they had made a reasonable choice in the first place, the whole situation could have been avoided and they would have a faster, fun to drive, car.

CHRISPY

We'll have to agree to disagree on that.

People should do the research and have their goals for their car in mind. I personally feel if someone runs out and buys a cam without researching it that is their own problem.

If someone puts a 232/240 112 LSA cam in their stock converter 2.73 geared A4 car with stock manifolds etc they are just being stupid. (UNLESS they plan to upgrade gears/converter later

With todays tuning it is very easier to get a fairly large cam to idle and drive extremely well and make great power.

critter

iTrader: (9)

Chris and DenzSS -
IMHO, it is clear that if your criteria is ET/MPH, the whole combination is important. If your criteria is dyno numbers, the engine combination is important. If the criteria is a "hard lope" (a term I first saw here), then size of cam is important. The concept of "overcamming" is relative and has to be taken in the context of the goals.

DenzSS

I'll agree with that. I don't understand dyno racing, but it seems that a lot of people are into it. Hell, I've seen people spend thousands of dollars to gain 5rwhp just because they wanted to hit a number on the dyno.

I'll disagree with You can run a 216/216 @ .050" cam with a 106 lsa and it will shake like Katherine Hepburn in a paint shaker. If you really want to, you can tune the stock cam to idle like giganto-cam if you know what you're doing with LS1edit.

What my main complaint is context. People do not understand. I get calls and emails all the time about the latest "cam-of-the-month" as people start to get cam-envy when their buddies get a bigger cam. We need to educate the populace about HOW to choose a correct camshaft for their purpose.

CHRISPY

That is the point of this thread is it not?

DenzSS

You know as much as I do that this thread is too scattered and too long for the average guy to read, understand, and take advantage of.

Talking about valve events, ramp rates, etc do not really help the average joe on the street. IMO, we need to start a thread giving basic advice and basic explanations of camshaft selection. Basically a "Do and Don't" list. We could hopefully cut down a lot of the repetative questions and give these guys a basis to work from. Maybe start a camshaft FAQ sticky'd at the top of this section.

CHRISPY

That idea has been tossed around before

DenzSS

I have a few articles and basic writeups if we ever want to throw something like that together.

critter

iTrader: (9)

I wouldn't have a clue how to do that unless you set idle way rich or something. I knew a guy once that pulled a plug wire trying to get a drive-in lope. Of course he washed the cylinder and had to rebuild. But if you can do it with a tune, that would be a lot cheaper than a monster cam. However, what would your customer tell his buddies? He couldn't brag about his big camshaft

FWIW, I don't understand the dyno-heads either. I've said here before, I had a car dyno tuned once. It slowed down. It got better mileage and idled better, but that isn't what I was after. Since then, I tune at the track or on the street.
I hear ya, but the problem is that you have to convince the "hard lope" crowd that they don't want a "hard lope", or that they can get it with a mild cam and tune. Then you will have to convince the dyno-heads that they shouldn't give up midrange and buy a cam that has a power curve that is still climbing at 7K just for the sake of a slightly bigger number. I agree with you that education is needed, I just don't think it can be done

DenzSS

Well, we're pretty well in agreement there.

The problem we've found with dyno tuning is the inability to generate real-world loading on a purely intertial dyno. You just can't generate the loads present on the street or a 6K rpm launch on 30" slicks. Your tables are way off unless you get some street or track time to gather the necessary data. I have access to a dyno and can use it basically whenever I want, but to be honest most good tuning isn't done on a Dynojet. A combination of street and dyno can turn out incredible results.

The best results I've seen is using a good wideband and a good data logger on the street for both part-throttle and WOT. When you take that combo to the track, it makes things so much easier.