Wondering how to calculate how much dcr my custom grind can give me? Also can you have too much dcr and can it cause damage to the engine? I am also thinking of going with a .026" head gasket which should bring my compression to around 11.2:1. The cam specs I am shooting for are a 210/218@.50 with around .600 lift with very accelerated ramp rates. I am also considering what lsa I should go with on a cam with these specs? I was thinking around 104 lsa would make a killer street car without a lot of lope or loss in fuel economy. Is there a way to determine when too tight an lsa can start to lead to a loss of lowend power? How can I find it? I would like my hp/tq to peak before 5k at most. Don't want the car really lopey but from my understanding if I have short duration/high lift/ and steep ramps I can go really tight before I will really notice the lope. Also how high of a lift can I go on an LT1 without sacrificing reliability/driveability? No head porting planned/ no track/ no nos or blower.

Any help, thoughts, links, experiences are very much appreciated! Mods in sig

 

Well if you want to calculate your DCR you're going to need your advertised duration and intake/exhaust valve opening/closing times too.

And yes, too much DCR, I think below 9.0 is safe on pump gas but you're pushing it, will cause detonation an then holes in stuff.

 

A little knowledge can be very dangerous.

Get some professional help on your cam. Search LT1-LT4 section and you will get some ideas of whom to contact.

 

Absolutely!

With 11.2/1 compression, only 210 duration, and 104 LSA, I don't think the starter will even be able to crank the thing over. I wonder if it would reach 300 psi cranking compression. . .

Also, with only 210 at .050" and 1.7 rockers, I don't see you getting anywhere near .600 lift. Probably closer to .560 tops.

Furthermore, a tight LSA generally gains low-end and midrange.

Not sure why you want it to peak at less than 5k either. . .

Mike

 

What I meant by peak at (bad choice of words) is that I really don't want to sacrifice bottom end to make power past 5k. So I take it that I won't have enough compression to crank the motor? Is this due to overlap? What is the tightest lsa you can get away with on a cam with these specs and be driveable?

"Furthermore, a tight LSA generally gains low-end and midrange"

-that is exactly what I want I just don't know what lsa I should grind it on. I figure there is a point at which it is counterproductive just not sure how to find that point.
In a cam this small there probably won't be too much of a problem with having too much compression right? What about lca?

By the way does anyone know how to calculate DCR? (forgive my ignorance)

 

To keep bottom end the same as stock, just make sure the IVC is about the same as stock, or a little later if you've raised the static compression ratio.

What I was saying is that the cranking compression would be REALLY high with your proposed cam and compression. Cranking compression is closely related to DCR, and not related to overlap at all.

If I'm using the right numbers, stock LT1 has a DCR of 9.0/1, coincidentally (or not) the same thing that Loony said is a good limit.

Using your spec's, that number becomes 10.33, which is WAY too high for pump gas. This is why you don't see anybody else using cams that are 210/218 on a 104 LSA. By the way, I'm pretty sure that the factory head gasket is thinner than .026" so your compression will actually go down.

Listen to OldSStroker. Let someone else choose your cam or get a proven off-the-shelf cam. I don't think you're going to improve on them at all.

By the way, the Crane 210/224 - 112 LSA cam works very well. It idles nearly like stock and pulls great down low, but makes good power to 6000. With the stock static compression ratio, the DCR is 9.0/1. Coincidence? Don't think so. . .

Mike

 

Facotry head gasket is .050" on a LT1, .043" on a LT4 and .028" on a Imp.

I think your in the right ball park on your cam, but the difference between a pop fly and a grand slam or even a tripple here is a few numbers.

Bret