Which cam would you take for this app(asking for a friend)
12-29-2005, 11:33 AM
#11
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It depends on how close he wants to nail the specs. A single pattern cam is always good if you don't want to stray off too far from "what you bring in, let out". You could use the same ramp rates as cam 1 but, drop the duration and pick up a lot more torque where the 2500TC can use it. Another big factor is how much "lope" he wants his rig making at idle. Overlap is going to make power. So, drop it down to a 110LSA and you've picked up a good deal of average power.
Most advance their cam to pick up more low end... Well, there's another way. Run less duration and leave the ICL straight up or + 0.
But you could do something like a 218/218 .563/.563 110+0 and make a lot more usable power in my opinion.
This is exhaust reversion. You'll notice a lot of dyno graphs have a dip between 3000-4500RPM. Too much exhaust duration and advanced timing events are the key ingredients in this because of our intake limited setups.
Retarding your valve events and/or setting your ICL/ECL inline with the LSA helps fight that dip in low end power because now you've centered overlap around top dead center (TDC)
Here are some examples of that dip in midrange torque.
Dyno 1
Most advance their cam to pick up more low end... Well, there's another way. Run less duration and leave the ICL straight up or + 0.
But you could do something like a 218/218 .563/.563 110+0 and make a lot more usable power in my opinion.
but supposedly by degreeing the cam it will give alot of the bottom end back but I dont see how.
Retarding your valve events and/or setting your ICL/ECL inline with the LSA helps fight that dip in low end power because now you've centered overlap around top dead center (TDC)
Here are some examples of that dip in midrange torque.
Dyno 1
Last edited by Sport Side; 12-29-2005 at 11:54 AM.
12-29-2005, 11:39 AM
#12
I have been trying to convince him to drop the tc and get a 3K or 3200 he wants to run a 12.99 NA and it aint going to happen on that stall. He is going to do MAJOR weight reduction for that run though too. Yeah your cam choice seems alot more inline with what owuld work well with the 2500. Ill call him in a little bit and find out if he is going to keep the 2500 or if he will go bigger. Thanks for the help
12-29-2005, 12:05 PM
#13
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dude, its a few degrees. it wont make much difference either way.
I personally like high lift cams so id pick #1. Id assume they'd make similar power- #1 making more torque at lower rpm.
but that is just an assumption. they could have different timing (advance, retard) of valvetrain events.
I personally like high lift cams so id pick #1. Id assume they'd make similar power- #1 making more torque at lower rpm.
but that is just an assumption. they could have different timing (advance, retard) of valvetrain events.
12-29-2005, 10:07 PM
#14
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Which cam for me?
Ok fellas, since hopefully yall have gotten that straight!haha I have a 2001 2wd rcsb 4.8 5spd, and im debating on cam choices, my main two are the tr220 or the 224 on 112lsa. I drive it everyday and ive got 4.10s goin in it w posi. Which cam should i use, ive heard the 220 will make more power in the 4.8 but i dont know, doesnt make sense? So will yall please give me some advice on my cam choice.
Thanks,
Derek
Thanks,
Derek
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