LT-5 Head Air Flow # - ZR-1 Net Registry Forums

msorenso · 12-09-2015

Hi All,
Does anyone have a link or know what CFM the stock LT-5 heads flow at? Thanks you

Pete · 12-09-2015

I have them somewhere if i find them i will post them for you.
May i ask why you want them?

They mean nothing unless you test on same flow bench.

Pete

LGAFF · 12-10-2015

Copy from Corvette Forun
"Here's something that was posted on the ZR-1 Net by Greg Van Deventer:

Here's some intake numbers from a stock 1990 cylinder head tested @ 28" H2O
on a stock 3.900" liner with secondary port throttle assembly and clay
radius...

Lift CFM
.1 92.78
.2 167.97
.3 222.01
.4 246.84
.45 256.86
.5 263.44"

msorenso · 12-10-2015

Thank you for the posting. No problem, Just curious how they flow in comparison to other heads LT-1, L-31, Lt-4, LS1 etc.

rkreigh · 12-11-2015

new LS stuff is way better but it's not all about "raw cfm" flow quality, tumble, mix, detonation reistance and of course flow velocity make the LT5 work pretty good depite the rather low bench numbers

a good set of ported heads will sneak up on 340 cfm and support well over 700 ponies

above that you are a bit flow bound.

FYI the out of the box new LS7 heads flow 370+ which stomps the living crap out of our heads but of course a 4 valve head has many other advantages such as lighter valves, less valve shrouding, low tension springs

and pete is right, flow benches like dynos don't tell the whole story

SAM/CH ZR-1 · 12-11-2015

Quote:

Originally Posted by rkreigh

new LS stuff is way better but it's not all about "raw cfm" flow quality, tumble, mix, detonation reistance and of course flow velocity make the LT5 work pretty good depite the rather low bench numbers

a good set of ported heads will sneak up on 340 cfm and support well over 700 ponies

above that you are a bit flow bound.

FYI the out of the box new LS7 heads flow 370+ which stomps the living crap out of our heads but of course a 4 valve head has many other advantages such as lighter valves, less valve shrouding, low tension springs

and pete is right, flow benches like dynos don't tell the whole story

I wouldn't pay the final attention to max. cfm numbers.
There are other important things to consider. A 700 HP LT5 perform different and better than a 370 cfm flowing LS7.

We brought a C6 Z06 on the same car weight like a C4 ZR-1 and did some acceleration tests. The LS7 pulled in spite of its 427 cui pretty modest.

12-09-2015	#1
msorenso Join Date: Apr 2013 Location: South Dakota Posts: 85	LT-5 Head Air Flow # Hi All, Does anyone have a link or know what CFM the stock LT-5 heads flow at? Thanks you

12-09-2015	#2
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,679	Re: LT-5 Head Air Flow # I have them somewhere if i find them i will post them for you. May i ask why you want them? They mean nothing unless you test on same flow bench. Pete __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage

12-10-2015	#3
LGAFF Join Date: Mar 2007 Location: Crystal Lake, IL Posts: 7,194	Re: LT-5 Head Air Flow # Copy from Corvette Forun "Here's something that was posted on the ZR-1 Net by Greg Van Deventer: Here's some intake numbers from a stock 1990 cylinder head tested @ 28" H2O on a stock 3.900" liner with secondary port throttle assembly and clay radius... Lift CFM .1 92.78 .2 167.97 .3 222.01 .4 246.84 .45 256.86 .5 263.44" __________________ LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359

12-10-2015	#4
msorenso Join Date: Apr 2013 Location: South Dakota Posts: 85	Re: LT-5 Head Air Flow # Thank you for the posting. No problem, Just curious how they flow in comparison to other heads LT-1, L-31, Lt-4, LS1 etc.

12-11-2015	#5
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: LT-5 Head Air Flow # new LS stuff is way better but it's not all about "raw cfm" flow quality, tumble, mix, detonation reistance and of course flow velocity make the LT5 work pretty good depite the rather low bench numbers a good set of ported heads will sneak up on 340 cfm and support well over 700 ponies above that you are a bit flow bound. FYI the out of the box new LS7 heads flow 370+ which stomps the living crap out of our heads but of course a 4 valve head has many other advantages such as lighter valves, less valve shrouding, low tension springs and pete is right, flow benches like dynos don't tell the whole story __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)