Steeper ramps do not change the LCA, therefore they have no effect on overlap, they do have an effect on cam intensity though.

You can have 2 cams with identical LCAs and identical advertised duration numbers, but absolutely different ramps. the over lap will still have the same amount of duration, the valves are still off the seat the same amount, but the steeper ramped cam will have more .050 duration.

 

Lift w/ 1.6s would be .522/.529 (as listed by the mfg.) for me, but stated earlier in this thread....

Now I'm completely lost

Here's my cam...

Comp Cams Xtreme RPM Cam 212/218

Now, those heads supposedly don't increase in flow after .500 lift, I obviously don't believe that now. When do they?

With 1.7s, the lift would be .554/.562.

With reference to what I quoted earlier in the thread...

The issue of the valve being pushed off the seat seems to go out the window w/ the "roller" rocker.

The issue I'm worried about would be the telemetry of the pushrod itself. Is the ratio just greater on the valve side of the rocker arm?

Cliff notes: So, by the looks of what has been discussed in this thread, 1.7s "are" an option.

 

Well its like I said. Your not running lots of lift that would make 1.7s a stupid choice (.600) and Scorpion 1.7s are most likely cheaper than comps 1.6s so why not? I bet you will see more performance if you do. Do a search on the board there has been a couple guys with fairly good gains on 1.7s with stock heads even though they don't flow any better after .500

 

See obviously you need to look at some cam specs. The Xe's have more duration at .05 lift but actually have less advertised duration. So actually the lobes are smaller than a standard lobe of similar duration at .05 lift. They just spend more time at higher lifts so they make more power from a smaller lobe. Look at just the intake lobes. The hot cam intake lobe has 280 degrees of advertised duration vs the 224's intake lobe of 276 degrees of duration. Hmm it seems the hotcam's lobes are bigger. Even though the 224 has more duration at .050 lift. What did i tell you the Xe lobes are actually smaller than standard lobes yet they make more power. You said in your own post that more duration = more overlap. Read, learn, understand what you are talking about before you post. You are Owned B!tch.

 

Here is a link to flow numbers of LT1 heads. As you can see the heads don't increase in flow from .500 lift to .600 lift. So why increase the lift. Thats my opinion. Although you are running a small cam so you shouldn't have to run to big of valve springs to make it work. I just think the neg. out weigh the gains with 1.7 RR's.

 

That is not necessarily true. Overlap is affected by the opening and closing rates also, so if the valve timing is more or less aggressive around the seat, then you can have the overlap change also.

 

Could you post the link

What's the point of making a cam that has over .5 lift specified for stock applications?

I had a guy from another forum offer me a set of 1.6 RRs for 125, I can't pass up that deal, even though he says they are made by Vortech, never knew they made RRs :blah:

 

lol i can't believe i forgot the link. http://www.malcams.com/legacy/misc/headflow.htm

 

Steeper ramps do not change the LCA, therefore they have no effect on overlap, they do have an effect on cam intensity though.

You can have 2 cams with identical LCAs and identical advertised duration numbers, but absolutely different ramps. the over lap will still have the same amount of duration, the valves are still off the seat the same amount, but the steeper ramped cam will have more .050 duration.

Thanks WS Sick

 

LMAO. You ain't got the ***** to admit you are wrong. Thats hilarious. Well Jerm you can see that this guy doesn't know jack so i wouldn't listen to what he says.

 

Actually you both are kinda right, and kind of talking about the same things, but at from a different angle.

The facts are 2 cams with the same overlap and same LCA and advertized duration figures can have completely different ramps. Thats why alot of people look at the .050 duration, the .050 duration gives us the cams intensity, or how steep the ramp to max lift is.

 

no, we were comparing XE lobes. I realize that cams can have the same overlap and LCA, and yet have diff ramp rates. The whole arguement is that a cam with bigger duration at .050 can have less overlap then one that has a smaller duration at .050 because of the diff ramp rates equals less advertised duration.

 

Oh, yeah if the closing and opening points are different in duration figures then yeah the overlap will be different as well.

 

Yes I would agree. I didn't know the advertised duration of the Hotcam and still don't (trying to find that out.) If the advertised duration at .006 is more than the XE grind, then overlap can be more depending on valve opening and closing events. As far as I can see, Z95M6 may be right on this one. But I wouldn't say I'm your "Bitch" though. The score is 2-1 in my favor. Shame on me for not checking the advertised duration on the Hotcam.

 

Again you failed to understand what it is you were reading. You see he said he OWNED you AND that you are A bitch... not necessarily his bitch. Either way its overwhelmingly clear you have no idea what it is you are talking about. Perhaps next time you will do some actual research before opening your mouth in attempts to ridicule the small pool of individuals on this site who happen to have a thorough understanding of these touchy subjects.