Cathedral vs Ls3 test
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From: over dere
Cathedral vs Ls3 test "Both engines utilize 427 cubic-inch shortblocks with 9.8:1 static compression ratios. "
From the context of the article it appears the engines are NA. Who builds 427's NA 9.8:1 static compression ratios unless the engines are intended for forced induction later.
Someone must be wanting to run some cheap 87 Octane gas in their 427.
Would also like to see the details from 2,500 rpm to 5,000 rpm.
From the context of the article it appears the engines are NA. Who builds 427's NA 9.8:1 static compression ratios unless the engines are intended for forced induction later.
Someone must be wanting to run some cheap 87 Octane gas in their 427.
Would also like to see the details from 2,500 rpm to 5,000 rpm.
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From: over dere
The ls3’s look like they’re going to pull like a boss to 8000 and really widen that hp gape. The cathedrals are dropping like a stone past peak. The ls3 headed motor should never see under 5000 at the track
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Originally Posted by Joystick
It would have been interesting to see the curves below 5000, or avarage TQ//HP in the powerband.
Also, that power past peak is tremendous. You gain so much more actual torque at the tires by staying in the lower gear and riding that power curve down. I got one am glad to see someone finally spun the motor instead of letting up right when it peaked.
And it highlights what the rectangle guys have been saying -- you need rpm to take advantage of the rectangle ports. If you are not going to rev there is not much advantage if any.
Wonder how many poor performing ls3 Head combos are poorly driven...
I shift over 7k all the time. Llsr is the good. My power is usually fading pretty good by 7600, so that when I upshift.
Even on street, not unusual for me to hit 7400 clowning around.
Even on street, not unusual for me to hit 7400 clowning around.
Joined: Mar 2007
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From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...
This test is utter nonsense. If anyone just haphazardly slaps vastly different heads on the same short block and expects it to work they can fully expect to be disappointed.
If the test compared similar cathedral and rectangle port heads (CC, valve size, camber volume, and flow figures) without altering the valve events and top end - the results would be far more legitimate and telling. The problem is that focused empirical testing doesn't make for copious internetz clicks, and sure doesn't impress half-wit readers bench racing in their trailer parks. That and most "journalists" lack the capacity to objectively visit any topic as investigative journalism is a lost art - the highest volume of bullshit out the door wins.
So this is the crap we get.
If the test compared similar cathedral and rectangle port heads (CC, valve size, camber volume, and flow figures) without altering the valve events and top end - the results would be far more legitimate and telling. The problem is that focused empirical testing doesn't make for copious internetz clicks, and sure doesn't impress half-wit readers bench racing in their trailer parks. That and most "journalists" lack the capacity to objectively visit any topic as investigative journalism is a lost art - the highest volume of bullshit out the door wins.
So this is the crap we get.
LOL I hate these types of test.
I wouldn't run a cam spec'd for cathedrals on an LS3 headed setup and vise versa.
Like everyone else that compression ratio for N/A just sucks.
I'd like a little more detailed test with full specs of the heads valve sizes, chamber volume, intake volume etc....
I wouldn't run a cam spec'd for cathedrals on an LS3 headed setup and vise versa.
Like everyone else that compression ratio for N/A just sucks.
I'd like a little more detailed test with full specs of the heads valve sizes, chamber volume, intake volume etc....
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From: over dere
This test is utter nonsense. If anyone just haphazardly slaps vastly different heads on the same short block and expects it to work they can fully expect to be disappointed.
If the test compared similar cathedral and rectangle port heads (CC, valve size, camber volume, and flow figures) without altering the valve events and top end - the results would be far more legitimate and telling. The problem is that focused empirical testing doesn't make for copious internetz clicks, and sure doesn't impress half-wit readers bench racing in their trailer parks. That and most "journalists" lack the capacity to objectively visit any topic as investigative journalism is a lost art - the highest volume of bullshit out the door wins.
So this is the crap we get.
If the test compared similar cathedral and rectangle port heads (CC, valve size, camber volume, and flow figures) without altering the valve events and top end - the results would be far more legitimate and telling. The problem is that focused empirical testing doesn't make for copious internetz clicks, and sure doesn't impress half-wit readers bench racing in their trailer parks. That and most "journalists" lack the capacity to objectively visit any topic as investigative journalism is a lost art - the highest volume of bullshit out the door wins.
So this is the crap we get.
Look at the plotted points on the graph rather than the "best fit" curve line and you will see the induction and/or valvetrain wasn't very happy at a few points in the run for both engines.
Seeing those "dips" in the torque curve at similar point of both engines, I'd suspect it was the induction side of the engine, most likely the Holley Hi-Ram.
Address that issue, and I bet you find more power and a much better running combination.
Seeing those "dips" in the torque curve at similar point of both engines, I'd suspect it was the induction side of the engine, most likely the Holley Hi-Ram.
Address that issue, and I bet you find more power and a much better running combination.
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From: over dere
Joined: Mar 2007
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From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...
Two unequal heads yielding unequal results on two improperly spec'd combinations? Oh no, I am very much aware of what I am seeing.
But, hey... if you want to change my mind be my guest and get typing.
But, hey... if you want to change my mind be my guest and get typing.
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From: South Florida
Tap hamski grasping for them ls3's. Lol. Well smaller ports, no matter what shape, will hold you back at high rpm too. Of coarse you like this test. 280cc ls3 port vs 245cc cath port. Maybe 250cc with TEA work? Heck TFS has 265cc cath head & MAST has a 275cc cath head. I know there's bigger than that too. Find a test of a 260cc vs 295cc rec head & see which one makes more power at 5000-8000 rpm.
It's not just that either. MH Mike post was good. This is nonsense.
It's not just that either. MH Mike post was good. This is nonsense.