Brian98

Well i just got my 98 LS1 heads back
I need some input on these #'s
Stock intake valve 1.6 Fer. Exhaust
Intake Exh.
100--69 57
200--137 124
300--200 178
400--255 211
500--283 225
550--277 230
600--277 233
I'm not to sure why i'm stalling out after .550 on the intake,,,maybe stock size valve??i wouldn't think so. Let me know what you guys think of these #'ss

jimmyblue

iTrader: (11)

At .550" of lift you may well be limited by
some upstream port or bowl choke cross-section,
or turbulence rather than the valve lift *
circumference "cylinder surface area". At
some point this will certainly be true, I
figure you just found it.

Brian98

Well it makes since,,,,,,it may be a whole different ball game with the intake on,,,
Overall i think they did pretty good with ls1 heads...I was looking back at old post and noticed they flowed pretty well against ls6 portted/polished heads at 100-450 lift which your mainly in that area at most times.
I think when people are achieving 310+Cfm @500-600 there numbers lack around 200-450 lift
IMO <img border="0" alt="[USA]" title="" src="graemlins/patriot.gif" />

Brian98

<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

HITMANSS

Your intake flow at .500" is respectable, but the rest of the flow #'s seem way down. Did your porter remove the swirl bump?

The exhaust flow #'s seem very good, probably because of the aftermarket valves. You don't say whether they used a 6" pipe extension or not.

Brian98

Hitmann--
6" pipe extension?? you got me there,,not sure what that is..

Swirl bump-----r you talking about the bump inside the intake runner???
or r you talking about the bottom of the head??

They did remove a "Bump" inside the intake runner,, but other than that i'm lost...
I was kinda surprized that i lost flow after .550 but at the same time i'm no head porter

CHRISPY

Use a nice .525 lift cam and put some good duration in it and you should run decent numbers <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Cheers,
Chris

Brian98

decent numbers--------i hope for outstanding numbers <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
I just put the cam in today
222/224 566-568 112
I kinda mad about my flow numbers now.......
I've seen some peoples flow sheets keep on climbing after the .550 mark..

I paid about 1885.00 total for the p/p ,tit. retainers,918's, fer. exh valves and mill work
I thought i was saving alittle money,,,i'm not sure what everyone else is paying for heads with the work i have done,,,but i would like to see.

Brian98

<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

2000RATA

Those look like good numbers. They look like accurate numbers. Not inflated. Your car should run great. Rest easy.

HITMANSS

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Brian98:
<strong> Hitmann--
6" pipe extension?? you got me there,,not sure what that is..
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Many companies flow their heads w/ a 6" pipe attached to the exhaust port, because they will actually flow better w/ the pipe attached. My heads are Absolute's Stage 1x, and Jay told me he prefers to flow w/o the pipe extension so he can listen for any turbulence.

My point is that when you're comparing your flow numbers to other heads, make sure that it's an apples-to-apples comparison.

IMHO your exhaust flow numbers are excellent.