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420a 110lsa?
At least with V8s, 114 seems to be the popular LSA with boosted apps, so that youre not blowing boost out of the exhaust.
But the only turbo cams with decent lift and duration we can find for my friends I4 Avenger have a 110LSA. And it even says in the desc. that these cams reduce overlap for boosted apps. So what gives? Is 114 not a universal truth for boosted apps? |
You can use a 110 LSA. The old E303 cam I had in the Cobra with the 302 had a 110 LSA and it ran great. Though a 114 LSA will have a smoother idle, cleaner emissions and pull more vacuum. The new cam I'm installing in the Cobra now has a 114 LSA but the .050 duration is only 212/218. However that's about as much as I can go now and still pass tailpipe emissions.
Tell us more about the engine and what he plans to do with it. |
My cam is a 110 LSA too, but the consensus seemed to be that it was costing me a lot of hp. You dont think its so substantial?
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In my opinion a 110 is not giving up that much over a 114. Where he will feel it the most is in the lower RPM torque.
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The theory is that the 110 LSA bleeds off the boost but I can tell you that on my Cobra the boost didn't change going from the 302 with the 110 to the 347 with the 114. They both hit 11-12psi.
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sbc and sbf guys have been running 110 boosted applications for decades. Shit, tons of mustang guys running 117-119 on turbo applications. |
Ya, so then... all motors the same when it comes to LSA?
He is planning to buy adjustable cam gears to compensate. It must suck having limited options. |
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Is this a single cam engine or dual cams? If it's dual cams then I believe he can adjust the LSA.
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Dual, he can, thats why I mentioned the adjustable cam gears.
And Guy, if you look at the lift/ duration cut on an LS cam versus a SBC cam, comparable engine builds are WAY off. Thats why I thought the LSA might be different. |
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Google Comp LS1 cam specs.
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I don't have to. Ben's car has nearly identical can specs from what I recall. And the potential for his motor is the same as the potential for mine. Similar bore, stroke, compression etc why would the brand of v8 make a difference?
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:popcorn::cartman:
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You dont have to, but youre wrong. LS cams have way more lift and way less duration than comparable SBC cams. Why? I dont know. Ask Glenn
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*IF* there was any reason as to why there is a difference with lift vs duration is the LS heads are more capable of the higher ramp rates than SBC heads. But that's crap because any decent grinder will grind almost identical cams for what they are. My motor .600/.589 234/244 113 is a common ls1 grind. My grinder was very clear I needed good valve springs and pushrods to run a cam like that. Don't need to go all out on an lsx like you do a sbf or sbc
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I dont know shit about cams but this is my cam for the Supercharged LS2
211/230 @.050 valve lift and .558/.552 lift with 1.7 rockers and a 122.5 centerline |
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Ditto. Those seem like some odd specs.
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Im 239/ 245 at .05 and 520/540? |
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How would you explain? |
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Full LS9 cam specs: .004 duration 277/295 .050 duration 211/230 lift .562/.558 int. open@.004 8 BTDC int. close@.004 89 ABDC int. open@.050 18 ATDC int. close@.050 49 ABDC exh. open@.004 84 BBDC exh. close@.004 31 ATDC exh. open@.050 56 BBDC exh. close@.050 6 BTDC LSA 122.5 |
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Its funny that we're so similar with our taste in cars, but we argue so much. Hah
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http://www.compcams.com/Company/CC/c...csid=1093&sb=2
http://www.compcams.com/Company/CC/c...?csid=209&sb=0 What was your argument again? I don't even have to look at the actual specs, part number of the cam is enough to know its close. 280 series grind on a SBC is the same as a 280 series grind on an LS which is the same as a 280 series on a sbf. For comparitive purposes both are OE hydraulic roller. Since buying a shelf cam is RETARDED and custom grind is always the way to go, there's no argument to why what is what. These profiles were designed nearly 30 years ago. |
Guy... YOU JUST PROVED MY POINT! Come on man, admit you were wrong. You went on the comp website searching for similar cams and you still couldnt even find one!
What you posted is a 232/234 duration .595/ .6 lift LS1 cam, and a 230/236 duration .570/ .576 lift SBC cam. The LS cam has more lift, for a roughly equivalent duration. Admittedly, a closer gap than what I usually see, but still congruent with what I said. LS cams, less duration, more lift than SBCs. Find a SBC cam with a .6 lift cam, and the duration will be ridic. Now stop trying to prove me wrong and start discussing why there is a difference. I'm thinking, with more valve surface area you need less lift to flow the same amount of air? Maybe thats why this 420A 4 valve motor has way less lift. |
Yup, LS1 valves are smaller. 2.02 vs 1.89
It makes total sense if you think about it. As the valve lifts, it creates a cylindrical port for air to flow through. And the wider the valve, the less it needs to move (shorter the cylindrical port needs to be) to have the same surface area opening. |
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Here is your SBC Cam at a 1.7 Ratio Vs the ADVERTISED 1.6 Lobe Lift 0.361 VALVE LIFT .614/.607 Duration at .050 231/237 It's the same fucking cam, same profile grind, same shit different motor. ENGINE stuff, not brand. The neglegible difference in the specs is because one is a 280 Profile and the LS is a 281 Profile Come on now, i'm a cave man and even I figured out the math. |
Advertised lift is all that matters!! Thats how much the valve is moving! Who gives a shit what the base lift is!
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They design the cams with that fact that LS engines have different ratio rockers in mind. Duh
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What don't you get, you don't pic a cam based off what was factory, you go by the parts needed and the physical lobe lift every time. I have 1.72 Rockers in the blower motor and I have 1.6 Rockers in the race motor. Does that make any difference to what the actual cam specs are? Nope. |
There's a lot of arguing over nothing really. Adam, your buddy can adjust the LSA to whatever he wants. So have him put it on a dyno and run it with a 114 LSA and a 110 LSA and see what difference it makes.
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