Black Sunshine/ 00SS

iTrader: (1)

I'm not too good with math, someone break it down for me.

Going from the stock to a 1.85, lift changes to what?

Presetly have 232-236 112 ls, .600 .

What, if any, power gains am I looking at?

J-Rod

Roughly 234/238 (2 degrees increase)

Lift goes to 0.652

LSA should remain the same.

4thGENRETARD

It is advised that one should not use 1.85 with anything over a .50.

10thanvhawk

Power is claimed to be 10-20 from stock.
Depends on too much other details, head flow at lifts etc...
If your cam is spec'd at 1.7 then devide total advertised lift by 1.7..
.600 / 1.7 = .353 this should be your lobe lift, check your cam specs for lobe lift to be sure. Re multiply this by the new ratio 1.85 x .3529 = .653 this should be your new lift.

This DOES NOT add any more duration per say.. true your ramp rate will be execessively faster, check with your cam company as some cam designs are not ment to be used with higher ratio rockers. Higher ratio rockers do not add duration as a higher ratio of "0" lift is still .000, It will seemingly act like a longer duration cam by ramping lift as fast as one would have with a longer duration high lift cam, your .050 duration will jump up a half degree , if that, or so depending on lobe design. 1.85 rockers lift .054 where stock 1.7 was at .050 so there is very little difference added to the .050 lift duration.

J-Rod

The important lift (.050) will be arrived at sooner based upon the quicker ramp action of the higher ratio rocker. Here is an example of a 2002 Z06 cam with 1.7 and 1.85 rockers. Notice the duration goes up by ~2 degrees.

1.7

1.85

10thanvhawk

Thank you for that, I was off by .5 degrees per open and close, again it is up to the lobe design, and as I said, very little difference in duration.

RedHardSupra

iTrader: (1)

How did you get this? What's the formula? I'm trying to figure out what I am effectively going to get with '02 z06 cam (.551 lift) with 1.8 HS rockers.

thanks,
Marcin

J-Rod

Take the lift. Divide by the rocker arm ratio 1.7 . That gives you lobe lift. Now multiply by the new ratio 1.8. That gives you valve lift with the new rockers.

BIGBOS

Would I get any major benefits putting some 1.7's or 1.85's on my motor that has a really small 214/218 .540/.550 114lsa cam in it.......

Its in a 370 motor......supercharged

2xLS1

iTrader: (25)

So when you Cam Doctor a 02 LS6 cam it shows to be a 222/237 .551/.549? Anyone else notice this?

Colonel

I was going to ask the same thing. What's up with that??? The ZO6 cam is listed as being 204/218 117.5

Gary Z

You must not forget about coil bind and PV clearance. If you already have 0.600 lift, changing to 1.85 rockers seems like a very bad idea to me.