OP must’ve ran off.
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I hear what you are saying, but I'm not going to be trying to maximize torque at idle. I care about the torque range where the engine is operating for a given application. Bigger cam is relative and says nothing about the actual lobe profiles or overlap. And if we are timing our valve events correctly to the pressure wave frequencies, a little lope is fine. Especially if we have a healthy compression ratio our vacuum at idle will be sufficient. If you want to improve torque, we generally want less exhaust duration for a NA application. But that means we may need a tighter separation angle to get to our ideal overlap, thus resulting in some lope.
A lot of aftermarket camshafts have more exhaust duration than intake duration. Even truck cams. But just for fun, what do you suppose would happen if we take the exhaust lobe and make the duration the same as the intake?
For sure. I'm not saying we always need a tight LSA. It is going to vary a lot per engine and application. I believe we are saying much the same thing just in different ways. I'm just saying that we want to find the balance between lsa and duration to reach our overlap needs and sometimes we may want a tighter lsa, but not always. I like your second cam choice. I think that those same ex. and in. lobes with that lsa will be nice. What is your .006 duration and what ICL are you intending to install that on?You get more low-midrange torque at the slight expense of high RPM power. I have cammed engines with both single pattern and dual pattern grinds. I am actually changing a 218/228 on a 108 lsa out for a 219/219 on a 112 lsa in my 11:1 383. The 218/228 was the flat out wrong choice and to think it was actually spec'd and ground for a 9.6:1 350. Comp cam insisted it needed the long exhaust duration and tighter LSA. The 2nd cam is an Erson and both Lloyd Elliot and I had input on the specs.
I will be running it with 1.6 rockers and I am planning to put it in on a 108 ICL although straight up would make a bit more HP.For sure. I'm not saying we always need a tight LSA. It is going to vary a lot per engine and application. I believe we are saying much the same thing just in different ways. I'm just saying that we want to find the balance between lsa and duration to reach our overlap needs and sometimes we may want a tighter lsa, but not always. I like your second cam choice. I think that those same ex. and in. lobes with that lsa will be nice. What is your .006 duration and what ICL are you intending to install that on?
A lot of aftermarket camshafts have more exhaust duration than intake duration. Even truck cams. But just for fun, what do you suppose would happen if we take the exhaust lobe and make the duration the same as the intake?
I’m been listening, I wouldn’t mind knowing if you care to explain.
Thank you so much for taking the time to post this, it will take me some time to take all this in. I know I will have to reread this several times to get all this information to soak in.
I really appreciate all this information.