BYBYC5

sent ya mail

MyLS1Hauls

iTrader: (2)

Desktop Dyno...where else Like I said, its some fun stuff... But in order for the program to be fairly accurate, you need the right heads and you need to enter the cam specs in at .006 numbers, not the .050" and select "Seat to Seat".

BYBYC5

what are the .006 #s for this cam....
@.050 224/224
adv., 282/282
6BTDC 46ABDC 38BBDC -2ATDC .570 w/1.7s

MyLS1Hauls

iTrader: (2)

Advertised is the .006" specs, so it'd be a 282/282...but heres where it gets tricky...since thats a slower lobe and its not as radical as an XE-R, it has more advertised duration given the same at .050" and Desktop Dyno doesnt know this. It'll predict more power for a given XE lobe vs. an XE-R, but hey it'll get you close. An XE-R 224 lobe is only 273 advertised. Usually, for a given duration, and XE-R lobed cam will produce more power down low than an XE or HE lobe. Hopefully that wasnt too confusing??? Whos cam is that anyway?? It doesnt fit a Comp profile.

Edit:If you're not entering in an XE-R profile, or any other very aggressive hyd. roller cam, you need to select "Solid" under the cam type so the program will interpret it as if the lobes were "slower", and even "hyd flat" tappet for really slow roller lobes. For the above cam, I'd select "Solid"

TXNC5

It is a very interesting article. I would like to know what the author's actual qualifications are. I am not discounting his knowlwedge, but the article states that he is "a university lecturer on engine gas dynamics." I am not for sure what that means.

I am by no means a cam expert. I have replaced my heads a few times, my cam, I am rebuilding my differential (or at least I am going to try), as well as done my own tuning.

I like the general theory, but I still have several questions. First, did anyone notice the recommended cam specs on the 372 (bore) motor: 280/278 110LSA with .799/.749. Seems like a lot of lift to me. How long would that last? And the article states the lift figures might not be mechanically achievable. So does that mean you have to change the engine specs (different bore, stroke) or different heads? Second, it would be interesting to compare this theory (using the program) with a couple of tuners heads and their typical cams (particularly for stock CI). Third, if the lift determined can not be achieved (as mentioned), then how would the speced cam compare if all we did was decrease the lift. Fourth, how much of a role is tuning? I am assuming the author requires optimal tuning. Tuning these motors still seems to have a lot of "gray" area.

Anyway, I do think the tighter LSA's have some real value. Look at the World Challenge cam: 239/251 106. I put down 470rwhp (with a 4" stroke and through cutouts) with this cam, and it doesn't even have that much lift: .570/.570.

Hopefully, somebody (a vendor or GM High-Tech) will do some real world comparisons. Maybe two comparisons: one mostly race oriented and another mostly street oriented.

2000Z28M6

iTrader: (13)

This thread is giving me a headache. So much information, specs, and numbers to consider. Dont get me wrong I want to learn more. So I've been reading it for about 30mins. Can anyone clear up the ICL part seems this is the first time its come up when talking cams.

TXNC5

Many cams are made to be installed straight up. When a cam like this installed, as long as you line up the dots on the cam and crank sprockets you are good to go.

An ICL install refers to a method of installing the cam in which you determine the centerline (typically of the intake lobe) in relation to the crank. You must make sure that the ICL is what the manufacturer recommends.

The basic steps are:
1) Locate top dead center of piston #1 (using a stop)
2) Set the degree wheel to 0
3) Install the cam
4) Using a dial indicator to measure lift, locate peak lift of the cam on the intake
5) Set the dial indicator to 0
6) Rotate the engine until you reach .050 on the dial indicator, and note the degree measurement on the degree wheel
7) Rotate the engine the other direction, back to max lift, and back down to .050 on the other side of the lobe, and note the degree measurement
8) Add the two measurements together, and divide by two; this is how the cam is currently installed with respect to intake ICL
9) Adjust if necessary

This will ensure that the timing events are happening when the manufacturer intended them to happen.

2000 ws6

iTrader: (10)

Daily Aluminum Block- Do you have the grind number for your cam from comp?
I would like to get your cam and try it out.
Thanks

DONAIMIAN

iTrader: (18)

How would you go by fig out the overlap of a cam. If people could be set straight that LSA dosent really mean that the cam will idle better or wosre than the next set of spect It will be a lot more faster cars on the street with small cams, putting out better tq.

Colonel

I think wider LSAs certainly have their place on the street. You can't always just say, "Well, I'll run a low enough duration to make it idle." For example...

How little duration would you have to run with a 108 LSA to have the same idle characteristics of a 115 LSA? Let's say the 115 LSA is a 220/220 (we're talking pretty much a stock idle here)...what kind of duration would it take to make a 108, or even a 110 LSA, idle like that? That would certainly be a dog of a low revving cam.

I'm not saying that anyone here is suggesting a 110 LSA with an itty-bitty duration but I thought I would throw that out there just incase a reader might derive that idea from this thread.

93PONY

I tell you this....
In the LS1 you will never see me make an N/A cam that has 4 degrees of advance built in. ICL is very important for getting the correct valve events. I've retarded cams from their 'ground in' 4 degrees of advance to straight up & just a touch retarded (depending on application) & seen track gains of 1-2mph. + they tend to idle better.
With excessively exhaust bias cams however, to get the correct valve events it is sometimes neccessary to advance the cam. It really depends on the application/setup.
For the general LS1 off-shelf cams, yes, I would probably retard most of them.
If you guys want to post cam specs (.006/.050 duration, lift, & LSA) I would be happy to post the ICL I'd install the cam at for the basic off-road exhaust, LS6 intake, stock headed LS1.

For the TR224 112LSA I'd install it on a 112-113ICL. (4-5 degrees retarded from as ground)
The TR224 114LSA - 114-115ICL (4-5 degrees retarded from as ground)

Of course one should ALWAYS degree the cam to ensure it was ground correctly & that the desired ICL has been achived.

critter

iTrader: (9)

OK, for s&g, how about a Comp 278/278 @ 6, 230/230 @ 50, 0.592/0.592 112 lsa?
How would you modify your recommendation for stage 2 heads?
Do you consider long tube headers to be "basic off-road exhaust"? If not what changes for them?

93PONY

230/230 112LSA using XE-R lobes huh.
Nice. 6 degrees of overlap @.050, 151 degrees of duration at .200.

For this cam I'd install it 4-5 degrees retarded with stock or ported heads that have an intake to exhaust ratio of 75% or above. IMO installing it on a 112-113ICL will give the best results.
This cam will work well with N2O.

By off-road exhaust I mean headers, no cats, & a free-flowing cat-back. Ideally longtubes.

CAT3

iTrader: (9)

230/230 112LSA using XE-R lobes huh.
Nice. 6 degrees of overlap @.050, 151 degrees of duration at .200.

For this cam I'd install it 4-5 degrees retarded with stock or ported heads that have an intake to exhaust ratio of 75% or above. IMO installing it on a 112-113ICL will give the best results.
This cam will work well with N2O.

By off-road exhaust I mean headers, no cats, & a free-flowing cat-back. Ideally longtubes.


Mmmmmmmm sounds yummy! Got the exhaust, what cats...only one is my initials, and gee got stock heads too! Automatic friendly too....what lope?

dug

iTrader: (10)

My take on it is that you want to close the intake valve similar to where the intake valve closes on the ls6 cam. This would probably best match the intakes resonance. Anyone know what the specs are on the ls6 cam?

Also increasing advance and LSA will hurt midrange power by opening the exhaust valve too soon on expansion. Top end power wont be affected as much. Higher LSA cams should work well with converters that have a lot of shift extension because the engine rpms dont drop much. A manual trans might benefit with a tighter LSA by increasing midrange torque to help shift recovery.

The key is to spec the cam that best works with the intake manifold and lt headers. Runnin more overlap will take advantage of scavengin from headers. This could be used to counteract the intake restriction. Testing is needed to figure out what works.

The biggest advantage of runnin more overlap would be makin strong hp at lower rpms. You could probably make the same power with less overlap and a smoother idle, revin the engine higher.

93PONY

I wasn't going to say anything.....but this cam can be made a little 'hotter' & idle better by using a smaller exhaust lobe. Even with stage 2 heads. I'd use an XE-high lift 228 or 230 lobe on the exhaust. 228 for stock heads & 230 for ported. & with the 230/228 setup I'd tighten the LSA to 111 for a little more overlap.
May sound ridiculous to some of you guys.....but it would make more power then the XE-R 230/230 112LSA above.

Actually, that 230/230 .592 112LSA cam is pretty close to the lobes I just installed on my GF's Mustang. 230/230 110LSA 111ICL .598/.598 with 1.6's. A bit more aggressive, but because of the 1.7's on the LS1's it evens out pretty well. (within 1 degree at .200) The 110LSA gives it another 4 degrees of overlap compared to the 112LSA. Overlap = power. Guaranteed this cam I put in will make at least 25RWHP more then the 224/224 112LSA cam she had in there before....& her heads don't flow nearly as well as the stock LS1's. But....apples to oranges right.
Yeah right.

MyLS1Hauls

iTrader: (2)

112 ICL isnt 4 deg retarded?? Thats straight up. Or did you mean from the ground in 108ICL? That'll require you to spin the motor pretty good and really stock shortblocks cant handle much over 6500-6700. Also, whats your reasoning for using a slower lobe on the exhaust??? XEvsXER??? OK maybe use less duration, but not a slower lobe. Also, I still think that even on S2 heads more exhaust duration is still beneficial to high rpm hp.

93PONY

I ment 4-5 degrees retarded from 'as ground'.
It will not mean you'll have to spin it to the moon. Yes it will move the bulk of the power higher in the RPM, but the 15 inch runner intake will limit the RPM capability of the motor. Look at all the guys with huge cams & LS1/LS6 intakes, they don't spin it that much higher then the guys with smaller cams. Even the little 220/220 112LSA smogable cam I did made peak power above 6100rpm, which means shiftpoints of 6500+rpm.

The softer exhaust lobe is due to exhaust reversion. You have to remember....when the exhaust valve cracks open there is a LOT of pressure in the cylinder. This is basically natural boost pushing the exhaust out of the cylinder. The intake does not have this luxury in an N/A application. If you have too large of an exhaust lobe without having enough valve overlap to back it up (the vacuum left from the exhaust pulling in the intake gasses) the vaccum left in the cylinder when the exhaust leaves will actually pull the exhaust gasses back into the cylinder contaminating the intake air-charge.
Sometimes this is a hard concept to understand, but it's sound. Shortening the exhaust duration & increasing the overlap has shown to make drastic increases in power throughout the entire RPM band.