Cstraub

iTrader: (1)

Sorry, been out to a "rain" soaked NHRA event. Need to catch up. . .

Chris

J-Rod

Here is a small attachment to show a near stock Z06 (minus the airbox lid) vs a G5x3 car. As you can see HP and Torque are up across the board with the G5x3.

A G5X3 on a 112 has around 14 degrees of overlap @ .050.

A 232/232 108/108 has about 16 degrees of overlap.

A 242/242 106/106 has 30 degrees of overlap @ .050.

DenzSS

I need to catch up as well. Was working on my motor and doing a leakdown test on a 427.

J-Rod

A couple of links for folks if they want to do a bit of reading to help understand some of this...

http://www.chevytalk.com/tech/101/Cam_Theory.html

http://www.iskycams.com/degreeing.html

DenzSS

Yup. You nailed on the head. Ed is a good guy and a very good designer. In short, he doesn't give away info. Your best bet is to find someone to mentor you in this. It isn't easy to find, but can be done. The problem is, you'll be bound just like the rest of us to keep your mouth shut about certain things.

If anything, the information we're talking about will do more harm than good to the general public consumer. As we've stated before, it is an incredibly specialized field. Even if you know how it is done, it doesn't mean you can make the correct decisions yourself. You need a very functional understanding of fluid dynamics at the very least.

What you can do is learn enough to understand how camshafts are designed. Then you can look at a camshaft and give a broad brush of "looks close to what I expect" or "that looks way off". Essentially you need to become an informed consumer.

J-Rod

I agree that some folks on here do this for a living, and I don't want to take money out of their pocket, or food out of their mouth. But, on the other hand, knowledge is indeed power in this case in two respects.

One, it allows you to make better power if you understand things.

Two, it help you become an "informed consumer".

Too much of what is sold is the Monkey-see Monkey-do school of engine design i.e. "those guys did it, so lets copy them" or " if big is good REALLY BIG must be even better". If we can get folks educated on what they should be looking for their particular combo rather than generic stuff that may or may not work, I think it will go a long way towards a better consumer.

On top of that, it will allow the folks who know what they are doing to shine, and the ones who don't to be left behind.

I don't think you can ever have enough information. it how you collect it, and use it that matters. Keep in mind that many folks will still show up asking "which cam should I buy" since they have neither the time nor the intrest to get educated. But, some folks out here do want to be more than off- the shelf cam buyers. Thats what threads like these do. They help educate the folks who will be the better customers. When they come in, they have the info you'd normally have to spend time tracking down...

Cstraub

iTrader: (1)

Erik is correct, you can either "talk it" or "walk it". When I entered this business on the wholesale side and worked on commission only, I learned that the first sale to someone is exciting but not impressive. The 100th sale to that customer is impressive. I have to live with customer base, so if you don't produce, See Yah!!

Bink, IMO, yes. Even limited to the .570" lift, I feel the exhaust is way off on both duration and lift. . ..to much.

Chris

BADFNZ

iTrader: (19)

Do ya'll agree with this? I've read every cam discussion thread so far and this is knowledge I feel I've gained. I'm no expert but I did stay at a Holiday Inn last night

Bink

Thank you.


joel

Cstraub

iTrader: (1)

Bink, you're welcome. Most of my road race stuff has been vintage, GT-40's, Cobras, a few Camaro's. but following my recipe for torque band everyone has been pleased.

Chris

racer7088

""Since more compression likes more overlap, I started playing around the the VE calculator. As it sits, I have 1.2* of overlap at .050. If i take my same cam and put it on a 109 LSA instead of 112, the overlap jumps to 6.2* on a 106ICL. This might work well for me.""

Actually it's more like the opposite as in low compression engines usually employ tighter LSAs and higher compressions are needed for wider LSAs. Basically you use the heads, intake, exhaust, and cam to trap as much air and fuel as possible in the rpm band you want it and then compress it as much as you can without causing detonation problems for yourself. I figure compression at the end of when I am doing an engine and do the pistons after I know what heads and cam I am going to use. It's all a combination like everyone always says and yet never does!

99 Black Bird T/A

iTrader: (4)

What's the right order to go about building an engine?

Does it do something like this?

1. pick out the best head to can get
2. flow it (with and without intake) and see what you have to work with
3. decide on the right CID to use the airflow
4. pick a cam out

Cstraub

iTrader: (1)

I would say:
1. What is your goal, ie ET, stop light to stop light speed.
2. Budget
3. Builder/Mentor, this does not include magazines
4. Combination to reach goal
5. Part selection to get CID and proper cylinder head
6. Selection of camshaft and rocker arm ratio, we have not touched on ratio yet but
on the LS1's, split rocker ration is even more critical then ever thought of on old
SBC engines.

Chris

critter

iTrader: (9)

Here is, I think, a good example of what Cstraub and DenzSS have been talking about: TR230 vs. TRex. (cut,paste, and insert link didn't work: here it is as text: http://www.geocities.com/danwade@pac...ex-overlay.jpg sorry about that) This is a forged 346 with Kooks, LS6 intake, Crane rockers, etc. Full details are here.

Note how the TR230 (which is not really a small cam) make more torque and HP below about 5500 RPM although the TRex has about 18 HP more peak. Also note how the TR230 peaks about 6300, which is rather high for a street cam, while the TRex peaks about 6700 or 6800 and has lost hardly anything at 6900. It really seems a stretch to call the TRex a street cam. Sure, you can run it on the street, and folks do, but I have owned or driven enough large cam cars to know that a curve like that is not exactly street friendly. It is fun for a day or so, but gets tiresome quickly.

DenzSS

Bingo!

To add a few thoughts...

I can't begin to tell you how important finding a good mentor is in this field. Even if you're just doing this as a hobby, it is critical to find someone that is willing to pass on their knowledge and experience. What differentiates us from the average microbe out there is our abiility to learn from the mistakes of others. To quote Norm Brandes "Knowledge is what you get when you didn't get what you wanted." ...and I'm pretty sure he was paraphrasing Jere Stahl.

HumpinSS

iTrader: (1)

Geoshitties wont let us see the graph

DenzSS

One more thing to add...I keep seeing this on this forum.

People keep buying a camshaft and then go about trying to buy a cylinder head to match that camshaft. That is completely backwards.

If you're working with a stock engine, you buy the cylinder heads first and THEN match the camshaft to the heads. You'll never get a correctly matched setup if you go about it ***-backwards.

critter

iTrader: (9)

Sorry. Appears to work now.

Cstraub

iTrader: (1)

If we gave up that kind of torque to make that HP. . .we went the wrong direction.

Chris

DenzSS

I would definitely agree.

There appears to be a great deal of detonation present in both graphs. The 230 looks like tip-in detonation, the TREX is detonating at at tip-in and torque peak. Either that or someone has a really strange timing curve.