Don't understand this...

[99v6cam]

So I sent a cam request form into comp cams and they replied but i don't understand what they sent me. Can someone like decipher this for me.

---------------------------------
Corey,
For your 1999 Camaro, I recommend the #76-801-9 (See the Spec Card Below). The RPM Operating Range is 1000-5500. Take a look & let me know what you think.
If I can help you further with this, feel free to call me at 1-800-365-9145 Ext 582 between 8:00AM-5:00PM CST,
Monday-Friday. I will be glad to help you.
Thanks,
Darrel Miles
Cam Spec Card Inquiry
PART NO. 76-801-9
01 INTAKE MASTER 3105S
02 EXHAUST MASTER 3106S
03 ENGINE GM38 255HR12
04 GRIND NUMBER GM38 255HR12
INT EXH
05 HYDRAULIC Y/N YES 14 DUR @.050 201 205
INTAKE EXHAUST 15 LOBE LIFT .3120 .3000
06 VALVE ADJUSTMENT HYD HYD 16 ROCKER RATIO .00 .00
07 MAX GROSS VALVE LIFT .517 .498
08 DUR @ .006 TAPPET LIFT 255 262 17 LOBE SEPARATI 112.0
18 ADVANCE 4
09 VALVE TIMING OPEN CLOSE 19 VALVE SPRINGS
@ .006 10 INT 7- 27
11 EXH 38 13- DATE SETUP 11/19/2002
12 THESE SPECS ARE FOR CAM(S) INSTALLED
@ 108.0 INTAKE CENTERLINE

13 REMARKS

But just from looking at where it says it's operating range I don't think they took me seriously when I said I wanted a big cam.
I'm used to seeing cam specs laid out like this: 216/216 @ .050"
.507 intake .507 exhaust
111 LSA

[FireFighter]

They just sent you all of the specs for it, whats not to understand? Or are you just not sure what they mean?

[98Camaro3.8]

Don't ever go by what they say. Their cams are pretty small, nothing compared to the other aftermarket cams.

The specs of that cam are: 201°/205°, .499"/.480", 112 LSA.


What do you want out of the cam? N/A or power adder? Driveability?

[99v6cam]

everything just seemed cluttered to me and i cant piece them together, thanks for helping me out with that. I want it for a very strong n/a cam, and i now see that that is NOT a very strong n/a cam.

[98Camaro3.8]

For a great cam with power and drivability, you can't go wrong with the GT2 you listed.

[FireFighter]

I thought you already had bought a cam.

[99v6cam]

i just randomly took that from someones sig :-p I want bigger than that.

[99v6cam]

Originally posted by FireFighter:
I thought you already had bought a cam.

nope but im shopping (hence this post) drivability isn't much of an issue for me because i dont drive much. I don't mind a lopey idle or bad gas mileage (as long as its not like 2mpg)

[ August 17, 2005, 07:50 PM: Message edited by: 99v6cam ]

[99v6cam]

Ok I've been looking at the spec thing for a while and I'm confused because 98camaro3.8 said "201°/205°, .499"/.480", 112 LSA." and i see the 112 lsa in there and the 201/205 but i dont see .499 or .480 in there, but i do see .517/.498. I heard someone say something like you multiply the lift by the rocker ratio to get the valve lift and i have stock 1.6 rockers but that leaves me with a mere .321/.328 so that can't be right either so I'm just confused right now.

[98Camaro3.8]

Lobe Lift is .3120/.3000. Multiply those by 1.6 and you get .499"/.480".

I totally understand you're eager to learn all this, and I'm glad you are....just remember to learn it before spending a ****load of money. ;)

[99v6cam]

Originally posted by 98Camaro3.8:

just remember to learn it before spending a ****load of money. ;)

That's EXACTLY what I'm doing [img]smile.gif[/img]

[99v6cam]

Someone on another board said to me to send my own specs in to comp cams and tell them to make it.

That's the thing though, I'd love to just throw specs at em and say make it but I don't know enough about cams and the valvetrain to do so. I could just do the compare thing and wing it. Abbott n/a cam is 210/220, .512/.512, 112LSA so I could just pull numbers out of my @$$ like 220/235 etc etc but I would know wtf i was talking about because I don't know what number mean what (I know the middle number is the valve lift and the last one is lobe separation angle) but I dunno what the first pair mean and i dont know how the lobe separation angle affects anything. There's an old thread that explains em somewhat but I don't understand it much, I need someone to just spell that sh!t out for me.

[98Camaro3.8]

First numbers are the duration of the intake and exhaust. It's how long (in degrees) the lobe is open above a certain point, such as .05" above the base lobe. 216° @ .05" means when the lobe first comes up above .05", the cam will rotate 216° before it falls below it. It tells you how long the valve will be open. A high number here means the valve will be open longer than it would for a short duration. The longer the valve is open, the more time there is for air/fuel to enter, or exhaust to leave.

2nd number is the amount of lift. Lobe lift is how high the top of the lobe is above the base circle. .312" means the lobe is .312" tall. The rocker arm opens the valve more than the cam opens, because of the ratio. Stock rockers open the valve 1.6 times what the cam does. so if the cam lifts up .312", the rocker actually opens the valve .4992". To put it simply, more lift on the valve allows for more flow of air through the port, but at a somewhat slower speed. Lower lifts keep the flow velocity a little higher (Bernoulli's principle).

Lobe Separation Angle, or LSA, is the angular measure of the distance between the intake lobe and the exhaust lobe. 112° means the intake lobe is centered 112° after the center of the exhaust lobe. A smaller number here results in the intake valve opening closer to the exhaust valve. When you get to a certain point, you have valve overlap, which is when the exhaust and intake valves are momentarily open at the same time. This can be good for N/A applications because it can get all the "dirty" air out better. On a FI setup, the compressed air would just flow right through the 2 open valves. <simplified>


Whew, probably my longest post ever. [img]tongue.gif[/img]

[ August 17, 2005, 11:37 PM: Message edited by: 98Camaro3.8 ]

[99v6cam]

OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOH! Thank you! I thought I heard someone once say that turbo cars loved overlap... hmmm, guess not.

[Fredless]

Originally posted by 99v6cam:
i just randomly took that from someones sig :-p I want bigger than that.

Copy cat. He wants to run with the big dawgs in MMC now. [img]graemlins/rofl.gif[/img]

Seriously though, I'm happy with my GT2 cam. Bigger than the GT2 cam? Wait till you get the stock cam out and look at them side by side, you will see how tiny the stock one is compared to the GT2.

The 111LSA thumps quite nicely man. I hope you have around 900 dollars for parts alone.