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-   -   420a 110lsa? (http://www.motorgen.com/forum/showthread.php?t=49470)

enkeivette 06-13-2013 01:36 PM

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?

94cobra69ss396 06-13-2013 02:21 PM

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.

enkeivette 06-13-2013 02:33 PM

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?

94cobra69ss396 06-13-2013 02:38 PM

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.

BRUTAL64 06-13-2013 02:57 PM

Quote:

Originally Posted by 94cobra69ss396 (Post 116711)
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.

For forced induction the closer to 114 lsa the better.

94cobra69ss396 06-13-2013 03:28 PM

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.

Shaolin Crane 06-13-2013 03:35 PM

Quote:

Originally Posted by 94cobra69ss396 (Post 116718)
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.

It could be argued that the 110 was bleeding off boost with the 302 as the 347 should show less boost because of the increased displacement.

sbc and sbf guys have been running 110 boosted applications for decades. Shit, tons of mustang guys running 117-119 on turbo applications.

enkeivette 06-13-2013 03:57 PM

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.

Shaolin Crane 06-13-2013 04:13 PM

Quote:

Originally Posted by enkeivette (Post 116723)
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.

Port velocity, quench, efficiency etc etc etc Is motor stuff, not brand stuff.

94cobra69ss396 06-13-2013 04:31 PM

Is this a single cam engine or dual cams? If it's dual cams then I believe he can adjust the LSA.

enkeivette 06-13-2013 05:48 PM

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.

Shaolin Crane 06-14-2013 12:33 AM

Quote:

Originally Posted by enkeivette (Post 116732)
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.

Mmmm not from what I've experienced. My can(race motor) is the same as what would be ran in an ls1. Efficient heads, 347 cubic inch, etc.

enkeivette 06-14-2013 01:03 AM

Google Comp LS1 cam specs.

Shaolin Crane 06-14-2013 01:33 AM

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?

BRUTAL64 06-14-2013 07:30 AM

:popcorn::cartman:

enkeivette 06-14-2013 09:11 AM

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

Shaolin Crane 06-14-2013 09:39 AM

Quote:

Originally Posted by enkeivette (Post 116763)
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

40 Year old tech compared to what? Compare a new relevant custom grind for any motor and you'l see what I mean. Sure I can find some OLD stuff and use it for the argument but plain and simple what is in a catalog and what will be ground from a good grinder is different. Off the shelf cam specs don't take into account which heads you use and what kind of work they have. A sbc and a sbf are not much different and yet why is the new tech for sbf motors so limilar to the lsx stuff?

Shaolin Crane 06-14-2013 09:48 AM

*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

BRUTAL64 06-14-2013 10:43 AM

Quote:

Originally Posted by enkeivette (Post 116763)
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

Roller vs Flat tapped....Roller has MUCH more aggressive ramps.

blackax 06-14-2013 11:02 AM

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

94cobra69ss396 06-14-2013 11:21 AM

Quote:

Originally Posted by blackax (Post 116780)
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

Do you have the cam card?

Shaolin Crane 06-14-2013 12:39 PM

Ditto. Those seem like some odd specs.

BRUTAL64 06-14-2013 01:07 PM

Quote:

Originally Posted by blackax (Post 116780)
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

What is your LSA? 122.5 center line is probably for the intake...still a little weird....who makes the cam and what part number is it?

enkeivette 06-14-2013 01:47 PM

Quote:

Originally Posted by blackax (Post 116780)
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

Youve got way more lift and way less duration than me. And I have a roller cam.

Im 239/ 245 at .05 and 520/540?

Shaolin Crane 06-14-2013 01:50 PM

Quote:

Originally Posted by enkeivette (Post 116800)
Youve got way more lift and way less duration than me. And I have a roller cam.

Im 239/ 245 at .05 and 520/540?

See, and my blower motor has .566/.566 218/218 114*

How would you explain?

blackax 06-14-2013 02:20 PM

Quote:

Originally Posted by BRUTAL64 (Post 116792)
What is your LSA? 122.5 center line is probably for the intake...still a little weird....who makes the cam and what part number is it?

Its an OEM LS9 cam

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

enkeivette 06-14-2013 02:24 PM

Quote:

Originally Posted by Shaolin Crane (Post 116801)
See, and my blower motor has .566/.566 218/218 114*

How would you explain?

Burden of proof is on you not me. I said SBCs were different than LS1s. I dont care about SBFs, not relevant. Theres an example in front of you, explain the variance.

enkeivette 06-14-2013 02:33 PM

Its funny that we're so similar with our taste in cars, but we argue so much. Hah

Shaolin Crane 06-14-2013 07:19 PM

Quote:

Originally Posted by enkeivette (Post 116804)
Burden of proof is on you not me. I said SBCs were different than LS1s. I dont care about SBFs, not relevant. Theres an example in front of you, explain the variance.

I explained the "possible" variance, why would a 40 year old ford motor be so similar to a current tech chevy motor? Engine stuff, not brand stuff.

Shaolin Crane 06-14-2013 07:23 PM

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.

enkeivette 06-14-2013 08:59 PM

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.

enkeivette 06-14-2013 09:16 PM

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.

enkeivette 06-14-2013 09:25 PM

Quote:

Originally Posted by enkeivette (Post 3587)
Learned something, thought I'd share.

Camshaft duration is a measurement of how long the valve stays open in crankshaft degrees. And the measurement is taken from one specific lift point to that same closing point on the closing end of the ramp.



But, since duration is measured at the cam itself from the manufacturer you would think that rocker ratio is totally independent of this. Well yes, and no, and yes again.

What really matters is the lift at the valve (obviously) and if we measure the lift at the valve at a specific point (say .05 again) with a higher ratio rocker, the valve will reach that point slightly sooner and slightly later, creating a slightly longer degree arc.

Although, if we were to measure valve lift at .00000000000000000000001 (you get the point) there would be no difference in duration, as the cam begins to lift the valve when it begins to lift the valve, period. Rocker ratio cannot change this. However, we do not end the measurement at the very closing point of the ramp. Why not? Probably because there is a negligible amount of air flow at .00000000000000000000001 lift. :huh:

Is your head spinning? Mine is. :sm_up_there:

So in conclusion, yes rocker ratio can affect dynamic duration. The rule of thumb seems to be 2 degrees for every .1 ratio on the rocker arm.

In otherwords, if you had 220 degrees of duration with a 1.6 rocker on an LS1, you'd have 222 degrees with a 1.7 rocker. My cam is a 236 in, 242 ex. split duration with a 1.5 rocker and with my new 1.65 rockers, my duration will jump to 239 in. and 245 ex. :D

Ya, I understand the fuck out of cams bitches. Coming soon: Apollo Cams. Wheres 5.0 blow to make fun of my ego again?

Shaolin Crane 06-14-2013 10:19 PM

Quote:

Originally Posted by enkeivette (Post 116821)
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.

OMG are you kidding me? Look at the base circle, not the advertised lift. a cam can be whatever the fuck lift you want it to be a factory SBC rocker ratio is 1.5 vs 1.7 for factory ls1

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.

enkeivette 06-14-2013 11:26 PM

Advertised lift is all that matters!! Thats how much the valve is moving! Who gives a shit what the base lift is!

enkeivette 06-14-2013 11:34 PM

They design the cams with that fact that LS engines have different ratio rockers in mind. Duh

fiveohwblow 06-15-2013 12:44 AM

Quote:

Originally Posted by enkeivette (Post 116823)
Ya, I understand the fuck out of cams bitches. Coming soon: Apollo Cams. Wheres 5.0 blow to make fun of my ego again?

What's your obsession with me Adam? You're still offended because I don't like gm and that has what to do with this thread? I never spoke up in here until now, nor did I attack you or mention your ego. You're on some serious shit man.

Shaolin Crane 06-15-2013 02:42 AM

Quote:

Originally Posted by enkeivette (Post 116826)
Advertised lift is all that matters!! Thats how much the valve is moving! Who gives a shit what the base lift is!

Lobe lift is lobe lift is lobe lift. Not only did I prove you wrong, but I proved the SBC can is LARGER than the LS can. A rocker has absofuckinglutily nothing to do with the physical metal of the can. Rocker is simply something that aids in customizing your needs. Isky designed these profiles decades ago and EVERY OHV V8 uses them.

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.

94cobra69ss396 06-15-2013 08:51 AM

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.

Shaolin Crane 06-15-2013 09:26 AM

Quote:

Originally Posted by 94cobra69ss396 (Post 116834)
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.

Seriously, i dont know why this has lasted so long.


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