VAP

WHAT IS THE HIGHEST FLOWING CYLINDER HEADS CURRENTLY AVAILABLE FOR THE LS1-LS6 ENGINE. WHO MAKES THEM - PORTS THEM ETC. WHAT VALVE SIZES ARE THEY USING - ARE THERE CURRENTLY ANY AFTERMARKET HEADS AVAILABLE ? LIST THE FLOW FIGURES @ 28" AND FROM .100" TO .700" IF POSSIBLE - STATE THE FLOW FIGURES AT .600 TO .700" AT LEAST. HOW MUCH H.P CAN YOU MAKE NORMALLY ASPIRATED FROM THE LS1 OR LS6 INTAKE ? - THANKS

LS1derfull

School of Automotive Machinists in Texas has ported Ls1 castings with 335 cfm @.650" lift on intake with a 2.07" valve and 235 exhaust cfm at .650" with a 1.6" valve i believe. These are the highest #'s that i have heard of and there project car hauls ***.You might get in contact with them or Agostino racing engines, for their results.

lafnatu

very interested also.ttt

Air21

Are you going to be running a cam with .650 lift? If not, i wouldnt worry about what a head flows at .650. Might flow great on the top, but the bottem could suck ***. Flow isn't everything either, port velocity is very important.

Anyway TTT for ya

LS1derfull

My daily driver cam has just under .600" lift, if someone asks what best flowing heads are, i think they would consider larger cam also, putting there lift around .650" lift or so. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Terry Burger

iTrader: (4)

Best flow doesn't always mean most power or quickest ET.

Carlitos

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by VAP:
<strong>WHAT IS THE HIGHEST FLOWING CYLINDER HEADS CURRENTLY AVAILABLE FOR THE LS1-LS6 ENGINE. WHO MAKES THEM - PORTS THEM ETC. WHAT VALVE SIZES ARE THEY USING - ARE THERE CURRENTLY ANY AFTERMARKET HEADS AVAILABLE ? LIST THE FLOW FIGURES @ 28" AND FROM .100" TO .700" IF POSSIBLE - STATE THE FLOW FIGURES AT .600 TO .700" AT LEAST. HOW MUCH H.P CAN YOU MAKE NORMALLY ASPIRATED FROM THE LS1 OR LS6 INTAKE ? - THANKS</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You would probably be happier with a set of heads with the highest AVERAGE flow for a given lift range.

'Los

SStrokerAce

iTrader: (2)

I've heard of 350CFM out of LS6 ported heads.

Bret

SS00Blue

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Terry Burger:
<strong>Best flow doesn't always mean most power or quickest ET.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Mid-lift flow and power under the curve... That'll get ya down track. Always look at the mid-lift numbers! We've all heard of 320CFM @ .800 lift, and who gives a crap on a .566" cam?

MID-LIFT FLOW NUMBERS MAKE ETs!

SC

MyLS1Hauls

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by VAP:
<strong>WHAT IS THE HIGHEST FLOWING CYLINDER HEADS CURRENTLY AVAILABLE FOR THE LS1-LS6 ENGINE. WHO MAKES THEM - PORTS THEM ETC. WHAT VALVE SIZES ARE THEY USING - ARE THERE CURRENTLY ANY AFTERMARKET HEADS AVAILABLE ? LIST THE FLOW FIGURES @ 28" AND FROM .100" TO .700" IF POSSIBLE - STATE THE FLOW FIGURES AT .600 TO .700" AT LEAST. HOW MUCH H.P CAN YOU MAKE NORMALLY ASPIRATED FROM THE LS1 OR LS6 INTAKE ? - THANKS</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well, according to MTI, its them. They say that their S2 heads with 2.055, 1.60 valves are the highest flowing cylinder heads on the market.

Nine Ball

iTrader: (38)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Best flow doesn't always mean most power or quickest ET</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">You would probably be happier with a set of heads with the highest AVERAGE flow for a given lift range.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Mid-lift flow and power under the curve... That'll get ya down track. Always look at the mid-lift numbers!</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Pay attention to these comments and live by them. Anyone can hog out a set of heads so that they flow an awesome CFM at a huge lift. Port velocity and flow at mid-lift is more important than peak lift flows. Just like HP, we want the highest average under the curve. For heads we want the highest average flow for our useful range of lift.

Tony

BudH

iTrader: (3)

Mid lift flow is most important.

How much of the cycle is a .566 lift cam even at that lift.

For most of the intake or exhaust cycle, lift numbers are much lower than .566.

LS1derfull

Yes thats true but it is only fair to mention that the most critical flow point for extending V.E. is timed at peak piston velocity, which is at high valve lift point, this is the most important flow window to relieve restriction of cylinder filling.Strong average flow helps broaden torque curve which makes driveability and accelleration better, max power has different requirements. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

HOWQUICK

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>Yes thats true but it is only fair to mention that the most critical flow point for extending V.E. is timed at peak piston velocity, which is at high valve lift point, this is the most important flow window to relieve restriction of cylinder filling.Strong average flow helps broaden torque curve which makes driveability and accelleration better, max power has different requirements. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">to worry only about flow at peak piston speed is a mistake in itself. Peak piston speed is at 90deg to tdc/bdc....why is the cam centreline (peak lift) at 104-114?

Wouldn't it be fair to say that the "charge" is accellerated by the piston speed....but a lot of cylinder fill happens when the piston is de accellerating towards bdc....making port size hence velocity of the charge and mid lift flow figure even more important?

racer7088

Peak piston speed is actuall about 75 degrees down the bore.

Also big flow numbers are important to all out hp generation with equally large cams and high rpm and/or large engines. The SAM 418 inch SS has heads that actually are around 350 cfm but again that might be a little large for a smaller and lower rpm engine.

With smaller cams the lower and mid lifts become even more important than wit hthe bigger cams so this is what you want to look at for a great street head. I've seen very good heads from MTI and GTP etc. They know how to make these heads perform in the mid lift area for the street. The LSx heads in general are also awsome in this area due to the unshrouded nature of their chamber design and shallower valve angles they employ.

racer7088

Peak piston speed is actually about 75 degrees down the bore.

Also big flow numbers are absolutely important to all out hp generation with equally large cams and high rpm and/or large engines especially when acheived with correctly sized ports and valves. The SAM 418 inch SS has heads that actually are around 350 cfm but again that might be a little large for a smaller and lower rpm engine.

With smaller cams the lower and mid lifts become even more important than with the bigger cams so this is what you want to look at for a great street head. I've seen very good heads from MTI and GTP etc. They know how to make these heads perform in the mid lift area for the street. The LSx heads in general are also awsome in this area due to the unshrouded nature of their chamber design and shallower valve angles they employ.

<img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />

LS1derfull

HOWQUICK, i didnt say peak piston speed is the only point to be concerned with, i said its the most critical for max HP, and extending V.E.
As far as cam centerline not being at peak piston speed, with a 110* icl PEAK LIFT IS AT 70* b- bdc EXACTLY! When combo strays from this concept it is usually for benefitting from proper int. valve closing point. Remember strong low lift flow can contribute intake reversion and the resultant caminess that comes with it from exhaust dilution. SO THERE! <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

<small>[ April 10, 2002, 06:21 PM: Message edited by: LS1derfull ]</small>

HP-GURU

Peak piston speed occurs well before the intake valve is all the way open in 99% of combinations.

I can't speak for these 288@.050" setups though.

LS1derfull

Well its definitely a balancing act,and Assymetrical profiles dont even have max lift in the middle of duration.

HOWQUICK

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>HOWQUICK, i didnt say peak piston speed is the only point to be concerned with, i said its the most critical for max HP, and extending V.E.
As far as cam centerline not being at peak piston speed, with a 110* icl PEAK LIFT IS AT 70* b- bdc EXACTLY! When combo strays from this concept it is usually for benefitting from proper int. valve closing point. Remember strong low lift flow can contribute intake reversion and the resultant caminess that comes with it from exhaust dilution. SO THERE! <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">depending on conrod length is the actual max piston speed....regardless the piston is still de accelerating at max lift and after....resonance frequency and exhaust dilution? Well we do have to watch flow figures at low lift....