seadoo

so for example a 224/224 .581 lift 110lsa 110icl will make more power higher in the rpm range YET make even more torque in the low rpm range?

is this correct?

btw, this new forum rocks

SStrokerAce

iTrader: (2)

probably should throw this in with the LSA thread....

Honestly what we really need is a cam forum and all other engine parts.

The ICL just relates to you where the IVC and IVO points occur. A lower ICL will have a eariler IVC so it will raise the amount of DCR the motor sees, which will help the low end TQ.

Bret

seadoo

um... noobie to those terms sorry...
IVC, IVO, DCR ????

SScam68

iTrader: (20)

Intake Valve Closing
Intake Valvle Opening
Dynamic Compression Ration (actual compression ratio)

SStrokerAce

iTrader: (2)

Yeah this is going to be part of the board were those terms are going to be used more and more.

The DCR is the point from when the intake valve is closed to TDC.

Bret

JS

iTrader: (4)

Stroker so what happens if u run say a low int dur. such as 214 with a big ex dur 222 and set it up on a 115LSA to idle well but then throw 4 degree's of adv at it?

SStrokerAce

iTrader: (2)

It's going to idle well anyway.... 214/222 115LSA... sounds like a LS7 cam. Why would you want to close the intake valve sooner with the 4° advance?

again this should be connected to the LSA thread.

Bret

DAPSUPRSLO

iTrader: (14)

Well I would also through in the fact that icl will effect ec and eo, given the same lsa, which will also impact the power band. Generally a earlier opening of the exhaust valve results in an extended power band cause it reduces pumping losses by allowing for an extended time for the exhaust to be removed before the piston starts up on its exhaust stroke; however, it also reduces power in the mid range cause it allows the energy created by the power stroke to escape earlier during the downward motion of the piston.

DAPSUPRSLO

iTrader: (14)

What you are doing by moving the icl to the straight up position is opening and closing everything later. This is good in the sense that the intake valve will be open a little longer; however, bad in the sense that the exhaust valve will open later. In my opinion this makes your exhaust system become even more important in the performance of this cam. Remember, when I dynoed this cam on a 106 icl on the xe lobes I had approximately 36" long collector extensions (open headers), and my cam open the exhaust valve 4 degrees sooner. Morel of the story is do not run this cam with a restrictive exhaust. Good luck and like I said feel free to call, there are many variable that will result in better or worse performance out of this or any other cam.

JS

iTrader: (4)

I wanted to move the power into the middle rpm...
I also didnt wanna spin the car more than 6500 rpm....(Shift set at 6300)

DAPSUPRSLO

iTrader: (14)

Well in my opinion if you want to move it into the middle of the rpm band you definately want to RUN AWAY from the cam you originally suggested, just messn' with you, no but seriously I would not anything with a huge split and wide separation. You need to be looking at very minimal splits to single patterns with tighter lsa's. It's very easy, look at a comp master catalog, or on their website, and look at the various cams they recommend for different powerbands. If you want to sping to the moon (8500-9000rpm) then big splits with high lsa's are the key. If you want lower rpm bands then the smaller splits with tighter lsa's are the way to go. Like I told Seadoo, if you wanna keep your powerband below 6000 then my old 224 106icl 110lsa cam is a great cam (with un restricted exhaust). Now if you are wanting to drag race you need to be more concerned with power from 5000-6500 with there are better choices out there.

JS

iTrader: (4)

This cam was picked because of my bad exhaust flow..Shorty/HF cats and a X threw stock system,Was told the extra exhaust dur. would help..I also want to run a procharger and again was told this would be a cam for the blower too..

Right now its a dead stock idle,It pulls hard from 3500 to 6500
It really pulls hard and this is NA power as of now...

SStrokerAce

iTrader: (2)

So the fact that the motors that run in this area have different shaped head ports, E/I ratios that are vastly different, different valve placements in the bore and tons more compression have nothing to do with that, let alone the valve events need to happen at a different spot because of the RPM.

You might want to rethink this.

Bret

DAPSUPRSLO

iTrader: (14)

No, you are right, it has tons to do with it Bret. I was just making a GERNERAL statement. Not saying anything specific. I still think for an LS1 that this will hold true "in general" as well. Tight cams to me are around the 106-110 range while wide are 112-116 to me. Large splits are 8 or more degrees with tight splits being 8 or less.

There are so many things to consider we could go on for days discussing.

DAPSUPRSLO

iTrader: (14)

Oh, ok. A short headered exhaust system with cats will definately favor something with more of a split and wide separation like you said originally. The only way to get the max power in the midrange is to get rid of the cats and put some long tubes on it; however, if this is not feasable for you then you will always be limited.

Plus, if you are looking for a blower cam then that changes things considerable as well. You need to think about exactly what you want from the car and exactly what parts you will have on it when deciding what cam you are going to run in addition to what rpm band are you looking to make max power.

JS

iTrader: (4)

Well that was my orig plan (Blower) but PatrickG told me he liked this cam for my idea of a NA setup too...I was origonally going to go blower now I'm on the fence...

So I also thought of a AFR 205/62CC/.045 Cometic/LSX/90 and this little 214-222 559-566 115+4 running threw my shorties/hf cats/x and mufflers..I also went 3000 stall 2.3 STR (3200 flash)...Patrick thought this would be a pretty stealthy setup with good power to 6500 (6300 shift point)I really think this would be a nice quiet 390RW A4 with killer power all threw the rpm band?

I wouldnt be able to go procharger if I put the 62CC/.045's on but thats okay..
I'd be happy with 390RW with this setup...Especially threw an A4,what d ou think DaSupr...

SStrokerAce

iTrader: (2)

I don't really think that "big splits with high lsa's" are the key to big RPM... all depends on the setups.

Bret

Ben R

If we advance the cam we will bring the power band down in the RPM range (closing the intake valve sooner).

If we retard the cam we will bring the power band up in the RPM range (closing the intake valve later).

Most street engines like cams that have some advance ground into them (114 LSA and a 110 ICL). The more RPM that gets turned and the more piston speed the induction system sees the more the cam will want to be installed straight up (114 LSA and 114 ICL).

SStrokerAce

iTrader: (2)

Ben.... all that info is correct. The problem is how many times have you seen running a cam retarded make more power? Advancing the cam in some setups can cause P to V issues and then on top of that DCR issues.

A straight up cam is not a problem, but a retarded one is.

Bret

Ben R

It's very rare that a cam would be installed retarded in an engine, but if you have a cam that is way too small than you could retard it a few degrees to try to find some HP.

Same with advancing the cam. If you spec a cam and turns out it's too big, you can advance it a little ways to try to bring the power-band down. This one can be more common because a lot of people like to use OEM blocks in SBC/SBF applications. With the availability of inexpensive CNC'd cylinder heads it's easy to make 650+hp on a pump-gas engine.

PTV is always an issue when you start moving the cam around in the engine, and it's just another reason why it's sometimes better to leave the enigne specing and building to somebody with expernience. Might cost you a little extra but it will be worth it when you don't run into all of these little problems.