camshaft guide for new guys

[Seppo Kaitainen]

Just a note.... I made 220 through the stock exhaust manifolds and have put down 237 through pacesetter headers. Other that that, good job.

[pgriffith]

I like the idea of having a beginners cam guide to let new people know which cams have been used and what the effects are. But i would like it to be accurate as possible. So far you are off to a very good start. Lets keep picking at this post and see what we can come up with. And yes i think it is a good idea to have a final draft as a sticky post.

[oil pan 4]

I guess I can post this again:
The big cam theory.
As for the position of the piston and valve.
On a big cam it starts with over lap.
The intake valve opens as much as 15 and some times as much as 20 degrees (20 is more for 14,000rpm motor cycle engines) BTDC.
The exhaust valve closes lets say 8-10 degrees ATDC when the piston is moving down there is still exhaust getting blown out.
At low rpms this is bad. exhaust gets sucked into the intake runner at low rpms while there is vacuum in the intake. To take full advantage of this there must be positive pressure on the intake valve at high rpms when the intake valve starts opening at 15 degrees BTDC There is a slight vacuum in the chamber. because the exhaust valve opened before BDC, letting the exploding gas blowing its self out. but I'm not going to get to far into that yet.
As the intake valve starts really opening with the piston at 5-8 degrees (I mean open enough to let some air move) BTDC. There is intake air being sucked in and getting forced into the chamber chasing out the exhaust while the piston is moving up in the cylinder.
As both valves are open there most (about 1/16'') at the same time and the piston is at TDC the exhaust is sucking all of its self out and the intake air is starting to force its self and it is taking over.
Once the exhaust valve closes all the way the intake air is trapped and the piston is moving down.
The intake valve is open its most well after 90 ATDC. Its open it's most around 30-50 degrees before BDC depending on if its a big turbo cam or big N/A cam.
And closes as late as 40 degrees ABDC (don't think I have seen any that close later than that), that is when most of the air is sucked into the cylinder (ABDC). Yes there is a lot of air still getting sucked into the chamber because the runner air was accelerated during the time when the piston was between around 90 ATDC and full valve open. So now that the piston is moving up and air is getting into the chamber by means of some unseen force.
At this point the engine is super charging its self. The amount of self super chagrined is determined by a lot of factors, rpm, runners, intake harmonics, valve timing (mainly intake open ABDC), spark timing comes into play a lot when you do FI and more.
The self super charging really starts with the exhaust opening well before BDC on the power stroke and the exhaust blows its self out creating a slight vacuumed sucking the piston up the bore and some times contaminating the chamber with oil if you don't have good oil control.

AlsoMore 3.4L info than most people need.

[malice10985]

AZ3.8 and Seppo-

I made most of the changes you requested. I have the new hot sheet saved on my hard drive. I don't want to waste bandwith posting it untill I have made more changes.

AZ3.8 and OneQuickv6-

since you have cams very similar to the ones I posted, I want some power #'s or timeslips from you guys. Descriptions are nothing without raw data.

OneQuickv6, if you feel spunky, we would all appreciate a one paragraph writeup on your exact cam. (unless you are one of those dickwads that must "keep his power secrets to himself")

[OneQuickV6]

Originally posted by malice10985:


AZ3.8 and OneQuickv6-

since you have cams very similar to the ones I posted, I want some power #'s or timeslips from you guys. Descriptions are nothing without raw data.

OneQuickv6, if you feel spunky, we would all appreciate a one paragraph writeup on your exact cam. (unless you are one of those dickwads that must "keep his power secrets to himself")

LOL, I am working a ton right now, so not alot of time to do a full write-up, but I'll see what I can produce. And for the record: I'm not a dickwad ALL the time [img]smile.gif[/img]

[AZ3.8Camaro]

I lost .6 seconds on my timeslip with no other changes to the car. Both NA and on N20.
Would have lost much more on n2o have traction permitted. (Trapped 104 mph which equals 12 sec timeslip for most, on just a 100 shot dry.)

This cam works really well as a nitrous cam even though it isn't one (technically). It sounds wicked awesome, if you search, you can find a clip of it. It sets no codes on my car, and I am running a stock valvetrain except for LS1 springs (which are rumored to be v6 springs, or very close too them, anyways.)

I bought this cam looking for the biggest thing I could make streetable, I even expected an SES light, but it doesn't happen. I definately think it is an AWESOME cam for someone who drives their car more than once or twice a week.

In your other post, you can see that my car is the 4th quickest and THE fastest daily driven car on the board. Its all due to the cam... ;)

[malice10985]

OneQuickv6-

I get mad when people get on this board and brag about they power they produce, but don't tell anyone how they do it. I hate guys with "secret camshaft profiles" or "secret turbo specs". It just pisses me off. I meant that they are dickwads, not you. You are good about sharing info to better the community.

AZ3.8, changes noted. With your permission, I would like to plug your trap speed #'s into an online HP calculator, to get a VERY ROUGH ESTIMATE of an actual power increase. I will do the same with my cam. What is your NA trap speed?

[malice10985]

Originally posted by OneQuickV6:
</font><blockquote>quote:</font><hr />Originally posted by AZ3.8Camaro:
In your other post, you can see that my car is the 4th quickest and THE fastest daily driven car on the board. Its all due to the cam... ;)

Just because alot of us don't get to run at sea-level, or anywhere near there, you can have 4th for now. Also, "fastest" daily driven?? Where did you come up with that? </font>[/QUOTE]We had a contest in the lounge about a week ago. He had the best trap, and wickedsix had the best ET.

[malice10985]

Lets not start a pissing contest about drag racing.

OneQuickv6, do you have a write-up done yet for your cam?

[OneQuickV6]

Long write-up made short: here goes!

221/223 .541"/.525" 113LSA 109IC from CamMotion/TSP

Of course I had to modify the heads for the big lift, I ahd the valve guide bosses milled and used some Felpro off the parts store shelf viton valve seals to add more lift clearance. This is I have been told what ZZP and others sell as well, they just don't tell you they are Felrpo's that can be bought anywhere.

The cam was agreed upon by myself and a techie from CamMotion for great NA performance, but with the 113LSA, it loves up to about a 125 shot too, which I had for a good while (now I'm NA again). As with most any other aftermarket camshaft, this one needs all the intake and exhaust help, as well as some extra gear and convertor to make the best of it at the track!

I went with 3.73's out back for my M5 car. At the same time, I went ahed and ported the heads, intakes, and TB. IMO, anything over 210 duration needs a good tune! So of course we tuned it in. Will it throw a P0300 code?? YES, every time, all the time.

What else do you want? I feel like I'm typing in circles here [img]smile.gif[/img]

[malice10985]

You used to work at a dyno shop, so can you post some dyno numbers? I feel goofy making a cam guide with no approximate gains.

[Ju5t_B3at_Me2005]

also can anyone post up some approx mpg effects with the cams? this is a great thread, good idea malice

[OneQuickV6]

http://www.texas-speed.com/mattdyno.gif

That was with a very conservative nitrous tune, so there's probably an easy 10-15rwhp left in her with some timing and leaning her out a smidge.

[Turbo V6 Camaro]

My custom turbo grind
@.50
Lift: .335/.334
dura: 224*/215*
LSA: 116*

Valve timing @.50
.........open/close
Intake 2* BTDC / 42* ABDC
Exuast 49* BBDC/ 14-* ATDC

this cam will throw SES
MUST HAVE TUNING

WITH:
stock intakes
fully ported heads
57# hour injectors
and the rest of my mods

Running N/A for the 500 miles i drove the car i got avg. 26MPG city/hwy this cam does not wake up till 4200-4600 running the car N/A.

no numbers with the turbo yet.

[Zooomer]

ZZP has just released their GT3 cam for use with larger displacement 3800's (like strokers).