Why do people hate on stock ls3 castings
04-25-2017, 11:08 AM
#141
I see it Zbrown on YB. I'll have it tested (once I break it down) and try to take it to the max of what's capable for it. It's just that I've seen a few guy's who said they did it and I'm willing to try as it would be easy and cheap. Could learn something while I'm at it.
Last edited by Patron; 04-25-2017 at 11:13 AM.
04-25-2017, 11:14 AM
#142
FormerVendor
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Bavarian Head Engineers Hi all, there is the case of European, BMW, Porsche, Cosworth engine designers.
Those designs, in most cases, use a smaller inlet port with a LARGE inlet valve.
This allows for a LARGER inlet lobe with good torque and engine operating range.
The US emission laws are strict with requirement for "short" cams.
One way to overcome a "short" cam's effect on performance is to fit a larger inlet port.
Lance
Those designs, in most cases, use a smaller inlet port with a LARGE inlet valve.
This allows for a LARGER inlet lobe with good torque and engine operating range.
The US emission laws are strict with requirement for "short" cams.
One way to overcome a "short" cam's effect on performance is to fit a larger inlet port.
Lance
04-25-2017, 02:41 PM
#144
Hi AGAIN, I was the first one to have an article, Chevy-Hi, YEARS AGO with a LS-346 at 600HP.
The head was AFR's LS-2, the camshaft was a D/D at 236/242 .600"/.550" 116 C/L, Flat Tops, MY 65mm ITB "Stack Intake", dyno exhaust on a DTS.
WHAT I STATE IS, the problem is NOT the head differences it IS the choice of Intake Manifolds.
The Intake Manifold choice has not been given much thought.
SURE, this thread is about "heads" but each head requires a specific manifold
style.
Comments ?
Lance
The head was AFR's LS-2, the camshaft was a D/D at 236/242 .600"/.550" 116 C/L, Flat Tops, MY 65mm ITB "Stack Intake", dyno exhaust on a DTS.
WHAT I STATE IS, the problem is NOT the head differences it IS the choice of Intake Manifolds.
The Intake Manifold choice has not been given much thought.
SURE, this thread is about "heads" but each head requires a specific manifold
style.
Comments ?
Lance
Absolutely the intake manifold (aka restrictor plate) is critical.
In my own flow bench testing I've seen some intakes cut 50 to 60+ cfm off of the cylinder head flow with some of the plastic LS intakes.
Bring on the ITB's like Pantera EFI's 62mm set up or a Kinsler or Harrop for better results.
04-25-2017, 04:47 PM
#145
I know CoD, but at first glance I thought Martin was saying that a head can be more efficient at .600-.800" than at .300-.500". Using Discharge Coefficients to determine efficiency wouldn't make sense because it's almost physically impossible to have a head with better CoD numbers that high in the lift range, which is why I asked how one would determine efficiency.
But after rereading what Martin said, I think I understand now that he was actually saying that you want to pay attention to the efficiency of a head in different lift ranges depending on the application. For example, in a big lift solid roller combo, the CoD numbers in the .300-.500" range wouldn't be as important as the numbers in the .600-.800" range and vise versa. Using CoD to determine efficiency then makes more sense.
But after rereading what Martin said, I think I understand now that he was actually saying that you want to pay attention to the efficiency of a head in different lift ranges depending on the application. For example, in a big lift solid roller combo, the CoD numbers in the .300-.500" range wouldn't be as important as the numbers in the .600-.800" range and vise versa. Using CoD to determine efficiency then makes more sense.
Sorry if I didn't make my intention more clear. Your interpretation of my post is 100% correct.
04-25-2017, 04:51 PM
#146
I'd love to see what Coleman's car could do with a set of 275 radials. From what we've seen, if you can make them work off the starting line they're worth 2-3 mph and easily a tenth by just bolting them on. If you can get them to work down low, they're worth a lot more than a tenth...
04-25-2017, 08:18 PM
#149
10 Second Club
Thread Starter
04-25-2017, 08:23 PM
#150
10 Second Club
Thread Starter
Hi AGAIN, I was the first one to have an article, Chevy-Hi, YEARS AGO with a LS-346 at 600HP.
The head was AFR's LS-2, the camshaft was a D/D at 236/242 .600"/.550" 116 C/L, Flat Tops, MY 65mm ITB "Stack Intake", dyno exhaust on a DTS.
WHAT I STATE IS, the problem is NOT the head differences it IS the choice of Intake Manifolds.
The Intake Manifold choice has not been given much thought.
SURE, this thread is about "heads" but each head requires a specific manifold
style.
Comments ?
Lance
The head was AFR's LS-2, the camshaft was a D/D at 236/242 .600"/.550" 116 C/L, Flat Tops, MY 65mm ITB "Stack Intake", dyno exhaust on a DTS.
WHAT I STATE IS, the problem is NOT the head differences it IS the choice of Intake Manifolds.
The Intake Manifold choice has not been given much thought.
SURE, this thread is about "heads" but each head requires a specific manifold
style.
Comments ?
Lance
It's a very key element that's often overlooked. How often have you seen guys use an ls6 or ls3 intake on really good heads because everyone says they're "great intakes" but when in reality they're terrible for their application.
04-25-2017, 11:53 PM
#152
TECH Veteran
04-26-2017, 12:04 AM
#153
TECH Veteran
Brobinson216.... You better delete that last post about the Fast intake. Now that the msd intake is out the Fast is no longer the way to go.... anyway I love that post. Screw that other overated new intake thats out.
Martin... Coleman car hauls the mail!! I'm guessing it's on a stiff wall slick. However the 275 radials sounds interesting if they are faster than the slicks.
Martin... Coleman car hauls the mail!! I'm guessing it's on a stiff wall slick. However the 275 radials sounds interesting if they are faster than the slicks.
04-26-2017, 08:19 AM
#155
I'd love to see what Coleman's car could do with a set of 275 radials. From what we've seen, if you can make them work off the starting line they're worth 2-3 mph and easily a tenth by just bolting them on. If you can get them to work down low, they're worth a lot more than a tenth...
05-07-2017, 04:44 AM
#157
I built a mild 416 topped with a pair of L92 heads (CNC'd by GM) and a custom BTR cam, it made 468/421 with a loose converter, switched to PRC 237s cathedral heads and a smaller cam and made 490/450 right away. That proves that a correctly ported cathedral can easily outperform LS3 heads in the same application. Needless to say the car idles, drives, and cruises almost like stock with these heads!
05-08-2017, 06:27 PM
#160
For racing I would think the head with least and largest bottle necks will rev more with any type cam. Higher rpm equals more power. Check out Wallace racing formula for max possible rpm entering port cfm and cid. Then reducing buy the smallest cross section spec in the port. Match a cams rpm capability to that equation and you will have your engines max potential. Build accordingly. lol.